We present an in-depth evaluation of the scalability and accuracy of the GPU porting of the N-body code for hydrodynamic cosmological simulations OpenGadget3 . While technical details of our GPU porting were presented in Ragagnin et al. (2020), in this work we focus on assessing the accuracy of the ported modules: the short range gravity integrator, the different components of the hydrodynamic solver, and the conjugate gradient solver for thermal conduction. We ran several tests that gradually increase the number of physical modules included: a gravity-only cosmological simulation; a hydrodynamical shock tube test; a non-radiative zoom-in simulation of a galaxy cluster in a cosmological box; and a full-physics zoom-in simulation of a galaxy in a cosmological box. Comparing the results obtained with the GPU implementation to those from the classical CPU version, we find excellent agreement across all tests, with small differences on very small scales. For the individual physical modules, we find a GPU chip-to-chip speedup ranging from <mml:math><mml:mrow><mml:mo>≍</mml:mo><mml:mn>3</mml:mn><mml:mo>−</mml:mo><mml:mn>5</mml:mn></mml:mrow></mml:math>. For more complex cosmological and hydrodynamical setups, where a large number of physical processes and overheads contribute to the total workload, the observed total chip-to-chip speedup (with the same number of nodes and CPUs per node) is <mml:math><mml:mrow><mml:mo>≍</mml:mo><mml:mn>2</mml:mn><mml:mo>−</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:math>. We ran our tests on four different supercomputers: Leonardo Booster (CINECA), MareNostrum-V (BSC), SuperMUC-NG2 (LRZ), and the CIP cluster of the Faculty of Physics at the Ludwig-Maximilians-Universität (LMU).

We show that, for stationary geometries whose linearized fluctuation equations separate into radial and angular Heun equations, a pair of diffeomorphisms projects the full problem onto two coupled, isospectral Gauss hypergeometric problems in complementary spacetime regions. This projection requires Robin boundary conditions to be imposed at the intersection between the complementary regions, which are uniquely fixed by requiring the two diffeomorphisms to match there. The method provides an independent derivation of recent results obtained from the correspondence between Heun connection coefficients and instanton partition functions in the Nekrasov-Shatashvili limit. As an application, we identify a subset of modes in Kerr-de Sitter and Kerr-anti-de Sitter black holes that, in the near-extremal limit, continuously reduce to a basis of the Schwarzian/Jackiw-Teitelboim functional space of gravitational fluctuations.

Many quarkoniumlike states have been observed above open-flavor thresholds, but their organization and internal structure remain unsettled. We study the isoscalar hidden-charm and hidden-bottom sectors in Born--Oppenheimer effective field theory (BOEFT), between the spin--isospin averaged $S+S$ and $S+P$ thresholds. At leading order, heavy-quark spin decouples, and the quarkonium static potential mixes through string breaking with the lowest tetraquark/open-flavor BO potentials of the same quantum numbers. These potentials are constrained by QCD symmetries, their short- and long-distance behavior, and lattice-QCD data. The only calibrated parameter is the lowest $1^{--}$ adjoint meson mass, fixed from the shallow multiplet associated with the $χ_{c1}(3872)$. Using $T$-matrix, $K$-matrix, and complex-scaling methods, we determine bound states and resonance poles, their masses, pole widths from the included nonstrange $S+S$ channels, normalized pole couplings, and prescription-dependent quarkonium--open-flavor composition measures. Uncoupled hybrid BOEFT multiplets are included as reference levels. The spectrum exhibits a common heavy-quark-spin-symmetry multiplet organization. Most poles are predominantly quarkonium resonances localized at short distances, with the largest open-flavor components closest to threshold. The same equations also generate shallow, spatially extended, open-flavor-dominated states with molecular long-distance characteristics. Their binding energies, radii, and small quarkonium components are highly sensitive to the adjoint meson mass, whereas the higher spectrum is more stable. Together with the hybrid reference levels, the spectrum provides multiplet assignments for most candidates. States not naturally accommodated point to the need for hidden-strange and $S+P$ tetraquark/open-flavor BO sectors and for hybrid--tetraquark and hybrid--quarkonium mixings.

We present a numerical computation of the two-loop QCD scattering amplitudes for the production of a top-antitop quark pair in association with a $W$ boson ($t\bar{t}W$) at the LHC in the generalised leading-colour approximation, retaining the exact dependence on the top-quark and $W$-boson masses. Rather than pursuing a fully analytic calculation, we employ a hybrid framework that combines numerical evaluation with strong algebraic and analytic control, allowing ultraviolet and infrared singularities as well as large intermediate cancellations to be treated exactly. This is achieved by expressing the finite remainder in terms of a set of special functions with rational coefficients. The special functions are evaluated numerically by solving differential equations through power-series expansions, while the values of the rational coefficients are reconstructed, point by point, from finite-field evaluations. The calculation is performed in the 't Hooft-Veltman scheme and validated against an independent implementation in conventional dimensional regularisation employing a substantially different computational strategy. We finally provide the colour- and polarisation-summed hard functions evaluated on the phase-space grid used in a previous computation of the next-to-next-to-leading-order QCD corrections to the $t\bar{t}W$ cross section.

Short-orbit gaseous exoplanets are the best targets to study atmospheric dynamics. A time series of emission observations collected at various photometric filters (phase curves) provides insights into atmospheric flows. Modern observations reveal a wide variety of phase curves, but their utility for probing atmospheric circulation as a function of altitude has not yet been explored in detail. We aim to understand the properties of phase curves and their connection to underlying atmospheric flows, as well as to define a set of multiwavelength observations that could be used to resolve these flows as a function of altitude. We utilized a subset of the solar metallicity models from the grid of ADAM/GCM and state-of-the-art radiative transfer codes to predict phase curves. We made predictions for a variety of photometric filters on board the Spitzer, TESS, CHEOPS, HST, and JWST missions, and explored the sensitivity of each filter to flows at various atmospheric depths. Our calculations show that the main parameter that regulates the phase-curve offsets in our models is the atmospheric temperature, although high metallicity can also have strong impact by reducing phase-curve offsets. This is not fully supported by available observations, which possibly indicates a missing physical process in the models. The predicted contribution functions suggest that the best combination of photometric filters to study atmospheric flows is NIRCam filters because they are sensitive to a wide range of pressures between 10 bar and 1e-4 bar depending on planet temperature, respectively. High-resolution spectroscopy is predicted to detect differential Doppler shifts of 1-4 km/s between molecular bands formed at different altitudes, providing an independent probe of vertical circulations.

Some free-form reconstructions of the dark energy equation of state suggest that dynamical dark energy is the only explanation for the observed data. In this letter we argue that early Universe solutions to the Hubble tension (around or before recombination) generically cause the evidence for this claim to strongly reduce, establishing a tight connection between the early and late cosmology. In particular, the level of evidence for dynamical dark energy depends on the parameters $H_0 r_\mathrm{d}$ and $Ω_\mathrm{m}$ and early universe solutions typically push towards higher values of $H_0 r_\mathrm{d}$ and lower values of $Ω_\mathrm{m}$, where such evidence is reduced.

The association of broad-lined Type Ic (Ic-BL) supernovae with long-duration gamma-ray bursts (GRBs) has been known for 28 yr. However, only about 70 GRB supernovae (GRB-SNe) have been identified, of which only one-half have spectroscopic classifications. At z = 0.153, GRB 260310A is the twelfth spectroscopically confirmed GRB-SN discovered within 1 Gpc, offering a critical opportunity to follow one of these rare supernovae in detail. We present optical to near-infrared imaging and spectroscopy of GRB 260310A and SN 2026fgk out to 65 days after discovery. The optical afterglow is among the brightest ever observed from a GRB. Spectra obtained more than 2 weeks after the explosion reveal broad absorption features that securely identify SN 2026fgk as a Type Ic-BL supernova (SN). Modeling of the multiwavelength (grizJK_s) lightcurve shows that the SN is approximately one-half the luminosity (k_98bw = 0.4─0.6) of the canonical GRB-SN 1998bw. We derive a nickel mass of M_Ni = 0.4─0.5 M_⊙with a total ejected mass of M_ej ≍ 4─6 M_⊙and kinetic energy E_K = (3─8) × 10⁵¹ erg. The GRB exploded at an extremely large offset of 15 kpc from its host galaxy. Long-slit spectra reveal a "bridge" of nebular emission extending along the galaxy's disk to the GRB location, which has a subsolar metallicity (∼0.4 Z_⊙), compared to a near-solar metallicity for the host galaxy. This indicates that the large offset arises from the galaxy's extended light profile rather than an isolated environment.

We present the implementation of an anisotropic viscosity solver within the magnetohydrodynamics (MHD) framework of the TREESPH code OPENGADGET3. The solver models anisotropic viscous transport along magnetic-field lines following the Braginskii formulation and includes physically motivated limiters based on the mirror and firehose instability thresholds, which constrain the viscous stress in weakly collisional plasmas. To validate the implementation, we performed a suite of standard test problems ─ including two variants of the sound wave test, circularly and linearly polarized Alfvén waves, fast magnetosonic wave, and the Kelvin─Helmholtz instability ─ both with and without the plasma-instability limiters. The results show excellent agreement with the AREPO implementation of a similar anisotropic viscosity model, confirming the accuracy and robustness of our method. Our formulation integrates seamlessly within the individual adaptive time-stepping framework of OPENGADGET3, avoiding the need for subcycling. This provides efficient and stable time integration while maintaining physical consistency. Finally, we applied the new solver to a cosmological zoom-in simulation of a galaxy cluster as a proof-of-concept application, demonstrating its capability to model anisotropic transport and plasma microphysics in realistic large-scale environments. Our implementation offers a versatile and computationally efficient tool for studying anisotropic viscosity in magnetized astrophysical systems.

JWST observations of Cassiopeia A have revealed the "Green Monster" (GM), a pockmarked region of shocked circumstellar medium (CSM) characterized by circular holes surrounded by bright rings. The origin of these structures remains debated, with proposed mechanisms including post-shock sculpting by ejecta fingers and pre-shock puncturing by fast-moving knots (FMKs). We investigate the physical viability of the FMK-driven scenario using three-dimensional hydrodynamic simulations of FMKs interacting with a dense circumstellar shell, followed by the passage of the supernova remnant forward shock. By exploring a range of knot properties and shell densities, we compare the resulting hole-ring systems with JWST observations. Primary FMKs reproduce the qualitative morphology of the GM but generally produce hole-ring systems larger than the observed $1^{\prime\prime}-3^{\prime\prime}$ ($\sim0.016-0.048$ pc) structures unless the knots are relatively slow ($\lesssim8000$ km s$^{-1}$) and the shell is dense ($n_{\rm sh}\gtrsim200$ cm$^{-3}$). Moreover, the resulting structures are short-lived, becoming significantly distorted within $30-60$ yr after the forward-shock passage. The GM's diverse hole-ring systems and complex kinematics cannot be attributed to a single idealized scenario, but can be instead explained by the simultaneous action of three mechanisms operating within a structured, heterogeneous CSM. While large cavity relics are carved by early-stage primary FMKs, compact pristine rings are produced by recent "first contact" punctures of secondary knots from fragmented ejecta fingers, and older structures are continuously sculpted by long-term post-shock interactions with large-scale ejecta fingers.

Context: Wide-area radio continuum surveys require reliable optical and infrared counterpart identification, but high optical source densities and extended or multi-component radio morphologies make this challenging. Aims: We present optical and infrared counterpart catalogs for MeerKLASS L-band and UHF-band on-the-fly continuum sources using KiDS DR5 and DESI Legacy Imaging Surveys DR10 (LS DR10), including counterpart probabilities, redshifts, and host-galaxy properties. Methods: We developed the Stellar-mass Enhanced Density Association (SEDA) method, an empirical framework that compares candidate densities around radio positions with those in a position-displaced control catalog. For galaxies we use positional offset, stellar mass, and redshift; quasar candidates are treated separately using offset and mid-infrared selection. A second-pass search associates multi-component radio sources with common hosts. Results: In the L-band survey, we identify 20,400 KiDS-based counterparts with $P_{\rm true}>0.5$, corresponding to 66% of L-band sources within the KiDS footprint. In the UHF-band survey, we identify 61,633 LS DR10 counterparts, corresponding to 81% of the radio sources. Spectroscopic redshifts are available for 22% and 44% of the L-band and UHF-band counterparts, respectively. The redshift distributions show low-redshift star-forming galaxies, intermediate-redshift radio galaxies, and a high-redshift tail dominated by quasars. SEDA also recovers rare radio-loud quasars, including QSO J2318-3113 at $z=6.44$ and UHF_DR1 J+111111.8+053626.6 at $z=5.24$. Conclusions: SEDA provides a data-driven route to counterpart identification for wide-area radio surveys with complex source morphologies. The catalogs enable future MeerKLASS studies of radio source populations, host-galaxy demographics, and rare high-redshift radio quasars.

NGC 1399, the bright central galaxy of the Fornax cluster, hosts an extensive population of globular clusters (GCs) extending beyond 200 kpc into its outer halo, about 6.5 effective radii (Re). We conducted dynamical mass modelling of NGC 1399 out to 5 Re (~150 kpc), using a comprehensive radial velocity catalogue of GCs, combining data from the Fornax cluster VLT spectroscopic survey (FVSS) with prior measurements from the literature. Applying spherical Jeans equations, we performed dispersion-kurtosis modelling of NGC 1399's GC kinematics to derive its mass profile and GC orbital anisotropy. We also investigated the impact of including intra-cluster GCs in the mass modelling, selected based on spatial segregation and a velocity $σ$-clipping method. Our findings indicate that both cusp-like (NFW) and core-like (Burkert) halos can reproduce the observed kinematics of GCs. Including the intra-cluster GCs in the mass modelling yields broadly consistent mass profiles for both halo types, with the full GC sample giving a virial mass of log $\log M_{\rm vir} = 13.81 \pm 0.09~M_{\odot}$ for the NFW halo, slightly higher than the value inferred for the Burkert halo. Regardless of the dark matter halo profile adopted, we observe that the intra-cluster GCs exhibit radial anisotropy in the outskirts, especially among the blue, metal-poor GCs. These results suggest that GCs in NGC 1399's outer halo are influenced by an additional halo component associated with the galaxy cluster potential. The radial anisotropy observed in these outer-halo GCs provides strong dynamical evidence supporting their accretion from external sources, consistent with prior photometric and spectroscopic studies of GCs. This study highlights the importance of including intra-cluster GCs in dynamical mass modelling to fully account for the contribution of dark matter to the cluster gravitational potential.

Gravitational wave observations have found over 300 merging binary black holes, yet their origins remain uncertain. Recent work showed that many may come from isolated stellar binaries whose orbits shrink through stable mass transfer. If true, their spins may help to distinguish this channel from other formation pathways. We investigate the tidal spin up of black hole progenitor stars with detailed modeling of binaries undergoing stable mass transfer. We calculate the tidal torques by solving tidally excited oscillation modes and predict the resulting black hole spins. We find a diverse spin distribution strongly affected by the mass transfer histories of the progenitors. Binaries can form black holes with moderate spins ($0.1\lesssimχ_\mathrm{eff}\lesssim0.3$) if they only go through case A or case B mass transfer. In the former case, they can become super-synchronized upon detachment, while in the latter case, the donor is usually only partially stripped, leaving a puffy envelope where strong tides are excited. If both case A and case AB mass transfer occur, the resulting black hole spins are almost always negligible. As the mass transfer history is jointly determined by mass ratio and initial binary period, our results predict an anti-correlation between black hole spins and mass ratio, consistent with limited evidence from data. Our results can also potentially explain the case of GW190412, a moderately-spinning binary with a high mass ratio. We discuss the limitations of our methods and additional physics (e.g., nonlinear tides, case C, and L2 mass transfer) that need to be incorporated in future work.

Contrary to the common lore that observable lepton-number violation (LNV) is inevitably suppressed by tiny neutrino masses, we identify a class of seesaw models in which arbitrarily large LNV can naturally coexist with sub-eV neutrino masses. We construct a symmetry-protected texture-zero structure in the neutrino Yukawa couplings and heavy Majorana mass matrix that gives rise to the required accidental symmetry, thereby protecting the light neutrinos from acquiring mass even in the presence of arbitrarily large LNV in the heavy sector. Small neutrino masses arise naturally from lifting the texture-zero structure while preserving the underlying symmetry. The resulting framework offers a rich and experimentally accessible phenomenology, predicting Heavy Neutral Leptons with sizeable active-sterile mixing over a broad range of experimentally accessible masses, giving rise to observable LNV signatures at collider and intensity-frontier experiments.

The remoTES design, developed within the COSINUS experiment, enables a broader range of materials to be operated as cryogenic calorimeters read out with Transition Edge Sensors (TESs). In this configuration, the TES is fabricated onto a separate chip and thermally coupled to the absorber via a gold (Au) link. The remoTES concept has been successfully tested on various target materials. To further enhance detector performance and to fully exploit the advantages of the remote coupling design a series of optimization studies has been conducted using silicon (Si) absorbers as benchmark. This work presents an evaluation of several measurements aimed at reducing the thermal boundary resistance and enhancing signal transmission across Si remoTES interfaces, specifically from the absorber to the phonon collector and from the phonon collector to the TES. By testing a new Au link design and three distinct phonon collector configurations, Au, copper, and aluminum (Al)/Au, we achieved a baseline resolution of (21.5 +/- 0.3)eV using the Al/Au phonon collector.

Classical Cepheid metallicities trace recent chemical enrichment and help assess systematics in Cepheid-based distance measurements. They are derived mainly from high-resolution optical spectroscopy, which provides the benchmark abundance scale but limits measurements to nearby systems. Extending such studies to more distant Cepheids with extremely large telescopes requires complementary low-resolution near-infrared methods and careful treatment of model--data residuals. We test whether low-resolution SpeX/IRTF Y+J-band spectra can yield metallicities compatible with homogenised optical abundances. We analyse 14 Galactic classical Cepheids with periods of approximately 13--69 d, supplemented by two shorter-period stars from the IRTF Spectral Library. Using Bayesian full-spectrum fitting based on MARCS/TURBOSPECTRUM spectra and a regularised covariance likelihood, we infer [M/H] and compare it with homogenised optical [Fe/H]. For the primary 14-star sample, the inferred metallicities reproduce the optical reference scale with a mean offset of -0.05 dex, a scatter of 0.09 dex, and a robust scatter of 0.12 dex; the median posterior uncertainty is 0.22 dex. Including the two additional stars changes these values only slightly. Compared with a diagonal likelihood, the covariance-aware treatment reduces the mean offset and improves the stability of the uncertainty calibration. Low-resolution Y+J spectra therefore contain usable metallicity information for classical Cepheids when short-range correlated residuals and localised modelling imperfections are treated explicitly. The resulting near-infrared metallicity scale provides a practical foundation for extending Cepheid metallicity work to larger and more distant samples.

We present the discovery of EP250827b/SN 2025wkm, an X-ray flash (XRF) discovered by the Einstein Probe (EP), accompanied by a broad-line Type Ic supernova (SN Ic-BL) at z = 0.1194. EP250827b possesses a prompt X-ray luminosity of ∼10⁴⁵ erg s⁻¹, lasts over 1000 s, and has a peak energy E_p < 1.5 keV at 90% confidence. SN 2025wkm possesses a double-peaked optical light curve (LC), though its bolometric luminosity plateaus after its initial peak for ∼20 days, consistent with a central engine injecting additional energy into the explosion. Its spectrum transitions from a blue to red continuum with clear blueshifted broad absorption features consistent with a SN Ic-BL classification. We do not detect any transient radio emission and rule out the existence of an on-axis, energetic jet ≳10⁵⁰ erg assuming a typical LGRB circumburst constant density (n ≍ 10⁻³─10⁻¹ cm⁻³) and microphysical parameters (ϵ_e = 0.1 and ϵ_B = 0.01). In the model we invoke, the collapse gives rise to a long-lived magnetar, potentially surrounded by an accretion disk. Magnetically driven winds from the magnetar and the disk mix together and break out with a velocity ∼0.35c and interact with an extended circumstellar medium with radius ∼10¹³ cm, generating X-ray breakout emission through nonthermal free─free processes. The disk outflows and magnetar winds power blackbody photospheric emission as they cool adiabatically and thermalize, producing the first SN peak. The spin-down luminosity of the magnetar and radioactive decay of ⁵⁶Ni power the late-time emission. We end by discussing the landscape of XRF-SNe within the context of EP's recent discoveries.

Tidal disruption events (TDEs) have traditionally been discovered in optical sky surveys through targeted searches of nuclear transients. However, it is expected that some TDEs will occur outside the galaxy nucleus, arising from wandering black holes (BHs) originating in galaxy mergers. Here, we present observations of TDE 2025abcr, the first optical TDE discovered in the outskirts of a host galaxy. The TDE was identified by a custom "off-nuclear" implementation of the machine learning classifier tdescore, which classifies new ZTF transients based on their lightcurves. Follow-up observations confirm that TDE 2025abcr is a TDE-H+He, occurring 9<inline-formula> <mml:math><mml:mover><mml:mrow><mml:mo>.</mml:mo></mml:mrow><mml:mrow><mml:mtext>″</mml:mtext></mml:mrow></mml:mover></mml:math> </inline-formula>5 (9.3 kpc projected distance) from the nucleus of a massive galaxy (M_⋆ = 10^11.18±0.03M_⊙) with a central BH mass of 10^8.82±0.65M_⊙. TDE 2025abcr itself was likely disrupted by a much lighter BH (10^6.09±0.53M_⊙, as estimated with peak luminosity scaling relations). The BH was either dynamically ejected from the nucleus or lies at the center of a very faint tidally stripped dwarf galaxy undergoing a minor merger. Late-time observations of TDE 2025abcr could confirm the origin of this apparent "wandering" BH. The rate of highly offset (≳3 kpc) TDEs can be constrained to <10% of the nuclear TDE rate, but our discovery implies that many dozens of similar sources will be detected by the Vera C. Rubin Observatory each year with resolvable offsets.

We present a Bayesian reconstruction of the local density and velocity fields traced by the 2MASS Redshift Survey (2MRS) and test the inferred gravitational flow against independent Cosmicflows-4 (CF4) galaxy-group peculiar velocities. The fiducial reconstruction is the maximum a posteriori (MAP) solution of a Zel'dovich-approximation forward model, constrained by the 2MRS redshift-space distribution through an unbinned Poisson point-process likelihood. The model assumes Gaussian initial conditions and includes the 2MRS selection function, the Zone of Avoidance, redshift-space distortions, and a distance-dependent galaxy-bias prescription. The MAP field is obtained by optimization of the posterior, while Hamiltonian Monte Carlo is used to draw posterior samples and constrained realizations within the same framework. The reconstructed velocity field agrees well with CF4 in object-by-object, density─velocity correlation, and shell-by-shell reflex-dipole tests. These comparisons are made at the CF4 redshift-space positions and do not require smoothing the observed CF4 velocities to the MAP resolution. We also evolve constrained initial conditions with GADGET-4. The real-space density retains the large-scale Zel'dovich structure while developing additional nonlinear small-scale structure, and the redshift-space distribution develops nonlinear Fingers of God. The results show that the 2MRS field-level reconstruction captures the large-scale gravitational flow of the nearby Universe and provides initial conditions suitable for constrained simulations.

Understanding the origin and chemical properties of gas accreted by supermassive black holes (SMBHs) is essential for linking black hole growth to galaxy evolution. Using a suite of 30 high-resolution cosmological zoom-in simulations, we investigate the chemical properties of gas accreted onto SMBHs in massive galaxies with stellar masses of $10^{10.9-11.9}\,\rm M_\odot$ and black hole masses of $10^{8.5-9.7}\,\rm M_\odot$ at $z=0$. By tracing the full cosmological histories of individual gas particles, we identify their origins and enrichment pathways. The accreted gas is classified into four categories: ``early'' gas accreted during the early assembly phase of the main halo, ``external'' gas originating from other galaxies or subhalos, ``recycled'' gas enriched through stellar evolution processes within the primary galaxy, including asymptotic giant branch (AGB) winds and supernova ejecta, and ``smooth'' gas accreted from the intergalactic medium. We find that recycled gas dominates the accretion budget and is already metal rich at early epochs. Gas from other origins typically undergoes gradual chemical enrichment within the galactic environment prior to black hole accretion. The mean abundance ratios show only weak redshift evolution and are broadly compatible with the high metallicities inferred for quasar broad-line regions. Our results suggest that metal-rich gas supply to SMBHs arises naturally from cosmological galaxy evolution and stellar recycling.

Self-organized spatial patterns are central to nonequilibrium physics and cell biology, yet locating instabilities in multi-component, reaction-diffusion networks remains challenging because standard eigenvalue analyses scale with the number of biochemical states and rely on reaction kinetics often poorly constrained by experiments. Exploiting the common mass-conserving structure of protein reaction kinetics and the fact that nonlinear feedback is typically confined to membrane reactions while lateral membrane diffusion is negligible, we develop a geometric classification that predicts stationary, and approximately also oscillatory, pattern-forming instabilities from reactive equilibria. The developed criteria reduce the stability analysis from the full component space to the space of conserved species. On this reduced space, slope matrices---describing the change of equilibrium cytosolic densities with respect to total species densities---govern onset. Based on densities in chemical equilibrium, this approach eliminates the requirement of comprehensive kinetic knowledge frequently lacking in experimental systems. Thus, a broad range of instabilities can be understood as mass-redistribution instabilities---self-amplifying mass redistribution caused by shifting local equilibria. We apply these criteria to models for the Escherichia coli Min system and the Caenorhabditis elegans polarity system and show that the reduction extends to the mixed-dimensional dynamics in systems coupling bulk cytosolic dynamics with membrane dynamics on the boundary. Together, these results provide an interpretable, broadly applicable, and experimentally accessible framework for diagnosing and designing pattern formation in multicomponent nonequilibrium systems on the basis of conservation laws.

We combine spectral- and split representations to factorize multi-loop momentum space diagrams, in the Schwinger-Keldysh formulation for cosmological correlators, with massive scalars in the loop. This allows us to extend the resummation of loop contributions from flat to de Sitter space. Furthermore, in our split representation the signal part of the correlators can be identified directly on the integrand level from the spectral function. We apply this to describe the non-perturbative flow of the EFT background and the cosmological collider signals in a large-N model.

We study the free Maxwell field on the planar patch of four-dimensional de Sitter spacetime ($dS_4$). We review its bulk canonical quantization in the Bunch-Davies vacuum, and we give a representation-theoretic viewpoint by studying the transformation properties of single-particle states under infinitesimal dS transformations. By taking the late-time limit, we identify two late-time operators with scaling dimensions $∆=1$ (leading) and $∆=2$ (subleading). We introduce CFT-inspired inner products invariant under the dS group ($SO(4,1)$) for states created by late-time operators acting on the Bunch-Davies vacuum. We explain how the unitary discrete series representations of $SO(4,1)$ associated with the photon are furnished by both operators, in contrast with the Maxwell field on $AdS$ where the $∆=1$ operator corresponds to a non-normalizable mode. We also explain how the corresponding discrete series representations of $SO(4,1)$ split into a direct sum of representations corresponding to two helicities $+1$ and $-1$. This is achieved by taking advantage of the dS invariance of the self-dual and anti-self-dual sectors of the photon field strength. In our outlook, we draw inspiration from a recent proposal for the microscopic description of $dS_4$ higher-spin gravity where conformal gauge fields in 3 dimensions play a central role, and we investigate a possible connection of the $∆=1$ late-time operator with a conformal spin-1 gauge field in 3 dimensions.

AI Phe is an eclipsing binary star with an orbital period of 24.6 days for which the surface gravity and effective temperature are known from direct measurements to very high precision and accuracy. We have obtained high-quality spectroscopy of the K0 IV star during the total eclipse of the F7 V companion, and also obtained spectra with a very high signal-to-noise ratio for this star and its F7 V companion using the spectral disentangling technique. We have used these spectra to measure the abundances of iron and magnesium for both stars. We compare the values of [Fe/H] and [Mg/H] for the F7 V star and the K0 IV star to stars in M67, an open cluster of similar age and metallicity to AI Phe. We find that our [Fe/H] and [Mg/H] measurements clearly show the signature of elemental diffusion in the F7 V star. This suggests that AI Phe can be used to test models of single stars that include diffusion and mixing of elements.

The recently announced NA62 measurement of the $K^{+}\toπ^{+}ν\barν$ branching ratio, based on 2016--2024 data, is fully consistent with its very accurate Standard Model (SM) prediction. While it is not excluded that the final result based on 2016--2026 data will deviate from the SM prediction, the question arises whether a similar fate awaits the $K_{L}\toπ^{0}ν\barν$ decay. This decay is currently being searched for by the KOTO experiment, with the present upper bound roughly two orders of magnitude above its very precise SM prediction. The proposed KOTO II experiment aims to provide the first discovery of the $K_{L}\toπ^{0}ν\barν$ decay and measure its branching ratio. Building on the findings of several previous papers we demonstrate that in the presence of suitably chosen large new complex phases and of a small amount of new right-handed $\bar s d$ couplings, in addition to the left-handed ones, the $K_{L}\toπ^{0}ν\barν$ branching ratio can still be enhanced by one order of magnitude with respect to the SM prediction while keeping both $K^{+}\toπ^{+}ν\barν$ and $\varepsilon_K$ SM-like. Simultaneously the decays $K_S\toμ^+μ^-$, studied by LHCb, and $K_L\toπ^0\ell^+\ell^-$, searched for by KOTO II, can be strongly enhanced and the anomaly in the ratio $\varepsilon^{\prime}/\varepsilon$, as claimed by Dual QCD, removed. We illustrate this with an example of a specific $Z^\prime$ scenario.

Context. The propagation of ultra-high-energy cosmic rays (UHECRs) and ultra-high-energy gamma-rays remains an open question in astroparticle physics, with the intergalactic magnetic field (IGMF) playing a crucial role in deflecting charged particles and shaping electromagnetic cascade spectra. Characterizing the IGMF across cosmic large-scale structure is therefore essential for interpreting multi-messenger observations and constraining the magnetogenesis scenarios that seeded it. Aims. We aim to provide accurate IGMF models to the astroparticle physics community and test their properties and robustness. Methods. We analyze IGMF models derived from the constrained cosmological simulation SLOW alongside a set of rescaled magnetic field models. We further introduce a novel algorithm to determine an "ideal position" for galaxies lying below the constraining power of the initial conditions, enabling accurate line-of-sight magnetic field extraction toward relevant sources. Results. The models span a wide range of filling factors and sample distinct regions of the electron density-magnetic field strength phase space in filaments, while converging in the cores of galaxy clusters; the simulated field from SLOW best reproduces the IGMF derived from the electromagnetic gamma-ray cascade. Models extracted using the introduced "ideal position" yield improved accuracy and may benefit multi-messenger studies more broadly. The large-scale structure drift of simulated clusters exploited by the algorithm also offers a potential route to refining the simulation's constrained initial conditions.

Self-assembly of supramolecular structures in cells and synthetic applications often proceeds under unfavorable biochemical conditions and at low copy numbers of final target structures, ranging from tens of bacterial microcompartments to a single bacterial flagellum per cell. Spatial organization through coupled reaction compartments of different reactivity (delay-facilitated assembly) can recover high yield in such environments at the mean-field level, but its robustness to stochastic fluctuations at low target numbers is unclear. Using stochastic simulations of a minimal two-compartment model, we show that delay-facilitated assembly is susceptible to a stochastic yield catastrophe at low target numbers: even when each compartment in isolation allows for high-yield assembly, slow exchange between them induces a substantial drop in the final yield. We trace the mechanism to a specific assembly stage, where the random order of rate-limiting exchange events of subunits and partially completed structures determines the ratio of productive growth to excess nucleation. Restricting the exchange of larger structures -- either by suppressing it entirely or letting exchange rates decrease with size -- restores most of the yield without altering the mean-field behavior. The same phenomenology appears for two-dimensional hexagonal subunits and in a cytosol-membrane geometry, where diffusion-limited exchange naturally implements the required size dependence. Our results show that equal success of assembly strategies at high target numbers does not imply their equal success at low target numbers, and that competing slow events occurring in random order are a common signature of stochastic yield catastrophes.

We present new \compass high-statistics measurements of the peripheral production of $ηπ^-$ and $η^\prime π^-$ pairs in the reactions $π^- p \to η^{(\prime)}π^- p$. For the first time, we perform an unbinned analysis of the high-mass region of the $ηπ^-$ and $η^\primeπ^-$ systems, which allows us to disentangle the exchange mechanisms governing their production. We report the first observation in high-energy scattering of an exotic Reggeon with high significance exceeding $5\,σ$ for both channels, which is, most likely, related to the exotic $π_1(1600)$.8

(abridged) Motivated by upcoming surveys like LSST, we estimate tidal disruption event (TDE) rates using the constrained cosmological Simulation of the LOcal Web (SLOW) to test the limitations of traditional 2D analytical extrapolations within a fully 3D framework. We aim to provide reliable TDE budgets extracted from the simulated zoom-in volumes of the digital counterparts of the Coma, Hercules, Shapley, Virgo, and Perseus supercluster environments, and the Fornax galaxy cluster. From the zoom-in boundary volumes of the six environments, reaching radial extents of $55-92\,$Mpc, we extracted black hole demographics (including spin) and their host galaxy properties to establish a filter scheme that strictly preserves dynamically stable "main-sequence" black holes. We further classified host galaxies as cuspy or cored based on the slope of their 3D stellar density profile measured within $1\,$kpc as a proxy for unresolved nuclear structure and applied the relativistic Kesden efficiency correction to the filtered sample. We find an average volumetric and per black hole TDE rate of $\approx 600\,$Gpc$^{-3}\,$yr$^{-1}$ and $\approx 4.5\times 10^{-5}\,$yr$^{-1}$ across all six environments, respectively. Although our absolute TDE rates match early literature estimates, the underlying spatial distribution fundamentally differs. Central core rates are heavily reduced by dynamical depletion and direct capture constraints, meaning the total TDE budget is overwhelmingly dominated by cuspy satellite galaxies in the extended cluster halos. TDE yields are driven by black hole demographics and spatial concentration rather than total cluster mass. Actively assembling superclusters (e.g., Hercules) reduce per-black-hole TDE efficiencies via merger-driven black hole mass growth, whereas low-mass environments (e.g., Fornax) are highly efficient due to unmerged, low-mass black holes.

Detection of primordial $B$-mode polarization in the cosmic microwave background (CMB) from tensor perturbations generated during inflation is a major scientific goal of future CMB missions. Its success will strongly depend on the characterization of polarized foregrounds, a challenge that the LiteBIRD satellite aims to tackle with its 15 frequency bands ranging from 40 to 402 GHz. In this work, we forecast the ability of LiteBIRD to characterize polarized dust and synchrotron emission in the diffuse interstellar medium (ISM), at the angular power spectrum level. From simulated LiteBIRD intensity and polarization maps with different foreground complexities, we compute cross-frequency angular power spectra and fit them to dust and synchrotron spectral energy distributions, which are modeled by a modified black body and a power law, respectively. We find that LiteBIRD will be able to measure the dust temperature, dust and synchrotron spectral indices and spatial correlation with dispersions as low as $σ(T_{\rm d})\sim0.2$ K, $σ(β_{\rm d})\sim0.006$, $σ(β_{\rm s})\sim0.04$ and $σ(ρ)\sim10^{-2}$, as well as to detect and quantify deviations from the proposed parametric model due to variations of the emission properties in the three dimensions of our Galaxy. Additionally, LiteBIRD is likely to rule out the power-law model of polarized foreground angular power spectra suggested by Planck data. It will also be able to detect differences in the values of $β_{\rm d}$, $T_{\rm d}$, and $β_{\rm s}$ between $E$ modes, $B$ modes, and intensity in the diffuse ISM for the first time, highlighting the joint variations of the physical conditions and the magnetic field structure across the Galaxy. We conclude that in addition to detailed studies of CMB polarization, LiteBIRD will open a new window onto the physical conditions governing the ISM of the Milky Way.

Merging supermassive black holes (SMBHs) in low- and intermediate-mass galaxies are important sources for future millihertz gravitational-wave observatories such as LISA. Predicting the delay between galaxy coalescence and SMBH merger is therefore critical for modelling the observable SMBH merger population. Using the KETJU code, we perform 16 equal-mass galaxy merger simulations as part of the Resolving supermAssive Black hole Binaries In galacTic hydrodynamical Simulations (RABBITS) series to investigate SMBH binary evolution in galaxies with stellar masses below $M_{\star}\lesssim10^{10}\,{\rm M}_{\odot}$. We systematically vary the strength of stellar feedback by altering the supernova outflow velocity by a factor of $\sim4$, while still producing galaxies consistent with observed scaling relations. We find post-hardening SMBH merger time-scales spanning $\sim30$-$500\,{\rm Myr}$, with stronger stellar feedback producing systematically longer merger delays through its impact on the central stellar density of the merger remnants. Across our suite, merging time-scales vary by more than an order of magnitude, demonstrating that uncertainties in stellar feedback alone can translate into large uncertainties in SMBH merger delays. At the onset of hardening, the binary evolution remains consistent with stellar-dynamical hardening models based on the local stellar density and velocity dispersion near the binary sphere of influence. Using KETJU as a benchmark, we show that merging time-scales can be recovered with useful accuracy when these nuclear stellar properties are extrapolated from scales up to $\sim 100\,R_{\rm infl}$. These results provide a promising route for modelling SMBH mergers in cosmological simulations.

The NA62 experiment has measured the branching ratio of the rare decay $K^+\toπ^+ν\barν$ using data collected in 2023 and 2024 at the CERN SPS, obtaining ${\rm B}_{\rm 2023-2024}(K^+\toπ^+ν\barν) = \left(7.2^{+2.3}_{-2.1}\right)\times10^{-11}$. With results from data collected between 2016 and 2022, the analysis gives ${\rm B}_{\rm 2016-2024}(K^+\toπ^+ν\barν) = \left(9.6^{+1.9}_{-1.8}\right)\times10^{-11}$, corresponding to a relative precision of $20\%$. This value is consistent with Standard Model predictions.

Context: Episodic accretion outbursts have been shown to occur in protoplanetary discs due to thermal instability at the inner edge of the dead zone. These outbursts periodically heat up the dead zone, significantly altering the composition/chemistry and accretion onto the star. Aims: We investigate how these accretion outbursts affect the inner disc composition and how different dust compositions and properties affect the outbursts' dynamics. Methods: We run vertically integrated axis-symmetric dust and gas evolution models using the TriPoD method, including dust opacity dependent heating and cooling, a dead zone model, and compositional tracking of dust, including the evaporation and condensation of volatiles. Results: When considering dust to be made up of a condensation sequence of silicates and volatiles, the outburst evaporates most of the dust within 0.5 au. The fast re-condensation and subsequent viscous evolution reset the disc between bursts. Additionally, we find that the burst cycle period and maximal accretion rate directly correlate with the dust sublimation temperature.

The nebular phase of a supernova (SN) occurs several months to years after the explosion, with asymmetries created by the explosion encoded into the line profiles of the emission lines. To make accurate predictions for these line profiles, non-local thermodynamic equilibrium (NLTE) radiative transfer calculations need to be carried out. In this work, we use EXTRASS (EXplosive TRAnsient Spectral Simulator) ─ which was recently upgraded into a full 3D NLTE radiative transfer code (including photoionization and line-by-line transfer effects) ─ to perform such calculations. EXTRASS is applied to a 3D explosion model of a <inline-formula><tex-math>$9.0\, \mathrm{ M}_\odot$</tex-math></inline-formula> H-rich progenitor, evolved into the homologous phase. Synthetic spectra are computed and lines from different elements are studied for varying viewing angles. Line profile properties strongly correlate with a primary Ni plume in the ejecta. The model spectra are compared against observations of SN 1997D and SN 2016bkv. The model can create good line profile matches for both SNe, and reasonable luminosity matches for He, C, O, and Mg lines for SN 1997D ─ however H<inline-formula><tex-math>$\alpha$</tex-math></inline-formula> and Fe I lines are too strong. Key diagnostic lines of low-mass core-collapse SNe (CCSNe), e.g. differentiating Fe CCSNe from electron capture SNe, are upheld from 1D to 3D. However, both line profiles and line luminosities differ in 3D across viewing angles, enabling the possibility of detailed comparisons to observed spectra to infer asymmetries imprinted by the explosion. We show that even the fastest <inline-formula><tex-math>$^{56}$</tex-math></inline-formula>Ni is traceable in nebular phase line profiles.

A first-order phase transition could occur in the late Universe when vacuum energy begins dominating the energy density (<inline-formula><mml:math><mml:mrow><mml:mi>z</mml:mi><mml:mo>≲</mml:mo><mml:mn>0.3</mml:mn></mml:mrow></mml:math></inline-formula>) and convert some latent heat into other forms such as invisible radiation. This generic possibility also has concrete motivation in particle physics models, which invoke a multitude of vacua to address theoretical puzzles. The naïve constraint on such an event comes from measurements of the Hubble expansion rate, but this can only probe transitions involving <inline-formula><mml:math><mml:mrow><mml:mi>O</mml:mi><mml:mo>(</mml:mo><mml:mn>10</mml:mn><mml:mo>)</mml:mo><mml:mo>%</mml:mo></mml:mrow></mml:math></inline-formula> of the dark energy. In this Letter, we show that significantly tighter constraints appear when accounting for phase transition fluctuations affecting CMB photon propagation anisotropically. For instance, if a completed phase transition has <inline-formula><mml:math><mml:mrow><mml:mi>β</mml:mi><mml:mo>/</mml:mo><mml:msub><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mrow><mml:mo>⋆</mml:mo></mml:mrow></mml:msub><mml:mo>≲</mml:mo><mml:mn>25</mml:mn></mml:mrow></mml:math></inline-formula>, current CMB data limit the associated vacuum energy released to less than 1% of the dark energy. A transition to negative vacuum energy (quasi-anti─de Sitter) is allowed only for <inline-formula><mml:math><mml:mrow><mml:mi>β</mml:mi><mml:mo>/</mml:mo><mml:msub><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mrow><mml:mo>⋆</mml:mo></mml:mrow></mml:msub><mml:mo>≳</mml:mo><mml:mn>300</mml:mn></mml:mrow></mml:math></inline-formula>. For <inline-formula><mml:math><mml:mrow><mml:mi>β</mml:mi><mml:mo>/</mml:mo><mml:msub><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mrow><mml:mo>⋆</mml:mo></mml:mrow></mml:msub><mml:mo>≲</mml:mo><mml:mn>500</mml:mn></mml:mrow></mml:math></inline-formula>, the Universe will not crunch for at least 14 Gyr.

Magnetars are young, isolated neutron stars that possess an exceptionally strong magnetic field, with surface dipolar strengths on the order of <inline-formula><mml:math><mml:mrow><mml:msup><mml:mn>10</mml:mn><mml:mn>15</mml:mn></mml:msup><mml:mspace></mml:mspace><mml:mi>G</mml:mi></mml:mrow></mml:math></inline-formula>. One of the plausible scenarios for generating such a strong field is an exponential amplification by a turbulent convective dynamo during the protoneutron star phase. However, the short expected duration of the convection (<inline-formula><mml:math><mml:mrow><mml:mo>∼</mml:mo><mml:mn>10</mml:mn><mml:mspace></mml:mspace><mml:mi>s</mml:mi></mml:mrow></mml:math></inline-formula>) imposes a stringent constraint on the dynamo growth rate. We perform an extensive set of 82 three-dimensional convective dynamo simulations in the anelastic approximation and investigate the kinematic phase to quantify the dynamo growth rate <inline-formula><mml:math><mml:mi>γ</mml:mi></mml:math></inline-formula>. We find that <inline-formula><mml:math><mml:mi>γ</mml:mi></mml:math></inline-formula> increases with both the magnetic Prandtl number <inline-formula><mml:math><mml:mtext>Pm</mml:mtext></mml:math></inline-formula> and the Rayleigh number <inline-formula><mml:math><mml:mtext>Ra</mml:mtext></mml:math></inline-formula>, with the most unstable mode becoming highly nonaxisymmetric and multipolar. We further observe a gradual transition from large-scale to small-scale dynamo as the magnetic Reynolds number <inline-formula><mml:math><mml:mtext>Rm</mml:mtext></mml:math></inline-formula> increases, resulting in a magnetic field that is predominantly concentrated at small scales. The trend remains unchanged when the outer magnetic boundary condition is varied. Since resolving the increasingly small scales becomes numerically impractical, we employ the theoretical small-scale Kazantsev dynamo model to explore the large <inline-formula><mml:math><mml:mtext>Pm</mml:mtext></mml:math></inline-formula> regime characteristic of protoneutron stars. The model qualitatively captures the growth rate behavior observed in simulations and, upon extrapolation to the large <inline-formula><mml:math><mml:mtext>Pm</mml:mtext></mml:math></inline-formula> limit, indicates that <inline-formula><mml:math><mml:mi>γ</mml:mi></mml:math></inline-formula> is only weakly dependent on the resistivity in a PNS. Under conditions relevant to the PNS, this model predicts a magnetic energy growth rate of the order of <inline-formula><mml:math><mml:mrow><mml:mo>∼</mml:mo><mml:mn>1</mml:mn><mml:mspace></mml:mspace><mml:msup><mml:mi>ms</mml:mi><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula>.

Silicon detectors are commonly used for spectroscopy of low-energy particles. For electrons in the 1 MeV range, a rather large thickness of 2mm is required to entirely stop the electrons and commercial options are scarce. With the instrument PERC at the FRM II, we aim to measure beta spectra from polarised and unpolarised neutrons in order to determine the axial-vector coupling constant, the element $V_\textrm{ud}$ of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix, and to search for hypothetical scalar and tensor contributions. We present the characterisation of a commercially available, pixelated detector to assess its suitability to measure the entire electron energy spectrum of free neutron beta decay.

Context. The nuclear bulge of the Milky Way harbors stellar populations that provide crucial insights into galaxy formation processes and serve as a nearby analog for understanding bulge formation in external galaxies. However, detailed studies of this region are severely hampered by extreme and highly variable interstellar extinction, which obscures the intrinsic stellar properties and impedes accurate stellar mass determinations. Aims. Our goal is to measure the extinction law toward the nuclear bulge and to estimate its stellar density. Methods. We developed a method for determining the extinction law toward the nuclear bulge by kinematically selecting red clump stars that belong to this region. We created a reddening map with a high spatial resolution and computed stellar mass with completeness-corrected red clump star counts, scaled from empirical measurements. Results. We find a total-to-selective extinction ratio of A_K/E_H-K = 1.259 ± 0.074 and an extinction ratio of A_H/A_K = 1.794 ± 0.046, which are consistent with previous works. The reddending map with the high spatial resolution shows clear filamentary structures and a gradient in the extinction over the giant molecular cloud G0.253+0.016 (i.e., the Brick). From the star counts, we measured a stellar mass of 12.2 ± 2.6 × 10⁸ M_⊙ for the nuclear bulge, in agreement with other mass estimates.

Context. Measurements of the shear induced by weak gravitational lensing around galaxy cluster lines of sight are the gold standard for calibrating cluster observable─mass relations, enabling a robust and precise inference of cosmological parameters. The "weak-lensing mass bias" is the systematic offset between the true halo mass and the mass that is inferred from the lensing data using an imperfect model for the halo mass distribution. Aims. We studied the impact of cosmology on the lensing mass bias to inform future cosmological analyses of galaxy clusters. Methods. We created synthetic lensing shear maps for 115 920 projections of clusters with M_200c > 1.56 × 10¹⁴ h⁻¹ M_⊙ in a suite of MAGNETICUM simulations. The simulation boxes are 896 h⁻¹Mpc per side and are set up with 15 different combinations of the cosmological parameters Ω_m, Ω_b, σ₈, and H₀. Assuming a Navarro─Frenk─White profile, we extracted "weak-lensing mass" measurements and quantified their bias (b_WL) with respect to the true halo mass. To investigate the impact of baryonic effects, we performed the analysis on gravity-only simulations and on their full-physics hydrodynamical counterparts. Results. We confirm that assuming a fixed halo concentration or a fixed concentration─mass relation leads to cosmology-dependent changes in the mass bias. We report changes of up to ∆lnb_WL = 0.030 with respect to the bias obtained at the fiducial WMAP7 cosmology. Adopting a model for the concentration that also depends on cosmology absorbs the changes in halo profiles, and we recover essentially constant values for the mass bias. Our analysis of hydrodynamical simulations suggests that future, more accurate models will also need to explicitly account for the strength of baryonic effects. Conclusions. The variation in the cluster weak-lensing mass bias over the range of cosmological parameters we probe here is small compared to the overall systematic error budget in current cluster lensing analyses. Nonetheless, we recommend the use of a model for halo concentration that explicitly depends on cosmology.

Radiation is crucial not only for observing astrophysical objects, but also for transporting energy and momentum. However, accurate on-the-fly radiation transport in astrophysical simulations is challenging and computationally expensive. Here we introduce AREPO-IDORT (implicit discrete ordinate radiation transport), a scheme coupled to the explicit magnetohydrodynamic (MHD) solver in the 3D moving-mesh code AREPO. The discrete ordinate scheme means that we directly solve the specific intensities in discrete directions. We solve the time-dependent relativistic radiation transport equation via an implicit Jacobi-like iterative finite-volume solver, which overcomes the small radiation time-steps needed by explicit methods. Compared to commonly used moment-based methods, such as flux-limited diffusion (FLD) or M1 closure, this scheme has the advantage of correctly capturing the directions of radiation in both optically thick and thin regions. It is based on the scheme developed for the adaptive mesh refinement code ATHENA++, but we generalise the scheme to support (1) an unstructured moving-mesh, (2) local time-stepping, and (3) general equations of state. We show various test problems that commonly used moment-based methods fail to reproduce accurately. To apply the scheme to a real astrophysics problem, we show the first global 3D radiation hydrodynamic simulation of the entire convective envelope of a red supergiant star. We even marginally resolve the photosphere, which is a known challenge for global 3D simulations of stars. For this problem, the radiation module only takes less than half of the total computational cost. Our current scheme assumes grey radiation, is first-order accurate in both time and space, and is memory-intensive (especially for large cosmological simulations), but we discuss potential avenues for future improvements. We expect that our scheme will enable more accurate multi-scale radiation MHD simulations involving supersonic bulk motions, ranging from planet formation in protoplanetary disks, stars and associated transients, to accretion flows near black holes.

Despite the growing number of compact active galactic nuclei (AGN) at $z>4$ discovered by JWST, their formation and evolution remain poorly understood. This paper investigates the large-scale environment of GN-77652, a compact AGN at $z=5.229$ observed as part of the JWST NIRSpec IFU Large Program BlackTHUNDER and complemented by deep multi-band NIRCam imaging. GN-77652 lies in close proximity to a 12 kpc-long filament composed of multiple sources at $z\simeq5.23$, spanning a remarkable range in stellar masses ($M_{\star}=0.7-13 \times 10^8$ ${M_\odot}$), gas phase metallicities (12$+$log(O/H) $=$ 7.6-8.5) and star formation rates (SFR $=0.4-6$ ${M_\odot}$ yr$^{-1}$). The [OIII]$λ$5007 kinematics reveals a smooth large-scale velocity gradient centred on the central, massive ($M_{\star}\simeq1.1\times10^9$ ${M_\odot}$) and metal rich ($Z\sim0.6$ $Z_{\odot}$) system of the group. In this source, only 2.4 kpc (projected) from GN-77652, [OIII]$λ$4363 line diagnostics provide possible evidence for a second AGN. GN-77652 exhibits a shallow ($-30$ to $+20$ km s$^{-1}$) velocity gradient that is consistent with disk rotation according to dynamical modelling. The Lyman-Werner radiation field produced by the filament is too weak for the black hole (BH) in GN-77652 to have formed recently via direct collapse. However, the required conditions may have existed at earlier epochs, or alternative scenarios (e.g. a recoiling BH ejected from the filament) could also be plausible. The whole system is expected to coalesce in $150-440$ Myr, also motivating an exploration of its future evolution through toy-model extrapolations and numerical simulations. Our analysis suggests that the compact AGN appearance of GN-77652 represents a transient evolutionary phase, consistent with the apparent decline with redshift in number density of compact AGN identified with JWST.

Simulation-based inference (SBI) is a powerful inference technique for cases where the exact functional form of the likelihood is not known. A prime example is the likelihood of cross-correlation power spectra of the cosmic microwave background (CMB) fields at low multipoles, ℓ ≲ 10. In this paper, we investigate a parity-violating cross-correlation between E- and B- mode polarization fields using SBI. The EB correlation at low ℓ is essential to distinguish between possible axion dark energy and dark matter interpretations of 'cosmic birefringence', a rotation of the plane of linear polarization of the CMB, recently reported from WMAP, Planck, and Atacama Cosmology Telescope data. We use neural likelihood estimation to infer the likelihood of the EB correlation at low ℓ and show that it is highly non-Gaussian. We then employ neural posterior estimation to constrain the scalar field mass (m_ϕ ), the cosmic birefringence amplitude (gϕ _in/2), and the instrumental miscalibration angle (α), from simulated datasets. We find that the posterior on m_ϕ shows two regimes, with a transition marked by 10^-32 eV, highlighting a strong sensitivity to the scale dependence of cosmic birefringence. To quantify this behavior, we compute the probability p(m_ϕ < 10^-32 eV) for various fiducial values of m_ϕ . We find that α and the contribution of lensed B modes ultimately limit our ability to exclude the dark energy scenario fully.

We developed a text-to-structured query language (SQL) system based on large language models (LLMs) using in-context learning and applied it to the Automatic Learning for the Rapid Classification of Events (ALeRCE) astronomical database. ALeRCE is a community broker for the Zwicky Transient Facility and the Vera C. Rubin Observatory. The system enables users to query the database in natural language (NL) and generates executable SQL queries. To develop and evaluate the system, we constructed a set of 110 NL-SQL pairs. We propose a step-by-step generation framework comprising four modules: schema linking, query classification, prompt decomposition, and self-correction. The performance of 13 LLMs was evaluated using in-context learning and prompt engineering techniques. Text-to-SQL performance was assessed using the perfect-match (PM) rate for row identifiers (e.g., object identifiers) and column identifiers (i.e., column names). The proposed step-by-step framework consistently outperforms a direct-inference baseline, while the self-correction module consistently reduces execution errors. For Claude Opus 4.6, PM performance on row (column) identifiers is high for simple queries, reaching 0.97 (0.94), and decreases with query complexity to 0.44 (0.72) for medium queries and 0.59 (0.49) for hard queries. Among the 13 models evaluated, the best-performing LLMs for the text-to-SQL task are Claude Opus 4.6, Gemini 2.5 Pro, Gemini 3 Flash, and GPT-5.2-Codex.

We present the largest and most homogeneous catalog of radial velocity (RV) measurements for field RR Lyrae (RRL) variables, based on both proprietary and publicly available spectroscopic data. The sample includes 17,563 RRLs pulsating in the fundamental mode (12,353 RRab), in the first overtone (5,011 RRc), and in double-mode (199 RRd). The RV curve (RVC) templates for metallic and Balmer lines were used to derive RV amplitudes and $V_γ$ velocities, defined as the RV of the stellar barycenter with respect to the Sun. The typical accuracy across the catalog is on average 3.8 km s$^{-1}$ for well-sampled RVCs, 6.5 km s$^{-1}$ for RVCs with 3-7 phase points and 11.3 km s$^{-1}$ for RVCs with fewer than three phase points. The use of different spectroscopic diagnostics and RVC templates provides, within the errors, very similar $V_γ$ velocities. We found that the metallicity dependence of RV amplitudes is vanishing for metallic lines, but becomes increasingly significant for H$γ$ and H$δ$. Moreover, the scaling relations between photometric (V, $G_{BP}$, G, $G_{RP}$) and RV amplitudes are linear for RRc and nonlinear for RRab variables, independently of the adopted diagnostic. This circumstantial evidence indicates that convection affects more luminosity than RV amplitudes when moving from the blue (hot) to the red (cool) edge of the instability strip. The spectroscopic Bailey diagram (RV amplitude versus period) shows a smooth transition and a reduced spread at a fixed period, when moving from metal-poor to metal-rich RRLs. Finally, we also found evidence that the metallicity distribution function of Blazhko RRLs is skewed toward the metal-intermediate and metal-rich regimes.

Protoplanetary disks represent a crucial stage in the evolution of Young Stellar Objects towards the formation of fully formed planetary systems. While substantial progress has been made in the last decades in the characterization of the dust and molecular gas in these systems, the ionized component remains poorly understood. Ionized gas traces important processes such as photoevaporation, accretion, disk winds, and jets, and therefore is key to studying disk dynamics, evolution, and ultimately planet formation. In this paper, we investigate the capabilities of the forthcoming SKA telescope to probe this component in protoplanetary disks within nearby star forming regions. We present state-of-the-art simulations of photoevaporative, magneto-thermal, and magnetohydrodynamic winds, and generate theoretical predictions and synthetic SKAO observations to assess its potential in detecting and characterizing free-free emission and Hydrogen recombination lines. Finally, we discuss synergies with complementary facilities and how they will provide a comprehensive, multi-scale view of disk winds and offer critical insights on the mechanisms driving disk evolution and the onset of planet formation.

Combining deep, wide-area X-ray surveys with multi-wavelength catalogues provides insights into rare, highly-accreting AGN and low-mass galaxies at low redshift, the latter potentially representing local analogues of the first galaxies in the early Universe. We use the four-pass eROSITA All Sky Survey to select the largest catalogue of X-ray AGN in a highly complete sample of low-redshift galaxies, including low-mass (logM*/Msol<10) ones. We probe their distribution of specific accretion rates, $λ$_SAR, and the cumulative AGN fraction above varying $λ$_SAR thresholds. Our parent sample consists of ~5.35 million galaxies selected from the Legacy Survey DR10 with z-band fluxes brighter than 20 mag and redshifts 0.03<z<0.2. We place particular emphasis on the detailed characterisation of our sample, including estimating unbiased physical galaxy properties and rigorous cleaning and validation of the X-ray aperture photometry and host-galaxy associations. We identify 874 X-ray AGN in low-mass galaxies, most of them newly discovered as X-ray emitters. Thanks to a Bayesian framework that makes use of the X-ray information from all parent sample galaxies, we constrain the specific accretion rate distribution, p(log$λ$_SAR | M*, z), across a wide range of $λ$_SAR and uncover second-order mass-dependent effects. We detect a break at high $λ$_SAR, possibly indicating Eddington-limited, self-regulated black hole growth. Integrating p(log$λ$_SAR | M*, z) above $λ$_SAR>10^-3, we find a cumulative AGN fraction of ~1% for low-mass galaxies, placing a firm lower limit on the black hole occupation fraction in this regime. Overall, our specific accretion rate distributions, sampling down to the as-of-yet unexplored low-mass regime, highlight a more nuanced, mass-dependent view of AGN growth and accretion history that must be taken into account in future modelling.

Deep spectroscopic samples can improve photometric redshift (photo-z) estimates and reduce uncertainties on redshift distributions. Such improvements can increase the cosmological constraining power of large imaging-based experiments such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) and mitigate what may be a limiting systematic effect. We present results from the "DESI-Deep pilot" program, which was designed to assess the capability of the Dark Energy Spectroscopic Instrument (DESI) on the 4m Mayall telescope to measure redshifts of galaxies as faint as expected lensing samples for early LSST data (m_i ≤ 24.5). We find that DESI is remarkably efficient at this task, with redshift success rates comparable to the results of observations from 10 m class telescopes with only ∼2 × longer integration time (rather than ∼8 × longer as would be expected from aperture-area scaling), while simultaneously achieving ∼30 times larger multiplexing. We also find that the signal-to-noise ratio of the spectra scales as expected for background-limited observations even for the longest exposure times (∼7 hr) and faintest targets in the program. These results demonstrate that DESI could provide the definitive redshift sample for the early years of LSST with a modest investment of observing time. Based upon the results of this program, we provide updated predictions for the time required to collect benchmark samples for photo-z training and calibration using a variety of spectroscopic facilities. Finally, we describe a potential "DESI-Deep" survey designed to train and calibrate photo-z's for imaging experiments, and provide forecasts of its impact on cosmological inference.

Late infall can replenish the building materials of planets in protoplanetary disks and dramatically alter their structural evolution. The resulting pressure bumps effectively accumulate dust, facilitate grain coagulation, and trigger planetesimal formation via the streaming instability. In this work, we investigate the potential for planetesimal and planet formation, as well as the emergence of observable substructures, in disks undergoing late-stage infall. We utilize a comprehensive modeling framework that couples dust coagulation and dynamics, planetesimal formation, N-body gravity, planetary growth, and planet-disk interactions. Our results show that the abundant dust supply and the migration barrier created by the infalling gas enable the rapid formation of gas giants via pebble and gas accretion within one million years, even at large orbital distances (~70 au). These giants, in turn, exert torques that generate multiple secondary disk substructures, fostering multi-generational planetesimal formation and resulting in diverse planetary system configurations. The planetesimals exhibit distinct dynamical properties that are determined by their formation epoch and environment, which are analogous to the small-body populations in the outer Solar System. Both the infall- and planet-induced substructures are clearly visible in synthetic 1.3-mm continuum observations, closely resembling the multi-ring disks detected in ALMA surveys. Our model provides a new perspective on the origin of distant giant planets, long-lasting planetesimal formation, and the prevalence of disks with multiple substructures.

The Population III.1 theory for supermassive black hole (SMBH) formation predicts a very early (z ∼ 20─25) transient phase, the "Pop III.1 Flash," of cosmic reionization powered by supermassive stars that are SMBH progenitors. The Universe then quickly recombines to become mostly neutral, with this state persisting until galaxies begin to reionize intergalactic gas again at z ∼ 10. The overall Thomson scattering optical depth, τ, from the Flash has been shown to be τ_PopIII. 1 ∼ 0.03, leading to a total τ ∼ 0.08─0.09. Such a value, while significantly larger than that previously inferred from Planck observations of the low-l EE polarization power spectrum of the cosmic microwave background (CMB), can help relieve several "tensions" faced by the standard ΛCDM cosmological model, especially the preference for negative neutrino masses and dynamic dark energy. Here we compute EE power spectra of example models of the Flash. We find that, because of its very high redshift, the contribution to l ≲ 6 modes is dramatically reduced compared to usual low-z reionization models for the same value of τ, while the power at l ≳ 6 is boosted. Thus the Pop III.1 reionization scenario provides a natural way to increase τ, while remaining closer to the latest CMB low-l polarization observations.

Modern radio interferometers deliver large volumes of data containing high-sensitivity sky maps over wide fields of view. These large-area observations can contain various and superposed structures such as point sources, extended objects, and large-scale diffuse emission. To fully realize the potential of these observations, it is crucial to build appropriate sky emission models that separate and reconstruct the underlying astrophysical components. We introduce aim-resolve, an automatic and iterative method that combines the Bayesian imaging algorithm resolve with deep learning and clustering algorithms in order to jointly solve the reconstruction and source extraction problem. The method identifies and models different astrophysical components in radio observations while providing uncertainty quantification of the results. By using different model descriptions for point sources, extended objects, and diffuse background emission, the method efficiently separates the individual components and improves the overall reconstruction. We demonstrate the effectiveness of this method on synthetic image data containing multiple different sources. We further show the application of aim-resolve to an L-band (856─1712 MHz) MeerKAT observation of the radio galaxy ESO 137-006 and other radio galaxies in that environment. We observe a reasonable object identification for both applications, yielding a clean separation of the individual components and precise reconstructions of point sources and extended objects along with detailed uncertainty quantification. In particular, the method enables the creation of catalogs containing source positions and brightnesses and the corresponding uncertainties. The full decoupling of sky emission model and instrument response makes the method applicable to a wide variety of instruments or wavelength bands.

We present ALETHEIA, a new emulator of the non-linear matter power spectrum, <inline-formula><tex-math>$P(k)$</tex-math></inline-formula>, built upon the evolution mapping framework. This framework addresses the limitations of traditional emulation, the need to densely sample high-dimensional parameter spaces, by focusing on h-independent cosmological parameters, which can be separated into those defining the linear power spectrum shape (<inline-formula><tex-math>$\boldsymbol {\Theta }_{\mathrm{s}}$</tex-math></inline-formula>) and those affecting only its amplitude evolution (<inline-formula><tex-math>$\boldsymbol {\Theta }_{\mathrm{e}}$</tex-math></inline-formula>). The combined impact of evolution parameters and redshift is compressed into a single amplitude parameter, <inline-formula><tex-math>$\sigma _{12}$</tex-math></inline-formula>. ALETHEIA uses a two-stage Gaussian Process emulation: a primary emulator predicts the non-linear boost factor as a function of (<inline-formula><tex-math>$\boldsymbol {\Theta }_{\mathrm{s}}$</tex-math></inline-formula>) and <inline-formula><tex-math>$\sigma _{12}$</tex-math></inline-formula> for fixed evolution parameters, while a second one applies a small linear correction based on the integrated growth history. The emulator is trained on shape parameters spanning <inline-formula><tex-math>$\pm 5\sigma$</tex-math></inline-formula> of Planck constraints and a wide clustering range <inline-formula><tex-math>$0.2 \lt \sigma _{12} \lt 1.0$</tex-math></inline-formula>, providing predictions for <inline-formula><tex-math>$0.006\, {\rm Mpc}^{-1} \lt k \lt 2\, {\rm Mpc}^{-1}$</tex-math></inline-formula>. We validate ALETHEIA against N-body simulations, demonstrating sub-per cent accuracy. When tested on a suite of dynamic dark energy models, the full emulator's predictions show a variance of approximately 0.2 per cent, a factor of five smaller than that of the state-of-the-art EUCLIDEMULATOR2 (around 1 per cent variance). Furthermore, ALETHEIA maintains sub-per cent accuracy for the best-fitting dynamic dark energy cosmology from recent Dark Energy Spectroscopic Instrument (DESI) data, a model whose parameters lie outside the training ranges of most conventional emulators. This demonstrates the power of the evolution mapping approach, providing a robust and extensible tool for precision cosmology.

We present FlowSN, a statistical framework using simulation-based inference (SBI) with normalizing flows to account for selection effects in observational astronomy. Failure to account for selection effects can lead to biased inference on global parameters. An example is Malmquist bias, where detection limits result in a sample skewed towards brighter objects. In Type Ia supernova (SN Ia) cosmology, these selection effects can systematically shift the inferred posterior distributions of cosmological parameters, necessitating the development of robust statistical frameworks to account for the biases. SBI enables us to implicitly learn probability distributions that are analytically intractable to calculate. In this work, we introduce a novel approach that employs a normalizing flow to learn the non-analytic selected SN likelihood for a given survey from forward simulations, independent of the assumed cosmological model. The resulting likelihood approximation is incorporated into a hierarchical Bayesian framework, and posterior sampling is performed using Hamiltonian Monte Carlo to obtain constraints on cosmological parameters conditioned on the observed data. The modular learnt likelihood approximation can be reused without retraining to evaluate different cosmological models, providing a key advantage over other SBI approaches. We demonstrate the performance of this methodology by training and testing the SBI technique using realistic LSST-like SNANA simulations for the first time. Our FlowSN approach yields accurate posterior estimates on cosmological parameters, including the dark energy equation of state <inline-formula><tex-math>$w_\text{0}$</tex-math></inline-formula>, that are an order of magnitude less biased than those obtained with conventional techniques and also exhibit improved frequentist calibration.

Analyses of baryon acoustic oscillations (BAO) commonly employ template-based methods to extract compressed parameters from the clustering of dark-matter tracers, which are then interpreted in terms of ratios of the sound-horizon scale and cosmological distances relative to a fiducial cosmology. A small mismatch between the sound-horizon scale derived from the standard analytic formulation (integral over the sound speed) and the effective scale imprinted in clustered matter can, however, introduce a systematic bias in cosmological inference. We extend previous work to a broader class of cosmological models, quantify this bias for surveys with DESI-like precision, and propose strategies to correct for the effect. We find that the induced bias becomes a significant fraction of the statistical uncertainty for deviations from the fiducial cosmology, at the level of |∆Ω _m | = 0.03 and |∆N _eff| = 0.3, and for very precise data corresponding to a forecasted Year-5 DESI survey (or other stage IV dark energy galaxy surveys). We present several ways to correct for this effect, suitable for a variety of applications. We therefore recommend that analyses exploring such parameter regimes either apply the proposed corrections or include an appropriate systematic error budget.

A hallmark of the computational campaign in nuclear and particle physics is the lattice-gauge-theory program. It continues to enable theoretical predictions for a range of phenomena in nature from the underlying Standard Model. The emergence of a new computational paradigm based on quantum computing, therefore, can introduce further advances in this program. In particular, it is believed that quantum computing will make possible first-principles studies of matter at extreme densities, and in and out of equilibrium, hence improving our theoretical description of the early universe, astrophysical environments, and high-energy particle collisions. Developing and advancing a quantum-computing-based lattice-gauge-theory program, therefore, have turned into a vibrant and fast-moving area of research in theoretical nuclear and particle physics. These lecture notes introduce the topic of quantum computing lattice gauge theories in a pedagogical manner, with an emphasis on theoretical and algorithmic aspects of the program, and on the most common approaches and practices, to keep the presentation focused and useful. The Hamiltonian formulation of lattice gauge theories is introduced within the Kogut-Susskind framework, the notion of Hilbert space and physical states is discussed, and some elementary numerical methods for performing Hamiltonian simulations are discussed. Quantum-simulation preliminaries and digital quantum-computing basics are presented, which set the stage for concrete examples of gauge-theory quantum-circuit design and resource analysis. A step-by-step analysis is provided for a simpler Abelian gauge theory, and an overview of our current understanding of the cost of quantum computing quantum chromodynamics is presented in the end. Examples and exercises supplement the material, and reinforce the concepts and methods introduced throughout.

Cosmology stands at a crossroads. The Hubble tension has reached a nominal significance above $7σ$, while analyses combining DESI BAO and Type Ia supernova data show emerging hints of departures from $Λ$CDM. Meanwhile, high-precision CMB measurements from ACT and SPT enable a timely and more stringent reassessment of proposed solutions to the tension. In this paper, we revisit the $H_0$ Olympics, a systematic contest comparing proposed alternatives to $Λ$CDM using common datasets, likelihoods, and statistical criteria. In this updated edition, the $H_0$ World Cup, we subject fourteen representative solutions to a common analysis of current CMB, BAO, and SN data. The contenders span four broad mechanisms: late-time modifications of the expansion history, modified recombination, additional pre-recombination radiation, and early non-radiative energy injection. Relative to the original analysis, the present competition includes models and mechanisms proposed in the intervening years and evaluates all contenders using both Bayesian and Frequentist tests of tension and model performance, letting the neutrino mass sum vary. We further test if late-time extensions through curvature or the Chevallier-Polarski-Linder (CPL) dark energy parametrization can aid the success of the models. Finally, we subject the leading contenders to dedicated robustness tests involving alternative CMB likelihoods and multipole cuts, supernova samples, large-scale-structure information, and big-bang nucleosynthesis constraints. This framework assesses both the ability of each mechanism to ease the Hubble tension and the robustness of our conclusions to datasets and analysis choices.

The Hubble tension has reached a nominal significance above $7σ$, while new high-precision measurements of the cosmic microwave background (CMB) and baryon acoustic oscillations (BAO) sharpen the test of proposed solutions. Using a common framework, we compare fourteen representative alternatives to the standard $Λ$ Cold Dark Matter ($Λ$CDM) model in light of up-to-date CMB, BAO and supernovae data to gauge their ability to resolve the tension. The models span late-time modifications, modified recombination, and exotic pre-recombination expansion histories driven by additional radiation or a localized dark energy injection. We evaluate each proposal with complementary frequentist and Bayesian measures of the residual calibration tension and of the improvement in the joint fit. Both approaches identify the same broad hierarchy. Early dark energy and early modified gravity models perform best, shifting the $H_0$ inference without local measurement priors toward $70\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$ and reducing the residual discrepancy with SH0ES to approximately $2.5-3.6σ$, depending on the model and statistic, while receiving strong support over $Λ$CDM in the combined fit. Varying the electron mass at recombination yields an intermediate improvement, whereas the enhanced-radiation and late-time scenarios do not improve over $Λ$CDM. This Letter summarizes the group stage of the competition; in a companion paper (Paper II) we present the results of an exhaustive set of analyses and assess their robustness to variations in modeling assumptions and datasets.

Context. The atmospheres of transiting exoplanets can be studied spectroscopically using space-based or ground-based observations. Each has its own set of strengths and weaknesses, so there are benefits to both approaches. This is especially true for more challenging targets such as cooler, smaller exoplanets whose atmospheres most likely contain many molecular species and cloud decks. Aims. We aim to study the atmosphere of the warm Neptune-like exoplanet WASP-107 b (T_eq ≍ 740 K). Several molecular species have been detected in this exoplanet in studies using the space-based JWST, and we aim to confirm and expand upon these detections by using the ground-based VLT and evaluating how well our findings agree with previously retrieved atmospheric parameters. Methods. We observed two transits of WASP-107 b with VLT/CRIRES⁺ and created cross-correlation templates of the target atmosphere based on results from previous studies. We created different templates to investigate the impact of varying volume mixing ratios of species and the inclusion or exclusion of clouds. Considering this target's observational challenges, we created simulated observations prior to evaluating our real data in order to assess our expected detection significances with the cross-correlation technique. Results. We report cross-correlation signals of two molecular species, CO (~6σ) and H₂O (~4.5σ), in our K_p − v maps. This supports previous space-based detections and demonstrates, for the first time, the capability of VLT/CRIRES⁺ to detect species in targets cooler than hot Jupiters using transmission spectroscopy. We show that our analysis is sensitive to the inclusion of clouds but less so to different volume mixing ratios. Interestingly, our signal maximum deviates notably but consistently from its expected location in the K_p direction of our maps, and we speculate on the possible reasons for this effect. We demonstrate that the error budget for these relatively cool exoplanets is severely reduced in comparison to hotter exoplanets and emphasise the need for further work in the context of high-resolution spectroscopy.

The explosion of a star is first marked by the shock wave breaking out of the stellar surface, producing a burst of ultraviolet and X-ray radiation. These events are observationally rare, despite likely accompanying the majority of supernovae (SNe). Here, we report on our multiwavelength observing campaign of the closest Einstein Probe fast X-ray transient (FXT) EP260321a at z = 0.0344. The thermal (kT = 130 eV) X-ray emission with peak luminosity of 1.0 × 10⁴⁵ erg s⁻¹ points to a shock breakout origin. We demonstrate that EP260321a is accompanied by a broad-lined Type Ic supernova, SN 2026gzf. The supernova (SN) properties, including its spectral evolution, lightcurve evolution, and expansion velocities, are all typical of the energetic stripped-envelope SNe associated with gamma-ray bursts (GRBs). However, deep X-ray upper limits obtained with the Chandra X-ray Observatory do not detect an X-ray afterglow, and instead exclude the afterglow of known GRBs or FXTs. If the stellar explosion launched a successful relativistic jet, we require that it had both a low Lorentz factor of Γ₀ < 30 and a kinetic energy of E_kin < 10⁴⁹ erg for a stellar wind density of A_* ≳ 1. We propose that EP260321a originated from a mildly relativistic, weak outflow that was choked by the progenitor star. This scenario is capable of naturally explaining its low X-ray luminosity and lack of prompt gamma-ray emission. EP260321a bridges the gap between SN 2008D and low-luminosity GRBs, suggesting a greater diversity in the physical parameters of stripped stars as they undergo terminal collapse.

We explore the formation of intermediate-mass black holes (IMBHs), potential seeds for supermassive black holes (SMBHs), via runaway stellar collisions for a wide range of star cluster (surface) densities (<inline-formula><tex-math>$4\times 10^3 \lesssim \Sigma _\mathrm{h} \lesssim 4\times 10^6 \, \mathrm{M_\odot \, pc^{-2}}$</tex-math></inline-formula>) and metallicities <inline-formula><tex-math>$(0.01 \lesssim Z \lesssim 1.0 \, \mathrm{Z_\odot })$</tex-math></inline-formula>. Our sample of isolated (>1400) and hierarchical (30) simulations of young, massive star clusters with up to <inline-formula><tex-math>$N=1.8\times 10^6$</tex-math></inline-formula> stars includes collisional stellar dynamics, stellar evolution, and post-Newtonian equations of motion for black holes using the BIFROST code. High stellar wind rates suppress IMBH formation at high metallicities (<inline-formula><tex-math>$Z \gtrsim 0.2 \, \mathrm{Z_\odot }$</tex-math></inline-formula>), and low collision rates prevent their formation at low densities (<inline-formula><tex-math>$\Sigma _\mathrm{h}\lesssim 3\times 10^4 \, \mathrm{M_\odot \, pc^{-2}}$</tex-math></inline-formula>). The assumptions about stellar wind loss rates strongly affect the maximum final IMBH masses (<inline-formula><tex-math>$M_\bullet \sim 6000 \, \mathrm{M_\odot }$</tex-math></inline-formula> versus <inline-formula><tex-math>$M_\bullet \sim 25\,000 \, \mathrm{M_\odot }$</tex-math></inline-formula>). The total stellar mass loss from collisions and collisionally boosted winds before <inline-formula><tex-math>$t=3$</tex-math></inline-formula> Myr can together reach up to 5─10 per cent of the final cluster mass. We present fitting formulae for IMBH masses as a function of host star cluster <inline-formula><tex-math>$\Sigma _\mathrm{h}$</tex-math></inline-formula> and Z which can be used to seed SMBHs in high-resolution cosmological hydrodynamical simulations and in semi-analytic models for galaxy formation. Our results favour IMBH formation in dense low-metallicity environments similar to <inline-formula><tex-math>$z\sim 10$</tex-math></inline-formula> JWST (James Webb Space Telescope) proto-globular clusters. IMBH formation is suppressed in the high-metallicity and low-density conditions of the local Universe.

We present a systematic study of the environments of 25 luminous quasars at z > 6.5 from the ASPIRE program. Using JWST/NIRCam wide-field slitless spectroscopy data, we identified 487 galaxies at 5.3 ≲ z ≲ 7.0 exhibiting [O III] emission. Among these, 122 [O III] emitters lie within ∣∆v_los∣ < 1000 km s⁻¹ of the quasars, corresponding to a ∼9.4-fold enhancement relative to the average galaxy density at other redshifts. Furthermore, we identified 16 [C II]-emitting galaxies at the quasar redshifts from Atacama Large Millimeter/submillimeter Array (ALMA) mosaic observations. A cross-correlation function analysis between quasars and [O III]+[C II] emitters yields a cross-correlation length of <inline-formula> <mml:math><mml:msubsup><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mi>QG</mml:mi></mml:mrow></mml:msubsup><mml:mo>=</mml:mo><mml:mn>8.6</mml:mn><mml:msubsup><mml:mrow><mml:mn>8</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>0.55</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.51</mml:mn></mml:mrow></mml:msubsup><mml:mspace></mml:mspace><mml:msup><mml:mrow><mml:mi>h</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup><mml:mspace></mml:mspace><mml:mi>cMpc</mml:mi></mml:math> </inline-formula> and an autocorrelation of <inline-formula> <mml:math><mml:msubsup><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mi>QQ</mml:mi></mml:mrow></mml:msubsup><mml:mo>=</mml:mo><mml:mn>15.7</mml:mn><mml:msubsup><mml:mrow><mml:mn>6</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>2.70</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>2.48</mml:mn></mml:mrow></mml:msubsup><mml:mspace></mml:mspace><mml:msup><mml:mrow><mml:mi>h</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup><mml:mspace></mml:mspace><mml:mi>cMpc</mml:mi></mml:math> </inline-formula>, indicating that z ∼ 7 quasars reside in dark matter halos with <inline-formula> <mml:math><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mi>halo</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>1</mml:mn><mml:msup><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mn>12.2</mml:mn><mml:msubsup><mml:mrow><mml:mn>7</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>0.26</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.21</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:msup><mml:mspace></mml:mspace><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mo>⊙</mml:mo></mml:mrow></mml:msub></mml:math> </inline-formula> and have a quasar lifetime of <inline-formula> <mml:math><mml:msub><mml:mi>t</mml:mi><mml:mi>Q</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mn>1</mml:mn><mml:msup><mml:mn>0</mml:mn><mml:msubsup><mml:mn>7.05</mml:mn><mml:mrow><mml:mo>−</mml:mo><mml:mn>1.01</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.95</mml:mn></mml:mrow></mml:msubsup></mml:msup><mml:mspace></mml:mspace><mml:mi>yr</mml:mi></mml:math> </inline-formula>. Notably, the number of [O III]-emitting galaxies at quasar redshifts varies significantly from field to field, ranging from 0 to 20, highlighting a diverse quasar environment. Remarkably, seven quasars trace significant galaxy overdensities (i.e., protoclusters), with δ_gal > 5 within a volume of V ∼ 500 cMpc³. We also find that ∣∆v_los∣ increases rapidly toward smaller galaxy─quasar separations in protocluster fields, consistent with galaxy kinematics around extremely massive halos in cosmological simulations. By combining JWST and ALMA data, we reveal the complex and diverse environments of these early quasars, providing robust evidence that the earliest luminous quasars are effective tracers of galaxy overdensities, albeit with substantial field-to-field variation.

The subparsec proximity around the Sgr A^⋆ supermassive black hole (SMBH) in the center of the Milky Way contains an inner cluster of eccentric S-stars with randomly oriented orbits, a midway-disk of clockwise-rotating stars (CWSs), and a surrounding population of off-the-disk stars (ODSs). Despite their diverse kinematic properties, all three populations appear to be massive (WR/O/B types) and have similarly limited life span τ_⋆ ∼ 6─15 Myr. Several scenarios, including star formation induced by SMBH's close encounters with one or more gas clouds as well as impulsive close scattering by a putative intermediate-mass companion (IMC) of Sgr A^⋆ possible an intermediate-mass black hole, have been proposed to explain the origin and dynamical evolution of S-stars, CWSs, ODSs, as well as hyper-velocity stars in the Galaxy. However, their coexistence and the origin of a recently discovered zone of avoidance in S-stars' eccentricity-pericentric-distance distribution remain enigmatic. Here, we construct a unified model to comprehensively take into account these stars' interaction with each other, their single natal disk, and an independent IMC. We show their disparate present-day orbits would only be concurrently attainable, within their multi-Myr age, under the combined influence of IMC's secular perturbation and these stars' resonant relaxation in a depleting gaseous-disk environment.

Westerlund 1 (Wd1) is the most massive young star cluster known in the Milky Way and a key laboratory for studying the early dynamical evolution of massive clusters. Owing to its high extinction, the internal kinematics of its intermediate-mass stellar population remain largely unexplored. We aim to characterize the internal kinematic properties of Wd1 using a homogeneous census of near-infrared (NIR) selected cluster members and their proper motions (PMs). We considered PMs from the VIRAC2 catalog, based on multi-epoch VVV/VVVX observations. For $1286$ candidate members previously identified through NIR photometry and astrometry (Paper I), we computed their PMs relative to the cluster mean motion and analyzed them as a function of position and radius. We also investigate radial trends, test the robustness of the results against the assumed cluster center, and search for preferred directions of motion. We detect a statistically significant signature of expansion in the outer regions of Wd1, with the radial component of the relative PMs increasing with distance from the cluster center. The expansion appears asymmetric, with the strongest gradient detected along a PA$=84\degree \pm 8\degree$ in the plane of the sky and with $5.9σ$ significance. We also find hints for inward radial motions in the central region, consistent with ongoing mass segregation, but only at $\approx 2σ$ significance. Taken together, these results are consistent with a nearly monolithic formation scenario.

(abridged) We develop a flexible analytical framework for modeling blastwave evolution in arbitrary environments and use it to investigate how large-scale galactic structure affects the dynamics and morphology of evolved SNRs and SBs. We introduce FRANZ (FRamework for ANalytical one-Zone blastwave dynamics), a modular thin-shell model that follows the local evolution of a shock-surface segment in environments characterized by arbitrary density, velocity and gravitational fields. After validating the model against well-established analytical results, we apply it to study the effects of vertical stratification, galactic shear and dense galactic substructure on blastwave evolution. FRANZ reproduces the classical evolution of blastwaves in uniform media while extending to complex environments. We derive criteria for disk break out in stratified media, characterize the timescales on which differential rotation deforms blastwaves and identify a new mechanism, by which it can suppress the momentum coupling in continuously-driven blastwaves. Interactions with dense filaments modify both shock-surface morphology and dynamics and confound the interpretation of the expansion history of observed remnants, which depends on the density distribution prior to the onset of explosions, which is fundamentally inaccessible from the observed state. In highly structured media with a high volume-filling factor of diffuse gas, ages inferred from the observed state may be systematically overestimated. FRANZ provides a computationally inexpensive and extensible framework for studying blastwaves in realistic galactic environments. It offers a useful complement to numerical simulations for interpreting observations of evolved SNRs and SBs and for developing improved models of stellar feedback in large-scale simulations.

Collisionless shocks are common in astrophysical systems and stand as sites of particle acceleration. While particles at perpendicular shocks may not return to the upstream region, at oblique shocks a fraction of energetic electrons manage to escape the shock and travel upstream. An extended region known as the electron foreshock is formed, where these reflected particles drive various instabilities that may promote electron acceleration. Here we present the first 2D3V particle-in-cell (PIC) simulations of electron─ion nonrelativistic oblique shocks that explore the interaction of the foreshock with preexisting compressive turbulence with a relative amplitude of 15% based on estimates of the interstellar medium. We find that preexisting turbulence influences the emergence and behavior of the whistler-wave instability, as it enhances the amplitudes of the magnetic field fluctuations and leads to larger nonlinear structures. This impacts the dynamics of the reflected electrons, resulting in a shorter and hotter electron foreshock. At the end of our simulations, with preexisting upstream turbulence we observe nonthermal electrons that are more numerous, reach higher energies, and carry a larger portion of the total energy.

The X-ray luminosity function (XLF) of active galactic nuclei (AGN) provides an observational probe of the growth of supermassive black holes (SMBHs) across cosmic time. With its large survey grasp, Spectrum Roentgen Gamma (SRG)/eROSITA samples the luminosity--redshift plane with a depth--area balance complementary to pencil-beam surveys, providing the volume needed to detect rare luminous AGN, previously limited by small-number statistics. We measure the soft XLF, leveraging an eROSITA sample spanning approximately eight orders of magnitude in luminosity out to $z\simeq6$. This enables us to study luminosity-dependent evolution with improved constraints, and to infer both the SMBH accretion history and optical/UV missed AGN population. We introduce a new redshift-dependent smoothly broken power-law parameterisation in which all XLF model parameters are allowed to evolve continuously with redshift. We find lower space densities for moderately and very luminous AGN at low redshift, while the abundance is higher than previously found at the highest redshifts. Comparisons to optical/UV quasar LFs converted to rest-frame $2\!-\!10\,\mathrm{keV}$ show that the UV-missed fraction decreases with luminosity, and, in the most luminous bin, increases with redshift. Integrating the XLF yields a black-hole accretion-rate density peaking at $z \simeq 1.5$, with the corresponding cumulative black-hole mass density indicating $\sim80^{+11}_{-23}\%$ obscured growth relative to locally-inferred BH mass estimates derived from scaling relations and missed by the soft X-ray selection of our sample. With this work, we release the eROSITA DR2 AGN catalogue, including counterparts and their redshift information. We then discuss how these results can inform future spectroscopic, photometric, and X-ray survey strategies aimed at improving AGN demographic constraints.

We provide a new formal extension of the BFSS matrix model by an additional 5-bracket. Maximal supersymmetry leads us to promote the BFSS 2-bracket structure constants to a dynamical field governed by a Chern-Simons-like kinetic term, as well as a novel potential self-duality relation with respect to the 5-bracket. We show that the full pseudo-action is invariant under maximal supersymmetry and that the associated supersymmetry algebra closes upon invoking a number of BPS-like quadratic constraints. This result hinges on a conspiracy of properties of the $SO(9)$ gamma matrices and the 2- and 5-brackets. Compellingly, the resulting model seems to realize some features expected of a theory containing M5-branes and opens up the possibility of further including higher brackets for the M6- and M9-branes.

Inclusive hadronic decay widths remain a long-standing challenge for first-principles QCD. We present a framework combining lattice QCD with strongly-coupled potential nonrelativistic QCD (pNRQCD) to compute inclusive P-wave heavy quarkonium decays to light hadrons. At leading order in the velocity expansion, all nonperturbative effects, apart from the square of the derivative of the wavefunction at the origin, are encoded in a single universal moment of the two-point chromoelectric correlator, which we determine for the first time from a quenched lattice QCD calculation matched to $\overline{\mathrm{MS}}$ via the gradient flow. Combined with perturbative short-distance coefficients and the square of the derivative of the wavefunction at the origin, our result reproduces the observed $χ_{cJ}(1P)$ widths and, at the same time, provides predictions for the unmeasured $χ_{bJ}(nP)$ widths. The framework extends naturally to inclusive decays and production of ordinary and exotic hadrons.

We present the first experimental search for the $N$-naturalness tower of neutrinos using a global analysis of publicly available neutrino data. As a potential solution to the hierarchy problem, the $N$-naturalness model employs a varying Higgs mass parameter among $N$ dark sectors and encodes the required fine-tuning of the placement of the sectors in a parameter $r$. We report exclusion limits on the parameter space ($r$, $N$), for normal and inverted ordering and in case the neutrino is Majorana or Dirac. In the case of a Majorana neutrino, we can rule out $N\leq 10^4$ sectors with $r\geq 0.1$. This is particularly exciting as it shows that a gauge and gravitational unification around $M_{GUT}$, which is a benchmark scenario of the $N$-naturalness framework with $N=10^4$ without fine-tuning, is ruled out by neutrino experiments.

Hydrogen-isotopologues are commonly used to trace the chemical processing and origin of hydrogen-bearing species throughout the Universe, however, their abundance remains unconstrained for extrasolar planets. Here, we report atmospheric retrieval evidence for the deuterated water molecule HDO in an exoplanet atmosphere, retrieved from James Webb Space Telescope transmission spectra of the hot Jupiter WASP-39 b, resulting in a deuterium-to-hydrogen ratio in water of $4.0^{+1.3}_{-1.1} \times 10^{-3}$. The inferred value is substantially higher than those measured for the Solar System gas giants and overlaps numerically with values reported for some protostellar and inner Solar System environments. This enrichment may reflect either inherited water-rich material accreted beyond the snow line or isotopic processing in the observable atmosphere through transport, photochemistry, and subsequent escape.

Quasars are luminous objects that provide insights into the physics and evolution of supermassive black holes (SMBHs) and their accretion flows, galaxy evolution, and even cosmology. In this study, we present an exploratory study based on the ongoing fifth generation of the Sloan Digital Sky Survey (SDSS-V) and its unique dual-hemisphere, wide-field, and multi-object spectroscopic capabilities, with the aim of creating a comprehensive, all-sky quasar sample. The targets were selected through two novel methods, GUA and Skewt-QSO, that rely primarily on data from WISE and Gaia, aiming to address gaps in previous large quasar samples. Our sample includes over 250,000 spectroscopically confirmed quasars reaching z~5, with tens of thousands of newly identified quasars in the southern hemisphere. The selection methods are highly pure, with well over 80% of the spectra collected being genuine quasars; the main contaminants are M-type stars. The detailed spectral decomposition procedure we employed shows that the quasars in the sample span a wide range of luminosities (Lbol~$10^{44}-10^{48} erg s^{-1}$), SMBH masses (MBH~$10^6-10^{10}$ Msun), and accretion rates (L/LEdd~0.01-1). The distributions of these properties are consistent with those of previous quasar catalogs, which are based on past generations of SDSS, once we account for potential selection biases related to the various survey depths. Our findings confirm that novel selection methods based on optical+IR colors and/or astrometry can yield a large, high-purity quasar sample over wide sky areas, including in cases where more nuanced multi-band photometry and/or multi-wavelength data in the X-ray or radio is not available. This SDSS-V sample, which will continue to grow, establishes a robust reference for future southern (time-domain) surveys, while enhancing and complementing our understanding of quasar demographics and SMBH evolution.

In Hamiltonian systems, the only basis-independent quantity is the spectrum. Given a spectrum, quantum mereology seeks preferred tensor-product decompositions into local subsystems, leading to the emergence of locality. Causal order, however, remains fixed by the Hamiltonian time evolution. In contrast, higher-order quantum theory permits more general processes that need not possess a definite global causal order. In the process-matrix framework, specifying a process requires a choice of subsystems corresponding to the input and output Hilbert spaces of each agent. A change of basis redefines both the agents and the corresponding decompositions into subsystems, while leaving the spectrum of the process matrix invariant. Here, we study how causality arises from this spectrum. First, we derive spectral constraints on processes compatible with definite causal order. Second, we show that, in the thermodynamic limit, generic quantum processes admit a preferred decomposition with a definite causal order. This suggests a mechanism for the emergence of classical causality only from algebraic ingredients.

Machine learning (ML) has become integral to fundamental physics, accelerating statistical workflows from data acquisition through inference and hypothesis testing. As ML systems grow increasingly autonomous, ensuring their reliability for discovery claims becomes critical. This review synthesizes the VERaiPHY (Validation & Evaluation for Robust AI in PHYsics) initiative's frameworks for rigorous ML assessment across particle physics, astrophysics, and cosmology. We establish when verification is essential by contextualizing ML within the statistical discovery workflow. We emphasize fundamental limitations: inductive bias is unavoidable, sample complexity bounds learning, and experimental constraints limit discovery. We reflect on physicists' evolving role as both experimental designers and evaluators whose judgments encode scientific rigor into AI systems. Responsible integration requires understanding ML's transformative potential alongside its intrinsic boundaries.

Neutral hydrogen (HI) traces the dark matter distribution of the Universe. Upcoming surveys such as the Square Kilometre Array Observatory (SKAO) will trace neutral hydrogen up to z < 6 using several detection techniques including Intensity Mapping, which offers a unique window to explore the post-reionization Universe. Beyond two-point statistics promise to extract additional non-Gaussian information but require an accurate modelling of observational systematics such as foregrounds and the telescope beam. This work develops a theoretical model for the HI one-point probability density function (PDF) in spherical cells based on large-deviation statistics and spherical collapse for dark matter along with a nonlinear tracer bias and stochasticity parameterisation. It incorporates foreground removal and telescope beam effects that are validated against high-resolution simulations. We show that, despite these observational systematics, the HI PDF is able to capture additional non-Gaussian information from HI intensity maps compared to the power spectrum and can thus tighten constraints on cosmological parameters, breaking the degeneracy between the linear bias and the clustering amplitude.

The cosmic web preserves a record of the physics that shaped the universe in its earliest moments, the period of exponential expansion known as cosmic inflation. However, if inflation involves significant nonlinear interactions, there are no direct theoretical predictions for the resulting cosmic web. We present the first simulation of the entire history of the universe, from deep in the inflationary epoch to the present-day cosmic structure. Applying this to axion-U(1) inflation, we find that early-universe interactions enhance small-scale structure at high redshift, imprinting the matter power spectrum and the mass function of dark matter halos with signatures of a modified primordial curvature power spectrum and non-Gaussianity. These signatures make high-redshift galaxy surveys, 21-cm observations, and line-intensity mapping promising probes of inflationary physics. More broadly, this ab initio approach provides a novel framework for mapping the signatures of nonlinear inflationary dynamics onto observable cosmic structures across cosmic time.

We study the effect of viscosity on the Sunyaev-Zeldovich signal in a simulated constrained Coma cluster analog. We aim to provide alternative constraints on the amount of viscosity in the ICM. We use the Coma cluster realization with different levels of viscosity from the LOWER DECKS zoom-ins of the SLOW constrained simulations. We generate mock thermal and kinetic Sunyaev-Zeldovich maps and and analyze their statistics. We compare them to Planck observations. Viscosity shows a consistent trend in thermal SZ (tSZ) profiles, increasing the signal in the center and suppressing it in the outskirts. Viscosity also has a strong effect on the tSZ power spectrum, elevating its amplitude on all scales. Comparisons with Planck observations suggest that the effective ICM viscosity is below $5\%$ of the Spitzer value. Unsharp masking reveals an effect on small scales, which are, however, not yet detectable with current observational data. The thermal Sunyaev-Zeldovich effect shows clear and consistent trends that allow us to probe the effective viscosity of the ICM. Our analysis suggests suppressed ICM viscosity below $5\%$ of the Spitzer value, consistent with previous X-ray analysis. Our results validate the strength of the SZ effect as an independent method to constrain ICM viscosity.

Neural simulation-based inference enables parameter estimation for complex models, but typically requires the user to specify a simulator encoding a fixed model structure. We present a framework for joint model selection and parameter estimation that combines large language models for program synthesis with neural simulation-based inference. Given a natural language description of the system and data under investigation, an LLM proposes candidate simulator programs which are iteratively refined via feedback-driven mutation and evaluated using neural density estimation. The approach enables simulation-based inference over a pool of models, not just parameters within a fixed model. On benchmarks spanning deterministic dynamics, stochastic epidemic models, and dark matter substructure inference from gravitational-lensing images, the method identifies plausible model families from open-ended prompts, with accuracy that reflects the information content of the data and identifiability of candidate models.

HD 98800 is a young hierarchical quadruple system composed of the tight binaries AaAb and BaBb on a wide, highly inclined outer orbit. The B subsystem hosts a circumbinary disc in a polar configuration, and the geometry of the system offers a rare opportunity to observe the passage of the disc around BaBb in front of AaAb. We aim to update the overall orbital solution to offer precise time windows of the main occultation features by combining the orbit with the state-of-the-art knowledge of the disc's structure. We combine new and published radial-velocity measurements and multi-wavelength astrometry for the outer AB orbit and both inner subsystems, AaAb and BaBb, in a joint orbital fit. The revised solution is consistent with previous dynamical masses and improved the outer orbit, reducing the uncertainties in the period and periastron epoch by about a factor of two. It also narrows the predicted crossing-phase windows to 5--15 days at the 1σ level, improving the timing of ingress, egress, and the first cavity-crossing predictions. These results provide a more accurate timing framework for future observations of the occultation, although the predicted epochs remain model-dependent because of uncertainties in the disc structure.

We compute the matching of QCD quark-antiquark currents onto the set of the two-particle and three-particle two-jet operators in soft-collinear effective theory (SCET) at next-to-leading order (NLO) in the perturbative QCD series, including for the first time operators up to second order in the power expansion in the transverse momentum over energy. These results contribute to the ongoing programme of computing power corrections and summing power-suppressed logarithmically enhanced terms for event shapes in the two-jet region and deep-inelastic scattering in the Bjorken-$x\to 1$ limit. The three-particle operators depend on the partonic momentum fractions of two partons moving into the same direction. When one of the momentum fractions approaches zero, the coefficient functions are shown to satisfy endpoint factorization relations, which allow for a consistent cancellation of endpoint singularities among various terms in the complete factorization formula for power corrections.

One of the major challenges in axion dark matter haloscope searches is a loss-less tuning mechanism that is able to cover a significant frequency range around the haloscope's central frequency. In this article, we report on the implementation and performance of an axion haloscope dubbed Vertical-cut Optimised Resonant Tunable cavity for dark matter EXploration (VORTEX) centred at $8.5$ GHz with a tuning range of around $800$ MHz. The performance of this setup is measured at temperatures in the mK range and compared to simulation. In addition, we test the cavity-mode structure of this cavity type directly via the `bead-pull method' and observe satisfactory agreement with expectations. The arrangement is poised to be used in an upcoming RADES (Relic Axion Detection Exploratory Setup) data-taking campaign employing a $12$ T solenoid magnet.

The spiral galaxy NGC 1385 is characterized by a vigorous and protracted history of star formation, particularly in its central regions, leading to a current star formation rate that surpasses those of comparable systems. We analyze the evolution history of the galaxy using spatially resolved optical and submillimeter spectroscopy obtained from the PHANGS survey combined with WALLABY radio survey data. We construct radial distributions of star formation rate and the interstellar medium (ISM) neutral and molecular gas mass surface densities and measure the metallicity distribution of the stellar populations using a refined full-spectral fitting population synthesis method together with a determination of ISM oxygen abundances using H\,II region emission lines. The metallicities of the young stars and the ISM are similar and show an almost flat distribution. This is crucially different from previous work which had found a positive gradient for the average metallicities of the stars. We fit a chemical evolution model (incorporating gas infall, outflow, and radial inflow) to the observed data of NGC\,1385. Based on this fit, the evolution of NGC\,1385 is characterized by the typical inside-out disk formation of spiral galaxies -- even though our model does not assume an a priori shorter gas infall timescale for the inner disk than for the outer disk. However, the galaxy has experienced sustained star formation over gigayear timescales with a star formation efficiency a factor of two higher than normal. This explains the high metallicity of the young stars of 0.15 to 0.2\,dex higher than solar and the flat distribution of metallicity across the disk. The model predictions for the metallicities of the stars align well with the observed values, supporting the robustness of both our refined spectral fitting analysis and the inferred evolutionary scenario.

Neutrinos in dense astrophysical environments such as core-collapse supernovae (CCSNe) and neutron star mergers (NSMs) can undergo FFCs, which could develop on extremely small scales. A necessary condition for the occurrence of FFCs is the presence of a zero crossing in the electron lepton number (ELN) angular distribution of neutrinos. In this work, we explore machine learning (ML) approaches to detect non-axisymmetric ELN crossings in these environments, based on input features of the $ν_e$ and $\barν_e$ zeroth and first angular moments. Overall, the ML models demonstrate relatively good generalizability for most of the unseen test datasets generated by various methods that do not assume the same underlying angular distributions as used in the training set. Interestingly, while the model's performance is mediocre for an axisymmetric distribution dataset derived by solving the discretized Boltzmann transport equation under 1D CCSN background, imposing an artificial non-axisymmetry substantially improves the performance. We also find that for the flavor-equilibrated angular distributions, although our ML model trained based solely on ELN inputs performs poorly when the true crossings depend on the post-equilibrated angular distributions of heavy lepton neutrinos and antineutrinos, which become different, it delivers strong performance in detecting ELN crossings when the heavy-lepton neutrino and antineutrino distributions are artificially removed. This highlights the need for additional input features to further improve the model. This is a crucial step toward successfully integrating FFCs into large-scale CCSN and NSM simulations.

Line intensity mapping (LIM) is an emerging technique for probing the large-scale structure (LSS) in the post-reionisation era. This captures the integrated flux of a particular spectral line emission from multiple sources within a patch of the sky without resolving them. Mapping different galaxy line emissions, such as the HI 21-cm and CO rotational lines via LIM, can reveal complementary information about the bias with which the line emitters trace the underlying matter distribution and how different astrophysical phenomena affect the clustering pattern of these signals. The stage at which the structures in the "cosmic web" merge to form a single connected structure is known as the percolation transition. Using mock HI 21-cm and CO(1-0) LIM signals in the post-reionisation universe, we explore the connectivity of structures through percolation analysis and compare it with the underlying galaxy distribution. We probe the relative contributions of voids, filaments, and sheets to the galaxy density and line intensity maps using a morphological measure known as the local dimension. The CO(1-0) map exhibits an increased filamentary behaviour and larger contribution from sheets than the 21-cm map. We attempt to explain such an emission of the CO(1-0) line from biased environments. The upcoming SKA-Mid will produce tomographic intensity maps of the 21-cm signal at z ≲ 3 in Band-1. CO maps can be produced at these redshifts in phase 2 of SKA-Mid, where the frequency coverage is expected to increase up to ∼ 50 GHz. We present forecasts for the recovery of the local dimensions of these line intensity maps contaminated by thermal noise and line interlopers in SKA-Mid surveys.

Flavor instabilities in dense neutrino media trigger exponential growth of flavor waves, yet their nonlinear saturation remains poorly understood. We examine a simple proxy for this effect in the form of a single-wave solution of an axially symmetric fast flavor system. When the angular crossing is shallow and the growth rate of the instability correspondingly small, the flavor wave primarily affects resonant neutrinos that move in phase with it. The evolution of these resonant neutrinos becomes periodic, undergoing cycles of full flavor reversal. They feed power into the unstable wave, and subsequently return to their initial state, draining power back out. This new flavor pendulum captures the dynamics of weak, nearly monochromatic fast flavor instabilities. Since weakly unstable distributions always exhibit a narrow range of unstable wavenumbers, our model likely describes the earliest development of a flavor instability when it first appears. When the instability is not weak, the linear phase of a single-wave excitation does not connect to a regular nonlinear solution, unless the angle distribution consists of only two beams.

A dense neutrino plasma can exhibit collective flavor evolution caused by neutrino-neutrino refraction. Recently, a new class of exact nonlinear inhomogeneous solutions was discovered: single-wave (SW) solutions of the fast flavor system. The key property is that the flavor occupation numbers remain homogeneous, whereas the field of flavor coherence varies spatially with a single wave vector. The equations of motion for this structure resemble those of a collection of classical spins, in analogy with the homogeneous slow and fast flavor cases. In contrast, the SW system is not integrable (it does not possess Gaudin invariants) so that, while two-beam pendulum solutions are inevitable, they do not extend to a multi-angle system. We develop a taxonomy of all known nonlinear collective flavor solutions, explaining the overlap between categories and their differences.

Semi-classical dilaton gravity in (1+1)-dimensions remains one of the only arenas where quantum black holes can be exactly constructed, fully accounting for backreaction due to quantum matter. Here we provide a comprehensive analysis of the mass and thermodynamic properties of static asymptotically flat quantum black holes both analytically and numerically. First, we analytically investigate eternal quantum black hole solutions to a one-parameter family of analytically solvable models interpolating between Russo-Susskind-Thorlacius and Bose, Parker, and Peleg gravities. Examining these models in a semi-classically allowed parameter space, we find naked singularities may exist for quantum fields in the Boulware state. Using a quasi-local formalism, where we confine the black hole to a finite sized cavity, we derive the conserved energy and analyze the system's thermal behavior. Specifically, we show the semi-classical Wald entropy precisely equals the generalized entropy, accounting for both gravitational and fine grained matter entropies, and we find a range where the quantum black holes are thermally stable. Finally, we numerically construct eternal black hole solutions to semi-classical Callan-Giddings-Harvey-Strominger gravity and find that their thermal behavior is qualitatively different from their analytic counterparts. In the process, we develop an analytic expansion of the solutions and find it accurately approximates the full numerical solutions in the semi-classical limit.

The population of Jupiter-sized exoplanets with orbital periods between 10 and 200 days (WJs) exhibits a broad range of orbital eccentricities and system architectures, suggesting a diversity of formation and migration pathways. In this work, we report the detection and characterization of two new eccentric WJs, TOI-2147 b and TOI-6019 b, initially identified as planet candidates by the Transiting Exoplanet Survey Satellite (TESS). We combined TESS photometry with ground-based follow-up observations, including multiband photometry from LCOGT and MuSCAT2, high-angular-resolution speckle imaging, and high-precision radial velocity measurements from the high-resolution Manfred Hirt Planet Finder Spectrograph (MaHPS). Using these data, we were able to confirm the planetary nature of both candidates. TOI-2147 b has a radius of $10.5 \pm 0.3\,\mathrm{R}_\oplus$ and a mass of $116 \pm 22\,\mathrm{M}_\oplus$. It orbits its slightly metal-poor ($\mathrm{[Fe/H]} = -0.29^{+0.07}_{-0.08}$) G-type host star on an eccentric orbit ($e = 0.29 \pm 0.07$) with a period of 26.2 days. TOI-6019 b has a radius of $12.3 \pm 0.3\,\mathrm{R}_\oplus$ and a mass of $149 \pm 15\,\mathrm{M}_\oplus$. It orbits a slightly evolved, solar-metallicity G-type sub-giant with a period of 14.5 days on a significantly eccentric orbit ($e = 0.48^{+0.05}_{-0.04}$). Both planets have bulk densities below that of Jupiter, indicating mildly inflated radii, with interior structure modeling using GASTLI. This suggests that tidal heating from the nonzero eccentricities likely contributes to this inflation and disfavors large atmospheric metal enrichment. No significant signals from additional companions were detected in the radial velocity time series or transit timing variations. Together with the elevated eccentricities, this is consistent with a high-eccentricity migration origin for both systems.

Context: Westerlund 1 (Wd1), the most massive young star cluster in the Milky Way, is an excellent laboratory for studying star formation and early stellar evolution in a starburst-like environment. However, high extinction restricts studies of its stellar content, and focus on high-mass stars limits our knowledge of the full spatial extent of the cluster. Aims: We characterize the near-infrared (NIR) variability of the stellar population of Wd1, filling the mass gap between massive stars traced by Gaia and very low-mass stars from previous Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) studies, to provide a more complete view of cluster membership across solar and super-solar masses.} Methods: We exploited data from the VISTA Variables of the Vía Láctea survey and its extension (VVVX), using NIR point spread function (PSF) photometry and astrometric solutions from its latest data release, namely the VIRAC2 catalogs, mainly in the Ks band. Their large spatial coverage enables study of both the central regions and outskirts of the cluster. We applied HDBSCAN clustering algorithm in a 6D parameter space to differentiate cluster members from field contaminants, assessing robustness through Monte Carlo simulations. Variable sources along the line of sight were also identified and characterized. Results: We identify 1286 high-probability candidate members (12 < J < 18 mag) spanning $\sim 1.5$--$20\,M_{\odot}$, adopting both PARSEC 5 and 6 Myr isochrones ($A_{K_{\rm{s}}}=0.6\,\rm{mag}$, $d=4.23\,\rm{kpc}$). A considerable fraction (34%) shows statistically significant flux variations. We present, for the first time, a parametric analysis of variability modes of Wd1 candidate members in the Ks band, providing a membership catalog suitable for future kinematic studies.

Context. Detecting light reflected off the dayside of an exoplanet in high-resolution spectroscopic data has proved to be a notoriously difficult endeavour. Despite several attempts, the faint signal has yet to be detected. Aims. We present a new effort at finding reflection signatures and show how a strong rotational broadening of the reflected spectrum can complicate this objective. Methods. We introduce a new figure of merit that quantifies the favourability of different systems for a reflection study, the reflection spectroscopy metric. Applying this metric, we identify the KELT-9 system, which features a highly misaligned, rapidly rotating host star, as the target for a case study based on a spectroscopic time series obtained by CARMENES. We also perform an injection-recovery test to determine the detectability of the signal in our data and demonstrate its sensitivity to rotational line broadening. Results. The search for a genuine reflection signal in our data resulted in a non-detection. The injection-recovery test puts this finding into context by revealing the critical importance of taking rotational broadening into account when dealing with systems featuring rapidly rotating stars and large spin-orbit misalignments. Conclusions. The case study presented here underscores the need to incorporate stellar rotation and spin-orbit misalignment into assessments of a given planet's favourability to reflection studies.

The growth of primordial density fluctuations in the early Universe leads to an inhomogeneous dark matter distribution at high redshift, where semi-annihilation processes of the form $χχ\rightarrow χ^c ϕ$, with $ϕ$ being dark radiation, can occur with a sizable rate. Using a state-of-the-art model for the cosmological boost factor, we compute the resulting redshift-dependent flux of boosted dark matter particles generated by semi-annihilation, and we study the implications of the boosted component for structure formation and direct detection experiments. We find a model independent upper limit on the semi-annihilation cross-section from structure formation, which reads $\langleσ_{2\to1} v\rangle\leq4.2\times10^{-19}~\left(m_χ/1~\rm GeV\right)~\mathrm{cm}^3/{\rm s}$. Further, we find that the cosmological contribution to the boosted dark matter flux can be comparable to the galactic one, providing an $O(1)$ enhancement to the sensitivity of dark matter searches, thus slightly enhancing the discovery potential in direct detection experiments of semi-annihilation scenarios where the dark matter interacts with the nucleus.

The upgrade of the ALICE experiments Inner Tracking System (ITS3) aims to replace its innermost detection layers with bent wafer-scale CMOS MAPS sensors. This study examines the performance of ALPIDE chips, currently used in the ALICE ITS2, when operated in a bent configuration under realistic experimental conditions. Proton beams with energies of 80 MeV, 120 MeV and 200 MeV were used to study proton-proton elastic scattering on a polypropylene fiber target reconstructed using two opposing arms of trackers with sensors bent to radii of 18 mm, 24 mm and 30 mm. The measured low-momentum protons provided a testbed for investigating clustering behavior in high-energy loss events, where no significant impact of bending was observed on cluster size. Additionally, alignment strategies for bent detectors were evaluated using the distance of closest approach (DCA) and opening angle between scattered proton tracks as benchmarks. The achieved resolution matches expectations from simulations, confirming the suitability of bent MAPS sensors for future high-energy and nuclear physics applications.

We present constraints on the normal branch of the Dvali-Gabadadze-Porrati (nDGP) braneworld gravity model from the abundance of massive galaxy clusters. On scales below the nDGP crossover scale <inline-formula><mml:math><mml:msub><mml:mi>r</mml:mi><mml:mi>c</mml:mi></mml:msub></mml:math></inline-formula>, the nDGP model features an effective gravitylike fifth force that alters the growth of structure, leading to an enhancement of the halo mass function (HMF) on cluster scales. The enhanced cluster abundance allows for constraints on the nDGP model using cluster samples. We employ the South Pole Telescope (SPT) cluster sample, selected through the thermal Sunyaev-Zel'dovich effect with the SPT and with mass calibration using weak-lensing data from the Dark Energy Survey (DES) and the Hubble Space Telescope (HST). The cluster sample contains 1,005 clusters with redshifts <inline-formula><mml:math><mml:mn>0.25</mml:mn><mml:mo>&lt;</mml:mo><mml:mi>z</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>1.78</mml:mn></mml:math></inline-formula>, which are confirmed with the multicomponent matched filter algorithm using optical and near-infrared data. Weak-lensing data from DES and HST enable a robust mass measurement of the cluster sample. We use DES Year 3 data for 688 clusters with redshifts <inline-formula><mml:math><mml:mi>z</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.95</mml:mn></mml:math></inline-formula>, and HST data for 39 clusters with redshifts <inline-formula><mml:math><mml:mn>0.6</mml:mn><mml:mo>&lt;</mml:mo><mml:mi>z</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>1.7</mml:mn></mml:math></inline-formula>. We account for the enhancement in the HMF through a semi-analytic correction factor to the standard cosmology HMF derived from the spherical collapse model in the nDGP model. We then further calibrate this model using <inline-formula><mml:math><mml:mi>N</mml:mi></mml:math></inline-formula>-body simulations. In addition, for the first time, we analyze the primary CMB temperature and polarization anisotropy measurements from Planck PR4 within the nDGP model. We obtain a competitive constraint from the joint analysis of the SPT cluster abundance with the Planck PR4 data, and report an upper bound of <inline-formula><mml:math><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:msqrt><mml:mrow><mml:msub><mml:mi>H</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:msub><mml:mi>r</mml:mi><mml:mi>c</mml:mi></mml:msub></mml:mrow></mml:msqrt></mml:mrow><mml:mo>&lt;</mml:mo><mml:mn>1.41</mml:mn></mml:math></inline-formula> at 95% when assuming a cosmology with massive neutrinos.

Large-scale ionised outflows and nuclear obscuration are fundamental manifestations of AGN activity, yet direct observational evidence linking these phenomena remains scarce. We use the eROSITA Final Equatorial Depth Survey, among the largest uniform optical spectroscopic datasets of X-ray AGN, to investigate how AGN accretion rate affects ionised outflow kinematics and X-ray obscuration. Our sample comprises 2.840 AGN at z<0.82 with high-quality SDSS spectra. Through optical spectral fitting, we measure Eddington ratios ($λ_{Edd}$) and [O III] emission-line kinematics, tracing ionised outflows. In addition, we use archival eROSITA X-ray spectroscopy with X-ray stacking analyses to constrain the obscuration of the sample, $N_H$. We find that (1) 35% of the entire sample hosts a [O III] outflows ($W_{80}>600$ km/s), with the outflow incidence increasing with the AGN luminosity from 15% at $L_{AGN}<10^{44}$ erg/s up to 60% at $L_{AGN}>10^{46}$ erg/s; (2) the outflow incidence increases with Eddington ratio from 29% at $\log λ_{Edd}<-2.3$ to 50% at $\log λ_{Edd}>-1.7$; and (3) the AGN obscuration decreases with Eddington ratio, as sources with $\logλ_{Edd}>-1.7$ are 5 times less obscured than lower Eddington ratios AGN. In addition, we find that 1% of the sample populates the "forbidden region" of the $N_H-λ_{Edd}$ plane, where the outflow incidence peaks at 52%, consistent with a short-lived feedback phase. Notably, when matching the Eddington ratios samples in AGN luminosity, these trends vanish, implying that radiation pressure drives changes in outflow activity and obscuration, while the black hole mass does not play a significant role. Our results are in agreement with AGN radiative feedback scenarios, where the Eddington ratio regulates the AGN environment by driving powerful, galaxy-wide outflows and shaping the amount of circumnuclear material.

Gas motions provide insight into the dynamical history and physical processes within galaxy clusters. We investigate the kinematics of the ICM in the core of A496, a nearby, X-ray bright, strong cool-core cluster, using high-resolution data from the Resolve micro-calorimeter on board XRISM. We compared our measurement with other Resolve cluster core measurements and further compared our results with simulations and multiwavelength observations. From an optical redshift analysis, we found that the BCG is at rest with respect to the systemic velocity of the cluster. Despite multiple previously detected cold fronts and harboring a weak central radio source, Resolve observation shows that the core of A496 is dynamically quiescent. The ICM is moving with respect to the BCG with a LOS bulk velocity of $v_{\rm bulk}=-69_{-20}^{+25}\,\mathrm{km\,s}^{-1}$. We measured a turbulent velocity of $σ_{\rm v}=78_{-16}^{+18}\,\mathrm{km\,s}^{-1}$, the lowest value reported by the instrument on a cluster core to date. This value is in good agreement with the velocity dispersion of the H$α$ filament in the core, which may indicate condensation of ICM in the wake of the radio bubble. Assuming isotropic turbulence, the ICM turbulent velocity corresponds to a subsonic 3D Mach number of $0.15_{-0.03}^{+0.04}$ and a non-thermal pressure fraction of $1.2_{-0.5}^{+0.6}\,\%$. The mechanical AGN feedback from the recent activity of the central radio source is estimated to contribute about 7-9% to the ICM heating. The 1D LOS bulk velocity from the SLOW constrained Universe simulation is consistent with the measured value, suggesting that AGN feedback has a negligible contribution. The A496 SLOW turbulent velocity, as in other reported Resolve--simulation comparisons, is higher, but remains within $1.5σ$ uncertainty. A496 may represent one of the most quiescent sloshing cores observed so far.

We present an in-depth evaluation of the scalability and accuracy of the GPU porting of the N-body code for hydrodynamic cosmological simulations \og. While technical details of our GPU porting were presented in Ragagnin et al. (2020), in this work we focus on assessing the accuracy of the ported modules: the short range gravity integrator, the different components of the hydrodynamic solver, and the conjugate gradient solver for thermal conduction. We ran several tests that gradually increase the number of physical modules included: a gravity-only cosmological simulation; a hydrodynamical shock tube test; a non-radiative zoom-in simulation of a galaxy cluster in a cosmological box; and a full-physics zoom-in simulation of a galaxy in a cosmological box. Comparing the results obtained with the GPU implementation to those from the classical CPU version, we find excellent agreement across all tests, with small differences on very small scales. For the individual physical modules, we find a GPU chip-to-chip speedup ranging from $\approx3-5$. For more complex cosmological and hydrodynamical setups, where a large number of physical processes and overheads contribute to the total workload, the observed total chip-to-chip speedup (with the same number of nodes and CPUs per node) is $\approx2-3$. We ran our tests on four different supercomputers: Leonardo Booster (CINECA), MareNostrum-V (BSC), SuperMUC-NG2 (LRZ), and the CIP cluster of the Faculty of Physics at the Ludwig-Maximilians-Universität (LMU).

Parity-odd four-point correlation functions, or trispectra, of cosmic matter density fields provide a unique probe of fundamental symmetries in cosmology. Trispectra of primordial matter density fluctuations produced in the early universe are modified by the subsequent nonlinear structure formation. In this paper, we compute the nonlinear evolution of the parity-odd matter trispectrum to one-loop order, i.e., to third order in density fluctuations, within the framework of effective field theory of the large-scale structure of the universe. By analyzing the different terms in the perturbation series, we demonstrate the structure of infrared divergence cancellations, as required by the equivalence principle. We also derive the forms of the counterterms required to renormalize the ultraviolet divergences. Adopting a specific model for a primordial parity-odd trispectrum, we numerically compute the leading-order effects of nonlinear gravitational evolution and study its impact on baryonic acoustic oscillations within the signal. These calculations are essential for comparing the observed trispectra of nonlinear cosmic density fields with theoretical expectations.

Possible deformed neutron halos in silicon isotopes are investigated from both structure and reaction perspectives using the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) combined with the Glauber model. The experimental neutron separation energies of silicon isotopes are well reproduced by the DRHBc theory. Multiple halo criteria are examined, including the global ones based on root-mean-square radii and density profiles, as well as the microscopic ones based on single-particle orbitals and their spatial distributions. Calculations employing different density functionals and pairing strengths consistently indicate the emergence of p-wave neutron halos in ^43,45Si, accompanied by pronounced shape decoupling between the halo and the core. Moreover, the enhanced reaction cross sections and the narrow longitudinal momentum distributions of one-neutron removal residues provide additional evidence supporting the halo structures in ^43,45Si.

A highly successful approach to computing multi-loop scattering amplitudes is to reduce the Feynman integrals that arise to a smaller set of master integrals using integration-by-parts identities. These dimensionally-regulated master integrals can often be determined by solving a system of first-order partial differential equations with respect to masses and external invariants. The application of this method to large classes of problems became much more streamlined thanks to the introduction of $∊$-factorized canonical forms. There is increasing evidence that a canonical form can always be achieved, although the required transformation may involve transcendental functions related to the periods of geometrical objects such as elliptic curves or Calabi-Yau manifolds. Until now, obtaining numerical values for the master integrals in such cases has been difficult in practice, also due to the lack of closed-form expressions for the transcendental functions involved. We show that this obstruction is only apparent. Since the original master integrals satisfy linear differential equations with rational coefficients, any functions appearing in the transformation to a canonical basis satisfy, by construction, rational differential equations as well. By solving these auxiliary equations, the numerical evaluation of the canonical system reduces to solving an enlarged rational system. We implement this strategy in a C\texttt{++} package and apply it to the two-loop master integrals that enter di-jet and $γ$+jet hadro-production via a heavy-quark loop.

The production of a top-antitop quark pair in association with a $W$ boson constitutes one of the heaviest final states currently studied at the Large Hadron Collider (LHC) at CERN. Measurements of its production rate have consistently exceeded Standard Model predictions. Owing to the complexity of the two-loop amplitudes entering the double-virtual correction, next-to-next-to-leading-order (NNLO) QCD calculations for this process have so far employed dynamical approximations for the two-loop contribution. We present NNLO QCD predictions based, for the first time, on a direct computation of the required two-loop amplitudes in the generalised leading-colour limit.

We perform canonical quantization of general relativity, as an effective quantum field theory below the Planck scale, within the Becchi-Rouet-Stora-Tyutin (BRST)-invariant framework. We show that the promotion of constraints to dynamical equations of motion for auxiliary fields leads to the healthy Hamiltonian flow. In particular, we show that the classical properties of Einstein's gravity, such as vanishing Hamiltonian modulo boundary contribution, are realized merely as an expectation value in appropriate physical states. Most importantly, the physicality is shown not to entail trivial time evolution for correlation functions. In the present approach, we quantize the theory once and for all around the Minkowski vacuum and treat other would-be classical backgrounds as BRST-invariant coherent states. This is especially important for cosmological spacetimes as it uncovers features that are not visible in ordinary semiclassical treatment. The Poincaré invariance of the vacuum, essential for our quantization, provides strong motivation for spontaneously broken supersymmetry.

We compute resummed and matched predictions for jet angularities in hadronic Z+jet events, where the jet is initiated by a b-quark. The analysis is performed both with and without grooming the candidate jets using the SoftDrop algorithm. Mass effects are consistently included at both fixed-order and resummed levels. Our theoretical predictions also incorporate non-perturbative corrections from the underlying event and hadronization, implemented through parton-to-hadron transfer matrices extracted from dedicated Monte Carlo simulations with Sherpa. Finally, we compare results for b-jets with the ones from light-flavour jets, in order to quantify the impact of finite-mass effects.