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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

We present SBi3PCF, a simulation-based inference (SBI) framework for analysing a higher-order weak lensing statistic, the integrated 3-point correlation function (i3PCF). Our approach forward-models the cosmic shear field using the CosmoGridV1 suite of N-body simulations, including a comprehensive set of systematic effects such as intrinsic alignment, baryonic feedback, photometric redshift uncertainty, shear calibration bias, and shape noise. Using this, we have produced a set of DES Y3-like synthetic measurements for 2-point shear correlation functions ξ _± (2PCFs) and i3PCFs ζ _± across 6 cosmological and 11 systematic parameters. Having validated these measurements against theoretical predictions and thoroughly examined for potential systematic biases, we have found that the impact of source galaxy clustering and reduced shear on the i3PCF is negligible for Stage-III surveys. Furthermore, we have tested the Gaussianity assumption for the likelihood of our data vector and found that while the sampling distribution of the 2PCF can be well approximated by a Gaussian function, the likelihood of the combined 2PCF + i3PCF data vector including filter sizes of 90' and larger can deviate from this assumption. Our SBI pipeline employs masked autoregressive flows to perform neural likelihood estimation and is validated to give statistically accurate posterior estimates. On mock data, we find that including the i3PCF yields a substantial 63.8% median improvement in the figure of merit for Ω _m - σ ₈ - w ₀. These findings are consistent with previous works on the i3PCF and demonstrate that our SBI framework can achieve the accuracy and realism needed to analyse the i3PCF in wide-area weak lensing surveys.

We study Higgs-boson production in association with a top-quark pair (<inline-formula><mml:math><mml:mi>t</mml:mi><mml:mover><mml:mi>t</mml:mi><mml:mo>̄</mml:mo></mml:mover><mml:mi>H</mml:mi></mml:math></inline-formula>) at hadron colliders and present the first matching of next-to-next-to-leading order (NNLO) QCD corrections to parton showers using the MINNLO_PS method. For the two-loop amplitude, we employ two established approximations, based on the soft Higgs-boson and high-energy limits, respectively. For the first time, we also construct the latter in full colour and propose a pointwise combination of the two approximations across phase space. By assigning a conservative uncertainty estimate, which remains well below the perturbative uncertainties, we ensure robust and reliable differential predictions, explicitly validated at the one-loop level. Apart from the two-loop amplitude, all remaining ingredients of the MINNLO_PS calculation are included exactly. After thorough validation, we present a series of phenomenological results illustrating the impact of NNLO corrections and parton-shower effects. We consider fiducial predictions for the Higgs-boson decay into photons and include off-shell top-quark decays with tree-level spin correlations in both the dilepton and semileptonic channels. Our <inline-formula><mml:math><mml:mi>t</mml:mi><mml:mover><mml:mi>t</mml:mi><mml:mo>̄</mml:mo></mml:mover><mml:mi>H</mml:mi></mml:math></inline-formula> MINNLO_PS generator is publicly available within the Powheg framework.

The freedom to change Fock basis seems to ensure a minimum amount of locality in lattice theories in the following sense: If $\lbrace (\hat a_i^\dagger\,,\,\hat a_i)\rbrace$ for $i=1,\dots,n$ is a lattice of creation and annihilation operators and if a given Hamiltonian $\hat H$ induces highly non-local dynamics on that lattice, then it will usually be possible to change to a new set of operators $\lbrace (\hat b_i^\dagger\,,\,\hat b_i)\rbrace$ in terms of which the dynamics appear less non-local. We demonstrate this by turning a highly non-local random matrix model into a local, 1D lattice theory where particles can propagate in localized wave packets. More generally, we show that any Hamiltonian can be made to look like such a theory, with the lattice dispersion relation and the non-integrability of the theory depending on the spectrum of $\hat H$. We argue that our results are a step towards quantum mereology for fields.

So far, the majority of high-resolution spectroscopy studies on exoplanet atmospheres have focused on transiting planetary systems. Consequently, the atmospheres of non-transiting exoplanets remain poorly explored, and the potential of high-resolution spectroscopy for determining key planetary parameters beyond their atmospheric properties has not been fully exploited. We obtained high-resolution emission spectra of the non-transiting hot Jupiter 51 Peg b in the K band with VLT/CRIRES⁺ to study its atmospheric thermochemical and dynamical structure and derive additional planetary parameters from the Doppler shift of its spectral lines. Using the cross-correlation technique, we confirmed the spectral signature of H₂O in the planetary emission spectrum and a non-inverted atmospheric temperature profile. An indication was also found for the presence of atmospheric CO, although with a signal strength below the threshold for significant detection. The atmospheric chemical and thermal conditions were quantitatively constrained by use of a Bayesian retrieval framework, which yielded a high metallicity value (2.63_+0.93^−1.00 dex) suggestive of chemical quenching, a solar C/O ratio (0.54_−0.23^+0.18), and a temperature profile in the upper atmosphere in line with the expected planetary equilibrium temperature. Moreover, we measured an excess of spectral line broadening, which suggests the presence of atmospheric dynamics in the atmosphere of 51 Peg b. The planetary signal was recovered at an orbital semi-amplitude of 102.8_−9.1^+8.3 km s⁻¹, differing from previous high-resolution measurements. From the obtained orbital semi-amplitude, we further derived the surface gravity (3.15 ± 0.12 log cgs), mass (0.61_−0.05^+0.06 M_Jup), and orbital inclination (49.8_−5.7^+5.8 deg) of 51 Peg b. The mass and inclination values differ from those reported in earlier works. Overall, this study provides new constraints on the thermochemical and dynamical properties of 51 Peg b's atmosphere and demonstrates the potential of high-resolution emission spectroscopy for measuring parameters related to the planetary orbital motion.

We formulate the BCOV theory of deformations of complex structures as a pullback to the super moduli space of the worldline of a spinning particle. In this approach the appearance of a non-local kinetic term in the target space action has the same origin as the mismatch of pictures in the Ramond sector of super string field theory and is resolved by the same type of auxiliary fields in shifted pictures. The BV-extension is manifest in this description. A compensator for the holomorphic 3-form can be included by resorting to a description in the large Hilbert space.

Quantum simulators offer great potential for investigating dynamical properties of quantum field theories. However, preparing accurate nontrivial initial states for these simulations is challenging. Classical Euclidean-time Monte-Carlo methods provide a wealth of information about states of interest to quantum simulations. Thus, it is desirable to facilitate state preparation on quantum simulators using this information. To this end, we present a fully classical pipeline for generating efficient quantum circuits for preparing the ground state of an interacting scalar field theory in <inline-formula><mml:math><mml:mrow><mml:mn>1</mml:mn><mml:mo>+</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:math></inline-formula> dimensions. The first element of this pipeline is a variational Ansatz family based on the stellar hierarchy for bosonic quantum systems. The second element of this pipeline is the classical moment-optimization procedure that augments the standard variational energy minimization by penalizing deviations in selected sets of ground-state correlation functions (i.e., moments). The values of ground-state moments are sourced from classical Euclidean methods. The resulting states yield comparable ground-state energy estimates but exhibit distinct correlations and local non-Gaussianity. The third element of this pipeline is translating the moment-optimized Ansatz into an efficient quantum circuit with an asymptotic cost that is polynomial in system size. This work opens the way to systematically applying classically obtained knowledge of states to prepare accurate initial states in quantum field theories of interest in nature.

A system of classical interacting spins can develop collective instabilities, which, in the nonlinear regime, mimic the motion of a gyroscopic pendulum. Known as the flavor pendulum, this behavior appears among the collective modes of a dense neutrino plasma after a strong reduction of phase space through symmetry assumptions. It has been identified in homogeneous slow and fast flavor systems and, most recently, in single-wave solutions of the fast system. For the first time, we explain the reasons for its ubiquitous appearance. We show that a system of three classical spins must always be pendular, or only two in the presence of an external field. Furthermore, such a system always defines a continuum of vectors with time-independent length. If these are identified as interacting spins, they immediately lead to the continuum cases of slow and fast flavor pendula. As another new insight, any of these spins can be chosen as the pendulum, periodically exchanging flavor with the rest of the system.

Context. Extended low surface brightness emission has been identified in a number of protoplanetary disks, in tension with predictions of radial drift theory. Aims. We aim to investigate the nature and origin of faint, extended dust emission in the outer regions of protoplanetary disks, which we define as the "Halo", using multiwavelength (sub)millimeter continuum observations of three systems: Elias 2─24, IM Lup, and DM Tau. Methods. We utilized Atacama Large Millimeter Array (ALMA) observations of our targets to perform spectral energy distribution (SED) fitting with four dust compositions and derived radial profiles of their dust properties. Results. The halos identified in our sources account for 20─30% of the total flux density at (sub)millimeter wavelengths. In Elias 2-24, IM Lup, and DM Tau, we infer maximum grain sizes of 2 cm, <4 mm, and <9 mm, with the data best reproduced by porous amorphous carbon, compact amorphous carbon, and compact organic carbon compositions, respectively. Their total dust masses are 125₋₂₃⁺³⁴, 301₋₁₀₁⁺¹³⁹, and 829₋₃₇₈⁺⁷⁶¹ M_⊕, with corresponding halo masses of 33₋₆⁺¹², 103₋₁₇⁺²⁵, and 316₋₁₁₇⁺²⁰² M_⊕. The halos of IM Lup and DM Tau are dust rich with gas-to-dust mass ratios of 64 and 18, respectively. In all three disks, the dust drift and growth timescales are shorter than the disk ages, implying that the smooth outer disks should not exist. Conclusions. The halos in our sources hold relevant fractions of the total dust reservoir, demonstrating that they play an important role in alleviating the mass-budget problem. While the persistence of halos in IM Lup and DM Tau could be explained by late infall, the presence of centimeter-sized grains in Elias 2-24's halo suggests that unresolved dust traps also play a role.

Individual stars in the Milky Way (MW) and its satellites have been shown to trace galaxy stellar mass dependent sequences in the <inline-formula><tex-math>$\alpha$</tex-math></inline-formula>-abundance ([<inline-formula><tex-math>$\alpha$</tex-math></inline-formula>/Fe]) versus metallicity ([Fe/H]) plane. Testing the universality of such sequences has been elusive as deep absorption-line spectra required for [<inline-formula><tex-math>$\alpha$</tex-math></inline-formula>/Fe] and [Fe/H] measurements beyond the local group are mostly limited to integrated light from nearby, relatively high-mass, early-type galaxies. However, analogous to [<inline-formula><tex-math>$\alpha$</tex-math></inline-formula>/Fe] versus [Fe/H] for stars, we now have log(O/Ar) versus 12 + log(Ar/H) for the integrated nebular light of star-forming galaxies (SFGs). From Sloan-Digital Sky Survey observations of <inline-formula><tex-math>${\sim} 3000$</tex-math></inline-formula> SFGs out to z<inline-formula><tex-math>$\sim 0.3$</tex-math></inline-formula>, where we directly determined O & Ar abundances, we obtain for the first time the distribution of an ensemble of SFGs in the log(O/Ar) versus 12 + log(Ar/H) plane. We show that higher (<M<inline-formula><tex-math>$\rm _{*}$</tex-math></inline-formula>><inline-formula><tex-math>$\sim 2.6 \times 10^9\,$</tex-math></inline-formula>M<inline-formula><tex-math>$_{\odot }$</tex-math></inline-formula>) and lower mass (<M<inline-formula><tex-math>$\rm _{*}$</tex-math></inline-formula>><inline-formula><tex-math>$\sim 1.7 \times 10^7\,$</tex-math></inline-formula>M<inline-formula><tex-math>$_{\odot }$</tex-math></inline-formula>) SFGs clearly trace distinct mass dependent sequences in this plane. Such sequences are consistent with expectations from galaxy chemical evolution models of SFGs that are driven primarily by the interplay of core-collapse and Type Ia supernovae.

We show that $\sim$keV thermal solar neutrinos, arising from electroweak processes in the solar plasma, are kinematically accessible to large-volume dark matter direct detection experiments via electron ionization signatures. Using S2-only data from the XENONnT experiment, we place an upper limit on the thermal solar neutrino flux of $η\lesssim 1.2 \times 10^8$ times the standard model predicted value, while paired searches from XENONnT, LZ and PandaX give slightly weaker limits. The future XLZD experiment could improve these limits by orders of magnitude. While still far from a detection, this result establishes low-threshold direct detection experiments as a viable probe of the lowest-energy neutrino sources in astrophysics, with important implications for stellar physics and beyond.

The primordial black hole (PBH) mass function today develops a low-mass evaporation tail whose shape is universal with respect to the initial PBH mass distribution. This universality is fixed by the continuity equation and the Hawking mass-loss rate, but the tail is distorted if additional particle degrees of freedom participate in Hawking evaporation. Since this tail controls high-energy PBH photon emission, such distortions leave characteristic features in the gamma-ray spectrum. We show that these features provide a robust probe of new degrees of freedom, even for subdominant PBHs, within reach of future experiments and independent of visible-sector couplings or relic abundance.

Accretion outbursts have been observed in a variety of young stellar objects, but models of their dynamical evolution have been largely limited to axisymmetric models due to their computational cost. We investigate the azimuthal stability of accretion outbursts and the formation of planetesimals during these events. We performed high-resolution 2D, vertically integrated multifluid radiation-hydrodynamical simulations of the inner 10 au of protoplanetary disks with a dynamically growing dust population, including radiation transport and a realistic dust opacity model. Accretion outbursts are highly unstable to the Rossby-wave instability, with the burst front quickly diffusing into a large number of small-scale vortices that coalesce over time into a single, compact vortex and inducing azimuthal asymmetries. Vortices act as a source of vigorous turbulent diffusion, strongly suppressing planetesimal formation. Our results suggest that azimuthal asymmetries associated with accretion outbursts should be both common and detrimental to planet formation. Nevertheless, planetesimal formation will resume post-burst, as the burst-induced vortices eventually decay and the disk returns to a quiescent state featuring a pressure bump at ~1 au.

We present the first combined oscillation analysis of multiple atmospheric neutrino datasets, featuring data from Super-Kamiokande, IceCube-DeepCore, and KM3NeT/ORCA together with reactor data from Daya Bay. Such combinations have long been considered infeasible outside experimental collaborations; we demonstrate that a unified physics model can simultaneously describe all datasets with no significant parameter tensions. Fitting 839048 events across 1536 bins with 91 parameters, our combined analysis yields competitive measurements of the neutrino mixing parameters, and prefers the Normal over the Inverted Mass Ordering.

Many proposed self-interacting dark matter (SIDM) models give rise to radiative processes that can dissipate energy. Understanding their impact on astrophysical objects through simulations and comparing the results with observations may thus constrain SIDM models. In this work, we systematically investigate how dissipation alters the gravothermal evolution of isolated SIDM halos by independently varying dissipation and heat conduction and identify potential observational signatures. To this end, we present the first extension of the $N$-body formalism for frequent small-angle self-interactions (fSIDM) to include effective dissipation. We compare all results for isolated halos with a dissipative gravothermal fluid model to assess its validity and limitations. We find that dissipation qualitatively changes the gravothermal evolution of SIDM halos beyond simply accelerating collapse. Sufficiently strong central cooling can invert the usual role of heat conduction: the formation of an isothermal core is suppressed such that conduction remains directed inward throughout the evolution. Outer halo regions beyond the scale radius can cool efficiently rather than being heated by conduction, resulting in a larger region of mass infall and a less pronounced indentation between the core and the outer halo in the final density profile. These effects depend strongly on the cooling rate but are comparatively insensitive to the angular dependence of the self-interaction cross section. We further show that weakly dissipative self-interactions can explain the properties of the recently observed strong lens perturber in JVAS~B1938+666 with significantly shorter evolution times or, equivalently, smaller cross sections compared to the elastic case. Our results open a new route to connecting halo structure and recently reported compact objects to dark-sector microphysics.

Dark matter may emerge as a composite state of a dark sector which confines in a strongly first-order phase transition (PT). To avoid structure formation constraints on warm dark matter, the dark PT must occur above the keV scale. We investigate the cosmological signatures of this scenario, focusing on a keV- to MeV-scale PT. The stochastic nature of bubble nucleation sources curvature perturbations that can be constrained by various cosmological observations. Composite dark matter inherits the isocurvature perturbations generated during the PT and sources large-scale curvature perturbations. In contrast to a PT that reheats into dark radiation, the slower redshifting of dark matter enhances the infrared tail of the curvature perturbation upon horizon entry. The PT-induced perturbations compete with the suppression of the matter power spectrum due to the free-streaming of composite dark matter. We place limits on the PT strength and temperature from cosmic microwave background anisotropies, the Lyman-$α$ forest, and other probes of the small-scale matter power spectrum. In a minimal scenario where the relic density is determined by the PT parameters, this provides a concrete example of a dark matter model that is testable via measurements of cosmological perturbations -- even in the absence of a sizable nongravitational coupling to the visible sector.

We present a complete treatment of fifth-order renormalized galaxy bias at the one- and two-loop level in real space, including gradient corrections to deterministic bias operators at next-to-leading order. We then provide a complete computation of the two-loop power spectrum as well as the one-loop bispectrum and trispectrum of biased tracers, and demonstrate how to jointly model these statistics in a fully renormalized framework. These statistics also require stochastic renormalization of products of two, three or four operators at coincidence, which we include at leading order in gradients by means of an operator product expansion. We verify that all UV limits of loop integrals are absorbed by the counterterms we consider. Upon solving the resulting renormalization group equations, we find a pronounced scale-dependence of higher-gradient bias coefficients. Since our renormalization prescription is performed manifestly at the operator level, our results can also easily be extended to higher $N$-point functions, higher loop orders and field-level analyses.

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.

Remnant black holes (BHs) of massive stars ("light seeds") are a potential origin for supermassive black holes. We use magnetohydrodynamic simulations to study the formation and growth of light seeds in star-forming giant molecular clouds (GMCs) with masses 10⁵─10⁹ M_⊙, which evolve for ∼10─30 Myr and form compact star clusters, akin to high-redshift nuclear star clusters. In particular, the simulations resolve very massive stars (VMSs; 100─300 M_⊙), including their radiative and mechanical feedback, and model feedback-regulated accretion onto remnant BHs. We find that, even in compact GMCs capable of forming deep potential wells, the gas reservoir is expelled by sustained stellar feedback and is rapidly dispersed after supernova explosions. Remnant BH populations emerge ∼3 Myr after the starburst and concentrate at the cluster center (where ρ_BH ∼ 10⁴─10⁶ M_⊙ pc⁻³). With our fiducial subgrid BH accretion/feedback model, in situ BH accretion is inefficient for forming heavy seeds: some direct-collapse BHs briefly accrete at ∼(1─10) times the Eddington rate, but they reach only ∼400─500 M_⊙. A top-heavy initial mass function or natal kicks do not change this conclusion. Runaway accretion is only possible if the subgrid BH model allows a high fraction of Bondi inflow to reach the BH, in which case a few seeds can grow to ∼10⁶ M_⊙. We also discuss multiple-generation star formation that may be intrinsically correlated with remnant BH accretion.

Multiple mechanisms are proposed for the formation of giant molecular clouds (GMCs) ─ from gravitational free-fall caused by self-gravity, to stellar feedback-driven gas compression. Both the galactic environment and galaxy conditions could play an additional role in enhancing the formation via their gas surface density and star formation activity. In this paper, we make use of a catalog of 108 466 GMCs identified by F770W PHANGS-JWST imaging across 66 galaxies at a homogenized resolution of 30 pc. We measure the mass spectra in various galactic regions, whose power-law slopes vary from −1.2 to −2.0. We then estimate the formation time of each cloud using a model in which GMCs form by multiple feedback compression, and find that clouds with masses ≤10⁵ M_⊙ form in 20 Myr on average, and more massive clouds (∼10^{6 − 7} M_⊙) take up to 100 Myr. We also find that cloud formation proceeds most rapidly in the central regions of galaxies, with formation timescales that are typically shorter by ∼5 − 10 Myr compared to galactic disks. This effect is most pronounced in central molecular zones with enhanced star formation. This highlights the role of intense massive star formation, high molecular gas surface densities, and strong supersonic compressions in accelerating cloud formation. However, star formation is generally inefficient as the cloud lifetime is ∼1% of the molecular depletion time. The formation time of clouds is ∼0.1 dex longer than the free-fall time. This hints that magnetic fields, stellar feedback, or other mechanisms may prolong their formation instead of immediate free-fall collapse. This indicates a longevity of massive GMCs. The GMC ages also show only limited variation with galactocentric radius in both spiral and disk galaxies, suggesting that cloud formation proceeds similarly in these galaxy types.

We present gas-phase radial metallicity profiles for 20 main-sequence galaxies at 4 < z < 6 primarily based on JWST NIRSpec IFU observations obtained as part of the JWST-ALPINE-CRISTAL programme. Our study aims to connect the metallicity gradients of these galaxies with their kinematic properties from [C II] 158 μm ALMA observations. We mapped the radial profiles of oxygen abundance using the strong-line method, leveraging the rich set of rest-frame optical emission lines. Linear fits to the annular-binned radial profiles show that, on average, the metallicity gradients are slightly positive with a median of +0.039 ± 0.010 dex kpc⁻¹. However, only three galaxies show a gradient > 0.05 dex kpc⁻¹ at 1σ, and none have a significant negative gradient. There are no substantial systematic offsets in gradients when using different line diagnostics. We investigated the correlation between the metallicity gradients and the intrinsic gas velocity dispersion σ₀ as well as the V_rot/σ₀ ratio of the disks. Combining our sample with mass-matched literature samples at 3 ≲ z ≲ 7, we found a negative shallow correlation between V_rot/σ₀ and the metallicity gradients, but no strong relationships with σ₀. As V_rot/σ₀ increases towards later cosmic times, the observed negative trend with V_rot/σ₀ is consistent with the overall cosmic evolution of metallicity gradients from high to low redshifts. This suggests that disk maturity plays a crucial role in shaping the radial metallicity gradients. We do not find the metallicity gradients of disk galaxies to be significantly different from non-disk galaxies, which could be attributed to the frequent accretion events that took place in these gas-rich systems. Additionally, we find no strong dependence of metallicity gradients on stellar mass and only a marginal positive dependence on specific star-formation rate. Our study extends the efforts to connect the internal kinematics of galaxies with their gas-phase chemical enrichment at kiloparsec scales from cosmic noon to z > 4.

We present the discovery of SN 2025mkn, a gravitationally lensed Type II supernova. First detected as a blue transient in Zwicky Transient Facility (ZTF), 0<inline-formula> <mml:math><mml:mover><mml:mrow><mml:mi>.</mml:mi></mml:mrow><mml:mrow><mml:mi>″</mml:mi></mml:mrow></mml:mover></mml:math> </inline-formula>83 from a z = 0.42 elliptical galaxy, the follow-up SNIFS/UH2.2 m and LRIS/Keck spectra revealed absorption lines at z = 1.371. Later JWST NIRCam imaging shows that the bright transient is a close pair of point sources separated by <inline-formula> <mml:math><mml:mo>∼</mml:mo><mml:mn>0</mml:mn><mml:mover><mml:mrow><mml:mi>.</mml:mi></mml:mrow><mml:mrow><mml:mi>″</mml:mi></mml:mrow></mml:mover><mml:mn>07</mml:mn></mml:math> </inline-formula>, and a 30 times fainter counterimage opposite the lens, for which NIRSpec reveals strong Hα emission also at z = 1.371. The lightcurves and spectra are consistent with the Type II supernova source being magnified ≳100 times, with ∼250 required to reconcile its luminosity with that of nearby events such as SN 2023ixf. Lens models are consistent with such high magnifications, and always show that the faint image arrived first (undetected in earlier ZTF imaging), consistent with the later spectral phase of this fainter image. A fourth image is also predicted and possibly detected in the NIRSpec data. Lightcurve-based time-delay measurements are not possible due to the first image being the faintest; however, the resolved NIRSpec spectra offer a future opportunity for time-delay cosmography through supernova phase measurements.

Context. Mrk 421 displayed its highest flux state ever observed in February 2010 with very high tera-electronvolt fluxes and interesting cross-band correlations and a spectral energy distribution (SED) evolution not entirely consistent with the standard single zone leptonic synchrotron self-Compton model. The source was already in a high state in January 2010 and displayed strong variability in the days preceding the highest state. We study the temporal evolution of the spectra in January to extract information about the particle dynamics and the physical properties of the emission region. Aims. We build on the temporal variability and correlations studied in our previous work and attempt to improve the SED model fits with a physics-oriented approach. Methods. The The multi-wavelength data were processed and the SEDs were fit using JetSeT. The SED evolution and cross-band correlations were modelled using leptonic log-parabola with a low energy power-law branch (LPPL) and pile-up distributions that are predicted in a stochastic acceleration scenario. A simplified temporal evolution model was developed and fitted to the SEDs and the resulting trends and phenomenology were characterised in the context of the theoretical literature. An expanding emission region model was also tested. Results. We find the spectral variability to be in good agreement with stochastic acceleration. Our analysis suggests that the standard LPPL distribution develops a Maxwellian pile-up component at the transition from the acceleration-dominated to the cooling-dominated phase on 3 nights in the dataset, as is also hinted at by the very-high energy and X-ray light curves. The resulting phenomenology of our sequential snapshot evolution SED model agrees well with theoretical and numerical simulation studies on temporal evolution using the diffusion equation approach. Curvature in the electron energy distribution (EED) anti-correlates with the synchrotron peak frequency, as was expected from stochastic acceleration. We tested an alternate model with expanding emission region and the resulting EED spectral index, expansion velocity, and magnetic field index agree with prior works using datasets collected in different flaring states of the source.

One of the key limitations of large-scale structure surveys of the current and future generation, such as Euclid, LSST-Rubin or Roman, is the influence of feedback processes on the distribution of matter in the Universe. This effect, called baryonic feedback, modifies the matter power spectrum on non-linear scales much stronger than any cosmological parameter of interest. Constraining these modifications is therefore key to unlocking the full potential of the upcoming surveys, and we propose to do so with the help of Fast Radio Bursts (FRBs). FRBs are short, astrophysical radio transients of extragalactic origin. Their burst signal is dispersed by the free electrons in the large-scale structure, leading to delayed arrival times at different frequencies characterised by the dispersion measure (DM). Since the dispersion measure is sensitive to the integrated line-of-sight electron density, it is a direct probe of the baryonic content of the Universe. We investigate how FRBs can break the degeneracies between cosmological and feedback parameters by correlating the observed Dispersion Measure with the weak gravitational lensing signal of a Euclid-like survey. In particular, we use a simple one-parameter model controlling baryonic feedback, but we expect similar findings for more complex models. Within this model, we find that ∼ 5 × 10⁴ FRBs are sufficient to constrain the baryonic feedback significantly better than cosmic shear alone, tightening the constraints considerably (roughly by a factor of five). We also expect a 1.5-fold improvement in the sum of neutrino masses.

We present imaging and spectroscopic observations of supernova SN 2025wny, associated with the lens candidate PS1 J0716+3821. Photometric monitoring from the Lulin and Maidanak observatories confirms multiple point-like images, consistent with SN 2025wny being strongly lensed by two foreground galaxies. Optical spectroscopy of the brightest image with the Nordic Optical Telescope and the University of Hawaii 88-inch Telescope allowed us to determine the redshift to be z_SN = 2.008 ± 0.001, based on narrow absorption lines originating in the interstellar medium of the supernova host galaxy. At this redshift, SN 2025wny shows a very high rest-frame UV flux and broad spectral features even weeks after the explosion, which is consistent with superluminous supernovae of Type I. We find a high ejecta temperature and depressed spectral lines compared to other similar objects. We also measured, for the first time, the redshift of the fainter of the two lens galaxies (the 'perturber') to be z_p = 0.375 ± 0.001, which is fully consistent with the DESI spectroscopic redshift of the main deflector at z_d = 0.3754. Thus, SN 2025wny represents the first confirmed galaxy-scale strongly lensed supernova with time delays likely in the range of days to weeks, as judged from the image separations. This makes SN 2025wny suitable for cosmography, offering a promising new system for independent measurements of the Hubble constant. Following a tradition in the field of strongly lensed supernovae, we give SN 2025wny the nickname SN Winny.

Supermassive black holes and their host galaxies grow together over time, producing correlations between the black hole mass and various galaxy properties. Determining the evolution of these correlations requires precise measurements of the masses of distant black holes. We observed the gravitationally lensed quiescent galaxy MRG-M0138 at redshift 1.95 using James Webb Space Telescope integral field spectroscopy to spatially resolve the kinematics of stars within the black hole's sphere of influence. By using a foreground lens model and fitting stellar dynamical models, we determined the mass of its inactive black hole to be M_∙ = 6.0^+2.1_-1.7 × 10⁹ solar masses. Comparing this measurement to local galaxies, we found that M_∙ is higher than expected given the galaxy's bulge mass but consistent with the correlation of M_∙ with stellar velocity dispersion.

Unraveling the growth of supermassive black holes and their connection to host galaxies requires disentangling the active galactic nuclei (AGN) emission from that of the stellar populations in which they are embedded. When an AGN spectrum is observed at different activity phases, if the spectral decomposition properly recognizes the nuclear and stellar components, key physical properties ─ such as black hole mass, stellar mass, and stellar velocity dispersion ─ should remain consistent. These quantities are essential for scaling relations used to study the co-evolution of black holes and galaxies. We present a novel optical spectral-fitting approach that combines pPXF and PyQSOFit to robustly decompose spectra into stellar and AGN components. We applied this technique to three Sloan Digital Sky Survey samples with repeated optical spectra of the same objects at z ≤ 0.55: 32 changing-look AGN in bright and dim states and 15 quasars and 15 galaxies with three single-epoch and one stacked spectrum each and spanning a range of signal-to-noise ratios. For comparison with the literature, we also used SDSS spectra and photometric data from AGN in the eFEDS field as well as Gemini and VLT observations of some of our selected changing-look AGN. This analysis enabled us to evaluate the reliability of stellar mass, velocity dispersion, and black hole mass measurements, especially in relation to the AGN-to-total continuum contribution (f_AGN). For host-derived properties, especially when f_AGN < 0.8, our method yields consistent results. For single-epoch black hole mass estimates from Hα and Hβ, a 3σ confidence in the broad-line flux and full width at half maximum provides effective criteria for selecting reliable measurements. The reliability of our measurements was confirmed by their alignment with previously established scaling relations. Many changing-look AGN in our sample exhibit "breathing" broad-line regions, as determined from Hα analysis, while some deviate significantly, suggesting non-virialized systems across the spectral transition.

Compact protoplanetary discs are becoming increasingly prominent in observations. Their dispersal pathways may differ substantially from those of extended discs. We aim to quantify the role of the disc outer radius in internal photoevaporation, provide a simple scaling relation for compact discs, and test whether the resulting evolutionary tracks reproduce the observed inside-out clearing of young stellar populations. We performed radiation-hydrodynamic simulations of X-ray-driven photoevaporation for discs with different outer radii, and derived the dependence of the total mass-loss rate on the cut-off radius. We find that the surface mass-loss profiles are nearly independent of disc size, but their integrated wind rates are reduced according to the cumulative mass-loss rate distribution. We incorporated this scaling into disc population synthesis models. When the internal photoevaporation is applied only up to the cut-off radius compact discs evolve via inside-out clearing consistent with observational diagnostics, while when the cut-off radius is not considered, the disc spreading is hindered and the disc dispersal proceeds from the outside-in. The introduction of mild external photoevaporation present in nearby star-forming regions cannot prevent the disc spreading when the cut-off radius prescription is included, but it can much better explain the evolution of disc radii as a function of time. Disc dispersal prescriptions must include the dependence on disc cut-off radius to capture the evolution of compact discs. The proposed scaling provides a simple, physically motivated correction that better predicts the growing observational evidence for compact discs and inside-out dispersal.

We present a cosmological zoom-in simulation targeting the high-redshift compact progenitor phase of massive galaxies, with the most massive galaxy reaching a stellar mass of <inline-formula><tex-math>$M_{\star }=8.5\times 10^{10} \ {\rm M}_{\odot }$</tex-math></inline-formula> at <inline-formula><tex-math>$z=5$</tex-math></inline-formula>. The dynamics of supermassive black holes (SMBHs) is modelled from seeding down to their coalescence at sub-parsec scales due to gravitational wave (GW) emission by utilizing a new version of the KETJU code, which combines regularized integration of sufficiently massive SMBHs with a dynamical friction subgrid model for lower mass SMBHs. All nine massive galaxies included in this study go through a gas-dominated phase of early compaction in the redshift range of <inline-formula><tex-math>$z\sim 7{}\text{-}9$</tex-math></inline-formula>, starting at stellar masses of <inline-formula><tex-math>$M_\star \gtrsim 10^8\ \mathrm{M}_\odot$</tex-math></inline-formula> and ending at a few times <inline-formula><tex-math>$M_{\star }\sim 10^9\ \mathrm{M}_\odot$</tex-math></inline-formula>. The sizes, masses, and broad-band fluxes of these compact systems are in general agreement with the population of systems observed with James Webb Space Telescope known as 'Little Red Dots'. In the compact phase, the stellar and SMBH masses grow rapidly, leading to a sharp decline in the central gas fractions. The outer regions, however, remain relatively gas-rich, leading to subsequent off-centre star formation and size growth. Due to the very high central stellar densities (<inline-formula><tex-math>$\rho _{\star }\gtrsim 10^{13}\, \mathrm{M_\odot\,kpc^{-3}}$</tex-math></inline-formula>), the SMBHs merge rapidly, typically just <inline-formula><tex-math>${\sim} 4{\text{-}}35\ \mathrm{Myr}$</tex-math></inline-formula> after the SMBH binaries have become bound. Combining KETJU with the phenomenological PhenomD model resolves the complete evolution of the GW emission from SMBH binaries through the pulsar timing array frequency waveband up to the final few orbits that produce GWs observable with the future Laser Interferometer Space Antenna mission.

Baryonic feedback fundamentally alters the total matter distribution on small to intermediate cosmological scales, posing a significant challenge for contemporary cosmological analyses. Direct tracers of the baryon distribution are therefore key for unearthing cosmological information buried under astrophysical effects. Fast Radio Bursts (FRBs) have emerged as a novel and direct probe of baryons, tracing the integrated ionised electron density along the line of sight, quantified by the dispersion measure (DM). The scatter of the DM as a function of redshift provides insight into the lumpiness of the electron distribution and, consequently, baryonic feedback processes. Using a model calibrated to the BAHAMAS hydrodynamic simulation suite, we forward-model the statistical properties of the DM as a function of redshift. Applying this model to approximately 100 localised FRBs, we robustly constrain the governing feedback parameter, at 68% confidence. Our findings represent the first measurement of baryonic feedback using FRBs, relating to power spectrum suppression and demonstrating a strong rejection of no-feedback scenarios at greater than 99.7% confidence ( 3σ), depending on the FRB sample. We find that FRBs prefer fairly strong feedback, consistent with other measurements of the baryon distribution, as inferred from the thermal and kinetic Sunyaev-Zel'dovich effects. The results are robust against sightline correlations and modelling assumptions. We emphasise the importance of accurate calibration of the host galaxy and Milky Way contributions to the DM. Furthermore, we discuss implications for future FRB surveys and necessary improvements to current models to ensure accurate fitting of upcoming data, particularly that from low-redshift FRBs.

Context. Galaxy clusters are the largest gravitationally bound structures in the Universe, serving as key laboratories for studying structure formation and evolution. The intracluster medium (ICM), composed of hot plasma, dominates their baryonic content and is primarily observable in X-rays. The thermodynamic properties of the ICM, including pressure, temperature, entropy, and electron density, provide crucial insights into the physical processes shaping these systems, from accretion and mergers to radiative cooling and feedback. Aims. We investigate the thermodynamic properties of galaxy clusters within the Simulating the LOcal Web (SLOW) constrained simulations, which reproduce the observed large-scale structure of the local Universe. Our goal is to assess the reliability of these simulations in reproducing the observed ICM profiles of individual clusters and to explore the connection between cluster formation history and core classification. Methods. We extracted three-dimensional thermodynamic profiles from the simulations, assuming spherical symmetry. These profiles are directly compared to deprojected X-ray and Sunyaev─Zel'dovich (SZ) observational data for a sample of local clusters, including systems classified as solid cool-core (SCC), weakly cool-core (WCC), and non-cool-core (NCC) systems. Additionally, we analyze the mass assembly history of the simulated cluster counterparts to establish links between their formation pathways and present-day ICM properties. Results. The simulations successfully reproduce the global thermodynamic profiles of observed clusters, particularly in the pressure and temperature distributions within r₅₀₀. The electron density and entropy profiles of cool-core (CC) clusters show some discrepancies, likely due to resolution limitations and the treatment of feedback processes. We find that CC clusters typically assemble their mass earlier, while NCC clusters experience more extended merger-driven growth. WCC clusters exhibit intermediate accretion histories, suggesting an evolutionary transition between CC and NCC states. Conclusions. Our results demonstrate that constrained simulations provide a powerful tool for linking cluster formation history to present-day ICM properties. While the large-scale structure and bulk thermodynamic profiles are well reproduced, further refinements in subgrid physics, as well as higher resolution, are needed to improve the agreement in cluster core regions. These findings offer new insights into the evolution of cluster cores and their observational classification, reinforcing the importance of constrained simulations for studying galaxy clusters in a cosmological context.

Baryonic feedback redistributes matter on small to mid cosmological scales, ultimately limiting inferences from Stage IV galaxy surveys. Direct baryon tracers are crucial for recovering cosmological signals masked by astrophysical effects, and vice versa: galaxy formation and other astrophysical processes must be interpreted cosmologically. Fast radio bursts (FRBs) serve as such tracers: their dispersion measure (DM) records the line-of-sight integrated ionised electron density. The Square Kilometre Array (SKA) will be the only radio telescope capable of detecting many FRBs in the southern hemisphere, significantly enhancing synergy with surveys such as Rubin Observatory. This chapter completes the FRB trilogy by forecasting the SKA's potential to constrain the baryon distribution from cosmological to galactic scales and across cosmic time. We tackle this question by investigating the DM scatter as a function of redshift. We also study the statistical properties of the DM field and its cross-correlation with Stage IV galaxy surveys. Our focus is on cosmic shear and galaxy clustering. This shows that the SKA can play a crucial role in pinpointing baryonic feedback models, thereby greatly enhancing the cosmological constraining power of Stage IV galaxy surveys. Furthermore, we show that the SKA will be able to measure the properties of the circumgalactic medium using the scattering timescale of FRBs. Lastly, the large redshift range of FRB detections with the SKA can improve our understanding of the epoch of reionisation. It may also clarify the mechanism behind FRBs.

Fast radio bursts (FRBs) are brief, coherent radio pulses of extragalactic origin. They typically last from microseconds to milliseconds and have energies large enough to be visible over cosmological distances. Since FRBs interact with free electrons along their paths, the original burst is dispersed (Dispersion Measure, DM) and broadened (scattering). Furthermore, the burst's polarization is altered by Faraday rotation. Consequently, FRBs are excellent probes of the cosmological distribution of baryons, the expansion of the Universe, magnetic fields, and minuscule effects of fundamental physics that accumulate over vast distances. This chapter is the second of a trilogy of FRB chapters and discusses FRBs as a standalone probe. We first introduce the foundation of FRB observables related to those questions. Next, we lay the groundwork for forecasting SKA's potential by describing the method to simulate the expected FRB population observable with the SKA. These synthetic FRB catalogues are then used to investigate the SKA's potential to probe the Universe's expansion rate and fundamental physics, such as the equivalence principle and the existence of massive photons. Furthermore, we investigate the possibility of tracing cosmic magnetic fields and investigating different dark matter candidates.

The unprecedented statistical power of galaxy cluster catalogs from the SRG (Spectrum Roentgen Gamma)/eROSITA All-Sky Survey provides a unique opportunity to place stringent constraints on cosmological models through measurements of structure growth. Fully exploiting the potential of these large X-ray-selected cluster samples, however, requires robust statistical frameworks that accurately connect observable quantities to the underlying cosmological parameters. We develop and implement a simulation-based inference (SBI) framework for cosmological parameter estimation using a realistic mock-generation pipeline calibrated on eRASS1 simulations. Synthetic galaxy cluster catalogs are propagated through the survey selection function to produce mock eRASS1 observations that reproduce the data's statistical properties. At the core of the method lies a set-based neural network (GNN on sets) that encodes information from individual clusters and is coupled to a masked autoregressive flow for flexible posterior density estimation. This approach enables the use of the full cluster-level information content without compressing the observables into binned summary statistics. Our framework recovers the input cosmologies within the inferred uncertainties, and passes calibration tests, demonstrating robustness in the presence of realistic survey effects. We obtain mock constraints of 11.5% on $Ω_m$ and 4.4% on $σ_8$ averaged over a suite of simulated cluster catalogs matching the effective sample size of the data set (3,259 clusters). We achieve a precision comparable to that obtained with traditional MCMC analyses based on substantially larger cluster samples. The framework is readily extensible to more complex forward models and additional observables. This work highlights the potential of SBI methods for next-generation large-scale structure analyses with forthcoming X-ray cluster surveys.

Context. The archetypal blazar 3C 279 has a prominent relativistic jet and strong broadband variability across the electromagnetic spectrum. In April 2017, the Event Horizon Telescope (EHT) observed 3C 279 with an unprecedented angular resolution of about 20 μas, accompanied by one of the most extensive quasi-simultaneous multiwavelength (MWL) campaigns ever conducted, spanning from radio to TeV γ-ray energies.Aims. Taking advantage of this comprehensive MWL dataset, we investigated the physical processes governing 3C 279, with a particular focus on the formation, collimation, and acceleration of its relativistic jet and on the origin of its high-energy emission, including the underlying particle-acceleration mechanisms.Methods. We analyzed individual observations and multiband light curves. We also constructed a new quasi-simultaneous spectral energy distribution covering frequencies from the radio band to very high-energy (VHE) γ rays. We further performed a phenomenological modeling using the turbulent extreme multi-zone (TEMZ) model to constrain the fundamental physical properties of the source.Results. The EHT observations reveal a clear flux increase in the innermost core between April 5 and 11, 2017. Over a broader time span, radio observations at longer wavelengths reveal concurrent enhancements in the core flux and polarization around mid-April, coinciding with the ejection of a superluminal knot moving at (25 ± 2)c. Record UV–optical flares with strong polarization variability occurred in late March, followed by high-energy γ-ray activity that declined before the end of the EHT observing period. During this time, the source remained in a low X-ray state and exhibited no detectable VHE emission.Conclusions. The results of the TEMZ modeling indicate that the broadband spectrum and variability of 3C 279 might be explained with a jet scenario in which turbulent plasma cells are compressed by a stationary conical shock. Nonetheless, alternative interpretations, such as magnetic reconnection or a moving shock-in-jet event, remain possible. This coordinated MWL campaign advances our understanding of the origin of the jet and γ-ray emission in the blazar 3C 279, and it also provides a comprehensive publicly available dataset that will serve as a valuable reference for future studies.Key words: galaxies: active / galaxies: jets / gamma rays: galaxies / quasars: individual: 3C 279★ First author and project coordinator: giacomo.principe@inaf.itThis email address is being protected from spambots. You need JavaScript enabled to view it. .★★★★ For questions concerning H.E.S.S. results.

One of the current challenges in observational cosmology is obtaining high-precision polarisation maps of the CMB to measure primordial $B$-modes and constrain the tensor-to-scalar ratio ($r$). The weakness of this signal compared to foregrounds and $E$-to-$B$ leakage makes this task particularly challenging, requiring large detector arrays operating at multiple frequencies and extremely precise calibration. We present a cross-calibration algorithm to determine relative calibration of detectors within the same frequency band of a CMB experiment. The method iteratively compares single-detector maps with band-averaged maps and can be applied to any calibration parameter that can be observed and corrected at the map level, relaxing pre-flight calibration requirements and enabling post-processing validation. We validate the pipeline by calibrating the polarisation angle of simulated LiteBIRD observations, including both random detector miscalibration and wafer-level rotations. The algorithm converges to correct values with arcminute precision. Finally, we propagate residual calibration uncertainties through component separation and tensor-to-scalar ratio estimation pipelines using both parametric (FgBuster) and blind (HILC) methods. The induced bias on $r$ remains well below the LiteBIRD systematics budget of $δr < 6.5\times10^{-6}$, demonstrating that the method is suitable for next-generation CMB experiments.

We summarize the fabrication and optical characterization of small-format (2 x 2 x 2 cm$^3$) cast organic scintillators based on Eljen EJ-290 resin, doped with barium sulfate (BaSO$_4$) powder at mass fractions from 0 % to 5 %. The goal is to tune the scattering length of the scintillator largely independently of its absorption and light output, so that scintillation light is localized on a controllable spatial scale matched to the fiber pitch of wavelength-shifting (WLS) fiber read-out. The scattering length is found to decrease from 6.05(8) cm at 1 % to 0.83(1) cm at 5 %, while the absolute light yield falls by only about 15 %. These results are a first proof of concept that the photon-transport scale in cast scintillators can be engineered on purpose, enabling position-sensitive scintillator tiles for fiber-readout sampling calorimeters and large-area muon trackers. Full details are given in the accompanying paper.

We investigate the nature of the unassociated sources detected by the Fermi-LAT close (∣b∣ < 10°) to the Galactic plane, representing 16% of all sources in the 4FGL-DR4 catalog. The bulk of these sources (referred to as soft Galactic unassociated sources, SGUs) exhibit properties not found in known classes of gamma-ray emitters, as confirmed by a machine-learning classification approach. In particular, these properties include a steep, curved spectrum peaking below 1 GeV and a specific Galactic-latitude distribution with both a narrow and a broad component (dubbed the spike and the shoulder, respectively). Some source clusters are highlighted. New plausible source classes are explored, but only star-forming regions are found to account for a significant fraction (at most 10%) of the unassociated population. A thorough search for counterparts to the 175 brightest sources brings out a number of plausible counterparts but does not reveal clues about the nature of the whole population. We investigate the possibility that SGUs originate from mismodeled clumps of diffuse emission. Using Monte Carlo simulations, the SGU spectra can be reproduced in this scenario under an ad hoc condition concerning the clump spatial extension. The possible connection between the SGUs and gas not accounted for by the $^{12}$CO tracer is explored using the $^{13}$CO MOPRA data but leads to inconclusive results. The origin of SGUs being related to diffuse emission remains plausible. However, a scenario whereby SGUs represent a new class of gamma-ray emitters cannot be fully excluded.

We present cosmological constraints from the Dark Energy Survey Year 3 (DES Y3) weak lensing data using hierarchical hybrid statistics within a Bayesian simulation-based inference framework that is based on the Gower Street simulations. To maximize the precision of the inference, we have developed a new, information-theory based, data compression of the weak lensing maps to just seven highly informative summary statistics. The hybrid scheme exploits the high information content of the power spectrum, compressing both the power spectrum and neural-based summaries that are designed to extract further information. Our simulation-based approach enables principled forward modelling of all major sources of systematic uncertainty and survey properties into realistic mock observations, including the survey mask, photometric redshift uncertainties, intrinsic galaxy alignments, multiplicative shear calibration bias, source galaxy clustering, non-Gaussian shape noise, and non-linear structure formation. The summary statistics are then used in a Bayesian simulation-based inference pipeline. The inference is validated through coverage tests and checks for robustness against baryonic feedback. Assuming a $w$CDM cosmology, our analysis yields $S_8 = 0.808 \pm 0.017$, $Ω_{\rm m} = 0.325 \pm 0.024$, and $w < -0.766$ (marginalized posterior 68 per cent credible intervals). This rigorous combination of information theory, physics- and neural network-based extreme data compression, and principled Bayesian analysis improves the figure of merit for $(Ω_{\rm m}, S_8, w)$ by 60 per cent over the previous state-of-the-art, and by almost a factor of 3 over two-point analyses of the same data. They are the most precise joint constraints on $(Ω_{\rm m}, S_8, w)$ from weak gravitational lensing data alone of any survey to date. We intend to apply this analysis to the more recent DES Y6 data.

We apply a machine-learning-based inference method that exploits the joint Doppler parameter-column density (b-NHI) distribution from Lya forest decomposition to measure the thermal and ionization state of the intergalactic medium (IGM) in four redshift bins spanning z = 0.06 to 0.48, using 82 archival quasar spectra from the Cosmic Origin Spectrograph (COS) on board Hubble Space Telescope (HST). Our results show that the low-z IGM (z < 0.5) is extremely hot and nearly isothermal, with log(T0/K) = 4.45 (+0.08 / -0.12) [T0 = 28183 (+5700 / -6804) K] and gamma = 1.06 (+0.13 / -0.09) at z = 0.1. This temperature lies approx 7sigma (and 7 times) above the canonical prediction (log T0 approx 3.60, i.e. T0 ~ 4000 K, with gamma ~ 1.6 at z = 0), where the IGM is expected to have cooled long after He II reionization. We also measure the hydrogen photoionization rate to be log (GammaHI/s^-1) = -13.70 (+0.10 / -0.08) at z = 0.1, which is about approx 4sigma below the range predicted by current UV-background synthesis models (approx -13.3). To investigate the discrepancy between these high temperatures and theoretical models, we assess the impact of small-scale turbulence. By exploring a parameter grid in turbulent velocity (vtur) and GammaHI, we find that a standard IGM thermal and ionization state combined with unresolved turbulence of vtur simeq 15 km s^-1 can successfully reproduce the observed line widths at z = 0.1. Comparisons with high-resolution Space Telescope Imaging Spectrograph (STIS) expanded data indicate that the observed line widths are unlikely to be caused by instrumental resolution effects. Our findings suggest that either new heating mechanisms or unresolved turbulence are required to explain the unexpectedly broad Lya lines observed in the low-z IGM.

Identification and/or association of unidentified γ-ray sources with lower-energy counterparts represents a key challenge in modern astronomy, due to the relatively large positional uncertainty provided by γ-ray detectors. We selected unidentified Fermi objects (UFOs) positionally compatible with hard X-ray sources in the latest Palermo Swift-BAT hard X-ray Catalog and in the SRG/ART-XC all-sky X-ray survey Catalog, to identify lower-energy sources and possibly associate them to the UFOs. We found 17 UFOs with overlapping hard X-ray sources. We then collected soft X-ray data from Swift-XRT, Chandra-ACIS, XMM-Newton-EPIC, and eROSITA, identified 16 soft X-ray counterparts to the hard X-ray sources, and associate 15 with known astronomical objects, classified as: blazars/blazar candidates (two sources), Seyfert galaxies (five sources), X-ray binaries (two sources), generic X-ray sources (one source), cataclysmic variables (CVs; two sources), and variable stars (three sources). Blazars and Seyfert galaxies are likely lower-energy counterparts to the UFOs, since their mid-IR colors and broadband spectral energy distributions suggest significant jetted, nonthermal emission. X-ray binaries can be potential lower-energy counterparts to the UFOs, since this class of sources has been already observed to emit γ-rays. The generic X-ray source has been proposed as a pulsar candidate, and we therefore suggest that it can be the lower-energy counterpart to the UFO. CVs have been suggested as potential γ-ray emitters, so, if confirmed, the two sources classified as CVs would represent the first γ-ray emitting sources of this kind. Finally, we consider the association of the three variable stars with the UFOs unlikely.

The identification of ultra-high energy cosmic ray sources is one of the open challenges of high-energy astrophysics. As charged particles travel through the Universe, they are deflected by extragalactic magnetic fields and lose energy through interactions with background radiation, making source inference highly non-trivial. Existing approaches either rely on simplified propagation models or on computationally prohibitive Monte Carlo methods. Here we present a simulation-based inference framework trained on three-dimensional \texttt{CRPropa~3} propagation simulations that produces calibrated posterior distributions over source energy, distance, direction, and primary composition for individual UHECR events. The model combines a Deep Set encoder, handling the variable number of detected secondary particles, with a normalizing flow, and is trained on approximately 5 million simulated events covering a broad range of extragalactic magnetic field configurations. Validated on held-out simulations, all source parameters are recovered without systematic bias, with directional parameters best constrained and source distance most uncertain, consistent with the underlying propagation physics. Primary composition classification achieves $\geq$~98.2% accuracy across all mass groups. This framework provides a scalable and physically interpretable interface between detailed propagation simulations and Bayesian source inference relevant for current UHECR data.

We present next-to-leading-order (NLO) QCD and electroweak (EW) results using the dimension-6 SMEFT for all 2- and 4- body Higgs decays, for $Z$ and $W$ decays along with the corresponding EW precision observables, and for the Higgstrahlung process $e^+e^-\rightarrow ZH$ at $\sqrt{s}=240$, $365$ and $500$ GeV. The results are presented in the POPxf format for ease of use in experimental and phenomenological studies. Of particular utility is the total Higgs width, including all dimension-6 contributions at NLO. In addition, we present the differential distributions $dΓ/dm_{Z*}$ for $H\rightarrow l^+l^- Z^*, Z^*\rightarrow l^+l^-$ at NLO in the SMEFT.

The polarized light of the cosmic microwave background is sensitive to new physics that violates parity symmetry. For example, the interaction of photons with the fields of elusive dark matter and dark energy could cause a uniform rotation of the plane of linear polarization across the sky, an effect known as cosmic birefringence. We extract the cosmological rotation angle, <inline-formula><mml:math><mml:mi>β</mml:mi></mml:math></inline-formula>, using Bayesian analysis of parity-violating correlations, <inline-formula><mml:math><mml:mi>E</mml:mi><mml:mi>B</mml:mi></mml:math></inline-formula> and <inline-formula><mml:math><mml:mi>T</mml:mi><mml:mi>B</mml:mi></mml:math></inline-formula>, of polarization data from the Atacama Cosmology Telescope (ACT) Data Release 6. We use prior probabilities for instrumental miscalibration angles derived from the optics model for the ACT telescope and instruments, and marginalize over a residual intensity-to-polarization leakage. We measure <inline-formula><mml:math><mml:mi>β</mml:mi><mml:mo>=</mml:mo><mml:mn>0.21</mml:mn><mml:mn>5</mml:mn><mml:mi>°</mml:mi><mml:mo>±</mml:mo><mml:mn>0.07</mml:mn><mml:mn>4</mml:mn><mml:mi>°</mml:mi></mml:math></inline-formula> (68% confidence level), which excludes <inline-formula><mml:math><mml:mi>β</mml:mi><mml:mo>=</mml:mo><mml:mn>0</mml:mn></mml:math></inline-formula> with a statistical significance of <inline-formula><mml:math><mml:mn>2.9</mml:mn><mml:mi>σ</mml:mi></mml:math></inline-formula>. Although there remain systematics in the ACT data that are not understood and do not allow us to draw strong cosmological conclusions, this result is consistent with previous independent results from the WMAP and Planck missions. It is suggestive that independent data sets and analyses using different methodologies have yielded the same sign and comparable magnitudes for <inline-formula><mml:math><mml:mi>β</mml:mi></mml:math></inline-formula>.

Despite their feeble interactions, dense astrophysical neutrinos can behave collectively, exchanging flavor through waves of the neutrino plasma. Can collective interactions also induce pairing instabilities and reorganize the neutrino momentum distribution, in analogy to the superfluid instability of fermions? We show that, for standard weak interactions, pairing instabilities can arise only in the presence of discontinuities in the occupation number, such as the sharp Fermi surface responsible for superconductivity in metals. However, discretized energy spectra can mimic such discontinuities and artificially generate superfluid instabilities. These spurious instabilities disappear in the continuum limit.

The calculation of precise predictions for Higgs decays is a necessary ingredient for determining Higgs properties at the LHC and future colliders. We compute all two- and three- body Higgs decays at next-to-leading order (NLO) in both QCD and electroweak interactions using the dimension-6 Standard Model Effective Field Theory (SMEFT). Results for four-body Higgs decays that are accurate to NLO QCD/electroweak order in the SMEFT are obtained using the narrow width approximation. Our results are contained in a flexible Monte Carlo program, NEWISH, that is publicly available and we illustrate the impact of the NLO electroweak corrections for HL-LHC, Tera-Z, and Higgstrahlung projections.

We consider Loryons, particles beyond the Standard Model that receive a significant fraction of their masses from electroweak symmetry breaking, in the context of a two Higgs doublet model. Using scalar Loryons in the [1, 1], [1, 3] (as well as the equivalent [3, 1]) and the [2, 2] representations of the custodial SU(2)_L × SU(2)_R global symmetry as benchmarks, we study the constraints on the Loryon parameter space, focusing on unitarity, Higgs decay observables, and the absence of Loryon vacuum expectation values. We find that while neutral singlet Loryons remain viable for masses up to 700 GeV, representations containing charged scalars are severely constrained by LHC data, particularly as the fraction of mass generated by symmetry breaking increases.

We present new fitting functions for the velocity divergence auto- and cross-power spectra, $P_{θθ}(k)$ and $P_{δθ}(k)$, calibrated on gravity-only $N$-body simulations. By applying the Evolution Mapping framework, we revise existing prescriptions to introduce a physically motivated parametrisation in terms of the clustering amplitude $σ_{12}$, the RMS density fluctuation smoothed at $12\,\text{Mpc}$. This approach improves robustness and extends the range of applicability beyond that of previous models. Our fits are calibrated using a suite of multi-resolution simulations, with numerical convergence carefully quantified and sampling artefacts mitigated through a conservative patching strategy. This yields converged measurements up to $k\simeq0.56\,\mathrm{Mpc}^{-1}$ and percent-level accuracy for both $P_{θθ}(k)$ and $P_{δθ}(k)$ over a wide range of $σ_{12}$. Validation against independent simulations spanning a broad range of cosmological models confirms an accuracy of $1$-$2$ per cent on scales where the measurements are robust, systematically outperforming existing prescriptions. We further assess the impact of deviations from the exact evolution mapping relation induced by differing growth histories. For most cosmologies of practical interest, we find that neglecting these effects introduces only subdominant errors. We show that expressing fitting functions in $h$-dependent units leads to spurious, unphysical dependencies on the Hubble parameter, even for models with identical linear clustering. This provides strong empirical support for parametrising non-linear evolution in terms of $σ_{12}$ rather than $σ_{8}$. Our fitting functions provide a robust description of velocity power spectra, with direct applications to redshift-space distortion modelling in galaxy redshift surveys.

In December 2023, the Large-Sized Telescope prototype (LST-1) detected for the first time VHE $γ$-ray emission from the FSRQ OP~313 becoming the furthest blazar ever observed at VHE with z=0.997. We aim to characterize the $γ$-ray emission of OP 313 during this flare, comparing it with its average emission state in order to understand the processes leading to this detection. Its remarkable distance also enables studies on the Extragalactic Background Light (EBL), with the goal of evaluating the attenuation of VHE $γ$-ray photons. We characterize the $γ$-ray emission during the flare in December 2023 and the low emission state observed in January 2024 thanks to the LST-1 and MAGIC data and quasi-simultaneous \textit{Fermi}-LAT observations. This dataset also enables us to evaluate the EBL attenuation by systematically exploring the EBL intensity over the $γ$-ray spectrum. Finally, we study the multi-wavelength emission and interpret the broadband spectral energy distribution (SED) within blazar radiative models including the thermal contributions from the accretion disc, dusty torus and broad line region. We also characterize the flare brightness in the high-energy (HE, $E>100$~MeV) $γ$-ray band, that was found to be a factor 50 above the average emission seen by \textit{Fermi}-LAT. The HE and VHE observations allow us to set constrains to the EBL density. Finally, thanks to the extensive multi-wavelength campaign organized, we are able to construct and model the broadband SED of OP~313 within the framework of a two-zone leptonic model where the $γ$-ray emission is produced via inverse-Compton scattering of the broad line region, accretion disk and dusty torus photon fields. However the dominant external photon field remains unknown, as several combinations are able to successfully explain the $γ$-ray emission observed.

Direct detection experiments have established the most stringent constraints on potential interactions between particle candidates for relic, thermal dark matter and Standard Model particles. To surpass current exclusion limits a new generation of experiments is being developed. The upcoming upgrade of the CRESST experiment will incorporate <inline-formula><mml:math><mml:mi>O</mml:mi></mml:math></inline-formula>(100) detectors with different masses ranging from ~2 g to ~24 g, aiming to achieve unprecedented sensitivity to sub-GeV dark matter particles with a focus on spin-independent dark matter-nucleus scattering. This paper presents a comprehensive analysis of the planned upgrade, detailed experimental strategies, anticipated challenges, and projected sensitivities. Approaches to address and mitigate low-energy excess backgrounds ─ a key limitation in previous and current sub-GeV dark matter searches ─ are also discussed. In addition, a long-term roadmap for the next decade is outlined, including other potential scientific applications.

Context. Studies of magnetospheric accretion and magnetic field topology in T Tauri stars have advanced over the years, but their applications to fully convective, very-low-mass T Tauri stars remain relatively unexplored. Aims. We aim to analyze the circumstellar environment of the very-low-mass dipper-like star JH 223 by investigating the accretion process and characterizing its large-scale magnetic field topology. Methods. We analyzed the photometric variability of JH 223 using observations from multiple telescopes, including K2, TESS, and LCOGT across different epochs. Additionally, we used Gemini/GRACES spectroscopic and CFHT/SPIRou spectropolarimetric data to investigate the star-disk interaction and to characterize the large-scale stellar magnetic field using Zeeman-Doppler imaging. Results. JH 223 is a fully convective classical T Tauri star with an age of about 3 Myr and a mass of 0.4 M_⊙. The large-scale surface magnetic field is predominantly poloidal, with a 250 G dipolar component. The dipole field strength and the mass accretion rate indicate that the disk gas truncation radius is located near the corotation radius (6 ± 1 R_★). The star-disk interaction, combined with the inclined dipole, generates accretion columns that warp the inner disk. As the star rotates, this warp periodically obscures the stellar surface every 3.31 days, producing the dipper light curves. The same period is also detected in variations of the radial velocity and the longitudinal magnetic field. The accretion columns, traced by strong redshifted absorption components in Hα and He I 1083nm, are associated with the inner disk warp, as they occur around the same rotational phase. The accretion process in JH 223 is dynamic, transitioning from an unstable to a stable regime over a few weeks, consistent with predictions from magnetohydrodynamic simulations of the star-disk interaction. Conclusions. Results from multi-technique observations suggest that the magnetospheric accretion model remains valid for fully convective very-low-mass young stars.

We examine the physical significance of torsion co-cycles in the cohomology of a projective Calabi-Yau three-fold for the (2,2) superconformal field theory (SCFT) associated to the non-linear sigma model with such a manifold as a target space. There are two independent torsion subgroups in the cohomology. While one is associated to an orbifold construction of the SCFT, the other encodes the possibility of turning on a topologically non-trivial flat gerbe for the NS-NS B-field. Inclusion of these data enriches mirror symmetry by providing a refinement of the familiar structures and points to a generalization of the duality symmetry, where the topology of the flat gerbe enters on the same footing as the topology of the underlying manifold.

We present an application of automatic differentiation for particle transport through matter using a Geant4-like radiation transport simulation with a full electromagnetic physics model. When differentiating this step-based transport, we observe exploding gradients driven by rare but extreme sensitivities at material boundaries, which propagate through subsequent transport and shower development. To obtain usable derivatives for optimization, we introduce a targeted mitigation strategy that stops gradient propagation through boundary-crossing operations under identifiable unstable conditions while leaving the forward (primal) simulation unchanged. We demonstrate that this enables stable, optimization-ready gradients in a detector-design problem.

We compute the primary Lund plane density for jets initiated by a massive (b) quark to single logarithmic accuracy in Quantum Chromodynamics (QCD). In order to capture mass effects, we consider quasi-collinear factorisation and we include contributions from the running of the QCD coupling and from collinear evolution, in a variable flavour-number scheme. Furthermore, the resummation of soft logarithms, including clustering effects, is performed numerically, keeping the full dependence on the b-quark mass. While our all-order results can be applied to both hadron and lepton colliders, we present, as first phenomenological application, the resummed calculation of the Lund plane density in e⁺e⁻ collisions at <inline-formula><mml:math><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt></mml:math></inline-formula> = M_Z, matched to tree-level matrix elements.

Neutron stars (NSs) are powerful factories for new particles with masses up to the 100 keV range. These compact stars contain significant populations of charged particles, notably protons, electrons and muons. We calculate the emission rates for new scalar, vector, and pseudoscalar bosons that predominantly couple to electrons and muons. For vector bosons, the in-medium renormalization of the effective couplings strongly modifies the emission rates, e.g., purely muon-philic vectors are predominantly emitted by ultra-relativistic electrons. We focus on bremsstrahlung in electromagnetic lepton-lepton or lepton-proton collisions in the ultradegenerate limit. When protons are superconducting, the scalar and vector energy loss rates scale as $T^4$, the pseudoscalar one as $T^6$, to be compared with $T^8$ for neutrino losses by the modified Urca process. For normal-conducting protons, the screening of transverse photons implies instead scalings with a power reduced by $1/3$ and thus $T^{11/3}$ for scalars and vectors, and $T^{17/3}$ for pseudoscalars. As the NS cools, such new particle losses would become important at late times, when surface photon emission begins to take over, which itself scales roughly as $T^2$ in terms of the internal temperature. Our results can be used to constrain the leptophilic coupling strengths through observed NS cooling ages.

We study scenarios in which ultralight dark matter (ULDM) causes oscillations of the Cabibbo--Kobayashi--Maskawa (CKM) matrix elements, considering two frameworks. The first, previously proposed in the literature, employs the Nelson--Barr mechanism to solve the strong CP problem and the CKM phase is identified with a pseudo-Nambu--Goldstone boson. The second, inspired by Froggatt--Nielsen flavor models, relies on quadratic couplings of the ULDM to the Standard Model while naturally suppressing linear couplings. On the experimental side, we outline a strategy to search for such oscillations at flavor factories using meson decays, focusing on the NA62 experiment as the most promising candidate for discovery thanks to its large kaon statistics. We show that the sensitivity of lifetime-based observables is parametrically degraded when the total particle flux is not known exactly, leading to a substantial loss of sensitivity compared to naive estimates. We therefore advocate alternative observables based on direct counting of events, which retain the expected $1/\sqrt{N}$ scaling and provide a robust probe of oscillating CKM elements. Our results highlight flavor experiments as a novel probe of ULDM through time-dependent signatures.

Experimental searches for fifth forces coupled to muons are fundamentally limited by the scarcity of muons in ordinary matter, whereas neutron stars contain abundant muon populations. We show that these compact objects therefore provide superior sensitivity across a broad range of mediator masses. Neutron-star cooling implies limits of $g_{ϕμ}\lesssim10^{-12}$ and $g_{V\!μ}\lesssim3\times10^{-13}$ on scalar and vector bosons with masses $m_X\lesssim100$ keV, whereas SN 1987A cooling implies only $g\lesssim3\times10^{-9}$. Moreover, hydrostatic equilibrium requires any long-range muonic force to be sufficiently weak, surpassing cooling bounds for $m_X\lesssim10^{-5}$ eV. Together, these observables provide the most stringent probes of muonic interactions over distance scales ranging from picometers to kilometers.

We propose a novel mechanism for generating the baryon asymmetry of the Universe through leptogenesis in a scenario where the right-handed neutrinos are heavier than the maximal temperature of the Universe, and are never produced on-shell neither by thermal nor by non-thermal mechanisms. We introduce a new scalar field, $ϕ$, lighter than the right-handed neutrinos, that couples to the latter via a Yukawa coupling, so that it decays into two lepton doublets and two higgs doublets via off-shell right-handed neutrinos. Then, we derive the CP asymmetry arising from the interference between tree-level and loop diagrams in the four-body decay, and we show that the generated baryon asymmetry can reproduce the observed value both in a scenario where $ϕ$ is responsible for the reheating of the Universe, and in a scenario where $ϕ$ is a generic scalar that remains in thermal equilibrium with the plasma.

Pattern formation in soft, active, and biological matter is described by two ostensibly distinct continuum frameworks: phase-field theories driven by chemical-potential gradients, and mass-conserving reaction-diffusion (McRD) dynamics governed by local interconversion kinetics. Here we establish a constructive, equation-level duality valid in the nonlinear, far-from-equilibrium regime. McRD is the broader class: every chemical-potential theory with conserved order parameters embeds as the slow dynamics on an attracting manifold of an McRD system; conversely, every McRD with attractive nullcline admits an exact chemical-potential representation in the fast-interconversion limit, with the constitutive relation set by the nullcline. The construction resolves the generic non-invertibility of the chemical-potential as a function of density in phase-separating regimes by embedding it as an attracting manifold in an extended two-field description with conserved total density. Gradient stiffness maps faithfully onto an intrinsic reaction-diffusion length set by the auxiliary field, yielding a diagonal-diffusion normal form whose interface profile matches the original Cahn-Hilliard model by construction. The duality yields an explicit dictionary for phase coexistence: the Maxwell equal-area construction is exactly equivalent to the reactive turnover-balance condition. It extends to weakly nonconservative dynamics, unifying reaction-arrested coarsening and mesa splitting, and to multicomponent theories with broken Maxwell symmetry. As a concrete payoff, the dual sharp-interface picture yields a closed-form velocity law for traveling waves in nonreciprocal Cahn-Hilliard dynamics, in quantitative agreement with simulations.

We have implemented two recently proposed dipole shower algorithms that have next-to-leading-logarithmic accuracy at leading colour in the Herwig event generator. We study their properties and compare them to Herwig's existing dipole and angular ordered parton shower algorithms. In addition to their improved properties in the logarithmic regime, we find important roles for their extrapolations into the hard regime, where we perform NLO matching, and into the infrared regime, where we perform cluster hadronization. We emphasise the importance of this infrared regime and the precise definition of the infrared cutoff used by each shower as the initial state for Herwig's hadronization model. Studying the results at the hadron level, we find important consequences of this infrared cutoff difference and propose it as a starting point for further study of the interplay between parton showers and hadronization models. We conclude by studying the models' tunability and identifying the best-fit parameters for each.

In the case of nonspinning compact binary systems on quasi-elliptic orbits, I obtain the conservative map between the constants of motion (energy and angular momentum) and the fundamental (radial and azimuthal) frequencies at the fourth post-Newtonian order, including both instantaneous and tail contributions. This map is expressed in terms of an enhancement function of the eccentricity, which is appropriately resumed to ensure accuracy for any eccentricity; in particular, I recover known results for circular orbits. In order to obtain this map, the local dynamics are expressed using an action-angle formulation. The tail term is treated as a perturbation, which is first localized in time, then Delaunay-averaged. Both operations require a contact transformation of the phase-space variables, which I explicitly control. Using the first law of binary black hole mechanics, I then obtain the orbit-averaged redshift invariant for eccentric orbits at fourth post-Newtonian order; when properly accounting for the tail contributions, it perfectly agrees with analytical self-force at postgeodesic order (Munna and Evans 2022 Phys. Rev. D 106 044004). Finally, I use these results to re-express the fluxes of energy and angular momentum obtained at third post-Newtonian order in Arun et al (2008 Phys. Rev. D 77 064035; 2009 Phys. Rev. D 80 124018) in terms of fundamental frequencies.

Confinement prohibits isolation of color charges, e.g., quarks, in nature via a process called string breaking: the separation of two charges results in an increase in the energy of a color flux, visualized as a string, connecting those charges. Eventually, creating additional charges is energetically favored, hence breaking the string. Such a phenomenon can be probed in simpler models, including quantum spin chains, enabling enhanced understanding of string-breaking dynamics. A challenging task is to understand how string breaking occurs as time elapses, in an out-of-equilibrium setting. This work establishes the phenomenology of dynamical string breaking induced by a gradual increase of string tension over time. It, thus, goes beyond instantaneous quench processes and enables tracking the real-time evolution of strings in a more controlled setting. We focus on domain-wall confinement in a family of quantum Ising chains. Our results indicate that, for sufficiently short strings and slow evolution, string breaking can be described by the transition dynamics of a two-state quantum system akin to a Landau-Zener process. For longer strings, a more intricate spatiotemporal pattern emerges: the string breaks by forming a superposition of bubbles (domains of flipped spins of varying sizes), which involve highly excited states. We finally demonstrate that string breaking driven only by quantum fluctuations can be realized in the presence of sufficiently long-ranged interactions. This work holds immediate relevance for studying string breaking in quantum-simulation experiments.

This year marks the (350^{\mathrm {th}}) anniversary of the discovery of the first animalcula (little animals) by van Leeuwenhoek in 1676. Flavour physics makes it possible to search for new animalcula at distance scales far shorter than those resolved by van Leeuwenhoek in 1676, and even shorter than those directly accessible at the Large Hadron Collider and the planned colliders in this century. I summarize various strategies for achieving this goal. While precise measurements of a wide variety of observables and their precise theoretical calculations, both within the Standard Model (SM) and beyond it, are indispensable in this context, in my view, it is crucial to develop strategies for the search for New Physics (NP) that go beyond the global fits that are very popular today. While effective field theories such as WET and SMEFT are formulated in terms of Wilson coefficients of the relevant operators, with correlations characteristic of the SM and of specific NP scenarios, the most direct tests of the SM and its extensions are, in my opinion, correlations among different observables, like branching ratios of numerous decays, that are characteristic of particular new animalcula at work.

The diffuse supernova neutrino background (DSNB) created by stellar core-collapses throughout cosmic history is on the verge of discovery, with SK-Gd showing early deviations from the background expectation and JUNO starting to take data. However, the interpretation of early DSNB data will face significant challenges due to degeneracies between astrophysical parameters and uncertainties in supernova neutrino modelling. This work explores how complementary astronomical observations can break these degeneracies. We utilize state-of-the-art detector descriptions, careful analyses of the backgrounds, and sophisticated DSNB simulations. In particular, we investigate whether early DSNB observations can constrain invisible supernovae, which have no optical emission but are powerful neutrino sources before being swallowed by a forming black hole. Leveraging the differences in the spectra between invisible and visible supernovae, we estimate the sensitivity of 1) detecting the existence of invisible supernovae, and 2) determining the fraction of invisible supernovae. Finally, we discuss how these conclusions depend on the spectral parameters of the black hole-forming component.

Dark matter decays into invisible particles can leave an imprint in large-scale structure surveys due to a characteristic redshift-dependent suppression of the power spectrum. We present a model with two quasi-degenerate singlet fermions, χ ₁ and χ ₂, in which the heavier state decays as χ ₂ → χ̅ ₂ νν on cosmological time-scales, and that also integrates non-zero neutrino masses. Remarkably, for parameters that yield the correct dark matter abundance via freeze-in and reproduce the observed neutrino masses, dark matter decay can accommodate detectable signals in forthcoming large-scale structure surveys, a diffuse anti-neutrino flux accessible to JUNO, and a gamma-ray line within the energy range probed by COSI. Both the cosmological lifetime of χ ₂ as well as the small (radiatively induced) mass splitting among χ _1,2 are a natural consequence of the mechanism of neutrino mass generation within this model. This highlights the potential role of large-scale structure surveys in probing some classes of neutrino mass models.

Magnetic fields between a supernova (SN) and Earth convert axions into gamma rays. The absence of such a signal in coincidence with SN 1987A neutrinos, using the coherent Milky Way field, provides well-studied constraints on $g_{ap}\times g_{aγ}$ (axion-proton times axion-photon couplings) and on $g_{aγ}$ alone. We show that the small-scale power of the turbulent magnetic field component boosts axion-photon conversion and, crucially, extends sensitivity to larger masses. The turbulent field components of the Milky Way and of the Large Magellanic Cloud (hosting SN 1987A) yield improvements of up to two orders of magnitude in $g_{ap}\times g_{aγ}$. Turbulence should likely impact the sensitivity of other searches based on other axion-photon conversion sites, such as starburst galaxies.

We show that the late-time dynamics of a minimal three-component mass-conserving reaction--diffusion system reduce to a scalar active field theory, Active Model B$^-$ (AMB$^-$), in which a density-dependent interfacial coefficient $κ(ϕ)$ turns negative at high density. This drives a finite-wavelength instability and stabilises microphase-separated patterns, in contrast to the unbounded coarsening of two-component mass-conserving systems. Unlike Active Model B$^+$, AMB$^-$ retains a chemical potential that remains a state function, inherited from the underlying conservation law, but admits no equation of state for the pressure.

We study the cosmological gravitational particle production (CGPP) of spin-<inline-formula><mml:math><mml:mfrac><mml:mn>3</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:math></inline-formula> particles during and after cosmic inflation, and map the parameter space that can realize the observed dark matter density in stable spin-<inline-formula><mml:math><mml:mfrac><mml:mn>3</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:math></inline-formula> particles. Originally formulated by Rarita and Schwinger, the relativistic theory of a massive spin-<inline-formula><mml:math><mml:mfrac><mml:mn>3</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:math></inline-formula> field later found a home in supergravity as the superpartner of the graviton, and in nuclear physics as baryonic resonances and nuclear isotopes. We study a minimal model realization, namely a free massive spin-<inline-formula><mml:math><mml:mfrac><mml:mn>3</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:math></inline-formula> field minimally coupled to gravity, and adopt the name raritron for this field. We demonstrate that CGPP of raritrons crucially depends on the hierarchy between the raritron mass m_3/2 and the Hubble parameter at the end of inflation H_e, with high-mass and low-mass cases distinguished by the evolution of the sound speed c_s of the longitudinal (helicity-<inline-formula><mml:math><mml:mfrac><mml:mn>1</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:math></inline-formula>) mode, which is approximately unity at all times for heavy (relative to Hubble) raritrons and can become small or vanish for lighter raritrons, leading to a dramatic enhancement of production of high momentum particles in the latter case. Assuming the raritrons are stable, this leads to a wide parameter space to produce the observed dark matter density. Finally, we consider a time-dependent raritron mass, which can be chosen to remove the vanishing sound speed of the longitudinal mode, but which nonetheless enhances the production relative to the constant high-mass case, and in particular does not necessarily tame the high momentum tail of the spectrum. We perform our calculations using the Bogoliubov formalism and compare, when applicable, to the Boltzmann formalism.

Neural posterior estimation has emerged as a powerful tool for amortized inference, with growing adoption across scientific and applied domains. In many of these applications, the conditioning variable is a set of observations whose elements depend not only on the target but also on unknown factors shared across the set. Optimal inference therefore requires treating the set jointly, which in turn requires training the estimator at the deployment set size -- a regime where memory and compute quickly become prohibitive. We introduce a simple, theoretically grounded strategy that decouples representation learning from posterior modeling. Our method trains a mean-pool Deep Set on sets of size at most two, producing an encoder that generalizes to arbitrary set sizes. The inference head is then finetuned on pre-aggregated embeddings, making training cost essentially independent of the deployment set size N. Across scalar, image, multi-view 3D, molecular, and high-dimensional conditional generation benchmarks with N in the thousands, our approach matches or outperforms standard baselines at a fraction of the compute.

The gas-phase mass-metallicity relation (MZR) of galaxies shows a noticeable break in slope and increased scatter at low stellar masses, suggesting that the physical processes governing chemical enrichment differ between dwarf and high-mass systems. Dwarf galaxies are highly susceptible to internal and environmental mechanisms due to shallow potential wells. We assess whether a single MZR describes dwarf galaxies across diverse large-scale environments using the CAVITY parent sample. We examine the MZR and star formation rate (SFR) of dwarfs with stellar masses 8.9 < log(M_star/M_sun) < 9.5. Using SDSS optical spectra, we measured emission line fluxes via the pyPipe3D pipeline to derive the MZR and SFR for 353, 311, and 22 dwarf galaxies in voids, filaments, and clusters, respectively. We find a systematic variation in the MZR slope, which is steeper in voids (0.28 +/- 0.03) and progressively flatter in clusters (0.17 +/- 0.08), indicating an environmental dependence in this mass regime. When separated by local environment, isolated and non-isolated dwarfs in voids show no significant differences. Isolated dwarfs in filaments exhibit properties similar to void counterparts. However, non-isolated filament galaxies display flatter MZR slopes, comparable to cluster dwarfs. We report both large- and local-scale environmental dependencies in the gas-phase metallicity and MZR slope. Consistent with the pre-processing framework, our results indicate that the local environment becomes significant within cosmic web filaments, affecting the chemical enrichment and star formation of low-mass systems. This suggests that part of the MZR scatter in dwarf galaxies arises from environmental effects.

The evolutionary origin of Wolf-Rayet (WR) stars at solar metallicity is unclear. Single-star evolution from massive O stars, possibly via a luminous blue variable phase, is challenged by binary period distributions of different WR subtypes. Wd1-72 is a WN7b+O binary embedded in the collective wind of the Galactic young massive cluster Westerlund 1 (Wd 1). It is surrounded by highly structured nebulosity, with cometary tails pointing away from Wd 1 and quasi-spherical droplets towards it. In this Letter, we demonstrate that this morphology can be qualitatively reproduced by a hydrodynamic simulation of non-conservative Roche-lobe overflow (RLOF) mass loss into a cluster wind. Our model is based on a detailed binary evolution track consistent with key known properties of Wd1-72. Our work suggests Wd1-72 could be only ∼10 kyr post-RLOF, and the hydrogen-free nature of Wd1-72 favours this being a second or subsequent RLOF episode. Follow-up observations could make Wd1-72 a valuable benchmark for probing mass loss and mass transfer in forming gravitational-wave binary-progenitor systems.

This study explores the impact of observational and modelling systematic effects on cluster number counts and cluster clustering and provides model prescriptions for their joint analysis in the context of the Euclid survey. Using 1000 Euclid-like cluster catalogues, we investigated the effect of systematic uncertainties on cluster summary statistics and their auto- and cross-covariance, and performed a likelihood analysis to evaluate their impact on cosmological constraints, with a focus on the matter density parameter (Ω_m) and on the power spectrum amplitude (σ₈). Combining cluster clustering with number counts significantly improves cosmological constraints, with the figure of merit increasing by over 300% compared to number counts alone. We confirm that the two probes are uncorrelated, and the cosmological constraints derived from their combination are almost insensitive to the cosmology dependence of the covariance. We find that photometric redshift uncertainties broaden cosmological posteriors by 20─30%, while secondary effects such as redshift-space distortions (RSDs) have a smaller impact on the posteriors ─ 5% for clustering alone, 10% when combining probes ─ but can significantly bias the constraints if neglected. We show that clustering data below 60 h⁻¹ Mpc provides additional constraining power, while scales larger than the acoustic oscillation scale add almost no information on Ω_m and σ₈ parameters. The RSDs and photo-z uncertainties also influence the number count covariance, with a significant impact of about 15─20% on the parameter constraints. ★ This paper is published on behalf of the Euclid Consortium.

Exomoons around free-floating planets (FFPs) can survive their host planet's ejection. Such ejections can increase their orbital eccentricity, providing significant tidal heating in the absence of any stellar energy source. Previous studies suggested that liquid water could exist on such moons under thick CO<inline-formula><tex-math>$_2$</tex-math></inline-formula>-dominated atmospheres, but these models faced challenges with CO<inline-formula><tex-math>$_2$</tex-math></inline-formula> condensation and atmospheric collapse, particularly in the high-pressure regimes that favoured long-term habitability. To address this, we employ a self-consistent model, including radiative transfer and equilibrium chemistry with condensation, to simulate a more stable hydrogen-dominated atmosphere for a range of initial chemical compositions, including C, O, and N. We find that such atmospheres can effectively trap heat via collision-induced absorption of H<inline-formula><tex-math>$_2$</tex-math></inline-formula>, maintaining surface temperatures suitable for liquid water for time-scales of up to 4.3 Gyr, depending on the surface pressure, while not prone to condensation-induced collapse. Wet-dry cycling caused by the strong tides together with the alkalinity of dissolved NH<inline-formula><tex-math>$_3$</tex-math></inline-formula> could create favourable conditions for RNA polymerization and thus support the emergence of life.

We obtain 3D distributions of CO and SiO molecules from high spatial resolution (0.03─0.06 arcsec) Atacama Large Millimeter Array (ALMA) observations of SN 1987A at two different epochs. The evolution between these two epochs is consistent with homologous expansion. From these 3D maps, we reconstruct the 3D mass distributions of the ejecta in CO and SiO molecules, which we compare with those obtained by state-of-the-art, long-time hydrodynamical supernova explosion models computed with the PROMETHEUS-HOTB code for 10 different progenitors, including both red and blue supergiants. The models which best match the mass distributions correspond to explosions of binary-merger blue supergiant progenitors; at least two such models approximately reproduce the observed CO morphology. In contrast, the SiO velocity distribution and morphology are not as well reproduced in these models, indicating insufficient mixing of Si into the outer layers already at the progenitor stage. The theoretical models suggest a strong correlation between the centre of mass of the densest carbon- and oxygen-rich ejecta and the direction of the neutron-star kick. If such a correlation also applies to the CO emission in the ejecta of SN 1987A, the kick of the compact remnant is expected to point towards the observer, at an angle of approximately <inline-formula><tex-math>$45^\circ$</tex-math></inline-formula> to the north.

We use high-resolution UV-to-optical imaging from the Hubble Space Telescope (HST) to construct spatially resolved spectral energy distributions (SEDs) for seven nearby (z < 0.07) hard (14─195 keV) X-ray-selected broad-line active galactic nuclei (AGN) with L_bol = 10^43.26─10^45.34 erg s⁻¹. The high spatial resolution of HST, which physically resolves structures on the scale of ∼50 pc at z = 0.05, enables the separation of AGN and host-galaxy emission through morphological decomposition with GALFIT, yielding improved measurements of AGN properties compared to those obtained with lower-resolution Swift UV/Optical Telescope (UVOT) data. AGN UV magnitudes derived from HST imaging (e.g., F225W) can differ by more than a magnitude from those from Swift/UVOT UVM2 due to extended nuclear emission. Additionally, the inclusion of high-resolution data at longer wavelengths (e.g., F814W) can significantly affect the resulting SED fit. Comparing fits of accretion disk and extinction models using HST and Swift/UVOT data, we find significant differences in the resulting parameters, with average differences of 2.0 eV in the maximum disk temperature and 2.2 mag in the AGN host-galaxy extinction. These differences ultimately lead to significant changes in bolometric luminosities and X-ray bolometric corrections, with the HST-based fits yielding average increases of ∼0.57 dex and ∼0.66 dex, respectively. This demonstrates host-galaxy contamination in unresolved UV─optical data can strongly bias SED-based estimates of disk temperatures, extinction, bolometric luminosities, and X-ray bolometric corrections in AGN. Large-area, high-resolution imaging surveys from Euclid and the Nancy Grace Roman Space Telescope will extend these techniques to much larger AGN samples, enabling uniform, high-precision SED measurements in the near-IR.

To measure precise distances beyond the Magellanic Clouds and determine an accurate value of the Hubble constant, eclipsing binary systems composed of early-type stars can play a crucial role. However, it is fundamental to first obtain a reliable empirical surface brightness─color relation (SBCR) for the hottest possible stars. Based on our previous study of six detached eclipsing binaries composed of O- and B-type stars in the Large Magellanic Cloud, we calibrated the SBCR using 12 stars with V − K_s < ─0.6 mag. We found a significant difference between O-type and B-type stars in SBCRs, which are clearly separated in mass. The relation based on B-type stars is consistent with the relation for redder stars from the literature. This allowed us to provide a combined relation valid for stars less massive than ∼16 M_⊙in the wide color range −0.9 < V − K_s < 2.1 mag, with σ = 0.025 mag. Such a relation can provide extragalactic distances precise to as high as ∼1.2% given the sufficient quality and number of target objects. The relation for O-type stars (σ = 0.055 mag) remains uncertain due to its strong dependence on the method used to determine reddening and requires further study. However, we tested it on the only known eclipsing system in M33 and obtained distance modulus DM = 24.90 ± 0.17 mag, which perfectly agrees with the published distance to the system.

Changing-look active galactic nuclei (CL-AGNs) exhibit dramatic spectral variability on unexpectedly short timescales, challenging standard accretion flow models. Despite growing samples, the physical drivers of this extreme variability, and the potential link to host-galaxy properties, remain unknown. Regardless of the underlying mechanism, the transition between AGN-dominated and host-dominated spectra offers a unique opportunity to study relations between AGNs and their hosts within the same objects. We present intermediate-resolution spectroscopy of 23 CL-AGNs identified by the Sloan Digital Sky Survey V (SDSS-V), obtained with the Very Large Telescope/X-shooter and Gemini-N/GMOS. An analysis of the Mg II λ2798 emission line observed in the spectra demonstrates that the majority of these sources cannot be driven by variable obscuration. Our CL-AGNs roughly follow the M_BH─σ_* and M_BH─M_* relations of inactive galaxies, with a median black hole-to-stellar mass ratio of 0.38 %. We find no evidence that the stellar population properties of our CL-AGNs, including stellar mass, age, young stellar fraction, and star formation rate, differ from those of type 2 AGNs in SDSS. These results suggest that CL-AGNs reside in typical AGN host galaxies and that their extreme variability is likely unrelated to host-galaxy environment, supporting the idea that CL-AGNs are not a distinct population, but rather represent a phase of normal AGN activity. This result, in turn, implies that CL-AGNs can serve as useful probes of the AGN-host connection, providing access to both AGN-dominated and host-dominated spectra of the same systems.

HD 98800 is a nearby hierarchical quadruple system comprising two binaries orbiting each other. Surprisingly, despite its <inline-formula><tex-math>$\sim 10$</tex-math></inline-formula> Myr age and dynamic environment, the Ba-Bb component is surrounded by a compact gas-rich disc in a polar configuration. Previous millimetre continuum observations of this disc found a low millimetre spectral index (<inline-formula><tex-math>$\alpha \sim 2.1$</tex-math></inline-formula> up to 9 mm), potentially arising from large dust grains, optically thick emission, or both. Furthermore, the interpretation was complicated by emission mechanisms other than dust thermal continuum at longer wavelengths. We present new observations of this system with the Very Large Array (VLA) at 6.8 mm and 3 cm, providing crucial additional sampling of the emission at millimetre/centimetre wavelengths. By combining these with ancillary data, we derive a dust spectral index <inline-formula><tex-math>$\alpha _{\rm dust} \lt 3$</tex-math></inline-formula> for wavelengths <inline-formula><tex-math>$\le 1$</tex-math></inline-formula> cm. Our modelling suggests that the emission is optically thick at short millimetre wavelengths (<inline-formula><tex-math>$\lambda \le 3$</tex-math></inline-formula> mm) and it becomes at least partially optically thin for the VLA observations. The shallow spectral index thus indicates the existence of large grains in the disc. We also identify gyro-synchrotron emission from the A and B components at <inline-formula><tex-math>$\lambda \gtrsim$</tex-math></inline-formula>3 cm. The VLA images also reveal an azimuthal asymmetry at 6.8 and 8.8 mm, which is not present in high-resolution ALMA 1.3 mm data. After ruling out geometric and illumination effects, we interpret this asymmetry as a local dust overdensity, possibly induced by a vortex or a relic of the previous passage of the A component.

QCD axions would be copiously produced in the protoneutron star formed in a core-collapse supernova (SN). After escaping, they would convert into gamma rays in the Galactic magnetic field and, as recently shown, in that of the progenitor star itself. Here, we show that Type Ibc SNe—whose progenitors have lost their hydrogen or even helium envelopes—are the optimal targets for this search. The stripped progenitors are much more compact, and they show larger magnetic fields than both red and blue supergiants, the progenitors of Type IIP/L SNe. If the next galactic SN is of Type Ibc, Fermi-LAT or a similar gamma-ray satellite might be able to discover the QCD axion down to masses as small as <inline-formula><mml:math><mml:mrow><mml:msub><mml:mrow><mml:mi>m</mml:mi></mml:mrow><mml:mrow><mml:mi>a</mml:mi></mml:mrow></mml:msub><mml:mo>≃</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>4</mml:mn></mml:mrow></mml:msup><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>eV</mml:mi></mml:mrow></mml:math></inline-formula> (Peccei-Quinn scale <inline-formula><mml:math><mml:mrow><mml:msub><mml:mrow><mml:mi>f</mml:mi></mml:mrow><mml:mrow><mml:mi>a</mml:mi></mml:mrow></mml:msub><mml:mo>≃</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mn>11</mml:mn></mml:mrow></mml:msup><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>GeV</mml:mi></mml:mrow></mml:math></inline-formula>).

The most massive galaxies in the Universe also host the largest supermassive black holes (SMBHs), with masses of <inline-formula><tex-math>$10^9 \: \mathrm{{\rm M}_{\odot }}$</tex-math></inline-formula> and above. During their hierarchical assembly, these galaxies have experienced only a few major mergers at low redshift, but have accreted many low-mass galaxies across cosmic time, possibly hosting intermediate mass black holes (IMBHs). If some of these IMBHs migrate to the galactic centre, they may form compact sub-systems around the central SMBH. We investigate the evolution of such sub-systems, consisting of 10 <inline-formula><tex-math>$10^5 \: \mathrm{{\rm M}_{\odot }}$</tex-math></inline-formula> IMBHs at three different concentrations around a <inline-formula><tex-math>$10^9 \: \mathrm{{\rm M}_{\odot }}$</tex-math></inline-formula> SMBH. We evolve these systems both in isolation and in the presence of a companion SMBH, using MSTAR, a regularized integration method including relativistic effects up to post-Newtonian order 3.5PN. Our analysis focuses on gravitational-wave-driven intermediate-mass-ratio inspirals (heavy IMRIs) and direct plunges. We show that perturbations from a secondary SMBH enhance the number of IMBH direct plunges by more than a factor of 2, making them the dominant merger channel. These plunges and IMRIs with a central <inline-formula><tex-math>$10^9 \: \mathrm{{\rm M}_{\odot }}$</tex-math></inline-formula> SMBH will contribute to SMBH growth but will likely evade detection with future gravitational-wave interferometers and pulsar timing arrays (PTAs). However, for galaxies with lower-mass SMBHs (<inline-formula><tex-math>$M_\bullet \lesssim 10^8 \:\mathrm{{\rm M}_{\odot }}$</tex-math></inline-formula>), heavy IMRIs will be detectable with the Laser Interferometer Space Antenna (LISA) and can provide direct observational constraints on the existence of IMBHs, while the more numerous plunges will still remain hidden.

Context. Sub-Neptune extra-solar planets are abundant in the Milky Way, yet their atmospheric properties remain poorly understood. They frequently exhibit muted transmission spectra, with GJ1214b being the most prominent example. Following years of intense observing campaigns yielding featureless planetary spectra, more recent observations with JWST have revealed the first possible atmospheric signatures of H₂O, CH₄, and CO₂. Aims. We present high-resolution transmission spectroscopy of GJ 1214 b based on eight transits obtained with the CRIRES⁺ spectrograph in the K band. Methods. We used SYSREM to remove telluric and stellar signals from the data and searched for signatures of H₂O, CO, CH₄, H₂S, NH₃, and CO₂ using the cross-correlation technique. Results. We obtained non-detections for the first five molecules and used injection recovery tests to derive upper limits on the atmosphere. For CO₂ we measure a cross-correlation signal at S/N ~3.6, with a detailed investigation of the signal showing no obvious indication that it is caused by correlated noise. A Welch t-test confirmed that the in-trail, in-transit distribution is significantly different from the out-of-trail distribution at a 3.4σ confidence. Interpreting the data using a Bayesian retrieval framework, with multiple molecular species and free chemistry, resulted in a retrieved planet temperature of T_iso = 398₋₁₉₇⁺²⁸³ K, consistent with a value intermediate between the day- and night-side temperatures from JWST-derived temperature-pressure profiles at high altitudes, as expected for the planetary terminator. In addition, a metallicity of [M/H]= 0.48_−1.70^+0.89 was derived from the abundances of the retrieved molecules, along with an opacity deck pressure of log₁₀(P_c) = −3.04_−1.53^+2.52. A simpler equilibrium chemistry retrieval assuming CO₂ as the sole opacity source returned a compatible temperature, with smaller formal uncertainties (T_iso = 509₋₅₉⁺¹⁰² K), slightly higher metallicity ([M/H]= 1.51_−0.75^+0.68), and higher opacity deck pressure (log₁₀(P_c) = −0.88_−2.48^+1.95). While these sets of values correspond to relatively large signal amplitudes predicted for CO₂ features in the mid-infrared, they are compatible with JWST NIRSpec observations within the models' 1.5σ uncertainties. Conclusions. Further modelling and additional data are required to confirm the atmospheric signatures and obtain a comprehensive interpretation of low- and high-resolution data. Overall, our results support previous findings that CO₂ is likely to be a significant component of the atmosphere of GJ 1214 b.

Modeling the intrinsic alignment (IA) of galaxies poses a challenge to weak lensing analyses. Using the Dark Energy Survey Year 3 shape catalog, we expect less impact from IA when we limit the sample to blue, star-forming galaxies. The cosmological parameter constraints from this BLUE cosmic shear sample are stable to IA model choice, unlike passive galaxies in the full DES Y3 sample, the goodness-of-fit is improved and the <inline-formula><mml:math><mml:msub><mml:mi>Ω</mml:mi><mml:mi>m</mml:mi></mml:msub></mml:math></inline-formula> and <inline-formula><mml:math><mml:msub><mml:mi>S</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:math></inline-formula> better agree with the observations from Planck on the cosmic microwave background. Mitigating IA with sample selection in DES, rather than flexible model choices, can reduce uncertainty in <inline-formula><mml:math><mml:msub><mml:mi>S</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:math></inline-formula> by a factor of 1.5.

We utilize the Magneticum suite of hydrodynamical simulations to investigate the formation and evolution of cosmic voids from z = 5.04 to present day, using cold dark matter and (sub-) halo tracers in high-density samples. This includes the evolution of their global properties, such as size, shape, inner density, and average density, as well as their radial density profiles. Our results provide several key conclusions for void analyses in modern surveys. We demonstrate that a relative framework, which bins voids by their size percentile rather than absolute size, is required to mitigate selection effects and restore the true physical evolution of halo-defined voids. This confirms that void properties are more fundamentally tied to their rank within the contemporary population than to their size. Using this framework, we show that the evolution of halo voids stabilizes at redshifts below z ≃ 1, driven primarily by cosmic expansion rather than ongoing halo formation. We further find that the matter evolution around these stable voids is remarkably well-described by linear growth theory. However, deviations appear as non-linear growth on small scales and suppressed growth in the largest voids, potentially driven by a higher effective Ω_Λ and lower effective Ω_m within the separate universe picture. This late-time stability and the predictable evolution confirm voids as pristine laboratories for probing the nature of dark energy with upcoming surveys.