Nonlinearities in King plots (KP) of isotope shifts (IS) can reveal the existence of beyond-standard-model (BSM) interactions that couple electrons and neutrons. However, it is crucial to distinguish higher-order standard model (SM) effects from BSM physics. We measure the IS of the transitions <inline-formula><mml:math><mml:mrow><mml:msub><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>P</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub><mml:mo>→</mml:mo><mml:msub><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>P</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> in <inline-formula><mml:math><mml:mrow><mml:msup><mml:mrow><mml:mi>Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>14</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula> and <inline-formula><mml:math><mml:mrow><mml:msub><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>S</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo>→</mml:mo><mml:mmultiscripts><mml:mrow><mml:msub><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mn>5</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math></inline-formula> in <inline-formula><mml:math><mml:msup><mml:mi>Ca</mml:mi><mml:mo>+</mml:mo></mml:msup></mml:math></inline-formula> with sub-Hz precision as well as the nuclear mass ratios with relative uncertainties below <inline-formula><mml:math><mml:mn>4</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>11</mml:mn></mml:mrow></mml:msup></mml:math></inline-formula> for the five stable, even isotopes of calcium (<inline-formula><mml:math><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>40</mml:mn><mml:mo>,</mml:mo><mml:mn>42</mml:mn><mml:mo>,</mml:mo><mml:mn>44</mml:mn><mml:mo>,</mml:mo><mml:mn>46</mml:mn><mml:mo>,</mml:mo><mml:mn>48</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math></inline-formula>). Combined, these measurements yield a calcium KP nonlinearity with a significance of <inline-formula><mml:math><mml:mo>∼</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mn>3</mml:mn></mml:msup><mml:mi>σ</mml:mi></mml:math></inline-formula>. Precision calculations show that the nonlinearity cannot be fully accounted for by the expected largest higher-order SM effect, the second-order mass shift, and identify the little-studied nuclear polarization as the only remaining SM contribution that may be large enough to explain it. Despite the observed nonlinearity, we improve existing KP-based constraints on a hypothetical Yukawa interaction for most of the new boson masses between <inline-formula><mml:math><mml:mrow><mml:mn>10</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>eV</mml:mi><mml:mo>/</mml:mo><mml:msup><mml:mrow><mml:mi>c</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula> and <inline-formula><mml:math><mml:mrow><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mn>7</mml:mn></mml:mrow></mml:msup><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>eV</mml:mi><mml:mo>/</mml:mo><mml:msup><mml:mrow><mml:mi>c</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula>.

We formulate the BCOV theory of deformations of complex structures as a pull-back 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.

We present a first step toward field-level cosmological inference beyond the standard $Λ$CDM model, focusing on optimizing precision tests in the nonlinear regime of large-scale structure (LSS). As an illustrative case, we study the model-independent ``bootstrap'' coefficient of the second-order perturbation theory (PT) kernel for matter in real space, which we use as a proxy for new physics effects in the nonlinear sector. We discuss in details the ultraviolet (UV) cutoff dependence induced by discretizing fields on a grid, which requires proper renormalization to eliminate grid artifacts. We formulate a Wilsonian perturbative framework in which the evolution from a UV theory defined at a high cutoff $Λ_\text{uv}$ down to lower cutoffs is computed analytically, even beyond the validity of a derivative expansion. Within this framework, we develop an extended version of the GridSPT code incorporating the bootstrap parameterization and demonstrate how cutoff-independent predictions can be achieved through the inclusion of appropriate counterterms. We validate our approach at third- and fifth-order in PT, emphasizing the importance of higher-derivative contributions for unbiased parameter extraction. Our framework is readily extendable to biased tracers and redshift-space distortions.

Observations and high-resolution hydrodynamical simulations indicate that massive star clusters form through a complex hierarchical assembly. We use simulations including post-Newtonian dynamics (the BIFROST code) and stellar evolution (the SEVN module) to investigate this collisional assembly. With a full initial stellar mass function, we study the effect of initial binary, triple and massive single stars (450 $M_\odot$) on the assembly, structure, and kinematics of massive ($M_\mathrm{cl}\sim10^6 M_\odot$, $N=1.8 \times 10^6$) star clusters. Simultaneously, intermediate mass black holes (IMBHs), potential seeds for supermassive black holes, can form and grow in our models by stellar collisions, tidal disruption events (TDEs) and black hole (BH) mergers. At a fixed cluster mass, stellar multiplicity or a high mass limit increase the numbers (up to $\sim$ 10) and masses (up to $10^4 M_\odot$) of the formed IMBHs within the first 10 Myr of cluster evolution. The TDE rates peak at $Γ_\mathrm{tde}\sim 5 \times 10^{-5}$ yr$^{-1}$ after IMBH formation at $\sim 2$ Myr. In all simulations, we find gravitational wave driven mergers involving stellar BHs and IMBHs. Initial multiplicity or a high mass limit also result in IMBH-IMBH mergers. The IMBH masses correlate with the initial cluster masses, surface densities and velocity dispersions approximately as $M_\bullet \propto M_\mathrm{cl}$, $M_\bullet\proptoΣ_\mathrm{h}^\mathrm{3/2}$ and $M_\bullet\proptoσ^\mathrm{3}$. Our results suggest the dense $z\sim10$ star clusters recently observed by the James Webb Space Telescope host IMBHs with masses above $M_\bullet \gtrsim 10^4 M_\odot$.

Spatially resolved stellar kinematics has become a key ingredient in time-delay cosmography to break the mass-sheet degeneracy in the mass profile and, in turn, provide a precise constraint on the Hubble constant and other cosmological parameters. In this paper, we present the first measurements of 2D resolved stellar kinematics for the lens galaxy in the quadruply lensed quasar system \lensname, using integral field spectroscopy from the JWST's Near-Infrared Spectrograph (NIRSpec), marking the first such measurement conducted with the JWST. In extracting robust kinematic measurements from this first-of-its-kind dataset, we made methodological improvements both in the data reduction and kinematic extraction. In our kinematic extraction procedure, we performed joint modeling of the lens galaxy, the quasar, and its host galaxy's contributions in the spectra to deblend the lens galaxy component and robustly constrain its stellar kinematics. Our improved methodological frameworks are released as software pipelines for future use: \textsc{squirrel} for extracting stellar kinematics, and \textsc{RegalJumper} for JWST-NIRSpec data reduction, incorporating additional artifact cleaning beyond the standard JWST pipeline. We compared our measured stellar kinematics from the JWST NIRSpec with previously obtained ground-based measurements from the Keck Cosmic Web Imager integral field unit and find that the two datasets are statistically consistent at a $\sim$1.1$σ$ confidence level. Our measured kinematics will be used in a future study to improve the precision of the Hubble constant measurement.

In this work, we study the impact of an imperfect knowledge of the instrument bandpasses on the estimate of the tensor-to-scalar ratio $r$ in the context of the next-generation LiteBIRD satellite. We develop a pipeline to include bandpass integration in both the time-ordered data (TOD) and the map-making processing steps. We introduce the systematic effect by having a mismatch between the ``real'', high resolution bandpass $τ$, entering the TOD, and the estimated one $τ_s$, used in the map-making. We focus on two aspects: the effect of degrading the $τ_s$ resolution, and the addition of a Gaussian error $σ$ to $τ_s$. To reduce the computational load of the analysis, the two effects are explored separately, for three representative LiteBIRD channels (40 GHz, 140 GHz and 402 GHz) and for three bandpass shapes. Computing the amount of bias on $r$, $Δr$, caused by these effects on a single channel, we find that a resolution $\lesssim 1.5$ GHz and $σ\lesssim 0.0089$ do not exceed the LiteBIRD budget allocation per systematic effect, $Δr < 6.5 \times 10^{-6}$. We then check that propagating separately the uncertainties due to a resolution of 1 GHz and a measurement error with $σ= 0.0089$ in all LiteBIRD frequency channels, for the most pessimistic bandpass shape of the three considered, still produces a $Δr < 6.5 \times 10^{-6}$. This is done both with the simple deprojection approach and with a blind component separation technique, the Needlet Internal Linear Combination (NILC). Due to the effectiveness of NILC in cleaning the systematic residuals, we have tested that the requirement on $σ$ can be relaxed to $σ\lesssim 0.05$. (Abridged)

Strong gravitationally lensed supernovae (LSNe), though rare, are exceptionally valuable probes for cosmology and astrophysics. Upcoming time-domain surveys like the Vera Rubin Observatory's Legacy Survey of Space and Time (LSST) offer a major opportunity to discover them in large numbers. Early identification is crucial for timely follow-up observations. We develop a deep learning pipeline to detect LSNe using multi-band, multi-epoch image cutouts. Our model is based on a 2D convolutional long short-term memory (ConvLSTM2D) architecture, designed to capture both spatial and temporal correlations in time-series imaging data. Predictions are made after each observation in the time series, with accuracy improving as more data arrive. We train the model on realistic simulations derived from Hyper Suprime-Cam (HSC) data, which closely matches LSST in depth and filters. This work focuses exclusively on Type Ia supernovae (SNe Ia). LSNe Ia are injected onto HSC luminous red galaxies (LRGs) at various phases of evolution to create positive examples. Negative examples include variable sources from HSC Transient Survey (including unclassified transients), and simulated unlensed SNe Ia in LRG and spiral galaxies. Our multi-band model shows rapid classification improvements during the initial few observations and quickly reaches high detection efficiency: at a fixed false-positive rate (FPR) of $0.01\%$, the true-positive rate (TPR) reaches $\gtrsim 60\%$ by the 7th observation and exceeds $\gtrsim 70\%$ by the 9th. Among the negative examples, SNe in LRGs remain the primary source of FPR, as they can resemble their lensed counterparts under certain conditions. The model detects quads more effectively than doubles and performs better on systems with larger image separations. Although trained and tested on HSC-like data, our approach applies to any cadenced imaging survey, particularly LSST.

To give more credence to the M-theoretic Emergence Proposal it is important to show that also classical kinetic terms in a low energy effective action arise as a quantum effect from integrating out light towers of states. We show that for compactifications of type IIA on Calabi-Yau manifolds, the classical weak coupling Yukawa couplings, which are the triple intersection numbers of the Calabi-Yau threefold, can be obtained from the 1/2-BPS protected one-loop Schwinger integral over $D2$-$D0$ bound states, after employing a novel regularization for the final infinite sum of Gopakumar-Vafa invariants. Approaching the problem in a consecutive manner from 6D decompactification over emergent string to the ultimate M-theory limits, we arrive at a mathematically concrete regularization that involves finite distance degeneration limits of Calabi-Yau threefolds in an intriguing way. We test and challenge this proposal by the concrete determination of the periods around such degeneration points for threefolds with one Kähler modulus and the two examples $\mathbb P_{1,1,1,6,9}[18]$ and $\mathbb P_{1,1,2,2,6}[12]$.

We present COSMOS2025, the COSMOS-Web catalog of photometry, morphology, photometric redshifts and physical parameters for more than 700,000 galaxies in the Cosmic Evolution Survey (COSMOS) field. This catalog is based on our \textit{James Webb Space Telescope} 255\,h COSMOS-Web program, which provides deep near-infrared imaging in four NIRCam (F115W, F150W, F277W, F444W) and one MIRI (F770W) filter over the central $\sim 0.54 {\, \rm deg}^2$ ($\sim 0.2 {\, \rm deg}^2$ for MIRI) in COSMOS. These data are combined with ground- and space-based data to derive photometric measurements of NIRCam-detected sources using both fixed-aperture photometry (on the space-based bands) and a profile-fitting technique on all 37 bands spanning 0.3-8 micron. We provide morphology for all sources from complementary techniques including profile fitting and machine-learning classification. We derive photometric redshifts, physical parameters and non-parametric star formation histories from spectral energy distribution (SED) fitting. The catalog has been extensively validated against previous COSMOS catalogs and other surveys. Photometric redshift accuracy measured using spectroscopically confirmed galaxies out to $z\sim9$ reaches $σ_{\rm MAD} = 0.012$ at $m_{\rm F444W}<28$ and remains at $σ_{\rm MAD} \lesssim 0.03$ as a function of magnitude, color, and galaxy type. This represents a factor of $\sim 2$ improvement at 26 AB mag compared to COSMOS2020. The catalog is approximately 80\% complete at $\log(M_{\star}/{\rm M}_{\odot}) \sim 9$ at $z \sim 10$ and at $\log(M_{\star}/{\rm M}_{\odot}) \sim 7$ at $z \sim 0.2$, representing a gain of 1\,dex compared to COSMOS2020. COSMOS2025 represents the definitive COSMOS-Web catalog. It is provided with complete documentation, together with redshift probability distributions, and it is ready for scientific exploitation today.

A commonly employed method to detect protoclusters in the young universe is the search for overdensities of massive star forming galaxies, such as submillimeter galaxies (SMGs), around high-mass halos, including those hosting quasars. In this work, we study the Megaparsec environment surrounding nine physically associated quasar pairs between $z=2.45$ and $z=3.82$ with JCMT/SCUBA-2 observations at 450 $μ$m and 850 $μ$m covering a field of view of roughly 13.7 arcmin in diameter (or 32 Mpc$^2$ at the median redshift) for each system. We identify a total of 170 SMG candidates and 26 non-SMG and interloper candidates. A comparison of the underlying 850 $μ$m source models recovered with Monte Carlo simulations to the blank field model reveals galaxy overdensities in all fields, with a weighted average overdensity factor of $δ_{\rm cumul} = 3.4 \pm 0.3$. From this excess emission at 850 $μ$m, we calculate a star formation rate density of $1700 \pm 100$ M$_{\odot}$ yr$^{-1}$ Mpc$^{-3}$, consistent with predictions from protocluster simulations and observations. Compared to fields around single quasars, those surrounding quasar pairs have higher excess counts and more centrally peaked star formation, further highlighting the co-evolution of SMGs and quasars. We do not find preferential alignment of the SMGs with the quasar pair direction or their associated Ly$α$ nebulae, indicating that cosmic web filaments on different scales might be traced by the different directions. Overall, this work substantiates the reliability of quasar pairs to detect overdensities of massive galaxies and likely sites of protocluster formation. Future spectroscopic follow-up observations are needed to confirm membership of the SMG candidates with the physically associated quasar pairs and definitively identify the targeted fields as protoclusters.

We develop a new approach to Vlasov Perturbation Theory (VPT) that solves for the hierarchy of cumulants of the phase-space distribution function to arbitrarily high truncation order in the context of cosmological structure formation driven by collisionless dark matter. We investigate the impact of higher cumulants on density and velocity power spectra as well as the bispectrum, and compare to scale-free <inline-formula><mml:math><mml:mi>N</mml:mi></mml:math></inline-formula>-body simulations. While there is a strong difference between truncation at the first cumulant, i.e., standard perturbation theory (SPT), and truncation at the second (i.e., including the velocity dispersion tensor), the third cumulant has a small quantitative impact and fourth and higher cumulants only have a minor effect on these summary statistics at weakly non-linear scales. We show that spurious exponential growth is absent in vector and tensor modes if scalar-mode constraints on the non-Gaussianity of the background distribution function that results from shell crossing are satisfied, guaranteeing the screening of UV modes for all fluctuations of any type, as expected physically. We also show analytically that loop corrections to the power spectrum are finite within VPT for any initial power spectra consistent with hierarchical clustering, unlike SPT. Finally, we discuss the relation to and contrast our predictions with effective field theory (EFT), and discuss how the advantages of VPT and EFT approaches could be combined.

Quantum simulators offer great potential for investigating dynamical properties of quantum field theories. However, preparing accurate non-trivial 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 1+1 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.

The mass accretion rate of galaxy clusters is a key factor in determining their structure, but a reliable observational tracer has yet to be established. We present a state-of-the-art machine learning model for constraining the mass accretion rate of galaxy clusters from only X-ray and thermal Sunyaev─Zeldovich observations. Using idealized mock observations of galaxy clusters from the MillenniumTNG simulation, we train a machine learning model to estimate the mass accretion rate. The model constrains 68% of the mass accretion rates of the clusters in our data set to within 33% of the true value without significant bias, a ∼58% reduction in the scatter over existing constraints. We demonstrate that the model uses information from both radial surface brightness density profiles and asymmetries.

Since the dawn of physics, the task of the experimental physicist has been to design a setup and perform measurements. A new development has become clear: After the data has been measured, modern computation allows us to further extract information. This work presents a collection of new techniques based on numerical methods in statistics and machine learning for the IceCube Neutrino Observatory. It aims to extend the analysis possibilities in particle physics and neutrino astronomy.

Neutron beta decay offers many tests of the Standard Model of particle physics, including the determination of the beta asymmetry and the Fierz interference term. I present systematic studies regarding the recent Perkeo III measurement campaign with the aim to extract the Fierz term and the electron backscatter behavior in both Perkeo III and the new spectrometer PERC. I also present a design for PERC’s secondary detector and a measurement of the neutron depolarization induced by supermirrors.

Supernovae (SNe) are among the most energetic events in the Universe, injecting vast amounts of energy and enriched material into the interstellar medium (ISM). Their ashes, usually referred to as supernova remnants (SNRs) or superbubbles (SBs) in the case SNRs powered by the clustered explosions of many stars, play a central role in shaping the multiphase structure of the ISM, driving turbulence, regulating star formation, and contributing to galactic outflows. Despite their importance, many aspects of their long-term evolution and interaction with their galactic environment remain poorly understood, particularly in the context of a realistic, structured ISM.

In this thesis, I explore the dynamical evolution of SNRs across a range of scales and physical conditions. I begin by developing a novel one-zone blastwave model, based on the thin-shell and sector approximations, that is designed to capture the expansion of SNRs in non-uniform, time-dependent environments, including the effects of gravity, shear induced by differential rotation, and cooling. This model reproduces known analytic limits and serves as a foundation for exploring more complex configurations.

We present a readout electronics system designed for Compton scattering detection using silicon drift detectors (SDDs). This system represents the first component of a Compton telescope to be integrated into a CubeSat module as part of the ComPol project. The instrument is designed to observe Cygnus X-1, a binary system consisting of a black hole and a blue supergiant star, with the aim of measuring its X-ray spectrum and polarization. Through the detection of Compton events, the system will determine the angle and degree of polarization of the source. The payload consists of a Si-based detector to scatter the X-rays and a scintillating cerium bromide crystal (CeBr3) with silicon photon multiplier (SiPM) matrix for the detection of the scattered photons. The analog readout chain of the first detection system based on SDD matrices consists of charge preamplifiers, an analog pulse processor (ASIC), while a field programmable gate array (FPGA) module handles the digital data flow to the PC. Experimental characterisation of the prototype shows an energy resolution of 151 eV full width at half maximum (FWHM) with a shaping time of 3 μs. This paper presents the prototype boards designed for the final flight module, together with the results of tests performed with the prototype system.

Due to their inherent capabilities of capturing non-local dependencies, Transformer neural networks have quickly been established as the paradigmatic architecture for large language models and image processing. Next to these traditional applications, machine learning (ML) methods have also been demonstrated to be versatile tools in the analysis of image-like data of quantum phases of matter, e.g. given snapshots of many-body wave functions obtained in ultracold atom experiments. While local correlation structures in image-like data of physical systems can reliably be detected, identifying phases of matter characterized by global, non-local structures with interpretable ML methods remains a challenge. Here, we introduce the correlator Transformer (CoTra), which classifies different phases of matter while at the same time yielding full interpretability in terms of physical correlation functions. The network's underlying structure is a tailored attention mechanism, which learns efficient ways to weigh local and non-local correlations for a successful classification. We demonstrate the versatility of the CoTra by detecting local order in the Heisenberg antiferromagnet, and show that local gauge constraints in one- and two-dimensional lattice gauge theories can be identified. Furthermore, we establish that the CoTra reliably detects non-local structures in images of correlated fermions in momentum space (Cooper pairs) and that it can distinguish percolating from non-percolating images.

We apply the framework of Vlasov Perturbation Theory (VPT) to the two-loop matter power spectrum within $Λ$CDM cosmologies. The main difference to Standard Perturbation Theory (SPT) arises from taking the velocity dispersion tensor into account, and the resulting screening of the backreaction of UV modes renders loop integrals cutoff-independent. VPT is informed about non-perturbative small scale dynamics via the average value of the dispersion generated by shell-crossing, which impacts the evolution of perturbations on weakly non-linear scales. When using an average dispersion from halo models, the VPT power spectrum agrees with the one from the simulation, up to differences from missing three-loop contributions. Alternatively, treating the average dispersion as free parameter we find a remarkably stable prediction of the matter power spectrum from collisionless dynamics at percent level for a wide range of the dispersion scale. We quantify the impact of truncating the Vlasov hierarchy for the cumulants of the phase-space distribution function, finding that the two-loop matter power spectrum is robust to neglecting third and higher cumulants. Finally, we introduce and validate a simplified fast scheme fVPT that can be easily incorporated into existing codes and is as numerically efficient as SPT.

Most young stars and therefore planetary systems form in high-mass star forming regions and are exposed to ultraviolet radiation, affecting the protoplanetary disk. These regions are located at large distances and only now with JWST become accessible to study the inner disks surrounding young stars. We present the eXtreme UV Environments (XUE) program, which provides the first detailed characterization of the physical and chemical properties of the inner disks around young intermediate-mass stars exposed to external irradiation from nearby massive stars. We present high signal to noise MIRI-MRS spectroscopy of 12 disks located in three sub-clusters of the high-mass star-forming region NGC 6357. Based on their mid-infrared spectral energy distribution, we classify the XUE sources into Group I and II based on the Meeus scheme. We analyze their molecular emission features, and compare their spectral indices and 10 $μ$m silicate emission profiles to those of nearby Herbig and intermediate T Tauri disks. Despite being more massive, the XUE stars host disks with molecular richness comparable to isolated T Tauri systems. The 10 $μ$m silicate features show lower F$_{11.3}$/F$_{9.8}$ ratios at a given F$_{\mathrm{peak}}$, but current uncertainties prevent conclusions about their inner disk properties. Most disks display water emission from the inner disk, suggesting that even in these extreme environments rocky planets can form in the presence of water. The absence of strong line fluxes and other irradiation signatures suggests that the XUE disks have been truncated by external UV photons. However, this truncation does not appear to significantly impact the chemical richness of their inner regions. These findings indicate that even in extreme environments, IMTT disks can retain the ingredients necessary for rocky planet formation.

Individual stars in the Milky Way (MW) and its satellites have been shown to trace galaxy stellar mass dependent sequences in the $α$-abundance ([$α$/Fe]) vs metallicity ([Fe/H]) plane. Testing the universality of such sequences has been elusive as deep absorption-line spectra required for [$α$/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 [$α$/Fe] vs [Fe/H] for stars, we now have log(O/Ar) vs 12+log(Ar/H) for the integrated nebular light of star-forming galaxies (SFGs). From Sloan-Digital Sky Survey (SDSS) observations of $\sim3000$ SFGs out to z$\sim0.3$, 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) vs 12+log(Ar/H) plane. We show that higher (<M$\rm_{*}$>$\sim2.6\times10^9$M$_{\odot}$) and lower mass (<M$\rm_{*}$>$\sim1.7\times10^7$M$_{\odot}$) SFGs clearly trace distinct mass dependent sequences in this plane, qualitatively consistent with the mass dependence of chemical enrichment sequences observed for the stars in the MW and its satellites. Such sequences are consistent with expectations from galaxy chemical evolution (GCE) models that are driven primarily by the interplay of core-collapse and Type Ia supernovae.

We present a very deep CO(3-2) observation of a massive, gas-rich, main sequence, barred spiral galaxy at $z\approx1.52$. Our data were taken with the IRAM-NOEMA interferometer for a 12-antenna equivalent on-source integration time of $\sim$ 50 hours. We fit the major axis kinematics using forward modelling of a rotating disk, and then subtract the two-dimensional beam convolved best-fit model revealing signatures of planar non-circular motions in the residuals. The inferred in-plane radial velocities are remarkably large, of the order of $\approx60$ km/s. Direct comparisons with a high-resolution, simulated, gas-rich, barred galaxy, obtained with the moving mesh code AREPO and the TNG sub-grid model, show that the observed non-circular gas flows can be explained as radial flows driven by the central bar, with an inferred net inflow rate of the order of the SFR. Given the recent evidence for a higher-than-expected fraction of barred disk galaxies at cosmic noon, our results suggest that rapid gas inflows due to bars could be important evolutionary drivers for the dominant population of star-forming galaxies at the peak epoch of star and galaxy formation.

The liquid-vapor transition is a classic example of a discontinuous (first-order) phase transition. Such transitions underlie many phenomena in cosmology, nuclear and particle physics, and condensed-matter physics. They give rise to long-lived metastable states, whose decay can be driven by either thermal or quantum fluctuations. Yet, direct experimental observations of how these states collapse into a stable phase remain elusive in the quantum regime. Here, we use a trapped-ion quantum simulator to observe the real-time dynamics of ``bubble nucleation'' induced by quantum fluctuations. Bubbles are localized domains of the stable phase which spontaneously form, or nucleate, and expand as the system is driven across a discontinuous quantum phase transition. Implementing a mixed-field Ising spin model with tunable and time-dependent interactions, we track the microscopic evolution of the metastable state as the Hamiltonian parameters are varied in time with various speeds, bringing the system out of equilibrium. Site-resolved measurements reveal the emergence and evolution of finite-size quantum bubbles, providing direct insight into the mechanism by which the metastable phase decays. We also identify nonequilibrium scaling behavior near the transition, consistent with a generalized Kibble-Zurek mechanism. Our results demonstrate the power of quantum simulators to probe out-of-equilibrium many-body physics, including quantum bubble nucleation, a key feature of discontinuous quantum phase transitions, with application to studies of matter formation in the early universe.

Heavy chemical elements such as iron in the intra-cluster medium (ICM) of galaxy clusters are a signpost of the interaction between the gas and stellar components. Observations of the ICM metallicity in present-day massive systems, however, pose a challenge to the underlying assumption that the cluster galaxies have produced the amount of iron that enriches the ICM. We evaluate the iron share between ICM and stars within simulated galaxy clusters with the twofold aim of investigating the origin of possible differences with respect to observational findings and of shedding light on the observed excess of iron on the ICM with respect to expectations based on the observed stellar population. We evaluated the iron mass in gas and stars in a sample of 448 simulated systems with masses M500 > 1e14 Msun at z=0.07. These were extracted from the high-resolution (352 cMpc/h)^3 volume of the Magneticum cosmological hydrodynamical simulations. We compared our results with observational data of low-redshift galaxy clusters. The iron share in simulated clusters features a shallow dependence on the total mass, and its value is close to unity on average. In the most massive simulated systems, the iron share is thus smaller than observational values by almost an order of magnitude. The dominant contribution to this difference is related to the stellar component, whereas the chemical properties of the ICM agree well overall with the observations. We find larger stellar mass fractions in simulated massive clusters, which in turn yield higher stellar iron masses, than in observational data. Consistently with the modelling, we confirm that the stellar content within simulated present-day massive systems causes the metal enrichment in the ICM. It will be crucial to alleviate the stellar mass discrepancy between simulations and observations to definitely assess the iron budget in galaxy clusters.

We present analysis of the plateau and late-time phase properties of a sample of 39 Type II supernovae (SNe II) that show narrow, transient, high-ionization emission lines (i.e., "IIn-like") in their early-time spectra from interaction with confined, dense circumstellar material (CSM). Originally presented by Jacobson-Galán et al 2024a, this sample also includes multicolor light curves and spectra extending to late-time phases of 35 SNe with no evidence for IIn-like features at <2 days after first light. We measure photospheric phase light-curve properties for the distance-corrected sample and find that SNe II with IIn-like features have significantly higher luminosities and decline rates at +50 days than the comparison sample, which could be connected to inflated progenitor radii, lower ejecta mass, and/or persistent CSM interaction. However, we find no statistical evidence that the measured plateau durations and $^{56}$Ni masses of SNe II with and without IIn-like features arise from different distributions. We estimate progenitor zero-age main sequence (ZAMS) masses for all SNe with nebular spectroscopy through spectral model comparisons and find that most objects, both with and without IIn-like features, are consistent with progenitor masses <12.5 M$_{\odot}$. Combining progenitor ZAMS masses with CSM densities inferred from early-time spectra suggests multiple channels for enhanced mass loss in the final years before core collapse such as a convection-driven chromosphere or binary interaction. Finally, we find spectroscopic evidence for ongoing ejecta-CSM interaction at radii $>10^{16}$ cm, consistent with substantial progenitor mass-loss rates of $\sim 10^{-4}$--$10^{-5}$ M$_{\odot}$ yr$^{-1}$ ($v_w < 50$ km/s) in the final centuries to millennia before explosion.

Context. We present simulations of a massive young star cluster using \textsc{Nbody6++GPU} and \textsc{MOCCA}. The cluster is initially more compact than previously published models, with one million stars, a total mass of $5.86 \times 10^5~\mathrm{M}_{\odot}$, and a half-mass radius of $0.1~\mathrm{pc}$. Aims. We analyse the formation and growth of a very massive star (VMS) through successive stellar collisions and investigate the subsequent formation of an intermediate-mass black hole (IMBH) in the core of a dense star cluster. Methods. We use both direct \textit{N}-body and Monte Carlo simulations, incorporating updated stellar evolution prescriptions (SSE/BSE) tailored to massive stars and VMSs. These include revised treatments of stellar radii, rejuvenation, and mass loss during collisions. While the prescriptions represent reasonable extrapolations into the VMS regime, the internal structure and thermal state of VMSs formed through stellar collisions remain uncertain, and future work may require further refinement. Results. We find that runaway stellar collisions in the cluster core produce a VMS exceeding $5 \times 10^4~\mathrm{M}_{\odot}$ within 5 Myr, which subsequently collapses into an IMBH. Conclusions. Our model suggests that dense stellar environments may enable the formation of very massive stars and massive black hole seeds through runaway stellar collisions. These results provide a potential pathway for early black hole growth in star clusters and offer theoretical context for interpreting recent JWST observations of young, compact clusters at high redshift.

Virtually all extragalactic use cases of the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) require the use of galaxy redshift information, yet the vast majority of its sample of tens of billions of galaxies will lack high-fidelity spectroscopic measurements thereof, instead relying on photometric redshifts (photo-$z$) subject to systematic imprecision and inaccuracy best encapsulated by photo-$z$ probability density functions (PDFs). We present the version 1 release of Redshift Assessment Infrastructure Layers (RAIL), an open source Python library for at-scale probabilistic photo-$z$ estimation, initiated by the LSST Dark Energy Science Collaboration (DESC) with contributions from the LSST Interdisciplinary Network for Collaboration and Computing (LINCC) Frameworks team. RAIL's three subpackages provide modular tools for end-to-end stress-testing, including a forward modeling suite to generate realistically complex photometry, a unified API for estimating per-galaxy and ensemble redshift PDFs by an extensible set of algorithms, and built-in metrics of both photo-$z$ PDFs and point estimates. RAIL serves as a flexible toolkit enabling the derivation and optimization of photo-$z$ data products at scale for a variety of science goals and is not specific to LSST data. We thus describe to the extragalactic science community, including and beyond Rubin the design and functionality of the RAIL software library so that any researcher may have access to its wide array of photo-$z$ characterization and assessment tools.

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 $\mathcal{O}$(100) detectors with different masses ranging from $\sim$2g to $\sim$24g, 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.

Effective Field Theory (EFT) modeling is expected to be a useful tool in the era of future higher-redshift galaxy surveys such as DESI-II and Spec-S5 due to its robust description of various large-scale structure tracers. However, large values of EFT bias parameters of higher-redshift galaxies could jeopardize the convergence of the perturbative expansion. In this paper we measure the bias parameters and other EFT coefficients from samples of two types of star-forming galaxies in the state-of-the-art MilleniumTNG and Astrid hydrodynamical simulations. Our measurements are based on the field-level EFT forward model that allows for precision EFT parameter measurements by virtue of cosmic variance cancellation. Specifically, we consider approximately representative samples of Lyman-break galaxies (LBGs) and Lyman-alpha emitters (LAEs) that are consistent with the observed (angular) clustering and number density of these galaxies at $z=3$. Reproducing the linear biases and number densities observed from existing LAE and LBG data, we find quadratic bias parameters that are roughly consistent with those predicted from the halo model coupled with a simple halo occupation distribution model. We also find non-perturbative velocity contributions (Fingers of God) of a similar size for LBGs to the familiar case of Luminous Red Galaxies. However, these contributions are quite small for LAEs despite their large satellite fraction values of up to $\sim 30\%$. Our results indicate that the effective momentum reach $k_{\rm{Max}}$ at $z=3$ for LAEs (LBGs) will be in the range $0.3-0.6 ~h\rm{Mpc}^{-1}$ ($0.2-0.8~h\rm{Mpc}^{-1}$), suggesting that EFT will perform well for high redshift galaxy clustering. This work provides the first step toward obtaining realistic simulation-based priors on EFT parameters for LAEs and LBGs.

We present one of the largest uniform optical spectroscopic surveys of X-ray selected sources to date that were observed as a pilot study for the Black Hole Mapper (BHM) survey. The BHM program of the Sloan Digital Sky Survey (SDSS)-V is designed to provide optical spectra for hundreds of thousands of X-ray selected sources from the SRG/eROSITA all-sky survey. This significantly improves our ability to classify and characterise the physical properties of large statistical populations of X-ray emitting objects. Our sample consists of 13079 sources in the eROSITA eFEDS performance verification field, 12011 of which provide reliable redshifts from 0<z<5.8. The vast majority of these objects were detected as point-like sources (X-ray flux limit F(0.5-2 keV)>6.5x10^-15 erg/s/cm^2) and were observed for about 20 years with fibre-fed SDSS spectrographs. After including all available redshift information for the eFEDS sources from the dedicated SDSS-V plate programme and archival data, we visually inspected the SDSS optical spectra to verify the reliability of these redshift measurements and the performance of the SDSS pipeline. The visual inspection allowed us to recover reliable redshifts (for 99% of the spectra with a signal-to-noise ratio of >2) and to assign classes to the sources, and we confirm that the vast majority of our sample consists of active galactic nuclei (AGNs). Only ~3% of the eFEDS/SDSS sources are Galactic objects. We also show the diversity of the optical spectra of the X-ray selected AGNs and provide spectral stacks with a high signal-to-noise ratio in various sub-samples with different redshift and optical broad-band colours. Our AGN sample contains optical spectra of (broad-line) quasars, narrow-line galaxies, and optically passive galaxies. It is considerably diverse in its colours and in its levels of nuclear obscuration.

Nuclear fission leads to the splitting of a nucleus into two fragments^1,2. Studying the distribution of the masses and charges of the fragments is essential for establishing the fission mechanisms and refining the theoretical models^3,4. It has value for our understanding of r-process nucleosynthesis^5,6, in which the fission of nuclei with extreme neutron-to-proton ratios is pivotal for determining astrophysical abundances and understanding the origin of the elements⁷ and for energy applications^8,9. Although the asymmetric distribution of fragments is well understood for actinides (elements in the periodic table with atomic numbers from 89 to 103) based on shell effects¹⁰, symmetric fission governs the scission process for lighter elements. However, unexpected asymmetric splits have been observed in neutron-deficient exotic nuclei¹¹, prompting extensive further investigations. Here we present measurements of the charge distributions of fission fragments for 100 exotic fissioning systems, 75 of which have never been measured, and establish a connection between the neutron-deficient sub-lead region and the well-understood actinide region. These new data comprehensively map the asymmetric fission island and provide clear evidence for the role played by the deformed Z = 36 proton shell of the light fragment in the fission of sub-lead nuclei. Our dataset will help constrain the fission models used to estimate the fission properties of nuclei with extreme neutron-to-proton ratios for which experimental data are unavailable.

Star clusters can interact and merge in galactic discs, haloes, or centres. We present direct N-body simulations of binary mergers of star clusters with <inline-formula><tex-math id="TM0001" notation="LaTeX">$M_{\star } = 2.7 \times 10^4 \, \mathrm{M_{\odot }}$</tex-math></inline-formula> each, using the N-body code BIFROST with subsystem regularization and post-Newtonian dynamics. We include 500 <inline-formula><tex-math id="TM0002" notation="LaTeX">$\mathrm{M_{\odot }}$</tex-math></inline-formula> massive black holes (MBHs) in the progenitors to investigate their impact on remnant evolution. The MBHs form hard binaries interacting with stars and stellar black holes (BHs). A few Myr after the cluster merger, this produces sizable populations of runaway stars (<inline-formula><tex-math id="TM0003" notation="LaTeX">$\sim$</tex-math></inline-formula>800 with <inline-formula><tex-math id="TM0004" notation="LaTeX">$v_{\mathrm{ej}} \gtrsim 50 \, \mathrm{km\, s^{-1}}$</tex-math></inline-formula>) and stellar BHs (<inline-formula><tex-math id="TM0005" notation="LaTeX">$\sim$</tex-math></inline-formula>30) escaping within 100 Myr. The remnants lose <inline-formula><tex-math id="TM0006" notation="LaTeX">$\sim 30{{\ \rm per\ cent}}$</tex-math></inline-formula> of their BH population and <inline-formula><tex-math id="TM0007" notation="LaTeX">$\sim 3{{\ \rm per\ cent}}$</tex-math></inline-formula> of their stars, with <inline-formula><tex-math id="TM0008" notation="LaTeX">$\sim$</tex-math></inline-formula>30 stars accelerated to high velocities <inline-formula><tex-math id="TM0009" notation="LaTeX">$\gtrsim 300 \, \mathrm{km\, s^{-1}}$</tex-math></inline-formula>. Comparison simulations of isolated clusters with central hard MBH binaries and cluster mergers without MBHs show that the process is driven by MBH binaries, while those with a single 1000 <inline-formula><tex-math id="TM0010" notation="LaTeX">$\mathrm{M_{\odot }}$</tex-math></inline-formula> MBH in isolated or merging clusters produce fewer runaway stars at lower velocities. Low-eccentricity merger orbits yield rotating remnants (<inline-formula><tex-math id="TM0011" notation="LaTeX">$v_{\mathrm{rot}} \sim 3 \, \mathrm{km\, s^{-1}}$</tex-math></inline-formula>), but probing the presence of MBHs via kinematics alone remains challenging. We expect the binary MBHs to merge within a Hubble time, producing observable gravitational-wave (GW) events detectable by future GW detectors such as the Einstein Telescope and Laser Interferometer Space Antenna. The results suggest that interactions with low-mass MBH binaries formed in merging star clusters are an important additional channel for producing runaway and high-velocity stars, free-floating stellar BHs, and compact objects.

In some scenarios, the dark matter relic abundance is set by the semi-annihilation of two dark matter particles into one dark matter particle and one Standard Model particle. These semi-annihilations might still be occurring today in the galactic center at a significant rate, generating a flux of boosted dark matter particles. We investigate the possible signals of this flux component in direct detection and neutrino experiments for sub-GeV dark matter masses. We show that for typical values of the semi-annihilation cross-section, the sensitivity of current experiments to the spin-independent dark matter-proton scattering cross-section can be several orders of magnitude larger than current constraints from cosmic-ray boosted dark matter. We also argue that the upcoming DARWIN and DUNE experiments may probe scattering cross-sections as low as <mml:math><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>‑</mml:mo><mml:mn>37</mml:mn></mml:mrow></mml:msup><mml:mspace></mml:mspace><mml:msup><mml:mrow><mml:mi>cm</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:math> for masses between 30 MeV and 1 GeV.

Turbulent flows are known to produce enhanced effective magnetic and passive scalar diffusivities, which can fairly accurately be determined with numerical methods. It is now known that, if the flow is also helical, the effective magnetic diffusivity is reduced relative to the nonhelical value. Neither the usual second-order correlation approximation nor the various τ approaches have been able to capture this. Here we show that the helicity effect on the turbulent passive scalar diffusivity works in the opposite sense and leads to an enhancement. We have also demonstrated that the correlation time of the turbulent velocity field increases with the kinetic helicity. This is a key point in the theoretical interpretation of the obtained numerical results. Simulations in which helicity is being produced self-consistently by stratified rotating turbulence resulted in a turbulent passive scalar diffusivity that was found to be decreasing with increasing rotation rate.

We investigated the ability of the Euclid telescope to detect galaxy-scale gravitational lenses. To do so, we performed a systematic visual inspection of the 0.7 deg² Euclid Early Release Observations data towards the Perseus cluster using both the high-resolution I_E band and the lower-resolution Y_E , J_E, and H_E bands. Each extended source brighter than magnitude 23 in I_E was inspected by 41 expert human classifiers. This amounts to 12086 stamps of 10″ × 10″. We found 3 grade A and 13 grade B candidates. We assessed the validity of these 16 candidates by modelling them and checking that they are consistent with a single source lensed by a plausible mass distribution. Five of the candidates pass this check, five others are rejected by the modelling, and six are inconclusive. Extrapolating from the five successfully modelled candidates, we infer that the full 14 000 deg² of the Euclid Wide Survey should contain 100 000_{‑30 000}^{+ 70 000} galaxy-galaxy lenses that are both discoverable through visual inspection and have valid lens models. This is consistent with theoretical forecasts of 170 000 discoverable galaxy-galaxy lenses in Euclid. Our five modelled lenses have Einstein radii in the range 0'.'68 < θ_E < 1″.24, but their Einstein radius distribution is on the higher side when compared to theoretical forecasts. This suggests that our methodology is likely missing small-Einstein-radius systems. Whilst it is implausible to visually inspect the full Euclid dataset, our results corroborate the promise that Euclid will ultimately deliver a sample of around 10⁵ galaxy-scale lenses. ★This paper is published on behalf of the Euclid Consortium.

We present the ALMA-CRISTAL survey, an ALMA Cycle 8 Large Program designed to investigate the physical properties of star-forming galaxies at $4 \lesssim z \lesssim 6$ through spatially resolved, multi-wavelength observations. This survey targets 19 star-forming main-sequence galaxies selected from the ALPINE survey, using ALMA Band 7 observations to study [CII] 158 $μ$m line emission and dust continuum, complemented by JWST/NIRCam and HST imaging to map stellar and UV emission. The CRISTAL sample expanded to 39 after including newly detected galaxies in the CRISTAL fields, archival data, and pilot study targets. The resulting dataset provides a detailed view of gas, dust, and stellar structures on kiloparsec scales at the end of the era of reionization. The survey reveals diverse morphologies and kinematics, including rotating disks, merging systems, [CII] emission tails from potential interactions, and clumpy star formation. Notably, the [CII] emission in many cases extends beyond the stellar light seen in HST and JWST imaging. Scientific highlights include CRISTAL-10, exhibiting an extreme [CII] deficit similar to Arp 220; and CRISTAL-13, where feedback from young star-forming clumps likely causes an offset between the stellar clumps and the peaks of [CII] emission. CRISTAL galaxies exhibit global [CII]/FIR ratios that decrease with increasing FIR luminosity, similar to trends seen in local galaxies but shifted to higher luminosities, likely due to their higher molecular gas content. CRISTAL galaxies also span a previously unexplored range of global FIR surface brightness at high-redshift, showing that high-redshift galaxies can have elevated [CII]/FIR ratios. These elevated ratios are likely influenced by factors such as lower metallicity gas, the presence of significant extraplanar gas, and contributions from shock-excited gas.

Mass transfer in binary systems is the key process in the formation of various classes of objects, including merging binary black holes (BBHs) and neutron stars. Orbital evolution during mass transfer depends on how much mass is accreted and how much angular momentum is lost $-$ two of the main uncertainties in binary evolution. Here, we demonstrate that there is a fundamental limit to how close binary systems can get via stable mass transfer (SMT), that is robust against uncertainties in orbital evolution. Based on detailed evolutionary models of interacting systems with a BH accretor and a massive star companion, we show that the post-interaction orbit is always wider than $\sim10R_{\odot}$, even when extreme shrinkage due to L2 outflows is assumed. Systems evolving towards tighter orbits become dynamically unstable and result in stellar mergers. This separation limit has direct implications for the properties of BBH mergers: long delay times ($\gtrsim1 \rm Gyr$), and no high BH spins from the tidal spin-up of helium stars. At high metallicity, the SMT channel may be severely quenched due to Wolf-Rayet winds. The reason for the separation limit lies in the stellar structure, not in binary physics. If the orbit gets too narrow during mass transfer, a dynamical instability is triggered by a rapid expansion of the remaining donor envelope due to its near-flat entropy profile. The closest separations can be achieved from core-He burning ($\sim8-15R_{\odot}$) and Main Sequence donors ($\sim15-30R_{\odot}$), while Hertzsprung Gap donors lead to wider orbits ($\gtrsim30-50R_{\odot}$) and non-merging BBHs. These outcomes and mass transfer stability are determined by the entropy structures, which are governed by internal composition profiles. The formation of compact binaries is thus sensitive to chemical mixing in stars and may relate to the blue-supergiant problem.

RNA and proteins are the foundation of life and a natural starting point to explore its origins. However, the prebiotic relationship between the two is asymmetric. While RNA evolved to assemble proteins from amino acids, a significant mirror-symmetric effect of amino acids to trigger the synthesis of RNA was missing. We describe ambient alkaline conditions where amino acids, without additional chemical activators, promote RNA copolymerisation more than 100-fold, starting from prebiotically plausible ribonucleoside-2′,3′-cyclic phosphates. The observed effect is explained by acid-base catalysis, with optimal efficiency at pH values near the amine pKaH. The fold-change in oligomerisation yield is nucleobase-selective, resulting in increased compositional diversity necessary for subsequent molecular evolution and favouring the formation of natural 3′−5′ linkages. The elevated pH offers recycling of oligonucleotide sequences back to 2′,3′-cyclic phosphates, providing conditions for high-fidelity replication by templated ligation. The findings reveal a clear functional role of amino acids in the evolution of RNA earlier than previously assumed.

We present a novel way of probing non-gravitational dark matter interactions: dark astronomy, which leverages the dark radiation emitted by dissipative dark sectors. If the mediator of the dark matter self interactions is a dark photon with a small mass that kinetically mixes with the visible photon, the dark radiation flux becomes accessible to underground experiments. We argue that the emission may be dominantly longitudinally polarized, thereby enhancing the sensitivity of direct detection experiments such as XENON and SENSEI to this signal. We introduce a new detection mechanism based on resonant dark-photon-to-photon conversion at the surface of conducting materials, which offers unique directional sensitivity to dark radiation. This mechanism facilitates the development of experiments that combine dark matter detection techniques with methods of traditional astronomy, opening the possibility to map dark radiation sources within our galaxy.

We revisit the theory of background fields constructed on the BRST-algebra of a spinning particle with <inline-formula><mml:math><mml:mi>N</mml:mi></mml:math></inline-formula> = 4 worldline supersymmetry, whose spectrum contains the graviton but no other fields. On a generic background, the closure of the BRST-algebra implies the vacuum Einstein equations with a cosmological constant that is undetermined. On the other hand, in the "vacuum" background with no metric, the cohomology is given by a collection of free scalar- and vector fields. However, we show that only certain combinations of linear excitations, involving a vector field, can be extended beyond the linear level in turn, an Einstein metric in space-time.

A generalization of Wilson line operators at subleading power in the soft expansion has been recently introduced as an efficient building block of gravitational scattering amplitudes for non-spinning objects. The classical limit in this picture corresponds to the strict Regge limit, where the Post-Minkowskian (PM) expansion corresponds to the soft expansion, interpreted as a sum over correlations of soft emissions. Building on the well-studied worldline model with <inline-formula><tex-math>$$\mathcal{N}$$</tex-math></inline-formula> = 1 supersymmetry, in this work we extend the generalized Wilson line (GWL) approach to the case of spinning gravitating bodies. Specifically, at the quantum level we derive from first-principles a representation for the spin 1/2 GWL that is relevant for the all-order factorization of next-to-soft gravitons with fermionic matter, thus generalizing the exponentiation of single-emission next-to-soft theorems. At the classical level, we identify the suitable generalization of Wilson line operators that enables the generation of classical spin observables at linear order in spin. Thanks to the crucial role played by the soft expansion, the map from Grassmann variables to classical spin is manifest. We also comment on the relation between the GWL approach and the Worldline Quantum Field Theory as well as the Heavy Mass Effective Theory formalism. We validate the approach by rederiving known results in the conservative sector at 2PM order.

Muon conversion is one of the best probes of charged lepton flavor violation. The experimental limit is soon expected to improve by four orders of magnitude, thus calling for precise predictions of the shape of the signal spectrum. Equally important are precise predictions for muon decay-in-orbit, the main background for muon conversion. While the calculation of electromagnetic corrections to the two processes above the nuclear scale does not involve significant challenges, it becomes substantially more complex below that scale due to multiple scales, bound-state effects and experimental setup. Here, we present a systematic framework that addresses these challenges by resorting to a series of effective field theories. Combining Heavy Quark Effective Theory (HQET), Non-Relativistic QED (NRQED), potential NRQED, Soft-Collinear Effective Theory I and II, and boosted HQET, we derive a factorization theorem and present the renormalization group equations. Our framework allows for the proper calculation of precise predictions for the rates of the two processes, with crucial implications for the upcoming muon conversion searches. We also provide the most accurate prediction of the signal shape for those searches.

Feynman integrals are very often computed from their differential equations. It is not uncommon that the ɛ-factorised differential equation contains only dlog-forms with algebraic arguments, where the algebraic part is given by (multiple) square roots. It is well-known that if all square roots are simultaneously rationalisable, the Feynman integrals can be expressed in terms of multiple polylogarithms. This is a sufficient, but not a necessary criterium. In this paper we investigate weaker requirements. We discuss under which conditions we may use different rationalisations in different parts of the calculation. In particular we show that we may use different rationalisations if they correspond to different parameterisations of the same integration path. We present a non-trivial example — the one-loop pentagon function with three adjacent massive external legs involving seven square roots — where this technique can be used to express the result in terms of multiple polylogarithms.

We renormalize the soft function entering the factorization and resummation of the qg parton-scattering channel of the Drell-Yan process near the kinematic threshold <inline-formula><mml:math><mml:mover><mml:mi>s</mml:mi><mml:mo>̂</mml:mo></mml:mover></mml:math></inline-formula> → Q² at next-to-leading power in the expansion around z ≡ Q²/<inline-formula><mml:math><mml:mover><mml:mi>s</mml:mi><mml:mo>̂</mml:mo></mml:mover></mml:math></inline-formula> = 1, and solve its renormalization-group equation.

We here measure, for the first time, adjoint chromoelectric correlators at finite temperatures that encode the diffusion of quarkonium in the medium. Understanding the dynamics of quarkonium in the QGP plays an essential role in understanding quarkonium suppression and the QGP in general. We perform SU(3) gauge theory calculations and use gradient flow to improve the signal-to-noise ratio and chromoelectric field discretizations. The continuum limit and the zero-flow-time extrapolation are performed, and the final result is compared with perturbative results. We observe that the correlators at a high temperature are well described by the perturbative form; furthermore, we observe multiplicative scaling of the adjoint correlators with respect to the fundamental correlator describing heavy quark diffusion.

Collective oscillations in dense neutrino gases (flavor waves) are notable for their instabilities that cause fast flavor conversion. We develop a quantum theory of interacting neutrinos and flavor wave quanta, which are analogous to plasmons but also carry flavor. The emission or absorption of such flavor plasmons <inline-formula><mml:math><mml:mi>ψ</mml:mi></mml:math></inline-formula>, or "flavomons," changes the neutrino flavor. When an angular crossing occurs, the process <inline-formula><mml:math><mml:mrow><mml:msub><mml:mrow><mml:mi>ν</mml:mi></mml:mrow><mml:mrow><mml:mi>μ</mml:mi></mml:mrow></mml:msub><mml:mo>→</mml:mo><mml:msub><mml:mrow><mml:mi>ν</mml:mi></mml:mrow><mml:mrow><mml:mi>e</mml:mi></mml:mrow></mml:msub><mml:mo>+</mml:mo><mml:mi>ψ</mml:mi></mml:mrow></mml:math></inline-formula> is more rapid than its inverse along the direction of the crossing, triggering stimulated <inline-formula><mml:math><mml:mi>ψ</mml:mi></mml:math></inline-formula> emission and fast instability. Calculating the rate via Feynman diagrams matches the fast instability growth rate. Our novel <inline-formula><mml:math><mml:mi>ν</mml:mi></mml:math></inline-formula> and <inline-formula><mml:math><mml:mi>ψ</mml:mi></mml:math></inline-formula> kinetic equations, corresponding to quasilinear theory, describe instability evolution without resolving the small scales of the flavomon wavelength, potentially overcoming the main challenge of fast flavor evolution.

Ongoing and upcoming wide-field surveys at different wavelengths will measure the distribution of galaxy clusters with unprecedented precision, demanding accurate models for the two-point correlation function (2PCF) covariance. In this work we assessed a semi-analytical framework for the cluster 2PCF covariance that employs three nuisance parameters to account for non-Poissonian shot noise, residual uncertainties in the halo bias model, and sub-leading noise terms. We calibrated these parameters on a suite of fast approximate simulations generated by PINOCCHIO as well as full N-body simulations from OpenGADGET3. We demonstrate that PINOCCHIO can reproduce the 2PCF covariance measured in OpenGADGET3 at the few percent level, provided the mass functions are carefully rescaled. Resolution tests confirm that high particle counts are necessary to capture shot-noise corrections, especially at high redshifts. We performed the parameter calibration across multiple cosmological models, showing that one of the nuisance parameters, the non-Poissonian shot-noise correction (α), depends mildly on the amplitude of matter fluctuations (σ₈). In contrast, the remaining two parameters, β, which controls the bias correction, and γ, which controls the secondary shot-noise correction, exhibit more significant variation with redshift and halo mass. Overall, our results underscore the importance of calibrating covariance models on realistic mock catalogs that replicate the selection function of forthcoming surveys and highlight that approximate methods, when properly tuned, can effectively complement full N-body simulations for precision cluster cosmology.

Context. AGN feedback is a crucial ingredient for understanding galaxy evolution. However, a complete quantitative time-dependent framework, including the dependence of such feedback on AGN, host galaxy, and host halo properties, is yet to be developed. Aims. Using the complete sample of 682 radio AGN from the LOFAR-eFEDS survey (z < 0.4), we derive the average jet power of massive galaxies and its variation as a function of stellar mass (M_*), halo mass (M_h) and radio morphology. Methods. We compare the incidence distributions of compact and complex radio AGN as a function of specific black hole kinetic power, λ_Jet, and synthesise, for the first time, the radio luminosity function (RLF) by M_* and radio morphology. Our RLF and derived total radio AGN kinetic luminosity density, log Ω_kin/[W Mpc^‑3] = 32.15_‑0.34^+0.18, align with previous work. Results. Kinetic feedback from radio AGN dominates over any plausible inventory of radiatively driven feedback for galaxies with log M_*/M_⊙ > 10.6. More specifically, it is the compact radio AGN that dominate this global kinetic energy budget for all but the most massive galaxies (10.6 < log M_*/M_⊙ < 11.5). Subsequently, we compare the average injected jet energy (E̅_Jet) against the galaxy and halo binding energy (U_bin), and against the total thermal energy of the host gas (E_th) within halos. We find that compact radio AGN lack the energy to fully unbind galaxies, but complex AGN reach E̅_Jet > U_bin in the most massive systems (log M_*/M_⊙ > 11.5), where such energy is likely deposited beyond the typical galaxy sizes. On halo scales, neither compact nor complex radio AGN provide enough energy to fully disrupt the global gas distribution, especially not for the most massive clusters. On the other hand, E̅_Jet greatly surpasses the global E_th for groups, thereby providing a crucial input to the gas and thermodynamical balance in these systems. Finally, we show that AGN jets can also significantly impact the local thermodynamical balance in the cores of large groups and massive clusters. Overall, our findings provide important insights into jet powering, accretion processes and black hole-galaxy coevolution via AGN feedback.

Future ground- and space-based telescopes will enable the characterization of rocky exoplanets in reflected light, allowing for the observation of their albedo, which depends on surface, cloud, and atmospheric properties. Identifying key atmospheric, cloud, and surface features is essential for assessing the potential habitability of these exoplanets. We present reference spectra and phase curves for a spatially unresolved Earth-like exoplanet in reflected and polarized light, highlighting how wavelength-dependent and phase-angle-dependent reflectance reveals key planetary properties. Performing simulations with the 3D Monte Carlo radiative transfer code MYSTIC, we improve surface and cloud modeling by introducing validated wavelength-dependent albedo maps of Earth's seasonal and spectral features, as well as a novel treatment of subgrid cloud variability and inhomogeneities based on reanalysis data from ERA5. Our models incorporate high-resolution 3D cloud structures, demonstrating that subgrid cloud variability significantly affects both intensity and polarization. It reduces total reflectance and increases phase curve variability, especially at large phase angles where ocean glint dominates. Additionally, we show that neglecting realistic wavelength-dependent albedo maps leads to a significant overestimation of the vegetation red edge feature in reflected light spectra. Comparing an ocean planet to an Earth-like planet with seasonal cloud variability, we find that polarization is far more sensitive than intensity alone to identify the two scenarios. Moreover, polarization captures richer information on surface properties, making it a critical tool for breaking degeneracies in retrieval frameworks. We present detailed model simulations that provide a ground-truth reference for observing Earth as an exoplanet and that serve as critical benchmarks for developing observational strategies and retrieval frameworks for future telescopes targeting small rocky exoplanets. Furthermore, this study informs model requirements and establishes a framework to optimize strategies for characterizing rocky exoplanets, emphasizing the pivotal role of polarization in breaking retrieval degeneracies across different models.

We describe a family of twisted partition functions for the relativistic spinning particle models. For suitable choices of fugacities this computes a refined Euler characteristics that counts the dimension of the physical states for arbitrary picture and, furthermore, encodes the complete BV-spectrum of the effective space-time gauge theory originating from this model upon second quantization. The relation between twisted world-line partition functions and the spectrum of the space-time theory is most easily seen on-shell but we will give an off-shell description as well. Finally we discuss the construction of a space-time action in terms of the world-line fields in analogy to string field theory.

An accretion-induced collapse (AIC) or merger-induced collapse (MIC) of white dwarfs (WDs) in binary systems is an interesting path to neutron star (NS) and magnetar formation, alternative to stellar core-collapse and NS mergers. Such events could add a population of compact remnants in globular clusters; they are expected to produce yet unidentified electromagnetic transients including gamma-ray and radio bursts, and to act as sources of transiron elements, neutrinos, and gravitational waves. Here, we present the first long-term (≳5 s postbounce) hydrodynamical simulations in axisymmetry (2D), using an energy- and velocity-dependent three-flavor neutrino transport based on a two-moment scheme. Our set of six models includes initial WD configurations for different masses, central densities, rotation rates, and angular momentum profiles. Our simulations demonstrate that rotation plays a crucial role for the protoneutron star (PNS) evolution and ejecta properties. We find early neutron-rich ejecta and an increasingly proton-rich neutrino-driven wind at later times in a nonrotating model, in agreement with electron-capture supernova models. In contrast to that and different from previous results, our rotating models eject proton-rich material initially and increasingly more neutron-rich matter as time advances, because an extended accretion torus forms around the PNS and feeds neutrino-driven bipolar outflows for many seconds. AIC and MIC events are thus potential sites of r-process element production, which may imply constraints on their occurrence rates. Finally, our simulations neglect the effects of triaxial deformation and magnetic fields, yet they provide valuable reference cases for comparison with future long-term magnetohydrodynamic and 3D AIC studies.

Context. Through gravitational lensing, galaxy clusters can magnify supernovae (SNe) and thereby create multiple images of the same SN. This enables measurements of cosmological parameters (primarily the Hubble constant), which will be increasingly important in the context of upcoming surveys from the Nancy Grace Roman Space Telescope (Roman) and Vera C. Rubin Observatory. Aims. We study the prospects of detecting strongly lensed supernovae in cluster fiels with Roman's High Latitude Time Domain Survey (HLTDS) and the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST). Methods. We employed two approaches: one focusing on known multiply imaged galaxies (arcs) behind cluster fields, along with the SN rates specific to those galaxies (arc-specific), while the second is based on the expected number of lensed SNe exploding in a given volume behind a galaxy cluster (volumetric). We collected all the clusters in the literature that feature a) a well-constrained lens model and b) multiply imaged galaxies behind clusters with high-quality data for the multiply imaged galaxies behind clusters. This allowed us to determine the supernova rate for each galaxy. We provide predictions for 46 clusters visible to the Vera C. Rubin Observatory, as well as for 9 observable by Roman's HLTDS, depending on whether the clusters fall within the survey's observing field. Results. We predict that the number of multiply imaged SNe discovered by LSST in its first three years is 3.95 ± 0.89 from the first approach or 4.94 ± 1.02 from the second. Based on the current proposed observing strategy for the HLTDS, which specifies the requirements on galactic and ecliptic latitudes, the expected number of multiply imaged supernovae ranges from 0.38 ± 0.15 to 5.2 ± 2.2, depending on the specific cluster observed. However, the exact fields to be targeted remain a matter of discussion. Conclusions. We conclude that LSST offers great prospects for detecting multiply imaged SNe. If adequate follow-up campaigns are conducted, these capabilities will enable measurements of cosmological parameters independent of conventional probes. These predictions are effectively lower limits, as we only considered the most massive and well-studied clusters in the present work. Here, we provide a recommendation for HLTDS observing field selection, namely: either MACS J0553.4-3342 or Abell 1758a should be observed by the survey to maximize the number of potential multiply imaged SN discoveries.

Aims. The Spectrum Roentgen Gamma (SRG) eROSITA all-sky survey marks the beginning of the data-rich era by conducting population studies of tidal disruption events (TDEs) and other rare X-ray transients. This paper presents a systematic study of X-ray-selected canonical TDEs discovered in the western Galactic hemisphere of the first two eROSITA all-sky surveys (eRASS1 and eRASS2) performed between Dec 2019 and Dec 2020. Methods. We compiled a TDE sample from the catalog of eROSITA's extragalactic transients and variables eRO-ExTra, which includes X-ray sources with a variability significance and fractional amplitude over four between eRASS1 and eRASS2, not associated with known active galactic nuclei (AGNs). Each X-ray source is associated with an optical counterpart from the Legacy Survey DR10 (LS10). Canonical TDEs were selected based on their X-ray light-curve properties (single flare or decline), soft X-ray spectra (Γ>3), and the absence of archival X-ray variability and AGN signatures in their host photometry and spectroscopy. Results. We present 31 X-ray-selected TDE candidates associated with optical counterparts with redshifts of 0.02<z<0.34 and luminosities of 5.7×10⁴¹<L_X<5.3×10⁴⁴ ergs^‑1 in the 0.2‑6.0 keV rest frame. The sample contains 30 canonical TDEs and one off-nuclear TDE candidate. The X-ray luminosity function derived from this sample is best fit by a double power law with a luminosity break at 10⁴⁴ ergs^‑1, corresponding to the Eddington-limiting prediction. The result is in agreement with previous observational and theoretical estimates. This corresponds to a TDE volumetric rate of (2.3_‑0.9^+1.2) × 10^‑7 Mpc^‑3 yr^‑1 (≈1.2×10^‑5 events per galaxy per year). The TDE host galaxies show a green-valley overdensity, as was previously found in X-ray and optical studies. In addition, 20%, 30%, and 15% of our X-ray-selected sample exhibit flares in the optical, mid-infrared (mid-IR), or radio bands, respectively. We discuss the differences between X-ray, optical, and mid-IR TDE populations and the origins of multiwavelength flares in the context of the obscuring envelope and stream-stream collision models. Finally, we highlight TDE subpopulations that are not included in the canonical sample and should be explored in the future.

Context. Traditionally, weak lensing cosmological surveys have been analyzed using summary statistics that were either motivated by their analytically tractable likelihoods (e.g., power spectrum) or by their ability to access some higher-order information (e.g., peak counts), but at the cost of requiring a simulation-based inference approach. In both cases, even if the statistics can be very informative, they are not designed nor guaranteed to be statistically sufficient (i.e., to capture all the cosmological information content of the data). With the rise of deep learning, however, it has becomes possible to create summary statistics that are specifically optimized to extract the full cosmological information content of the data. Yet, a fairly wide range of loss functions have been used in practice in the weak lensing literature to train such neural networks, leading to the natural question of whether a given loss should be preferred and whether sufficient statistics can be achieved in theory and in practice under these different choices. Aims. We compare different neural summarization strategies that have been proposed in the literature to identify the loss function that leads to theoretically optimal summary statistics for performing full-field cosmological inference. In doing so, we aim to provide guidelines and insights to the community to help guide future neural network-based cosmological inference analyses. Methods. We designed an experimental setup that allows us to isolate the specific impact of the loss function used to train neural summary statistics on weak lensing data at fixed neural architecture and simulation-based inference pipeline. To achieve this, we developed the sbi_lens JAX package, which implements an automatically differentiable lognormal weak lensing simulator and the tools needed to perform explicit full-field inference with a Hamiltonian Monte Carlo (HMC) sampler over this model. Using sbi_lens, we simulated a wCDM LSST Year 10 weak lensing analysis scenario in which the full-field posterior obtained by HMC sampling gives us a ground truth that can be compared to different neural summarization strategies. Results. We provide theoretical insight into the different loss functions being used in the literature, including mean squared error (MSE) regression, and show that some do not necessarily lead to sufficient statistics, while those motivated by information theory, in particular variational mutual information maximization (VMIM), can in principle lead to sufficient statistics. Our numerical experiments confirm these insights, and we show on our simulated wCDM scenario that the figure of merit (FoM) of an analysis using neural summary statistics optimized under VMIM achieves 100% of the reference Ω_c‑σ₈ full-field FoM, while an analysis using summary statistics trained under simple MSE achieves only 81% of the same reference FoM.

Unveiling the physical structure of protoplanetary disks is crucial for interpreting the diversity of the exoplanet population. Until recently, the census of the physical properties of protoplanetary disks probed by mid-infrared observations was limited to the solar neighborhood (d ≲ 250 pc). However, nearby star-forming regions (SFRs) such as Taurus—where no O-type stars reside—are not representative of the environments where the majority of the planet formation occurs in the Galaxy. The James Webb Space Telescope (JWST) now enables observations of disks in distant high-mass SFRs, where strong external far-ultraviolet radiation is expected to impact those disks. Nevertheless, a detailed characterization of the population of externally irradiated disks is still lacking. We use the thermochemical code ProDiMo to model JWST/MIRI spectroscopy and archival visual/near-infrared photometry aiming to constrain the physical structure of the irradiated disk around the solar-mass star XUE 1 in NGC 6357 (d ≈ 1690 pc). Our findings are as follows. (1) Mid-infrared dust emission features are explained by amorphous and crystalline silicates with compositions similar to nearby disks. (2) The molecular features detected with MIRI originate within the first ∼1 au, consistent with results from slab models. (3) Our model favors a disk truncated at 10 au with a gas-to-dust ratio of unity in the outskirts. (4) Comparing models of the same disk structure under different irradiation levels, we find that strong external irradiation raises gas temperature tenfold and boosts water abundance beyond 10 au by a factor of 100.

Dynamic programming (DP) algorithms for combinatorial optimization problems work with taking maximization, minimization, and classical addition in their recursion algorithms. The associated value functions correspond to convex polyhedra in the max plus semiring. Existing Neural Algorithmic Reasoning models, however, rely on softmax-normalized dot-product attention where the smooth exponential weighting blurs these sharp polyhedral structures and collapses when evaluated on out-of-distribution (OOD) settings. We introduce Tropical attention, a novel attention function that operates natively in the max-plus semiring of tropical geometry. We prove that Tropical attention can approximate tropical circuits of DP-type combinatorial algorithms. We then propose that using Tropical transformers enhances empirical OOD performance in both length generalization and value generalization, on algorithmic reasoning tasks, surpassing softmax baselines while remaining stable under adversarial attacks. We also present adversarial-attack generalization as a third axis for Neural Algorithmic Reasoning benchmarking. Our results demonstrate that Tropical attention restores the sharp, scale-invariant reasoning absent from softmax.

In neutrino-dense astrophysical environments, these particles exchange flavor through a coherent weak field, forming a collisionless neutrino plasma with collective flavor dynamics. Instabilities, which grow and affect the environment, may arise from neutrino-neutrino refraction alone (fast limit), vacuum energy splittings caused by masses (slow limit), or neutrino-matter scattering (collisional limit). We present a comprehensive analytical description of the dispersion relation governing these unstable modes. Treating vacuum energy splittings and collision rates as small perturbations, we construct a unified framework for fast, slow, and collisional instabilities. We classify modes into gapped, where collective excitations are already present in the fast limit but rendered unstable by slow or collisional effects, and gapless, which are purely generated by these effects. For each class, we derive approximate dispersion relations for generic energy and angle distributions, which reveal the order of magnitude of the growth rates and the nature of the instabilities without solving directly the dispersion relation. This approach confirms that slow and collisionally unstable waves generally grow much more slowly than they oscillate. Consequently, the common fast-mode approximation of local evolution within small boxes is unjustified. Even for fast modes, neglecting large-distance propagation of growing waves, as usually done, may be a poor approximation. Our unified framework provides an intuitive understanding of the linear phase of flavor evolution across all regimes and paves the way for a quasi-linear treatment of the instability's nonlinear development.

The baryon fraction of galaxy clusters is a powerful tool to inform on the cosmological parameters while the hot-gas fraction provides indications on the physics of the intracluster plasma and its interplay with the processes driving galaxy formation. Using cosmological hydrodynamical simulations from The Three Hundred collaboration of about 300 simulated massive galaxy clusters with median mass $M_{500}\approx7 \times 10^{14}$M$_{\odot}$ at $z=0$, we model the relations between total mass and either baryon fraction or the hot gas fractions at overdensities $Δ= 2500$, $500$, and $200$ with respect to the cosmic critical density, and their evolution from $z\sim 0$ to $z\sim 1.3$. We fit the simulation results for such scaling relations against three analytic forms (linear, quadratic, and logarithmic in a logarithmic plane) and three forms for the redshift dependence, considering as a variable both the inverse of cosmic scale factor, $(1+z)$, and the Hubble expansion rate, $E(z)$. We show that power-law dependencies on cluster mass poorly describe the investigated relations. A power-law fails to simultaneously capture the flattening of the total baryon and gas fractions at high masses, their drop at the low masses, and the transition between these two regimes. The other two functional forms provide a more accurate description of the curvature in mass scaling. The fractions measured within smaller radii exhibit a stronger evolution than those measured within larger radii. From the analysis of these simulations, we conclude that as long as we include systems in the mass range herein investigated, the baryon or gas fraction can be accurately related to the total mass through either a parabola or a logarithm in the logarithmic plane. The trends are common to all modern hydro simulations, although the amplitude of the drop at low masses might differ [Abridged].

We investigate a geometric approach to determining the complete set of numerators giving rise to finite Feynman integrals. Our approach proceeds graph by graph, and makes use of the Newton polytope associated with the integral's Symanzik polynomials. It relies on a theorem by Berkesch, Forsgård, and Passare on the convergence of Euler-Mellin integrals, which include Feynman integrals. We conjecture that a necessary, in addition to a sufficient, condition is that all parameter-space monomials lie in the interior of the polytope. We present an algorithm for finding all finite numerators based on this conjecture. In a variety of examples, we find agreement between the results obtained using the geometric approach and a Landau analysis approach developed by Gambuti, Tancredi, and two of the authors.

The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) is a pathfinder mission toward a space-based observatory such as the Probe of Extreme Multi-Messenger Astrophysics (POEMMA). The aim of POEMMA is the observation of Ultra High Energy COsmic Rays (UHECRs) in order to elucidate their nature and origins and to discover $\gtrsim$ 20 PeV very high energy neutrinos that originate from transient and steady astrophysical sources. EUSO-SPB2 was launched from Wānaka New Zealand on May 13th, 2023 as a NASA Balloon Program Office test flight. The mission goals included making the first near-space altitude observations of the fluorescence emission from UHECR-induced extensive air showers (EASs) and making the first direct Cherenkov light emission from PeV cosmic rays traversing Earth's atmosphere. In addition, a Target of Opportunity program was developed for selecting and scheduling observations of potential neutrino sources as they passed just below the Earth's limb. Although a leaky balloon forced termination over the Pacific Ocean after 37 hours, data was collected to demonstrate the successful commissioning and operation of the instruments. This paper includes a description of the payload and the key instruments, pre-flight instrument characterizations in the lab and in the desert, flight operations and examples of the data collected. The flight was too short to catch a UHECR event via fluorescence, however about 10 candidate EAS events from cosmic rays were recorded via Cherenkov light.

We calculate the four-graviton scattering amplitude in Type II superstring theory at one loop up to seventh order in the low-energy expansion through the recently developed iterated integral formalism of Modular Graph Functions (MGFs). The machinery of the novel method allows us to propose a general form of the amplitude, which suggests that the expansion is expressible in terms of single-valued multiple zeta values and logarithmic derivatives of the Riemann zeta function at positive and negative odd integers. Furthermore, we comment on the transcendental behavior of the amplitude.

Next generation photometric and spectroscopic surveys will enable unprecedented tests of the concordance cosmological model and of galaxy formation and evolution. Fully exploiting their potential requires a precise understanding of the selection effects on galaxies and biases on measurements of their properties, required, above all, for accurate estimates of redshift distributions n(z). Forward-modelling offers a powerful framework to simultaneously recover galaxy $n(z)$s and characterise the observed galaxy population. We present GalSBI-SPS, a new SPS-based galaxy population model that generates realistic galaxy catalogues, which we use to forward-model HSC data in the COSMOS field. GalSBI-SPS samples galaxy physical properties, computes magnitudes with ProSpect, and simulates HSC images in the COSMOS field with UFig. We measure photometric properties consistently in real data and simulations. We compare $n(z)$s, photometric and physical properties to observations and to GalSBI. GalSBI-SPS reproduces the observed grizy magnitude, colour, and size distributions down to i<23. Median differences in magnitudes and colours remain below 0.14 mag, with the model covering the full colour space spanned by HSC. Galaxy sizes are overestimated by 0.2 arcsec on average and some tension exists in the g-r colour, but the latter is comparable to that seen in GalSBI. $n(z)$s show a mild positive offset (0.01-0.08) in the mean. GalSBI-SPS qualitatively reproduces the stellar mass-SFR and size-stellar mass relations seen in COSMOS2020. GalSBI-SPS provides a realistic, survey-independent galaxy population description at a Stage-III depth using only literature-based parameters. Its predictive power will improve significantly when constrained against observed data using SBI, thereby providing accurate $n(z)$s satisfying the stringent requirements set by Stage IV surveys.

The dynamics of phase-separated interfaces shape the behavior of both passive and active condensates. While surface tension in equilibrium systems minimizes interface length, non-equilibrium fluxes can destabilize flat or constantly curved interfaces, giving rise to complex interface morphologies. Starting from a minimal model that couples a conserved, phase-separating species to a self-generated chemical field, we identify the conditions under which interfacial instabilities may emerge. Specifically, we show that non-reciprocal chemotactic interactions induce two distinct types of instabilities: a stationary (non-oscillatory) instability that promotes interface deformations, and an oscillatory instability that can give rise to persistent capillary waves propagating along the boundaries of phase-separated domains. To characterize these phenomena, we develop a perturbative framework that predicts the onset, wavelength, and velocity of capillary waves, and quantitatively validate these predictions through numerical simulations. Beyond the linear regime, our simulations reveal that capillary waves undergo a secondary instability, leading to either stationary or dynamically evolving superpositions of different wave modes. Finally, we investigate whether capillary waves can facilitate directed mass transport, either along phase boundaries (conveyor belts) or through self-sustained liquid gears crawling along a solid wall. Taken together, our results establish a general framework for interfacial dynamics in active phase-separating systems and suggest new strategies for controlling mass transport in soft matter and biological condensates.

Spectropolarimetry, the observation of polarization and intensity as a function of wavelength, is a powerful tool in stellar astrophysics. It is particularly useful for characterizing stars and circumstellar material, and for tracing the influence of magnetic fields on a host star and its environment. Maintaining modern, flexible, and accessible computational tools that enable spectropolarimetric studies is thus essential. The SpecpolFlow package is a new, completely Pythonic workflow for analyzing stellar spectropolarimetric observations. Its suite of tools provides a user-friendly interface for working with data from an assortment of instruments and telescopes. SpecpolFlow contains tools for spectral normalization and visualization, the extraction of Least-Squares Deconvolution (LSD) profiles, the generation and optimization of line masks for LSD analyses, and the calculation of longitudinal magnetic field measurements from the LSD profiles. It also provides Python classes for the manipulation of spectropolarimetric products. The SpecpolFlow website includes an array of tutorials that guide users through common analysis cases using the software. SpecpolFlow is distributed as a free, open-source package, with fully documented tools (via an API and command line interface) which are actively maintained by a team of contributors.

Chemo-mechanical waves play a key role in force generation and long-range signal transmission in cells that dynamically change shape, for example, during cell division or morphogenesis. Reconstituting and controlling such chemically controlled cell deformations is a crucial but unsolved challenge for the development of synthetic cells. Here we present an optogenetic method to investigate the mechanism responsible for coordinating surface contraction waves that occur in oocytes of the starfish Patiria miniata during meiotic cell division. Using optogenetic stimuli, we create chemo-mechanical cortical excitations that are decoupled from meiotic cues and drive various shape deformations, ranging from local pinching to surface contraction waves and breakdown of the cell. A quantitative model entailing both chemical and geometry dynamics allows us to predict and explain the variety of mechanical responses to optogenetic stimuli. Finally, we qualitatively map the observed shape dynamics to understand how the versatility of intracellular protein dynamics can give rise to a broad range of mechanical phenotypes. More broadly, our results suggest a route towards real-time control over dynamical deformations in living organisms and can advance the design of synthetic cells and life-like cellular functions.

The pairwise Kinematic Sunyaev-Zel'dovich (kSZ) measures both the pairwise motion between massive groups and the amount of gas within them, providing a tracer for the cosmic growth. To interpret the cosmological information in kSZ, it is crucial to understand the optical cluster selection bias on the kSZ observables. Line-of-sight structures that contribute to both the optical observable (e.g. richness) and the kSZ signal can induce a correlation between these two quantities at fixed cluster mass. The selection bias arising from this correlation is a key systematic effect for cosmological analyses and has the potential to resolve the tension between the cosmological constraints from the DES-Y1 cluster counts, lensing, and Planck. In order to test for a kSZ equivalent of such a bias, we adopt an alternative mock richness based on galaxy counts within cylindrical volumes along the line-of-sight. We apply the cylindrical count method to hydrodynamical simulations across a wide range of galaxy selection criteria, assigning richness consistent with DES-Y1 to the mock clusters. We find no significant bias on pairwise kSZ, pairwise velocities, or optical depth, when comparing optically selected clusters to mass-selected halos, within our uncertainty limits of approximately 16, 10, and 8 per cent, respectively.

Quantum electrodynamics in <inline-formula><mml:math><mml:mrow><mml:mn>1</mml:mn><mml:mo>+</mml:mo><mml:mn>1</mml:mn><mml:mi>D</mml:mi></mml:mrow></mml:math></inline-formula> (QED2) shares intriguing properties with quantum chromodynamics (QCD), including confinement, string breaking, and interesting phase diagram when the nontrivial topological <inline-formula><mml:math><mml:mi>θ</mml:mi></mml:math></inline-formula>-term is considered. Its lattice regularization is a commonly used toy model for quantum simulations of gauge theories on near-term quantum devices. In this work, we address algorithms for adiabatic state preparation in digital quantum simulations of QED2. We demonstrate that, for specific choices of parameters, the existing adiabatic procedure leads to level crossing between states of different charge sectors, preventing the correct preparation of the ground state. We further propose a new adiabatic Hamiltonian and verify its efficiency in targeting systems with a nonzero topological <inline-formula><mml:math><mml:mi>θ</mml:mi></mml:math></inline-formula>-term and in studying string breaking phenomena.

When two massive objects (black holes, neutron stars or stars) in our universe fly past each other, their gravitational interactions deflect their trajectories^1,2. The gravitational waves emitted in the related bound-orbit system—the binary inspiral—are now routinely detected by gravitational-wave observatories³. Theoretical physics needs to provide high-precision templates to make use of unprecedented sensitivity and precision of the data from upcoming gravitational-wave observatories⁴. Motivated by this challenge, several analytical and numerical techniques have been developed to approximately solve this gravitational two-body problem. Although numerical relativity is accurate^{5, 6–7}, it is too time-consuming to rapidly produce large numbers of gravitational-wave templates. For this, approximate analytical results are also required^{8, 9, 10, 11, 12, 13, 14–15}. Here we report on a new, highest-precision analytical result for the scattering angle, radiated energy and recoil of a black hole or neutron star scattering encounter at the fifth order in Newton's gravitational coupling G, assuming a hierarchy in the two masses. This is achieved by modifying state-of-the-art techniques for the scattering of elementary particles in colliders to this classical physics problem in our universe. Our results show that mathematical functions related to Calabi–Yau (CY) manifolds, 2n-dimensional generalizations of tori, appear in the solution to the radiated energy in these scatterings. We anticipate that our analytical results will allow the development of a new generation of gravitational-wave models, for which the transition to the bound-state problem through analytic continuation and strong-field resummation will need to be performed.

We perform a lattice calculation of the correlators of two chromoelectric fields in the adjoint representation connected by adjoint Wilson lines at non-zero temperature. These correlators arise in the study of quarkonium dynamics and of adjoint heavy quark diffusion in deconfined matter. We work in SU(3) gauge theory using either gradient flow or multi-level algorithms for noise reduction, and discuss the renormalization of the correlators on the lattice. We find that a Casimir factor rescaling relates the adjoint correlators corresponding to the diffusion of an adjoint heavy quark and the octet-octet quarkonium transitions to the chromoelectric correlator in the fundamental representation describing the diffusion of a heavy quark.

The upcoming galactic core-collapse supernova is expected to produce a considerable number of neutrino events within terrestrial detectors. By using Bayesian inference techniques, we address the feasibility of distinguishing among various neutrino flavor conversion scenarios in the supernova environment, using such a neutrino signal. In addition to the conventional Mikheev-Smirnov-Wolfenstein, we explore several more sophisticated flavor conversion scenarios, such as spectral swapping, fast flavor conversions, flavor equipartition caused by nonstandard neutrino interactions, magnetically induced flavor equilibration, and flavor equilibrium resulting from slow flavor conversions. Our analysis demonstrates that with a sufficiently large number of neutrino events during the supernova accretion phase (exceeding several hundreds), there exists a good probability of distinguishing among feasible neutrino flavor conversion scenarios in the supernova environment.

Novel interactions beyond the four known fundamental forces in nature (electromagnetic, gravitational, strong, and weak interactions) may arise due to "new physics" beyond the standard model, manifesting as a "fifth force." This review focuses on spin-dependent fifth forces mediated by exotic bosons such as spin-0 axions and axionlike particles and spin-1 <inline-formula><mml:math><mml:mrow><mml:msup><mml:mrow><mml:mi>Z</mml:mi></mml:mrow><mml:mrow><mml:mo>'</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula> bosons, dark photons, and paraphotons. Many of these exotic bosons are candidates to explain the nature of dark matter and dark energy, and their interactions may violate fundamental symmetries. Spin-dependent interactions between fermions mediated by the exchange of exotic bosons have been investigated in a variety of experiments, particularly at the low-energy frontier. Experimental methods and tools used to search for exotic spin-dependent interactions, such as atomic comagnetometers, torsion balances, nitrogen-vacancy spin sensors, and precision atomic and molecular spectroscopy, are described. A complete set of interaction potentials, derived based on quantum field theory with minimal assumptions and characterized in terms of reduced coupling constants, are presented. A summary of existing experimental and observational constraints on exotic spin-dependent interactions is given, in the process illustrating the current research landscape and promising directions of further research.

In this study, we investigate the effects of high-density dark matter environments on astrophysical and cosmological phenomena. We focus on dark stars—compact objects primarily composed of dark matter—and analyze their potential impact on the cosmological reionization signal. Additionally, we examine how the high-density dark matter environment in the galactic center influences the outcomes of direct detection experiments. By combining theoretical models and simulations, this work provides new insights into the role of dense dark matter regions in both cosmic evolution and the detection of dark matter interactions.

We compute the partition function for the $N=1$ spinning particle, including pictures and the large Hilbert space, and show that it counts the dimension of the BRST cohomology in two- and four-dimensional target space. We also construct a quadratic action in the target space. Furthermore, we find a consistent interaction as a derived bracket based on the associative product of world line fields, leading to an interacting theory of multiforms in space-time. Finally, we comment on the equivalence of the multiform theory with a Dirac fermion. We also identify the chiral anomaly of the latter with a Hodge anomaly for the multiform theory, which manifests itself as a deformation of the gauge fixing.

So far, even the highest resolution galaxy formation simulations with gravitational softening have failed to reproduce realistic life cycles of star clusters. We present the first star-by-star galaxy models of star cluster formation to account for hydrodynamics, star formation, stellar evolution, and collisional gravitational interactions between stars and compact remnants using the updated SPHGAL + KETJU code, part of the GRIFFIN project. Gravitational dynamics in the vicinity of <inline-formula><tex-math id="TM0001" notation="LaTeX">$&gt;3$</tex-math></inline-formula> M<inline-formula><tex-math id="TM0002" notation="LaTeX">$_\odot$</tex-math></inline-formula> stars and their remnants are solved with a regularized integrator (KETJU) without gravitational softening. Comparisons of idealized star cluster evolution with SPHGAL + KETJU and direct N-body show broad agreement and the failure of simulations that use gravitational softening. In the hydrodynamical simulations of idealized dwarf galaxies run with SPHGAL + KETJU, clusters up to <inline-formula><tex-math id="TM0003" notation="LaTeX">$\sim 900$</tex-math></inline-formula> M<inline-formula><tex-math id="TM0004" notation="LaTeX">$_\odot$</tex-math></inline-formula> form compact (effective radii 0.1-1 pc) and their sizes increase by up to a factor of 10 in agreement with previous N-body simulations and the observed sizes of exposed star clusters. The sizes increase rapidly once the clusters become exposed due to photoionizing radiation. On average 63 per cent of the gravitationally bound clusters disrupt during the first 100 Myr of evolution in the galactic tidal field. The addition of collisional dynamics reduces the fraction of supernovae in bound clusters by a factor of <inline-formula><tex-math id="TM0005" notation="LaTeX">$\sim 1.7$</tex-math></inline-formula>; however, the global star formation and outflow histories change by less than 30 per cent. We demonstrate that the accurate treatment of gravitational encounters with massive stars enables more realistic star cluster life cycles from the earliest stages of cluster formation until disruption in simulated low-mass galaxies.

Galaxy and halo scaling relations, connecting a broad range of parameters, are well established from observations. The origin of many of these relations and their scatter is still a matter of debate. It remains a sizable challenge for models to simultaneously and self-consistently reproduce as many scaling relations as possible. We introduce the Magneticum Pathfinder hydrodynamical cosmological simulation suite, to date the suite that self-consistently covers the largest range in box volumes and resolutions. It is the only cosmological simulation suite that is tuned on the hot gas content of galaxy clusters instead of the stellar mass function. By assessing the successes and shortcomings of tuning to the hot gas component of galaxy clusters, we aim to further our understanding of the physical processes shaping the Universe. We analyze the importance of the hot and cold gas components for galaxy and structure evolution. We analyze 28 scaling relations, covering large-scale global parameters as well as internal properties for halos ranging from massive galaxy clusters down to galaxies, and show their predicted evolution from z=4 to z=0 in comparison with observations. These include the halo-to-stellar-mass and Kennicutt--Schmidt relations, the cosmic star formation rate density as well as the Fundamental Plane. Magneticum Pathfinder matches a remarkable number of the observed scaling relations from z=4 to z=0, including challenging relations like the number density of quiescent galaxies at cosmic dawn, the mass--size evolution, the mass--metallicity relation, the Magorrian relation, and the temperature--mass relation. We compile our data to allow for straightforward future comparisons. Galaxy properties and scaling relations arise naturally and the large scatter in observables at high redshift is crucial to distinguish the various galaxy formation models reproducing the z=0 relations.

The decay of metastable 'false vacuum' states via bubble nucleation plays a crucial role in many cosmological scenarios. Cold-atom analog experiments will soon provide the first empirical probes of this process, with potentially far-reaching implications for early-Universe cosmology and high-energy physics. However, an inevitable difference between these analog systems and the early Universe is that the former have a boundary. We show, using a combination of Euclidean calculations and real-time lattice simulations, that these boundaries generically cause rapid bubble nucleation on the edge of the experiment, obscuring the bulk nucleation that is relevant for cosmology. We demonstrate that implementing a high-density 'trench' region at the boundary completely eliminates this problem, and recovers the desired cosmological behavior. Our findings are relevant for ongoing efforts to probe vacuum decay in the laboratory, providing a practical solution to a key experimental obstacle.

Future telescopes will characterize rocky exoplanets in reflected light, revealing their albedo, which depends on surface, cloud, and atmospheric properties. Identifying these features is crucial for assessing habitability. We present reference spectra and phase curves for an unresolved Earth-like exoplanet in reflected and polarized light, showing how phase- and wavelength-dependent reflectance reveals key planetary properties. Using the 3D radiative transfer code MYSTIC, we enhance surface and cloud modeling with validated, wavelength-dependent albedo maps of Earth's seasonal and spectral features, alongside a novel treatment of sub-grid cloud variability using ERA5 reanalysis data. Our models, incorporating high-resolution 3D cloud structures, show that sub-grid cloud variability reduces total reflectance and increases phase curve variability, especially at large phase angles where ocean glint dominates. We also find that neglecting wavelength-dependent albedo maps overestimates the vegetation red edge in spectra. Comparing an Ocean planet to an Earth-like planet with seasonal cloud variability, we show that polarization is more sensitive than intensity alone in distinguishing both cases. Moreover, polarization captures richer surface details, making it a crucial tool for resolving retrieval degeneracies. Our simulations serve as a reference for observing Earth as an exoplanet and provide benchmarks for optimizing observational strategies and retrieval frameworks for future telescopes targeting small, rocky exoplanets.

We show experimentally that an effect of motion of ions, observed in a plasma-based accelerator, depends inversely on the plasma ion mass. The effect appears within a single wakefield event and manifests itself as a bunch tail, occurring only when sufficient motion of ions suppresses wakefields. Wakefields are driven resonantly by multiple bunches, and simulation results indicate that the ponderomotive force causes the motion of ions. In this case, the effect is also expected to depend on the amplitude of the wakefields, experimentally confirmed through variations in the drive bunch charge.

Context. The supernova remnant (SNR) Cassiopeia A (Cas A) offers a unique opportunity to study supernova (SN) explosion dynamics and remnant interactions with the circumstellar medium (CSM). Recent observations with the James Webb Space Telescope have unveiled an enigmatic structure within the remnant, termed "Green Monster" (GM), whose properties indicate a CSM origin. Aims. Our goal is to investigate the properties of the GM and uncover the origin of its intriguing pockmarked structure, characterized by nearly circular holes and rings. We aim to examine the role of small-scale ejecta structures in shaping these features through their interaction with a dense circumstellar shell. Methods. We adopted a neutrino-driven SN model to trace the evolution of its explosion from core collapse to the age of the Cas A remnant using high-resolution 3D magnetohydrodynamic simulations. Besides other processes, the simulations include self-consistent calculations of radiative losses, accounting for deviations from electron-proton temperature equilibration and ionization equilibrium, as well as the ejecta composition derived from the SN. Results. The observed GM morphology can be reproduced by the interaction of dense ejecta clumps and fingers with an asymmetric, forward-shocked circumstellar shell. The clumps and fingers form by hydrodynamic instabilities growing at the interface between SN ejecta and shocked CSM. Radiative cooling accounting for effects of non-equilibrium of ionization enhances the ejecta fragmentation, forming dense knots and thin filamentary structures that penetrate the shell, producing a network of holes and rings with properties similar to those observed. Conclusions. The origin of the holes and rings in the GM can be attributed to the interaction of ejecta with a shocked circumstellar shell. By constraining the timing of this interaction and analyzing the properties of these structures, we provide a distinction of this scenario from an alternative hypothesis, which attributes these features to fast-moving ejecta knots penetrating the shell ahead of the forward shock.

Context. Recent observations with the James Webb Space Telescope (JWST) have revealed unprecedented details of an intricate filamentary structure of unshocked ejecta within the young supernova remnant (SNR) Cassiopeia A (Cas A), offering new insights into the mechanisms governing supernova (SN) explosions and the subsequent evolution of ejecta. Aims. We aim to investigate the origin and evolution of the newly discovered web-like network of ejecta filaments in Cas A. Our specific objectives are: (i) to characterize the three-dimensional (3D) structure and kinematics of the filamentary network and (ii) to identify the physical mechanisms responsible for its formation. Methods. We performed high-resolution, 3D hydrodynamic (HD) and magneto-hydrodynamic (MHD) simulations to model the evolution of a neutrino-driven SN from the explosion to its remnant with the age of 1000 years. The initial conditions, set shortly after the shock breakout at the stellar surface, are based on a 3D neutrino-driven SN model that closely matches the basic properties of Cas A. Results. We found that the magnetic field has little impact on the evolution of unshocked ejecta, so we focused most of the analysis on the HD simulations. A web-like network of ejecta filaments, with structures compatible with those observed by JWST (down to scales ≈0.01 pc), naturally forms during the SN explosion. The filaments result from the combined effects of processes occurring soon after the core collapse, including the expansion of neutrino-heated bubbles formed within the first second after the explosion, hydrodynamic instabilities triggered during the blast propagation through the stellar interior, and the Ni-bubble effect following the shock breakout. The interaction of the reverse shock with the ejecta progressively disrupts the filaments through the growth of hydrodynamic instabilities. By around 700 years, the filamentary network becomes unobservable. Conclusions. According to our models, the filaments observed by JWST in Cas A most likely preserve a "memory" of the early explosion conditions, reflecting the processes active during and immediately after the SN event. Notably, a filamentary network closely resembling that observed in Cas A is naturally produced by a neutrino-driven SN explosion.

AT 2019aalc is a peculiar sequence of highly variable emission events observed towards the nucleus of the broad-line AGN SDSS J152416.66+045119.0. The system exhibited two distinct UV/optical flares (the first detected in 2019, the second one in 2023). Spectra obtained following the detection of the second flare revealed prominent Bowen fluorescence and high-ionization coronal emission lines, which were much weaker, if at all detectable, in a spectrum taken following the first flare. We present and analyze a large set of multi-wavelength, multi-epoch data for this source, with particular emphasis on optical spectroscopic monitoring conducted with the Las Cumbres Observatory network. During the relatively slow dimming that followed the second optical flare, the UV/optical light-curve shows a sequence of minor rebrightening events, while the Bowen fluorescence and the coronal lines vary (roughly) in tandem with these "bumps" in the broad-band light-curve. Most of the observed behavior of AT 2019aalc links it to the growing class of Bowen fluorescence flares (BFFs) while setting it apart from canonical tidal disruption events. However, AT 2019aalc has some outstanding peculiarities, including two short flares seen in its soft X-ray light-curve during the dimming phase of the second optical flare, and which do not seem to be linked to the emission line variations. We discuss the optical and X-ray properties of the source and possible scenarios of the origin of the flare, in particular radiation pressure instabilities in the (pre-existing) AGN accretion disk.

We propose heavy axions as a natural superheavy dark matter candidate in string theory, with the relic density of dark matter originating in quantum fluctuations during cosmic inflation. String Theory is well known for the possibility of having tens to hundreds of axion-like particles -- the axiverse. Moduli stabilization generates high-scale masses for many of these, placing them naturally in the superheavy regime of particle physics. We consider moduli stabilization in the KKLT framework, featuring a single volume modulus and $C_4$ axion, and a fiducial inflation model minimally coupled to the volume modulus. We demonstrate that both the volume modulus and the axion can be abundantly produced through gravitational particle production. The former is unstable and readily decays to Standard Model particles while the latter (the axion) can be stable and survives to constitute the present day dark matter.

Frequentist parameter inference using profile likelihoods has received increased attention in the cosmology literature recently since it can give important complementary information to Bayesian credible intervals. Here, we give a pedagogical review of frequentist parameter inference in cosmology and focus on when the graphical profile likelihood construction gives meaningful constraints, i.e. confidence intervals with correct coverage. This construction rests on the assumption of the asymptotic limit of a large data set such as in Wilks' theorem. We assess the validity of this assumption in the context of three cosmological models with Planck 2018 Plik_lite data. While our tests for the <inline-formula><mml:math><mml:mi>Λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula> model indicate that the profile likelihood method gives correct coverage, <inline-formula><mml:math><mml:mi>Λ</mml:mi><mml:mi>CDM</mml:mi></mml:math></inline-formula> with the sum of neutrino masses as a free parameter appears consistent with a Gaussian near a boundary motivating the use of the boundary-corrected or Feldman-Cousins graphical method; for <inline-formula><mml:math><mml:msub><mml:mi>w</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:mi>CDM</mml:mi></mml:math></inline-formula> with the equation of state of dark energy, <inline-formula><mml:math><mml:msub><mml:mi>w</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:math></inline-formula>, as a free parameter, we find indication of a violation of the assumptions. Finally, we compare frequentist and Bayesian constraints of these models. Our results motivate care when using the graphical profile likelihood method in cosmology.

Through gravitational lensing, galaxy clusters can magnify supernovae (SNe) and create multiple images of the same SN. This enables measurements of cosmological parameters, which will be increasingly important in light of upcoming telescopic surveys. We study the prospects of detecting strongly lensed SNe in cluster fields with the Nancy Grace Roman Space Telescope (Roman)'s High Latitude Time Domain Survey (HLTDS) and the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST). We employed two approaches: one focusing on known multiply imaged galaxies behind clusters, along with the SN rates specific to those galaxies, and another based on the expected number of lensed SNe exploding in a given volume behind a galaxy cluster. We collected all the clusters in the literature that feature a well-constrained lens model and multiply imaged galaxies behind clusters with high-quality data for the lensed galaxies. This allowed us to determine the SN rate for each galaxy. We provide predictions for 46 clusters visible to the Vera C. Rubin Observatory, as well as for 9 observable by Roman's HLTDS, depending on whether the clusters fall within the survey's observing field. We predict that the number of multiply imaged SNe discovered by LSST in its first three years is $3.95 \pm 0.89$ from the first approach or $4.94 \pm 1.02$ from the second. For the HLTDS, the expected number of multiply imaged SNe ranges from $0.38 \pm 0.15$ to $5.2 \pm 2.2$, depending on the specific cluster observed, however, the fields to be targeted remain a matter of discussion. We conclude that LSST offers great prospects for detecting multiply imaged SNe. Our predictions are effectively lower limits, as we only considered the most massive and well-studied clusters. We provide a recommendation for HLTDS observing field selection, namely: either MACS J0553.4-3342 or Abell 1758a should be observed by the survey.

During the accretion phase of a core-collapse supernova (SN), dark-photon (DP) cooling can be largest in the gain layer below the stalled shock wave. In this way, it could counteract the usual shock rejuvenation by neutrino energy deposition and thus prevent the explosion. This peculiar energy-loss profile derives from the resonant nature of DP production. The largest cooling and thus strongest constraints obtain for DP masses of 0.1–0.4 MeV, a range corresponding to the photon plasma mass in the gain region. Electron-capture supernovae, once observationally unambiguously identified, could provide strong bounds even down to nearly 0.01 MeV. For a coupling strength so small that neutrino-driven explosions are expected to survive, the DP cooling of the core is too small to modify the neutrino signal, i.e., our new argument supersedes the traditional SN1987A cooling bound.

Feedback from active galactic nuclei (AGN) is crucial for regulating galaxy evolution. Motivated by observations of broad absorption line winds from rapidly accreting supermassive black holes (SMBHs), we introduce the Mistral AGN feedback model, implemented in the Arepo code. Mistral comes in two versions: continuous radial (Mistral-continuous) and stochastic bipolar momentum deposition (Mistral-stochastic). Using the framework of the IllustrisTNG simulations, we explore the effect of Mistral on BH and galaxy properties, through an idealized Milky Way-mass galaxy and cosmological zoom simulations run down to $z=2$. Unlike standard thermal AGN feedback prescriptions, Mistral generates galaxy-scale winds that mimic outflows driven by BH accretion. Mistral-continuous produces short-lived galactic fountains, and is inefficient at regulating the growth of massive galaxies at $z=2$. In contrast, Mistral-stochastic efficiently suppresses star formation in massive galaxies, and reproduces the empirical stellar-to-halo mass and ($z=0$) BH-stellar mass relations. By supporting large-scale ($>50\,\rm kpc$) outflows while simultaneously preventing gas inflows, Mistral-stochastic additionally regulates the cold and hot gas fractions at both galaxy and halo scales. Mistral-stochastic therefore works self-consistently across the halo mass range explored $\left(10^{12}-3\times10^{13}\,\rm M_\odot\right)$, without adopting a SMBH-mass dependent AGN feedback scheme such as the one used in IllustrisTNG. Our model is a promising tool for predicting the impact of radiatively efficient AGN winds on galaxy evolution, and interpreting the growing population of high-redshift galaxies and quasars observed by JWST. This work is part of the "Learning the Universe" collaboration, which aims to infer the physical processes governing the evolution of the Universe.

Precision observations of orbital systems have recently emerged as a promising new means of detecting gravitational waves and ultra-light dark matter, offering sensitivity in new regimes with significant discovery potential. These searches rely critically on precise modeling of the dynamical effects of these signals on the observed system; however, previous analyses have mainly only relied on the secularly-averaged part of the response. We introduce here a fundamentally different approach that allows for a fully time-resolved description of the effects of oscillatory metric perturbations on orbital dynamics. We find that gravitational waves and ultra-light dark matter can induce large oscillations in the orbital parameters of realistic binaries, enhancing the sensitivity to such signals by orders of magnitude compared to previous estimates.

We use galaxy cluster abundance measurements from the South Pole Telescope enhanced by multicomponent matched filter confirmation and complemented with mass information obtained using weak-lensing data from Dark Energy Survey Year 3 (DES Y3) and targeted Hubble Space Telescope observations for probing deviations from the cold dark matter paradigm. Concretely, we consider a class of dark sector models featuring interactions between dark matter (DM) and a dark radiation (DR) component within the framework of the effective theory of structure formation (ETHOS). We focus on scenarios that lead to power suppression over a wide range of scales, and thus can be tested with data sensitive to large scales, as realized, for example, for DM–DR interactions following from an unbroken non-Abelian <inline-formula><mml:math><mml:mi>S</mml:mi><mml:mi>U</mml:mi><mml:mo>(</mml:mo><mml:mi>N</mml:mi><mml:mo>)</mml:mo></mml:math></inline-formula> gauge theory (interaction rate with power-law index <inline-formula><mml:math><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>0</mml:mn></mml:math></inline-formula> within the ETHOS parametrization). Cluster abundance measurements are mostly sensitive to the amount of DR interacting with DM, parametrized by the ratio of DR temperature to the cosmic microwave background (CMB) temperature, <inline-formula><mml:math><mml:msub><mml:mi>ξ</mml:mi><mml:mi>DR</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:msub><mml:mi>T</mml:mi><mml:mi>DR</mml:mi></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mi>T</mml:mi><mml:mi>CMB</mml:mi></mml:msub></mml:math></inline-formula>. We find an upper limit <inline-formula><mml:math><mml:msub><mml:mi>ξ</mml:mi><mml:mi>DR</mml:mi></mml:msub><mml:mo>&lt;</mml:mo><mml:mn>17</mml:mn><mml:mo>%</mml:mo></mml:math></inline-formula> at 95% credibility. When the cluster data are combined with Planck 2018 CMB data along with baryon acoustic oscillation (BAO) measurements we find <inline-formula><mml:math><mml:msub><mml:mi>ξ</mml:mi><mml:mi>DR</mml:mi></mml:msub><mml:mo>&lt;</mml:mo><mml:mn>10</mml:mn><mml:mo>%</mml:mo></mml:math></inline-formula>, corresponding to a limit on the abundance of interacting DR that is around 3 times tighter than that from CMB + BAO data alone. We also discuss the complementarity of weak lensing informed cluster abundance studies with probes sensitive to smaller scales, explore the impact on our analysis of massive neutrinos, and comment on a slight preference for the presence of a nonzero interacting DR abundance, which enables a physical solution to the <inline-formula><mml:math><mml:msub><mml:mi>S</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:math></inline-formula> tension.

The Euclid Wide Survey (EWS) is predicted to find approximately 170 000 galaxy-galaxy strong lenses from its lifetime observation of 14 000 deg² of the sky. Detecting this many lenses by visual inspection with professional astronomers and citizen scientists alone is infeasible. As a result, machine learning algorithms, particularly convolutional neural networks (CNNs), have been used as an automated method of detecting strong lenses, and have proven fruitful in finding galaxy-galaxy strong lens candidates, such that the usage of CNNs in lens identification has increased. We identify the major challenge to be the automatic detection of galaxy-galaxy strong lenses while simultaneously maintaining a low false positive rate, thus producing a pure and complete sample of strong lens candidates from Euclid with a limited need for visual inspection. One aim of this research is to have a quantified starting point on the achieved purity and completeness with our current version of CNN-based detection pipelines for the VIS images of EWS. This work is vital in preparing our CNN-based detection pipelines to be able to produce a pure sample of the >100 000 strong gravitational lensing systems widely predicted for Euclid. We select all sources with VIS I_E < 23 mag from the Euclid Early Release Observation imaging of the Perseus field. We apply a range of CNN architectures to detect strong lenses in these cutouts. All our networks perform extremely well on simulated data sets and their respective validation sets. However, when applied to real Euclid imaging, the highest lens purity is just ∼11%. Among all our networks, the false positives are typically identifiable by human volunteers as, for example, spiral galaxies, multiple sources, and artifacts, implying that improvements are still possible, perhaps via a second, more interpretable lens selection filtering stage. There is currently no alternative to human classification of CNN-selected lens candidates. Given the expected ∼10⁵ lensing systems in Euclid, this implies 10⁶ objects for human classification, which while very large is not in principle intractable and not without precedent. ★This paper is published on behalf of the Euclid Consortium.

We address the question whether the magneto-rotational instability (MRI) can operate in the near-surface shear layer (NSSL) of the Sun and how it affects the interaction with the dynamo process. Using hydromagnetic mean-field simulations of $αΩ$-type dynamos in rotating shearing-periodic boxes, we show that for negative shear, the MRI can operate above a certain critical shear parameter. This parameter scales inversely with the equipartition magnetic field strength above which $α$ quenching set in. Like the usual $Ω$ effect, the MRI produces toroidal magnetic field, but in our Cartesian cases it is found to reduce the resulting magnetic field strength and thus to suppress the dynamo process. In view of the application to the solar NSSL, we conclude that the turbulent magnetic diffusivity may be too large for the MRI to be excited and that therefore only the standard $Ω$ effect is expected to operate.

Dark matter (DM) particles can interact with particles of the Standard Model. Although there exist constraints from direct and indirect detection experiments, the dynamical evolution of astrophysical objects could provide a promising probe for these interactions. Obtaining astrophysical predictions is challenging and limited by our ability to simulate scatterings between DM and baryonic particles within N-body and hydrodynamics simulations. We develop a novel scheme that allows simulating these interacting dark matter (IDM) models and accurately accounts for their angular and velocity dependence, as well as the mass ratio between the DM and baryonic scattering partners. To describe DM-baryon interactions, we use an N-body code together with its implementation of smoothed-particle hydrodynamics and meshless finite mass. The interaction itself is realised in a pairwise fashion by creating a virtual scattering partner from the baryonic particle and letting it interact with a DM particle using a scattering routine initially developed for self-interacting dark matter. After the interaction, the virtual particle is rejoined with the baryonic particle, fulfilling energy and momentum conservation. Through several test problems, we demonstrate that we can reproduce their analytic solutions with our IDM scheme. We comment on various numerical aspects and challenges as well as describe the limitations of our numerical scheme. Furthermore, we study the impact of IDM on halo formation with a collapsing overdensity. Overall, it is possible to accurately model IDM within N-body and hydrodynamics simulations, commonly used in astrophysics. In consequence, our scheme allows for making novel predictions and obtaining new constraints of DM-baryon scattering.

The self-organization of proteins into enriched compartments and the formation of complex patterns are crucial processes for life on the cellular level. Liquid-liquid phase separation is one mechanism for forming such enriched compartments. When phase-separating proteins are membrane-bound and locally disturb it, the mechanical response of the membrane mediates interactions between these proteins. How these membrane-mediated interactions influence the steady state of the protein density distribution is thus an important question to investigate in order to understand the rich diversity of protein and membrane-shape patterns present at the cellular level. This work starts with a widely used model for membrane-bound phase-separating proteins. We numerically solve our system to map out its phase space and perform a careful, systematic expansion of the model equations to characterize the phase transitions through linear stability analysis and free energy arguments. We observe that the membrane-mediated interactions, due to their long-range nature, are capable of qualitatively altering the equilibrium state of the proteins. This leads to arrested coarsening and length-scale selection instead of simple demixing and complete coarsening. In this study, we unambiguously show that long-range membrane-mediated interactions lead to pattern formation in a system that otherwise would not do so. This work provides a basis for further systematic study of membrane-bound pattern-forming systems.

In the presence of a weak gravitational wave (GW) background, astrophysical binary systems act as high-quality resonators, with efficient transfer of energy and momentum between the orbit and a harmonic GW leading to potentially detectable orbital perturbations. In this work, we develop and apply a novel modeling and analysis framework that describes the imprints of GWs on binary systems in a fully time-resolved manner to study the sensitivity of lunar laser ranging, satellite laser ranging, and pulsar timing to both resonant and nonresonant GW backgrounds. We demonstrate that optimal data collection, modeling, and analysis lead to projected sensitivities which are orders of magnitude better than previously appreciated possible, opening up a new possibility for probing the physics-rich but notoriously challenging to access $μ\mathrm{Hz}$ frequency GWs. We also discuss improved prospects for the detection of the stochastic fluctuations of ultra-light dark matter, which may analogously perturb the binary orbits.

The ultra-hot Jupiter (UHJ) TOI-2109b marks the lower edge of the equilibrium temperature gap between 3500 K and 4500 K, an unexplored thermal regime that separates KELT-9b, the hottest planet yet discovered, from all other currently known gas giants. To study the structure of TOI-2109b's atmosphere, we obtained high-resolution emission spectra of both the planetary day- and nightsides with CARMENES and CRIRES$^+$. By applying the cross-correlation technique, we identified the emission signatures of Fe I and CO, as well as a thermal inversion layer in the dayside atmosphere; no significant H$_2$O signal was detected from the dayside. None of the analyzed species were detectable from the nightside atmosphere. We applied a Bayesian retrieval framework that combines high-resolution spectroscopy with photometric measurements to constrain the dayside atmospheric parameters and derive upper limits for the nightside hemisphere. The dayside thermal inversion extends from 3200 K to 4600 K, with an atmospheric metallicity consistent with that of the host star (0.36 dex). Only weak constraints could be placed on the C/O ratio ($>$ 0.15). The retrieved spectral line broadening is consistent with tidally locked rotation, indicating the absence of strong dynamical processes. An upper temperature limit of 2400 K and a maximum atmospheric temperature gradient of 700 K/log bar could be derived for the nightside. Comparison of the retrieved dayside T-p profile with theoretical models, the absence of strong atmospheric dynamics, and significant differences in the thermal constraints between the day- and nightside hemispheres suggest a limited heat transport efficiency across the planetary atmosphere. Overall, our results place TOI-2109b in a transitional regime between the UHJs below the thermal gap, which show both CO and H$_2$O emission lines, and KELT-9b, where molecular features are largely absent.

We update the Standard Model (SM) predictions for the lifetimes of the B⁺, B_d and B_s mesons within the heavy quark expansion (HQE), including the recently determined NNLO-QCD corrections to non-leptonic decays of the free b-quark. In addition, we update the HQE predictions for the lifetime ratios τ (B⁺)/τ (B_d) and τ (B_s)/τ (B_d), and provide new results for the semileptonic branching fractions of the three mesons entirely within the HQE. We obtain a considerable improvement of the theoretical uncertainties, mostly due to the reduction of the renormalisation scale dependence when going from LO to NNLO, and for all the observables considered, we find good agreement, within uncertainties, between the HQE predictions and the corresponding experimental data. Our results read, respectively, Γ(B⁺) = <inline-formula><mml:math><mml:msubsup><mml:mn>0.587</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.035</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.025</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula> ps^‑1, Γ(B_d) = <inline-formula><mml:math><mml:msubsup><mml:mn>0.636</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.037</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.028</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula> ps^‑1, Γ(B_s) = <inline-formula><mml:math><mml:msubsup><mml:mn>0.628</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.035</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.027</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula> ps^‑1, for the total decay widths, τ (B⁺)/τ (B_d) = <inline-formula><mml:math><mml:msubsup><mml:mn>1.081</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.016</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.014</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula>, τ (B_s)/τ (B_d) = <inline-formula><mml:math><mml:msubsup><mml:mn>1.013</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.007</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.007</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula>, for the lifetime ratios, and <inline-formula><mml:math><mml:msub><mml:mi>B</mml:mi><mml:mi>sl</mml:mi></mml:msub><mml:mfenced><mml:msup><mml:mi>B</mml:mi><mml:mo>+</mml:mo></mml:msup></mml:mfenced></mml:math></inline-formula> = <inline-formula><mml:math><mml:mfenced><mml:msubsup><mml:mn>11.46</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.32</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.47</mml:mn></mml:mrow></mml:msubsup></mml:mfenced><mml:mo>%</mml:mo></mml:math></inline-formula>, <inline-formula><mml:math><mml:msub><mml:mi>B</mml:mi><mml:mi>sl</mml:mi></mml:msub><mml:mfenced><mml:msub><mml:mi>B</mml:mi><mml:mi>d</mml:mi></mml:msub></mml:mfenced></mml:math></inline-formula> = <inline-formula><mml:math><mml:mfenced><mml:msubsup><mml:mn>10.57</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.27</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.47</mml:mn></mml:mrow></mml:msubsup></mml:mfenced><mml:mo>%</mml:mo></mml:math></inline-formula>, <inline-formula><mml:math><mml:msub><mml:mi>B</mml:mi><mml:mi>sl</mml:mi></mml:msub><mml:mfenced><mml:msub><mml:mi>B</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:mfenced></mml:math></inline-formula> = <inline-formula><mml:math><mml:mfenced><mml:msubsup><mml:mn>10.52</mml:mn><mml:mrow><mml:mo>‑</mml:mo><mml:mn>0.29</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.50</mml:mn></mml:mrow></mml:msubsup></mml:mfenced><mml:mo>%</mml:mo></mml:math></inline-formula>, for the semileptonic branching ratios. Finally, we also provide an outlook for further improvements of the HQE determinations of the B-meson decay widths and of their ratios.

The M-theoretic emergence proposal claims that in an isotropic decompactification limit to M-theory the full effective action is generated via quantum effects by integrating out only the light towers of states of the theory. In the BPS particle sector, these include transversally wrapped $M2$- and $M5$-branes possibly carrying Kaluza-Klein momentum. This implies that a longitudinally wrapped $M5$-brane, i.e. a wrapped $D4$-brane, is not to be included in emergence computations. In this work we collect explicit evidence supporting this point by examining an $F^4$ gauge coupling in six dimensions, making use of the duality between heterotic string theory on $T^4$ and strongly coupled type IIA on K3. In this instance, the M-theoretic emergence proposal can be viewed as a tool for making predictions for the microscopic behavior of string theoretic amplitudes.

We compute differential distributions for Drell–Yan processes at the LHC and the Tevatron colliders at next-to-next-to-leading order in perturbative QCD, including fiducial cuts on the decay leptons in the final state. The comparison of predictions obtained with four different codes shows excellent agreement, once linear power corrections from the fiducial cuts are included in those codes that rely on phase-space slicing subtraction schemes. For Z-boson production we perform a detailed study of the symmetric cuts on the transverse momenta of the decay leptons. Predictions at fixed order in perturbative QCD for those symmetric cuts, typically imposed in experiments, suffer from an instability. We show how this can be remedied by an all-order resummation of the fiducial transverse momentum spectrum, and we comment on the choice of cuts for future experimental analyses.

In this paper, the first in a series, we present a new theoretical model for the global structure and dissipation of relativistically magnetized collisionless shock waves. Quite remarkably, we find that in contrast to unmagnetized shocks, the leading energy dissipation channel does not involve collective plasma interactions. Rather, it is a consequence of nonlinear particle dynamics. We demonstrate that the kinetic-scale shock transition can be modeled as a stationary system consisting of a large set of cold beams coupled through the magnetic field. The fundamental mechanism governing shock dissipation relies on the onset of chaos in orbital dynamics within quasiperiodic solitonic structures. We discuss the impact of upstream temperature and magnetization on the shock profile, recovering the magnetic field compression, downstream velocities, and heating expected from the Rankine-Hugoniot jump conditions. We deduce a rate of entropy generation from the spectrum of Lyapunov exponents and discuss the thermalization of the beam distribution. Our model provides a general framework to study magnetized collisionless shock structures.

The authors present a new method to analytically prove global stability in ghost‑ridden dynamical systems. The proposal encompasses all prior results and consequentially extends them. In particular, it is shown that stability can follow from a conserved quantity that is unbounded from below, contrary to expectation. Novel examples illustrate all of the results. The findings take root on a careful examination of the literature, here comprehensively reviewed for the first time. This work lays the mathematical basis for ulterior extensions to field theory and quantization, and it constitutes a gateway for inter‑disciplinary research in dynamics and integrability.

Quasi-periodic eruptions (QPEs) are rapid, recurring X-ray bursts from supermassive black holes, believed to result from interactions between accretion disks and surrounding matter. The galaxy SDSS1335+0728, previously stable for two decades, exhibited an increase in optical brightness in December 2019, followed by persistent active galactic nucleus (AGN)-like variability for 5 yr, suggesting the activation of a ~10⁶-M_⊙ black hole. Since February 2024, X-ray emission has been detected, revealing extreme ~4.5-d QPEs with high fluxes and amplitudes, long timescales, large integrated energies and a ~25-d superperiod. Low-significance UV variations are reported, probably related to the long timescales and large radii from which the emission originates. This discovery broadens the possible formation channels for QPEs, suggesting that they are linked not solely to tidal disruption events but more generally to newly formed accretion flows, which we are witnessing in real time in a turn-on AGN candidate.