高能暂现源 · 每日文献综述

Dual active galactic nuclei (AGNs) are expected in hierarchical galaxy evolution models, in which low-mass galaxies merge to build more massive ones. While observational evidence for dual AGNs is growing in massive galaxies, no clear detection has yet been found in the low-mass regime. We used photometry and spectroscopy from the first Euclid Quick Data Release, combined with a collection of multi-wavelength data from the Dark Energy Spectroscopic Instrument (DESI), the LOw-Frequency ARray (LOFAR) high band antenna, and counterparts in X-ray and mid-infrared catalogues to identify dual AGNs at redshift z ≲ 1. Focusing on low-mass galaxies with stellar masses below 10<SUP>10</SUP> M<SUB>⊙</SUB>, we find nine dual AGN candidates with projected separations ranging from ∼20 to 51 kpc. We also find 49 dual AGN candidates in more massive galaxies. We derive a dual AGN fraction of 0.1% for the low-mass galaxies and estimate that these systems likely trace a population of progenitor black hole pairs that may evolve into bound binaries and eventually coalesce, emitting gravitational waves in the LISA band. These results constitute the first sample of spectroscopically confirmed dual AGN candidates in low-mass galaxies and have important implications for models in which supermassive black holes grow from lower-mass black holes located in low-mass galaxies, as well as for predictions of gravitational waves from low-mass binary black holes. ★ This paper is published on behalf of the Euclid Consortium.

Neutrino flavor conversion profoundly impacts the explosion mechanism and multi-messenger emissions of core-collapse supernovae. Yet, state-of-the-art hydrodynamic simulations of neutrino-dense astrophysical environments cannot account for neutrino quantum kinetics, necessitating subgrid schemes to model the impact of neutrino self-interaction on the quasi-steady-state flavor configuration. We present semi-analytical approximations for the outcomes of both slow and fast flavor conversions in quasi-homogeneous systems with periodic boundary conditions. Independent of the mass ordering, our ansatz demonstrates excellent agreement with multi-angle and multi-energy solutions of the neutrino kinetic equations across a wide range of representative (anti)neutrino distributions.

Small-scale eruptive phenomena in the solar corona including miniature flux ropes and associated cool plasma condensations are not fully understood despite increasing high-resolution observations. We perform forward modeling based on a 2.5D MHD simulation capturing homologous flux rope eruptions, in-situ condensation leading to a mini-prominence, and subsequent post-flare coronal rain. Synthetic diagnostics are obtained using optically-thin EUV and UV emissions, and non-LTE radiative transfer treatment for the H$α$ line. The synthetic EUV emission reveals the flux ropes as bright rim-like structures. The corresponding UV diagnostic shows bright region, which is co-spatial with the dark core due to embedded cool plasma ($\sim$ tens of kK) inside the flux rope, identifying an erupting mini-prominence. Spectral synthesis of Si IV 1402.77 A indicates an upward motion of the mini-filament, and reveals the presence of two predominant velocity components during eruption. At a later stage, thermal instability in post-flare arcades produces coronal rain with temperatures of $\approx 10^4$ K. The EUV diagnostics reveal brightening at the downstream of the rain blob, indicating localized heating associated with compressional effects. The H$α$ spectral synthesis shows enhanced absorption signatures and red-shifted profiles corresponding to downflows of the coronal rain blobs up to $\approx 23$ km s$^{-1}$, whereas the Si IV 1402.77 A spectral profile shows the maximum downflow velocity of $\approx50$ km s$^{-1}$, highlighting the evidence of thermodynamic and kinematic structuring within the falling rain blobs. The synthetic diagnostics provide clear, multi-wavelength signatures that can guide future high-resolution observations, and highlight the importance of small-scale reconnection-driven processes in shaping the multi-thermal structure (between MK to kK) of the solar corona.

The self-similar growth of massive galaxy clusters suggests that radial profiles of their key thermodynamic properties should have identical shapes after proper mass- and redshift-dependent re-scaling. This property, tested within the virial radius on samples of well-studied individual objects, together with clear and robust observational characteristics such as sensitivity and background accounting, enables the possibility of stacking observations that can be confronted with identically-derived population-averaged predictions from theory or numerical simulations at large radii. Such a comparison not only eliminates effects of inevitable stochasticity in properties of individual objects, but also allows one to reach higher sensitivity for the faintest regions on the outskirts of the clusters. In this study, we conduct a one-to-one comparison of the observed and simulated average soft X-ray surface brightness profiles of several dozen massive galaxy clusters at low redshift. We find a very good out-of-the-box agreement between the 0.3 - 2.3 keV surface brightness profile of stacked galaxy clusters recently measured by SRG/eROSITA and the corresponding predictions from the Magneticum cosmological hydrodynamical simulations, which are known to reproduce other scaling relations observed for massive galaxy clusters. A significant difference between the observed and simulated profiles is present in the very central region, where effective implementation of the AGN feedback likely results in excessive gas redistribution within the core. The simulations predict a very noisy surface brightness profile beyond several times the virial radius of the cluster, with the mean signal being orders of magnitude lower than the local radially-flat but strongly fluctuating emission background, meaning that a proper detection of this component would be very challenging even with larger samples in the future.

GW231123 is an exceptional gravitational wave event for which different waveform models yield significantly different inferred source parameters. Residual tests provide a direct way to assess whether each waveform model gives an adequate description of the observed signal. In this work, we extend the conventional residual-test methods by subtracting the 100 highest likelihood waveforms, rather than only the maximum likelihood waveform for each model, thereby propagating waveform reconstruction uncertainty into the residual analysis. This ensemble-based approach turns the residual test from a single waveform diagnostic into a robustness test over the local high likelihood waveform manifold. We further perform injection tests to quantify the detectability of cross-model waveform discrepancies in realistic detector noise. The large-scale implementation of these analyses is made possible by the high speed and low computational cost of our residual testing framework, which is based on three goodness-of-fit tests: the Kolmogorov-Smirnov test, the Anderson-Darling test, and Pearson's chi-squared test.

We construct a nonlinear electrodynamics (NLED) model for a static magnetic black hole. Rather than imposing a regular center, we require a Maxwell weak-field limit, finite magnetic self-energy, a positive and subluminal electromagnetic cone, the standard energy conditions, and a static exterior that satisfies known sufficient stability criteria. A positive mixture of power kernels restricts the exponent to $1/4<γ\leq1/2$. For the minimal two-kernel model, with $γ_1=1/3$ and $γ_2=1/2$, the field equations admit an exact solution in terms of incomplete beta functions. For the branches with nonnegative Schwarzschild mass parameter $M_0$, the metric function is strictly increasing, so there is at most one positive-radius horizon and no inner Cauchy horizon. We construct the maximal extension and show that the black-hole, horizonless, and critical branches have spacelike, timelike, and null singularities, respectively. The representative black-hole families have positive temperature and negative fixed-charge heat capacity. Electromagnetic waves split into ordinary and extraordinary optical branches. We calculate their photon spheres, shadow radii, instability rates, and illustrative Event Horizon Telescope size bands. We also construct ISCO-truncated thin-disk images. The full images remain close, but jointly normalized residual maps and radial profiles reveal a coherent branch-dependent shift near the lensed inner edge and the critical region. The extraordinary branch moves the critical curve outward and partly compensates the shadow reduction caused by magnetic charge.

We study black hole formation resulting from the collapse of a homogeneous and isotropic dust ball within a framework built upon loop quantum cosmology. Using loop dynamics formulated for Lemaitre-Tolman-Bondi spacetimes---which reduce to the asymmetric loop quantum cosmological bounce scenario---we analyze the dust ball undergoing power-law contraction followed by a de Sitter-like expansion. We discover an emergence of a physical shock at the dust ball surface, characterized by a continuous induced metric and a discontinuous extrinsic curvature arising from a dynamical mismatch between the expanding interior and the contracting exterior vacuum shells. Furthermore, we explicitly derive two variants of Schwarzschild-like line elements for the vacuum sector, and we demonstrate that the resulting spacetime is geodesically complete featuring a rich causal structure. This establishes, for the first time, fully dynamical regular black hole formation within a framework consistent with loop quantum cosmology.

We construct a novel Kerr-like black hole solution embedded in a general double power law dark matter environment by applying the Newman--Janis algorithm to a Schwarzschild-like seed geometry. This framework provides a unified rotating spacetime for arbitrary double power law density profiles and reveals how dark matter modifies the horizon structure, extremal spin, and curvature properties of rotating black holes. Remarkably, we find that the rotation--halo interplay can eliminate essential curvature singularities for Dehnen-type profiles with $γ\leq2$, despite the singular nature of the corresponding static configurations. We then investigate the spectroscopic signatures of the dark matter environment through massive scalar perturbations in the Dehnen $(1,4,γ)$ halo. Using an analytical low-frequency matching method, we derive the quasibound state spectrum, the onset condition for scalar cloud formation, and superradiant amplification factor, showing that the halo parameters $ρ_0 r_0^3$ and $γ$ leave characteristic imprints on the scalar spectrum. Increasing the halo density or the cusp strengthens the binding of quasibound states and enhances their decay, shifts the scalar cloud threshold, and suppresses superradiant amplification effectivity by narrowing the allowed frequency window and lowering the amplification factor peak. Finally, we analyze rotational energy extraction from thermal scalar fields and demonstrate that the efficiency is controlled by the interplay between the thermal spectrum and the superradiant instability, with lower temperatures and less cuspy density profiles yielding more efficient energy extraction.

The inspiral and merger of two supermassive black holes (SMBHs) releases immense energy in low-frequency gravitational waves (GWs). Recent pulsar timing array (PTA) observations of the stochastic nHz GW background (GWB) are consistent with a SMBH binary origin. GW data from PTAs and from the upcoming Laser Interferometer Space Antenna (LISA) can probe late-stage binary evolution where electromagnetic constraints are scarce. However, the complexity of the relevant astrophysics necessitates a well optimized approach. I argue that a key physical quantity to constrain with PTAs is the orbital semi-major axis at which binary inspiral transitions from the astrophysical to the GW-dominated regime ($a_{\rm GW}$). This quantity should be treated as a free parameter in analysis of the GWB. Using this premise, I present a simple analytic framework for modeling SMBH binary inspiral in an "inside-out" fashion. At orbital separations slightly larger than $a_{\rm GW}$, a power-law scaling for the astrophysical inspiral timescale is assumed, while the outermost phase (prior to the PTA regime) is simply modeled via a delay time. I show that the GWB spectral shape and amplitude are most sensitive to $a_{\rm GW}$ (normalized to $10^9 M_{\odot}$, equal-mass binaries and expressed in gravitational units), with weaker dependence on the inner power-law index and the outer delay time. The GWB is largely insensitive to the mass and mass-ratio scaling of $a_{\rm GW}$ and to the boundary between the inner and outer astrophysical inspiral regimes. I compare with models for gas- and stellar-driven binary inspiral and discuss implications for LISA and for GW source parameter inference.

We apply the Gaussian covariance formalism to develop a semi-analytical covariance model for the joint analysis of pre-reconstruction, post-reconstruction, and cross full-shape galaxy power spectra. We model the reconstruction-reduced, scale-dependent cross shot noise using displacement-field statistics and introduce a new estimator that directly measures this term. Using the measured power spectra and the modeled shot-noise predictions as inputs, we construct the Gaussian covariance while accounting for correlations between the pre- and post-reconstruction density fields. We validate the resulting semi-analytical Gaussian covariance against mock catalogues. Using emulator-based parameter inference, we demonstrate that the semi-analytical Gaussian covariance adequately captures the dominant contribution to the covariance structure of the full data vector ($P_{\ell}^{\rm pre}, P_{\ell}^{\rm post}, P_{\ell}^{\rm cross}$). For the joint fit to these three power spectra, it yields cosmological constraints consistent with those obtained using the mock-based numerical covariance over the adopted fitting ranges: $k_{\rm max}=0.18\,h\,{\rm Mpc}^{-1}$ for $P_{\rm pre}$ and $P_{\rm post}$, and $k_{\rm max}=0.12\,h\,{\rm Mpc}^{-1}$ for $P_{\rm cross}$.

We perform a joint cosmological analysis using angular power spectra of galaxy clustering, galaxy-shear cross correlation, and cosmic shear (hereafter referred to as photo-3x2-pt) measured from the Hyper Suprime-Cam year-3 (HSC-Y3) weak lensing shape catalog. We employ the pseudo-$C_\ell$ method to measure these power spectra and use the template deprojection method to mitigate systematics in the galaxy density maps. We perform a standard Bayesian likelihood analysis for cosmological inference based on the measured photo-3x2-pt, including contributions from intrinsic alignments of galaxies, galaxy clustering bias, lensing magnification effect, baryonic feedback effect, and source redshift distribution errors. For a flat cold dark matter model, we find a 68% credible interval of $0.76 \le S_8 \le 0.81$. This result is consistent with those of the HSC-Y3 cosmic shear analyses (Dalal et al. 2023, Li et al. 2023), but is $\sim 25$% tighter than theirs. We also perform a performance test using mock catalogs that mimic the HSC-Y3 data to validate our photo-3x2-pt analysis. Through Bayesian parameter inference of mock data, we verify that unbiased estimates can be obtained for the key cosmological and nuisance parameters, including $S_8$, model parameters of intrinsic alignment, galaxy clustering bias, and shift parameters of the source redshift distributions.

An axion driven toward a thermal minimum need not remain a coherent condensate. We derive the coupled attenuation of the field mean and production of stochastic momentum modes in an expanding plasma. A single momentum dependent optical depth partitions every mode between coherent power and Bose occupation, placing standard misalignment, partial relaxation, and stochastic production in one dynamical relation. Finite spatial and temporal response suppresses high momentum production, so the stochastic relic has lower mean momentum and a shorter free streaming length than an equilibrium population at fixed mass and bath temperature. A weakly coupled realization produces the dark matter abundance, reduces inherited coherent isocurvature, and confines production correlations to scales removed by collisionless propagation. Thermal relaxation therefore determines the composition, momentum distribution, and transported structure of axion dark matter.

We develop a quantitative framework for charge assisted Penrose extraction in Reissner--Nordström Anti-de Sitter black holes surrounded by a Kiselev type anisotropic dark energy sector. The generalized electrostatic ergosphere is defined by the balance between redshift and electrostatic work. Under explicitly stated monotonicity assumptions on the lapse and electrostatic potential, we prove uniqueness of the exterior ergosphere boundary and of the turning point of negative energy trajectories. We derive a local upper bound on the escaping energy, formulate a finite radius reception criterion appropriate to AdS asymptotics, and map the allowed extraction domains in terms of the mass, charge, cosmological constant, Kiselev normalization, and state parameter. We also introduce first order adiabatic discharge and accretion laws for slowly varying mass and charge, clarifying the regime in which the evolving horizon and ergosphere can be tracked consistently. The results provide controlled analytic and numerical diagnostics for charged Penrose extraction in RN--AdS backgrounds with a dark energy environment, while clearly separating local kinematic bounds from backreaction, radiative losses, and near extremal stability effects.

We derive and test kinematic upper bounds on charged energy extraction in the purely electric branch of a static $f(R,T)$ black hole family sourced by an Euler--Heisenberg type nonlinear electromagnetic sector. The analysis is restricted to external, minimally coupled probe particles on the fixed background. In this electric solution the field remains Coulombic up to an additive gauge constant; the nonlinear electromagnetic and matter-coupling coefficients therefore affect extraction indirectly through the metric, the event-horizon position, and the global causal structure. We obtain a general local bound retaining nonzero angular momentum and radial velocity of the negative energy fragment, and identify the commonly used zero angular momentum turning-point choice as an upper envelope rather than a generic decay configuration. A co-moving split supplies a locally four momentum-conserving benchmark. We classify horizons with the double root conditions $\mathcal F=\mathcal F'=0$, distinguish asymptotically flat, de Sitter, and anti-de Sitter branches, and impose the corresponding global outward-accessibility criterion. In the de Sitter static patch the electrostatic energy is referenced to the cosmological horizon, so the relevant scale is $Q(1/r_+-1/r_c)$ rather than $Q/r_+$. Reproducible scans compare Reissner--Nordström, Einstein--Euler--Heisenberg type, $f(R,T)$--Maxwell, and full $f(R,T)$--Euler--Heisenberg type backgrounds. The results show that the branch-referenced horizon potential controls the local upper envelope, whereas the asymptotic structure determines whether an outward trajectory can reach infinity, a cosmological horizon, or only a finite outer turning point.

We solve cyclic finite-dimensional quantum histories for arbitrary time-dependent unitary steps, without assuming that one step has finite order. The propagation Hamiltonian is a unitary connection Laplacian on a cycle; its complete gauge invariant is the monodromy $M=U_{L-1}\cdots U_0$. Its spectrum is $λ_{a,k}=1-\cos((2πk-θ_a)/L)$, where $e^{iθ_a}\in\mathrm{spec}(M)$. Thus the exact history sector is isomorphic to $\mathrm{Fix}(M)$, while frustration, the gap above a nonempty zero-energy sector, the determinant, and the finite-temperature trace are obtained in closed form. Ordinary spectral data recover the multiset of monodromy phase cosines but not phase orientation; low energy certifies proximity to an exact relational history. We then define the predictive quotient of a sharp finite clock relative to an accessible operator system as the unique coarsest event alphabet preserving all conditional statistics on a history sector. A finite-error theorem shows that threshold clustering recovers this quotient when the minimum diamond separation of inequivalent event channels exceeds four times the estimation error, and proves an optimal record-count bound. With full matrix access and homogeneous step $U$, the minimal number of clock events is the projective order of $U$. We distinguish the normalizer of the clock algebra from transformations preserving the coherent history code and classify oriented exact sharp clock changes by $U(r)\times\mathbb{Z}_L$ on a rank-$r$ history sector; without orientation the cyclic factor becomes dihedral. Reversible changes of full-information clock fibers are necessarily unitary, so irreversible coarse-graining is not exact clock covariance. Minimal realizations of a complete history Gram kernel are uniquely unitarily equivalent, with a finite-data Procrustes bound. Independent finite-matrix code verifies the main results.

We investigate gravitational and Kerr-Newman extensions of an information-theoretic black-hole entropy that satisfies the Nernst formulation of the third law of thermodynamics. The entropy is identified with the Kullback-Leibler divergence between a mass-dependent Bernoulli ensemble and an unbiased reference ensemble, and therefore measures relative information rather than the logarithm of the number of black-hole microstates. We show perturbatively that its temperature and entropy can be reproduced by an infrared deformation of General Relativity. To linear order in the deformation couplings, the surface-gravity temperature and the Wald entropy agree with the information-theoretic results. In an explicit realization, the matching generates a positive effective cosmological term whose smallness is related to the large microscopic parameter $N$. We also propose an extension to Kerr-Newman black holes based on the irreducible mass. This construction preserves the connection with the horizon area and the semiclassical limit, while distinguishing geometrical extremality from the universal statistical-freezing endpoint, which is independent of angular momentum and charge.

Hypervelocity stars (HVSs) are stars with velocities high enough to escape the Milky Way, but their identification depends sensitively on distance estimates, particularly for distant giants. In this work, we search for metal-poor HVS candidates by combining LAMOST DR13 spectroscopy with Gaia DR3 astrometry. We calibrate a metallicity-dependent color--absolute-magnitude relation for normal metal-poor giants using a high-quality reference sample, and apply it to derive photometric distances for 41{,}331 stars. The relation reproduces the reference absolute magnitudes with a scatter of 0.24\,mag, corresponding to an intrinsic distance uncertainty of $\sim$9.7\%. Combining these distances with Gaia proper motions and LAMOST radial velocities, we identify 13 initially unbound candidates under the Galactic potential from \citet{McMillan2017}. Spectral inspection indicates that several are chromospherically active binaries or other non-standard systems for which a giant-star calibration is unreliable; removing these contaminants leaves nine metal-poor HVS candidates. Backward orbit integrations suggest that one candidate is most consistent with a disk origin, while three have trajectories suggestive of an association with the Sagittarius stream.

Galaxy mergers drive both the size growth and the transformation from discs to spheroids, yet the prescriptions used to model these processes in semi-analytic frameworks have not been tested against the realistic merger population in cosmological hydrodynamical simulations. Using $\approx 4{,}500$ mergers identified in the EAGLE simulation, we test an energy-conservation estimator for post-merger galaxy sizes and quantify merger-driven morphological transformation. The predicted remnant half-stellar-mass radius matches the simulated descendant size with a scatter of $\approx 0.12$-$0.15$ dex and no significant systematic dependence on progenitor properties, while a commonly used dissipation correction applied to gas-rich mergers under-predicts the post-merger size by up to $\approx 0.4$ dex in a cosmological context and increases the overall scatter. The per-merger size growth increases monotonically with the stellar mass ratio of the merging pair, from $\lesssim 0.03$ dex for minor mergers to $\approx 0.10$ dex for equal-mass mergers. From the energy-conservation estimator, we analytically derive the size growth efficiency per unit accreted stellar mass, $η\equiv \mathrm{d}\log_{10} r_{\star}/\mathrm{d}\log_{10} M_{\star}$, and show that $η$ reaches $\approx 2$ only in the idealised limit of collisionless minor mergers with zero orbital energy; as $η$ is highly sensitive to the orbital energy at the time of merging, the minor merger channel cannot be established as the driver of the rapid size growth of massive galaxies without better constraints on this quantity. Beyond the size growth, mergers systematically reduce rotational support and increase triaxiality in proportion to mass ratio, but even the most nearly equal-mass mergers do not always fully destroy the disc, in tension with the complete disc destruction assumed in several semi-analytic models.

We present uGMRT Band-3 observations of the Galaxy and Mass Assembly (GAMA)-23 field. The observations consist of a total of 33 hours spread over 50 pointings, corresponding to $\sim$ 56 minutes per pointing at the central frequency of 325 MHz. The final image mosaicked from these pointings has a central off-source RMS noise of $109\,μ\mathrm{Jy}/\mathrm{beam}$ and covers an area $65.31\,\text{deg}^2$ with a resolution of $15.8''$. This wide-area deep-field observation provides a radio source catalog of 5741 sources with flux densities ${\geq}\,5σ$. We present complementary uGMRT observations overlapping with the high-frequency ASKAP EMU survey. We derived the spectral index from the matched sources in the GAMA-23 field for the first time. We have studied the statistical properties of diffuse Galactic synchrotron emission (DGSE) in the GAMA-23 field using six different latitude target pointings. We fitted DGSE in the form of power law $C_{\ell} = A(1000/{\ell})^{β}$. Our DGSE amplitude range of $A = 1-20\,{\text{mK}}^2$ and $β$ varies between $1.5-2.4$. This work presents one of the first characterizations of DGSE in the southern sky at 325 MHz, setting a precedent for foreground modeling required for sensitive radio observations with the upcoming SKA.

In this study, we estimated the angular diameter distances to two high-redshift active galactic nuclei (AGNs), OJ 248 (z = 0.939) and 4C +38.41 (z = 1.814), using 43 GHz radio light curves. The aim of this work is to extend AGN variability-based distance measurement methods to the high-redshift regime. The distance estimates were analyzed under two assumptions for the maximum intrinsic brightness temperature TB,int: (1) the equipartition temperature, and (2) the sample-averaged TB,int. As a representative result, when adopting the equipartition temperature, the angular diameter distances to OJ 248 and 4C +38.41 are estimated to be 7592.7 +/- 396.7 Mpc and 11069.8 +/- 1216.9 Mpc, respectively. In addition, Doppler factors were calculated using the inverse-Compton method, and additional distance estimates were obtained based on these values. Our error budget analysis shows that the most significant systematic uncertainty arises from epoch selection. These results indicate that systematic effects have a substantial impact on the derived distance estimates and limit their reliability, particularly in the high-redshift regime. Reducing these uncertainties will require improved observational cadence and reduced post-fit noise. AGN variability provides an alternative approach to distance estimation. However, our results reveal significant limitations in the current methodology and indicate that further methodological and observational improvements are required before its cosmological applicability can be reliably assessed.

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

Modern physics has achieved extraordinary empirical success while retaining much of the absolute, unobservable structure introduced by Newton, largely without questioning its necessity. We investigate how far this structure can be eliminated by adopting a relational ontology guided by Leibniz's principle of sufficient reason. Removing absolute position, orientation, time and, finally, scale leads naturally to a formulation of the gravitational $N$-body problem where only dimensionless ratios are physically meaningful. Within this framework, the scale-invariant variety $V$ becomes a central quantity, providing a measure of structure, a natural ordering of shapes, and an emergent gravitational arrow of time. We argue that the resulting formulation unifies classes of Newtonian solutions previously regarded as distinct, uncovering a possible new symmetry, suggests a notion of explanation based on timeless spatial correlations rather than temporal evolution, and points towards a more economical ontology. Although developed in the context of Newtonian gravity, the principles proposed here may also offer a new perspective on general relativity and quantum mechanics.

Bow shocks are one the most commonly observed impact sites of massive star feedback. Their existence is often taken as evidence of the supersonic motion or even runaway nature of the massive star. Bow shock geometry is also used to infer the properties of the stellar wind. However, some bow shocks have been reported around sub-sonic massive stars or are orientated differently than the stellar direction of movement, suggesting a substantial influence of the interstellar medium (ISM). In this work, we quantitatively investigate the dominant cause of bow shock formation around massive stars. Starting from an infrared sample of known bow shocks, we measure the stellar peculiar velocities and degree of alignment of the bow shocks. We find that only half ($52\pm2\%$) of the bow shocks is driven by a supersonic star and that $70\pm2\%$ of bow shocks is substantially misaligned (>30 degrees). Of our sample, only $21\pm2\%$ of systems can be regarded as classical bow shocks, driven by a supersonic star in the direction of stellar movement. For the remaining $79\pm2\%$ of systems, the role of bulk ISM movement in creating the shock is equal to or dominant over the stellar movement. We then introduce a new statistical method to derive the magnitude of the ISM motions required to play this dominant role. We find that ISM motion of the order $10-15$ km s$^{-1}$, oriented randomly within the local standard of rest, suffices to explain the existence and orientations of the bow shocks in our sample. For the subset of systems facing HII regions, we find evidence that outflows at $>25$ km s$^{-1}$ from those regions drive the nearby shocks. We conclude that ISM motion is the dominant factor in creating massive star bow shocks and discuss how ignoring these motions can lead to underestimates of the stellar wind's mass loss rate by more than an order of magnitude.

Extreme-mass-ratio inspirals (EMRIs) encode more than $10^5$ strong-field orbital cycles and are key targets for space-borne gravitational-wave interferometers, yet coherent recovery of generic systems over astrophysically broad priors remains unresolved. Successive Mock LISA, LISA, and Taiji Data Challenges (MLDCs, LDCs, and TDCs) have not yet produced a complete, generally reliable solution for blind EMRI detection and parameter recovery across such priors. The central obstacle is a needle-in-a-haystack likelihood: six phase-evolution parameters span a vast domain, producing an exceptionally narrow global maximum amid numerous secondary maxima. We show that higher-likelihood secondary maxima concentrate progressively around the global maximum and can therefore guide an adaptive contraction of the search volume. We exploit this structure through a reduced-dimensional profile likelihood and a coherent hierarchical strategy to search for EMRI signals across the full 14-dimensional parameter space. This enables the first end-to-end coherent parameter estimation for generic EMRIs with astrophysically broad priors. In stationary Gaussian LISA noise, the search recovers two half-year analytical-kludge signals with signal-to-noise ratios near 50, yielding fitting factors of 0.989 and 0.971, fractional errors of $10^{-3}$--$10^{-2}$ in the phase-evolution parameters and near $3\%$ in the distance, and error of less than $0.1$ radian in the sky location. The method turns secondary maxima into guides for a coherent hierarchical search.

About 20% of white dwarfs are observed to host large-scale magnetic fields, but the origin of white dwarf magnetism remains uncertain. Small-scale turbulent dynamos (SSDs), which efficiently generate magnetic fields in solar and stellar convection simulations, have so far been studied in white dwarfs only through equipartition arguments in one-dimensional models. We therefore investigate whether turbulent convection in white dwarf surface layers can sustain SSD action through local three-dimensional radiation-magnetohydrodynamics simulations of a DA white dwarf with a convective pure-hydrogen atmosphere, including the full convection zone together with the underlying overshoot and stably stratified layers. Starting from a weak seed field of 1 mG, the magnetic energy undergoes exponential amplification before saturating at a magnetic-to-kinetic energy density ratio of about 5.5% at the visible surface, demonstrating that SSD action naturally generates kG-strength magnetic fields in convective white dwarf atmospheres. The resulting magnetic field is characterised by a mixed-polarity small-scale structure, with kG field concentrations contributing about 14% of the total unsigned magnetic flux at the visible surface. Despite a rate of magnetic energy generation amounting to roughly one-seventh of the bolometric flux, no significant modification of the mean stratification is found. Although these fields remain spatially unresolved for observations, they may contribute to spectral line broadening, suggesting that small-scale magnetism in white dwarfs could be more widespread than currently inferred from observations.

We study static, spherically symmetric axion--dilaton solutions of the tree-level four-dimensional string effective action. Using the sigma-model structure of the scalar sector, we show that the full family of static, spherically symmetric and asymptotically flat solutions is obtained as the $SL(2,\mathbb R)$ orbit of the pure-dilaton FJNW solution, and we characterize the associated axion--dilaton charge space. We then analyze the perturbative regime of these solutions by comparing the onset of $α'$ curvature corrections with that of string-loop corrections. Finally, we apply the string--black-hole correspondence criterion to the FJNW family by evaluating the local $α'$ curvature diagnostic at the physical size $R_{\rm typ}$ of a highly excited string state. With the normalization fixed on the Schwarzschild branch, Schwarzschild saturates the nominal $α'$ threshold at the correspondence surface, whereas every scalar-haired FJNW branch lies above it. More generally, independently of the common overall normalization within the matching prescription, every nonzero-hair branch has a larger curvature diagnostic at the correspondence surface than Schwarzschild. Away from the correspondence point, scalar-haired exteriors may remain under $α'$ control at sufficiently weak local self-gravity and may provide perturbatively controlled long-distance fields of highly excited string states whenever the local string coupling also remains weak.

We compute the lowest radial mode of spherically symmetric boson stars along equilibrium branches with a fixed number of radial nodes, considering both mini boson stars and quartically self-interacting models. By reformulating the pulsation equations in additive variables that remain regular at the zeros of the background scalar field, the eigenvalue problem can be integrated directly through the nodes of excited configurations. For all branches examined, the first zero of the constrained fundamental radial eigenvalue coincides, within numerical resolution, with the first simultaneous critical point of the Arnowitt--Deser--Misner (ADM) mass, Noether charge, and binding energy. We further evaluate the radial eigenvalue for the threshold models identified in nonlinear spherical evolutions of excited boson stars and find a simple empirical correlation with the node number and self-interaction strength. Our results provide a regular perturbative framework for excited boson stars and clarify the relation between constrained radial modes, equilibrium critical points, and nonlinear stability diagnostics.

We present a unified study of scalar, vector, and tensor quasinormal modes (QNMs) of Schwarzschild black holes corrected by a Gauss--Bonnet (GB) term in higher dimensions. Using a high-precision Chebyshev spectral method, we map the QNM spectra across $D\in\{5,6,7,8,10,11,12,26\}$ well beyond the regime where sixth-order WKB and characteristic-integration techniques remain reliable. Across the three spin sectors, we find several robust signatures of higher-curvature dynamics: the appearance of overdamped purely imaginary modes, non-monotonic behaviour in the real parts of higher overtones, and a strong amplification of the dimensionless QNM frequencies in string-motivated dimensions. In the scalar and vector sectors, we uncover an exact isospectrality between the scalar monopole ($\ell=0$) and vector dipole ($\ell=1$) at vanishing GB coupling, and we provide an analytic proof based on a Darboux factorisation of the corresponding Hamiltonians. In the tensor sector, we obtain the first numerical confirmation of the long-predicted instability in six dimensions; its onset is sharply captured by the Cohn--Calogero bound and leads to the mass threshold $GM\leq 158.1\,α^{3/2}$. No analogous instability is found for $D\geq 7$, and no tensor isospectrality occurs. Converting the dimensionless frequencies to physical units suggests that the amplified modes in higher dimensions may enter the sensitivity window of future space-based detectors such as DECIGO. The merged analysis provides a comprehensive benchmark for QNMs in Einstein--Gauss--Bonnet gravity and highlights the limitations of standard approximation schemes in the strong-coupling and high-overtone regimes.

We demonstrate, by studying precession-driven flows, that inertial wave hydrodynamic turbulence can drive a robust magnetic dynamo action. Motivated by the stronger damping of large-scale geostrophic vortices in rapidly rotating planetary and stellar interiors, we introduce a controlled damping of the vortices, which usually accompany inertial wave turbulence and feed on wave energy. It is shown that even a small vortex damping results in a significant increase of the growth rate of the dynamo due to inertial waves in the kinematic regime, allowing it to persist for magnetic Prandtl numbers as low as $Pm \sim 10^{-3}$ and Poincaré numbers $Po\sim 0.025$. These critical values of $Po$ and $Pm$ for the dynamo onset decrease with increasing Reynolds number. The onset and growth of the dynamo appear to correlate with the coherent fluctuations of kinetic helicity. Spectral analysis shows that magnetic energy growth is primarily due to inertial-wave-induced induction over a broad range of scales. These results establish inertial waves as an efficient mechanism for magnetic field amplification in rapidly rotating low-$Pm$ flows relevant to planetary and stellar interiors.

We investigate timelike particle dynamics, collision energetics, and photon frequency shifts in the perturbative variable-scalar curvature branch of asymptotically flat symmergent gravity. The low-energy vacuum action contains an $R^{2}$ correction whose coefficient is set by the boson--fermion imbalance of the underlying quantum field theory. At linear order, the exterior geometry is conformal to Schwarzschild spacetime through a radial mode satisfying a linear equation. We retain an independent boundary-condition-dependent amplitude and restrict the analysis to the perturbative domain. The two signs of the symmergent parameter $γ$ yield distinct profiles: $γ>0$ gives a Yukawa-suppressed deformation, whereas $γ<0$ produces an oscillatory inverse-radius deformation. We derive radial equations, effective potentials, circular-orbit and marginal-stability conditions for neutral, electrically charged, and spinning massive particles. Charged particles are treated in the test-field approximation, while spinning particles obey the Mathisson--Papapetrou--Dixon equations with the Tulczyjew condition. We also compute the center-of-mass energy of neutral-particle collisions and the frequency shifts of photons emitted tangentially by circular geodesic sources and detected by a static observer at infinity. The redshift and blueshift factors satisfy $(1+z_{+})(1+z_{-})=1/A(r_e)$, directly linking their product to the lapse function at emission. The $γ>0$ branch yields smooth, short-range deviations from Schwarzschild dynamics, whereas the $γ<0$ branch can generate oscillatory radial bands admitting circular-orbit solutions whose stability must be tested independently. These observables provide complementary probes of the variable-curvature sector, although their quantitative interpretation also depends on the deformation amplitude and, for the oscillatory branch, its phase.

We investigate the open quantum dynamics of a system of two masses interacting with an environment of linearized gravitational waves. We formulate the analysis in terms of the observable proper distance between the two masses, and show that the canonical variables obtained from the standard Lagrangian, expressed in terms of the Fermi normal coordinates, are not suitable for an effective description of the system. We resolve this issue through a unitary transformation that provides a physically meaningful system--environment decomposition and derive the master equation to leading order in $G$. Its dissipative sector reproduces the classical energy loss due to gravitational-wave emission, while the noisy contributions suppress coherences between states with different mass quadrupole, or effectively, different proper separations. In the regime where the proper distance can be described by considering small quantum fluctuations around an average distance $l_0$, the dynamics reduces to a Caldeira--Leggett-type equation, with a decoherence rate dependent on the baseline length $l_0$.

We report on the search performed for a diffuse astrophysical neutrino flux from the full sky and from a specific region of the Galactic plane, the Galactic Ridge. The study uses the dataset collected with the first KM3NeT/ARCA configurations with 6, 8, 19, and 21 active detection units, corresponding to a total livetime of 640 days. For the all-sky analysis, the fitted single-flavour astrophysical neutrino flux parameters, under the single power-law assumption, are $φ_0^{1f} = 3.0^{+2.1}_{-2.0} \times 10^{-18}$ GeV$^{-1}$ cm$^{-2}$ s$^{-1}$ sr$^{-1}$ with spectral index $γ= 3.00^{+0.30}_{-0.35}$ at 68% credible level. The Galactic Ridge fit does not yield constraints for the flux parameters with the current sensitivity. For both analyses upper limits are derived and compared with state-of-the-art measurements. While the analysis of these datasets has not yielded statistically significant results, the developed methods provide a solid basis for future measurements with the KM3NeT detector.

This work aimed to study Miras in the bulge and halo of our galaxy, including those in globular clusters. The AAVSO International Variable Star Index VSX catalogue was used to retrieve Mira variable stars, while the information about globular clusters were taken from the Harris \citep{Harris1976}, McMaster catalogue \citep{33} and Holger Baumgardt \citep{34} table. Stellar characteristics such as metallicity, $T_{\rm eff}$, parallax and colors were obtained by Gaia EDR3 catalogue, Gaia DR3 VariSumarry, Gaia DR3 catalogue, 2MASS Point Source Catalogue, AllWISE, and ZTF catalogue. The UPSILoN program, color-color or color-magnitude diagrams were used to verify that our stars are indeed Miras-type variable stars and whether they are O or C type Miras. To deal with extinction, which affects stars mainly in the galactic bulge, we used IRSA DUST archive, OGLE-III and recalculation to the extiction-free Wesenheit magnitude. We obtained data for 1608 Miras in the bulge, of which 308 are located in 15 globular clusters. For the stars in the halo, we obtained data for 1954 Miras, of which 4 are located in 3 globular clusters. Miras in the bulge show a bimodal metallicity distribution with peaks at \text{--}0.4 dex and $+$0.5 dex, while Miras in the halo show only one peak at $+$0.5 dex. The period of Miras in the bulge is, on average, 30 days longer than for Miras in the halo, and O-type Miras are more abundant in the bulge than C-type Miras. The dependence of the logarithm of the base 10 period on magnitude in the infrared part of the spectrum gives us a linear dependence, with the dependence inverting when a filter is used in the optical part of the spectrum, because of the dust around the Miras.

We investigate dark matter admixed neutron stars in which the neutron star coexists with an anisotropic dark matter halo described by the Einasto density profile, a model recently shown to produce regular, singularity-free black hole solutions~[Phys. Rev. D \textbf{113}, 043011 (2026)]. Solving the modified Tolman--Oppenheimer--Volkoff equations with two different equations of state (BSk19 and SLy4), we find that the dark matter halo significantly alters the neutron star structure. Furthermore, for a specific range of halo parameters, $g_{rr}^{-1}$ changes sign outside the stellar surface, forming an event horizon with the neutron star persisting as a regular configuration inside it--- ``neutron stars in black holes''. This configuration appears in both equations of state and does not depend on a specific choice of the equation of state. The discovery of this configuration provides a new perspective and a concrete computable instance for the study of what lies inside a black hole.

We report the detection of an extended 21-cm parsec-scale \ion{H}{i} structure toward the Mira variable V420\,Vul using archival Galactic Arecibo L-band Feed Array survey data. The emission exhibits a spatially coherent but intensity-asymmetric morphology that nevertheless retains a globally symmetric kinematic profile centered near $v_{\mathrm{LSR}} \sim 47.6\,\mathrm{km\,s^{-1}}$. At an adopted distance of $\sim 1.9$\,kpc, the structure extends over $\sim 20$\,pc, implying a dynamical timescale of order $10^6$\,yr. Although the total \ion{H}{i} mass ($\sim 70\,\mathrm{M_\sun}$) indicates that the atomic gas reservoir is heavily dominated by the ambient interstellar medium rather than pristine stellar ejecta, the spatially resolved spectra and position-velocity diagrams reveal an underlying symmetric velocity framework centered on the star. We interpret this as the dynamical imprint of the stellar wind preferentially channeling through a porous ambient cloud, demonstrating that cohesive kinematic records of late-stage stellar mass loss can be preserved over parsec scales and megayear timescales despite dominant interstellar coupling.

Megamaser distances can be measured without using the traditional distance ladder. As such, they provide an independent probe of the local expansion rate, quantified by the Hubble constant $H_0$. We re-analyze megamaser distance and redshift data to obtain a new, more accurate, estimate of $H_0$. The main improvement in our analysis is the use of a new velocity field reconstruction to correct redshifts for peculiar velocities. This reconstruction utilizes constrained cosmological simulations in addition to redshift survey data to more accurately capture both coherent flows as well as nonGaussian individual galaxy motions. We argue that previous estimates of $H_0$ from megamaser data were susceptible to bias due to peculiar velocities. By correcting for peculiar motions using this new reconstruction we obtain a value of $H_0$ that is consistent with the value from the Cosmic Microwave Background (CMB) and in tension with the value from the local distance ladder at greater than a $2σ$ level, whereas previous results showed consistency with the distance ladder and tension with the CMB at greater than $2σ$. Our results suggest that the Hubble tension is due to some heretofore undetermined systematic in the distance ladder rather than new physics.

In this work we investigate the inversion accuracy of stellar magnetic fields through the analysis of spectropolarimetric data. We performed several noise free tests to untangle the impact among the atmospheric and magnetic parameters in the data analysis. Using a single spectral line, we found that under ideal scenario, without noise, the magnetic parameters can be recovered with very high accuracy, while some of the atmospheric ones show a considerable incertitude. If multi-line profiles are considered instead, then the accuracy of the recovered atmospheric parameters increases significantly. Nonetheless, it is quite common that for the inversion of stellar spectropolarimetric data, the atmospheric parameters and the stellar inclination angle of the star are fixed; we show that this procedure could induce very high errors in the inference of the magnetic properties, specially in what concerns to fix the inclination angle. We show that even small deviations from the true inclination angles could have as consequence that the recovery of the magnetic properties of the star are no longer reliable. This is because we demonstrate that given a set of Stokes profiles observed along the rotational phase, they can be satisfactorily fitted regardless of the assumed stellar inclination angle, thereby revealing a degeneracy in the solution. Although this work validates the solution generation solely for a de-centered dipolar geometry, a comparable degeneracy is anticipated when modeling the magnetic field with higher order spherical harmonics, an effect that remains to be formally characterized.

Rare fluctuations in physical systems depend on the detailed microphysics responsible for the fluctuations. In classical statistical systems, the large deviation principle has elucidated the role of semi-classics in describing this regime, and has simultaneously provided a the mathematical foundation of statistical mechanics. Large deviation theory for quantum system is considerably less developed. As all physical systems are fundamentally quantum mechanical, this leaves a major gap in our understanding of rare fluctuations relevant to statistical physics, cosmology, and more. In this paper, we develop the practical aspects of the theory of large deviations relevant for calculating rare events in physical systems from quantum walks to cosmology. We first analyze the case of the anharmonic oscillator coupled to a bath, showing explicitly how the system evolves from dominantly statistical (e.g. thermal) to quantum fluctuations. We then generalize these results, showing that the dominant rare fluctuations minimize the measurement-induced relative entropy. This perspective provides a thermodynamic description of a wide range of open quantum systems. We apply these results to random walks that arise in cosmology through stochastic inflation. We show that the evolution of the density matrix of long wavelength fields on a fixed de Sitter background breaks the KMS symmetry, giving rise to a stationary density matrix that does not respect detailed balance.

We present a framework for decomposing solar-wind velocity distribution functions (VDFs) using orthogonal polynomial bases. We aim to establish a practical procedure for applying polynomial decompositions to in-situ spacecraft VDFs and to clarify how the resulting spectra of expansion-coefficient power can be used for noise reduction, VDF reconstruction, and diagnostics of velocity-space structure. The method represents measured VDF structure with Hermite-Hermite and Hermite-Laguerre expansions, providing a nonparametric description of departures from Maxwellians, such as anisotropy, skewness, beams, and suprathermal tails. Expansion coefficients are estimated by Gaussian-weighted quadrature after interpolation of measured distributions onto polynomial nodes. We demonstrate several applications of polynomial decomposition to Solar Orbiter, Parker Solar Probe, and Magnetospheric Multiscale 1 measurements, including noise identification through high-order spectral flattening, noise-reduced VDF reconstruction, and characterization of VDF-structure variations under different plasma conditions, e.g., turbulent solar-wind streams and shocks. For instance, noise-reduced reconstructed VDFs can provide smoother estimates of distinct ion populations and VDF gradients. Examples from solar-wind streams and collisionless-shock crossings further show that the resulting spectra respond to changes in parallel and perpendicular VDF structure, illustrating their potential for comparing kinetic modifications under different plasma conditions. Overall, orthogonal-polynomial decomposition provides a bridge between measured particle distributions and kinetic plasma physics by converting complex VDF morphology into quantitative velocity-space spectra.

Gravitational lensing of the cosmic microwave background (CMB) generates B-mode polarization that acts as a source of contamination to searches for B modes generated by primordial gravitational waves (PGWs). The strongest constraint on PGW B modes is already significantly limited by lensing B modes, as shown in the most recent BICEP result. In this work, we present CMB lensing B-mode templates constructed using SPT-3G and Planck data, which characterize the lensing B modes and can be used to improve PGW B-mode searches. We use SPT-3G data from the 2019 and 2020 observing seasons for the E modes and the CMB-reconstructed lensing potential, and a cosmic infrared background (CIB) map from Planck as an external lensing tracer. To test for extragalactic foreground biases in the lensing template, we consider CMB lensing reconstruction variants with different levels of foreground immunity: the standard and profile-hardened global minimum variance (GMV) quadratic estimators, and a polarization-only quadratic estimator. We validate the template construction using Gaussian simulations and Agora simulations with realistic non-Gaussian foregrounds. From simulations, we find that foreground-induced biases are strongly suppressed for the template constructed with the profile-hardened GMV + CIB tracer, with residual bias below 10% of the statistical uncertainty on the template power spectrum. Data difference tests on this template similarly show no evidence for significant foreground contamination. This foreground-immune lensing template achieves delensed residual BB power of $A_{\rm lens}^{\rm res} \simeq 0.48$ averaged over $20 \leq \ell \leq 200$, the highest delensing efficiency lensing template to date. These results demonstrate and validate a method to construct foreground-robust lensing templates which will be used in upcoming delensed PGW B-mode analyses of BICEP data.

JWST has provided unprecedented access to ultra-cool brown dwarfs and has pushed the boundaries of directly imaging temperate giant planets. As we continue to push toward detecting sub-Saturn and Neptune-like planets, it is crucial to develop atmospheric and evolutionary models that better capture the complexity and diversity of planetary atmospheres similar to the gas and ice giants in our Solar System. We present Sonora Flame Skimmer, the next suite of cloud-free 1D atmospheric and evolutionary models in chemical equilibrium and disequilibrium probing colder temperatures (down to 50 K), smaller objects (down to log(g) = 2), and a wide range of metallicities (10x sub-solar to 100x super-solar) and C/O ratios (solar to 2.5x solar). Beyond expanding the physical parameter space of previous Sonora models, we update the opacities and evolutionary model framework from Sonora Bobcat, as well as the chemical treatment of volatiles (H$_2$O, CH$_4$, NH$_3$) and carbon species such as CO$_2$ from Sonora Elf Owl. For the evolution of these substellar objects, we find that high-metallicity atmospheres lead to slower cooling compared to solar metallicity, while the strength of vertical mixing ($K_{\rm zz}$) has a negligible impact on the evolutionary tracks. At the highest metallicity explored here (100$\times$ solar), the deuterium-burning and hydrogen-burning minimum masses fall to 5.39 and 45.03 $M_{\rm J}$, respectively. All the models presented here, including the atmospheric structure, chemical profiles, spectra, synthetic photometry, and evolutionary models, are publicly available.

Standard observational probes lack the sensitivity to characterize the interplay between feedback-driven gas ejection and non-thermal pressure support in groups and clusters, and current models lack the framework to disentangle it. Recent first detections of the tSZ$\times$FRB cross-power spectrum (Takahashi et al, 2025; Sharma et al 2026) have been interpreted as constraining AGN feedback and $σ_8$, but the baryon models used do not independently parameterize non-thermal pressure support, leaving feedback efficiency and gas thermodynamics degenerate. We demonstrate that this cross-correlation provides sensitivity to the thermal and non-thermal structure of cluster gas that neither observable alone can achieve, because the tSZ effect traces electron pressure while FRBs trace solely electron density. Using the Baryon Pasting (BP) framework, which separately parameterizes feedback efficiency $ε_f$ and non-thermal pressure amplitude $A_{\rm nt}$, we show that their joint constraint breaks this degeneracy. In the noise-free limit, adding the cross-power spectrum reduces $r_{\rm cond}$ from $0.96$ to $0.08$ (a 12-fold reduction) and improves the joint figure of merit by a factor of 19, with the constraining power concentrated at cluster interior scales ($\ell \gtrsim 3000$). Recent detections are consistent with our fiducial model and disfavor weak feedback ($ε_f^{95\%} \gtrsim 2.40\text{--}3.67 \times 10^{-6}$ across datasets). With $5\times10^4$ FRBs from DSA-2000 combined with SO, we forecast $3.8\%$ fractional precision on $A_{\rm nt}$, improving to $2.3\%$ with CMB-HD. These constraints directly inform the hydrostatic mass bias, with immediate implications for cluster-based cosmological inference from eROSITA, SO, and CMB-HD.

We revisit the all-sky survey data, the Wide-field Infrared Survey Explorer (WISE) catalog, with an improved galaxy-selection criterion to investigate the inconsistency between the dipole anisotropy in the galaxy number count and the kinematic CMB dipole anisotropy. We apply a set of active galactic nuclei (AGN) selection criteria composed of a flux cut and multiple color cuts, and formulate an appropriate adaptation of the original Ellis & Baldwin (1984) formalism for our photometric survey samples whose spectral energy distributions deviate from a pure power-law form. We find that the newly sampled AGNs from the WISE catalog still bears an anomalous number-count dipole anisotropy, whose amplitude is ~ 2.5 times as large as that of the purely kinematic origin at a 5.3 sigma confidence level. We also find that the direction of our WISE-AGN dipole is ~ 3 sigma away from that of the CMB dipole. We discuss its possible cosmological implications: nonlinearity of the nearby universe and mismatch of matter-rest frame and the CMB-rest frame.

Dark matter and dark energy could be ultra-light pseudoscalar fields that couple to electromagnetism through a Chern-Simons term. This would cause a parity-breaking rotation of the plane of linearly polarized light from the cosmic microwave background, known as cosmic birefringence, which is not predicted by $Λ$CDM. Recent hints of a non-zero cosmic birefringence angle have been found in both the Planck Data Release 4 and ACT Data Release 6 datasets independently. This work jointly analyzes the polarized maps of both, leveraging the cross-power spectra between the two telescopes. Taking the reported instrumental priors at face value, the joint analysis yields $β= 0.277^{\circ} \pm 0.057^{\circ}$, which is non-zero with a statistical significance of $4.8σ$. A robustness test mitigating contamination from dust emission excludes $β= 0^{\circ}$ at $3.5σ$, and retrieving $β=0^{\circ}$ would require both the dust $EB$ modeling and instrumental priors to fail simultaneously. However, unresolved systematics in the data must be understood before we can draw strong cosmological conclusions.

We present the first N-body simulations of structure formation in the Generalized Cubic Covariant Galileon (GCCG) model. This theory extends the cubic covariant Galileon through power-law kinetic and cubic derivative interactions and admits tracker solutions leading to late-time cosmic acceleration. Previous studies of GCCG have mostly focused on the background, linear perturbations, or semi-analytic nonlinear prescriptions. Here we implement the nonlinear scalar-field equation in the ECOSMOG adaptive-mesh refinement code, allowing us to follow the coupled evolution of matter clustering and Vainshtein screening in the fully nonlinear regime. We quantify the impact of GCCG on the nonlinear matter power spectrum and compare the simulation results with predictions from the halo-model reaction approach. For the parameter choices considered, the GCCG model enhances the matter power spectrum relative to the corresponding QCDM cosmology, with the effect increasing towards low redshift and reaching approximately $7\%$ at $z=0$ in the transition to the nonlinear regime. At smaller scales, the enhancement decreases as a consequence of Vainshtein screening. We find that the reaction framework captures the qualitative behaviour of the simulations, while residual differences appear on deeply nonlinear scales. We also analyse the abundance of dark matter haloes, finding an enhancement relative to QCDM that becomes more pronounced towards lower redshift and in the high-mass tail. These simulations provide the first nonlinear calibration of structure formation in GCCG and establish the range of validity of efficient semi-analytical predictions for applications to forthcoming large-scale-structure surveys.

We present an exact analytical model of axisymmetric gravitational collapse leading to the formation of the Kerr black hole. The model depends only on the total mass ${\cal M}$ and a time dependent rotation parameter $a(v)$, and incorporates both the extremal Kerr black hole and a novel quasi extremal regime without requiring $a\approx{\cal M}$. The evolution develops curvature singularities induced by $a(v)$, which are expected to remain enclosed within a trapped region close to the evolving Kerr radius $r=h(v)$. It also predicts a transient anisotropic exterior curvature decaying as $1/r^2$, which may imprint observable signatures associated with the formation of a rotating black hole. The present construction should therefore be interpreted as an exact analytical description of the final stage of rotational gravitational collapse, immediately preceding the formation of the Kerr black hole.

We present The Maunder, a machine learning pipeline and resulting catalog of rotation periods for 148,746 main-sequence stars in the Kepler field. To overcome single-catalog systematics and the simulation-to-reality gap, our architecture employs a hybrid training objective: a joint-embedding self-supervised loss applied to all light curves, combined with a supervised loss trained strictly on cross-catalog consensus labels. By processing multi-scale time- and frequency-domain inputs over rolling windows, the model leverages conformalized quantile regression to output calibrated predictive intervals, providing statistically robust per-star rotation uncertainty metrics. This rolling-window inference reveals that 31,953 stars (21.5$\%$) exhibit bimodal rotational signals. By incorporating APOGEE $v \sin i$ measurements, we demonstrate that for distinct (non-harmonic) bimodals, the longer mode represents the true rotation, exposing a systematic failure mode wherein classical single-pass periodograms lock onto shorter aliases. Filtering by our calibrated confidence intervals yields a highly reliable subset of 119,428 stars. The catalog resolves various rotation-related phenomena: the metallicity dependence of rotation at fixed stellar mass, pointing on the role of metallicity in magnetic braking processes; tracing equatorial velocity and specific angular momentum directly across the Kraft break; recovery of empirical gyrochronology sequences and identification of hierarchical triple candidates among the synchronized-binary population. \emph{The Maunder} provides reliable rotation periods for the largest main-sequence population in \textit{Kepler}, allowing for population-level studies of rotation-based phenomena.

Modern cosmology and galaxy formation rely on an understanding of how cosmic baryons are distributed, a significant portion of which exists in the diffuse gas confined to halos. Fast radio bursts (FRBs) are a promising probe of the Universe's ionized gas. At low redshift, the contribution to the dispersion measure (DM) from the intergalactic medium (IGM) and intervening halos is subdominant, allowing us to study the circumgalactic medium (CGM) of the host galaxies, if the host interstellar medium (ISM) can be sufficiently suppressed. We select a sample of five local Universe FRBs with host halos spanning a wide range in mass (~10<SUP>11-13</SUP> M<SUB>⊙</SUB>), and with indicators that host ISM DM is negligible. We use these FRBs to constrain the CGM in each halo by comparing to simulations and measuring the CGM mass assuming a range of spherical gas profiles. We find that one of our sources, the only massive elliptical host galaxy, strongly disfavors low feedback scenarios in simulations, and has been evacuated of its baryons (~ 10% of the cosmological average <inline-formula> <mml:math><mml:mfrac><mml:mrow><mml:msub><mml:mrow><mml:mi>Ω</mml:mi></mml:mrow><mml:mrow><mml:mi>b</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>Ω</mml:mi></mml:mrow><mml:mrow><mml:mi>m</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:mfrac></mml:math> </inline-formula> within R<SUB>vir</SUB>). This galaxy shows evidence of a past episode of active galactic nucleus (AGN) activity, consistent with the picture of strong AGN feedback in galaxy group-scale halos. The gas mass measurements for the other sources tentatively support more baryon retention in L<SUB>*</SUB> galaxies compared to group-scale halos. Finally, we demonstrate that a large sample of local Universe FRBs will enable precision measurements of halo gas.

We present a comprehensive dataset of hot molecular cores (HMCs) in the W49A molecular cloud complex based on high-resolution ALMA observations, including the 1.3~mm continuum, 12 molecular lines, and the H30alpha recombination line. In total, 18 HMCs are identified in the CH$_{3}$CN ($J_K=12_3-11_3$) map, together with 20 continuum sources in the 1.3~mm map. Ten HMCs have peaks coincident within 0\farcs1 of the 1.3~mm continuum peaks, indicating that thermal dust emission dominates the 1.3~mm emission for these sources. Correlation analyses of the line luminosities suggest a common structural picture for HMCs, in which five distinct regions with different physical and chemical properties coexist: hot and dense gas (CH$_3$CN, HC$_3$N, HNCO, OCS, H$_2$CO), outflow gas (SiO, SO), envelope gas (SO$_2$, CH$_3$OH), extended gas ($^{13}$CS, DCN, C$^{18}$O), and ionized gas (H30alpha). We find an empirical relation $X(\mathrm{CH_3CN})=2.5\times10^{-7}\exp[-490/T_\mathrm{rot}]$ between the fractional abundance and rotation temperature of CH$_{3}$CN, suggesting that $T\gtrsim200$--300~K is required to achieve high abundances of $\sim10^{-7}$. We find that HMCs without embedded H/UCHII regions are more numerous than, or at least comparable in number to, HMCs with such regions, suggesting that the former may have longer lifetimes ($\sim$10$^{5}$~yr) than the latter ($\sim$10$^{4}$~yr). We discuss the implications of these results for the core accretion and competitive accretion models.

We introduce a measure of information loss for any quantum process that may be modeled by a prepare-evolve-measure scenario: Alice prepares an ensemble of states that gets sent via a quantum channel to Bob, who then measures the output. As a quantum channel models open system dynamics, our measure of information loss quantifies Bob's inability to retrodict with certainty which state Alice sent through the channel. By minimizing this measure over all possible pure state ensemble decompositions of a fixed state $ρ$, and over all POVMs on the output of a channel $\mathcal{E}$, we arrive at an intrinsic notion of information loss for any state-channel pair $(ρ,\mathcal{E})$. We show that the vanishing of information loss with respect to all states supported on a fixed codespace $\mathcal{H}_{\text{code}}$ is equivalent to a condition we term \emph{universal pristineness}, which ensures that orthogonal pure states in $\mathcal{H}_{\text{code}}$ get sent via the channel $\mathcal{E}$ to possibly mixed states whose supports are orthogonal. Moreover, we prove universal pristineness is equivalent to the Knill-Laflamme conditions in quantum error correction, which are necessary and sufficient for the existence of a perfect recovery channel for all states supported on $\mathcal{H}_{\text{code}}$. As an application, we apply our framework to the Hayden-Preskill model of black hole evaporation, demonstrating that the evaporation channel becomes asymptotically universally pristine, thereby providing a purely channel-theoretic formulation of Page-time information retrieval.

In this paper we construct the canonical harmonic coordinates of the Kerr metric within the multipolar post-Minkowskian (MPM) formalism to the fourth post-Minkowskian (4PM) order. Based on the well known Geroch--Hansen moments of Kerr metric and Gürsel's theorem, we derive the exact canonical MPM moments $\mathrm{M}_L,\mathrm{S}_L$, which are free of any gauge moments. With these moments, we iteratively compute the gothic metric perturbation $h^{μν}_{\mathrm{can}}$ up to 4PM order and compute the 4PM canonical metric $g_{μν}^{\mathrm{can}}$. The resulting spatial and time components of these metrics are even functions of the spin parameter $a$ while the mixed components are odd. This parity property distinguishes the canonical coordinates from other harmonic coordinates. To contrast this minimal-gauge construction, we also extract the 1PM source moments of the Kerr metric in the Jiang--Lin coordinates. We find that the Jiang--Lin representation possesses non-vanishing gauge moments starting from the 1PM order, whereas in the canonical representation gauge moments vanish to all orders. This comparison highlights the canonical coordinates as the most gauge-pure representation of the Kerr metric in the MPM framework. The complete canonical metric for the Schwarzschild case is also computed to all PM orders. A recent independent construction by Damgaard et al. using momentum-space recursion yields 4PM equivalent results expressed as a power series in $a$, providing a cross-validation of our closed-form 4PM canonical metric. The coordinate transformation linking the canonical Kerr coordinates to previously known harmonic Kerr coordinates remains an open problem.

Objective facts in quantum Darwinism are values recorded redundantly in many independently accessible fragments of the environment. Redundancy does not create additional logical information, so its thermodynamic meaning has remained unclear. We show that it creates an exact work asymmetry between controllers with different access architectures. For a record cloud $F$ and a partition $\mathcal{P}$ into blocks that cannot be jointly controlled, the reversible isothermal erasure penalty relative to a global controller is $k_{\mathrm{B}}T$ times the partition total correlation. If the source event $X$ is supplied as catalytic classical side information, subtracting the corresponding penalty gives the source-loss law $\mathcal{F}_{\mathcal{P}}^{T}=k_{\mathrm{B}}T\left[\sum_{B\in\mathcal{P}}I(X{:}F_B)-I(X{:}F)\right]$. We call this the thermodynamic factuality charge. It ranges from $-k_{\mathrm{B}}T H(X)$ for perfect secret sharing to $(|\mathcal{P}|-1)k_{\mathrm{B}}T H(X)$ for perfect broadcast objectivity. Its normalized form defines a thermodynamic record number between $0$ and $|\mathcal{P}|$. We derive Landauer--Darwin bounds, endpoint-rigidity certificates, exact growth and partition-refinement laws, spectrum-broadcast saturation, and closed formulas for noisy classical and quantum collision models. The theory does not modify quantum mechanics or posit objective collapse; it identifies the thermodynamic resource generated by redundant records under restricted control.

Although the Bekenstein-Hawking area law is consistent with the first and second laws of black hole thermodynamics, it appears to be in conflict with the third law, which in the Nernst formulation states that the entropy should either vanish or approach a universal constant in the zero-temperature limit. We argue that this tension reflects a limitation of the semiclassical area law rather than a fundamental feature of black hole thermodynamics. On this basis, we obtain an entropy formula that is consistent with the third law, and approaches Bekenstein-Hawking entropy in the high-temperature limit. The resulting entropy admits a simple microscopic interpretation, and it can be written as the Kullback-Leibler divergence between a mass-biased Bernoulli distribution and the uniform distribution on N microscopic bits. From this perspective, the thermodynamic black hole entropy admits an information-theoretic representation as an entropy deficit, namely as the relative entropy between the black hole ensemble and a maximally mixed reference ensemble. The Bekenstein-Hawking area law then emerges as the leading term in an $1/N$ expansion, while a universal mass scale $M_0=\sqrt{N}\,M_P$, interpreted as an absolute upper bound on the black hole mass, controls the bias of the underlying microscopic ensemble. The subleading terms represent finite-information corrections to the classical area law.

We study the gravitational effective action induced, at first order in the deformation parameter, by non-local $T\bar T$-like deformations of quantum field theories. Using a heat-kernel formulation, we extract the local geometric terms generated by stress-tensor two-point functions, and apply the construction to free fermions, massive Maxwell theory, and second-order Yang-Mills theory. While the resulting coefficients are generally model dependent, conformal field theories contain a universal sector fixed by the central charge $C_T$. After regularization and renormalization, this sector yields finite, scheme-independent contributions organized into a finite set of curvature invariants. We further analyze trace-trace deformations, for which the relevant contact terms are determined by the Weyl anomaly, and derive the corresponding finite gravitational action for a general class of minimal non-local kernels. These results provide a quantum effective-action realization of induced gravity in which universal conformal data determine calculable contributions to the emergent geometric response.

We study idealized levitated protocols that create spatial superpositions of massive test particles. For each protocol, we compare the dimensionless contrast-loss exponent of mass-proportional continuous spontaneous localization (CSL) with the Diósi--Penrose (DP) self-energy exponent $E_Gτ/\hbar$. We first prove that the point-particle CSL separation kernel has an exact random-unitary realization: Gaussian momentum kicks arriving at Poisson-distributed times produce the same unconditional decay of spatial coherence, although a pure state conditioned on the complete kick record remains pure. The separation kernel alone therefore specifies an operational decoherence law, not the occurrence of objective collapse. We then show that the ratio of the CSL and DP exponents is independent of particle mass and interrogation time. In the point-particle model it depends only on branch separation and an effective distance; for the standard GRW reference parameters, its resolved-superposition crossover is $x_*\approx1.91\,\mathrm{nm}$. For rigid spherical bodies with an arbitrary normalized radial mass profile, total mass, overall density scale, and interrogation time again cancel, leaving a dimensionless geometry factor. The results distinguish three requirements for a decisive experiment: detectable absolute effects, a controlled comparison of CSL and DP scales, and observables capable of discriminating physically different dynamics that share the same ensemble decoherence kernel.

We propose a novel analytic approach to the study of multi-component FLRW cosmologies and their perturbations. The dynamics is triggered by a single scalar field with a scalar potential codifying the energy density and pressure of the multi-component fluid. This description unifies standard Big Bang cosmologies, models of inflation and dark energy under a unique framework. The key to integrability is to express the scalar potential in terms of the Hubble function $H(φ)$ that plays the role of a fake superpotential, turning the dynamics into a first order problem, that may be analytically solved in a suitable time coordinate. In this framework, we propose integrable inflationary models with similar properties to the ones analysed in the literature and compatible with observations. Finally, we study scalar and tensor cosmological perturbations in each model by integrating Mukhanov-Sasaki equations via numerical and (semi-)analytic techniques. This allow us to compute the power spectrum, the spectral indices and the tensor-to-scalar ratio beyond the slow-roll approximation and compare our general results {against} the currently available observations and the theoretical predictions based on the slow-roll approximation.

We investigate the population of luminous red giant branch stars as a function of metallicity using Gaia XP metallicity combined with SDSS-V, GALAH, and LAMOST. After applying uniform selection criteria and extinction corrections, we construct absolute magnitude distributions across metallicity bins spanning [Fe/H] =-1 to >0.4. We find a systematic deficit of luminous giants at high metallicity, while the red clump and lower red giant branch populations remain largely unchanged. This behavior is consistent with enhanced mass loss at high metallicity, arising from either binary interactions or single-star evolution. This trend is robust across multiple surveys and persists within volume-limited subsamples (1-4 kpc), suggesting it is not driven by distance or selection effects. Synthetic stellar populations based on PARSEC isochrones reproduce the overall magnitude distributions but do not predict a decline in luminous giants with metallicity. Tests of potential systematics, including extinction effects and metallicity scale consistency using open clusters, do not account for the observed trend. We also find no evidence that survey-to-survey differences in metallicity drive the observed result. Together, these findings suggest a metallicity-dependent reduction in the number of luminous red giants that is not captured by current models. This result may have implications for stellar evolution at high metallicity, helium white dwarf formation, and the initial mass function as well as the UV upturn in metal-rich galaxies.

We study semiclassical geometries induced by turning on identical sinusoidal scalar sources on two asymptotic anti-de Sitter (AdS) boundaries. Varying the source strength, we find that large and small wormhole solutions appear beyond a certain threshold. Above this threshold, the large wormhole is always the dominant saddle in the two-boundary gravitational path integral; there is no regime where wormholes are subdominant. Under the ensemble interpretation of the gravitational path integral, this implies that once wormhole solutions exist, the putative ensemble has exponentially large fluctuations relative to the mean. This is unlike previously studied examples of wormholes sourced by inhomogeneous matter which have a region in parameter space where wormholes are subdominant, and therefore the ensemble is sharply concentrated around the mean. Interpreting the bulk geometries as holographic renormalization group (RG) flows, we also find that the sinusoidal modulation of scalar boundary sources results in effective holographic $β$-functions which are multivalued, indicating exotic RG flows. In particular, disconnected geometries correspond to flows that return to the starting fixed point in the infrared, while wormholes describe flows to a gapped phase in the infrared.

We investigate the spatial geometry of the Universe within the framework of a sign-switch dark energy scenario by extending the recently proposed $Λ_{\rm s}$CDM model to include a free curvature parameter $Ω_k$.In this framework, the effective cosmological constant undergoes a transition from a negative to a positive value at a characteristic redshift $z_{\dagger}$. Using the latest Planck 2018 cosmic microwave background (CMB) data, DESI DR2 baryon acoustic oscillation (BAO) measurements, and the PantheonPlus\&SH0ES Type Ia supernova sample, we derive joint constraints on the spatial curvature parameter $Ω_k$ and other cosmological parameters. We find that Planck data itself slightly favors a closed universe within both the $Λ_{\rm s}$CDM$+Ω_k$ and $Λ$CDM$+Ω_k$ frameworks, although spatial flatness remains well within the allowed uncertainties. When low-redshift probes were included, the curvature constraints were significantly tightened. In particular, the full Pk18+DR2+PP\&SH0ES dataset yields $Ω_k = 0.0001 \pm 0.0014$ for the $Λ_{\rm s}$CDM model, indicating a universe that is remarkably consistent with spatial flatness. We further analyzed the correlations between $Ω_k$, $H_0$, and $S_8$, finding that the inclusion of curvature and a sign-switch dark energy component helps stabilize cosmological parameter estimates while remaining compatible with current observational constraints. Model comparison using AIC and Bayesian evidence shows that the $Λ_{\rm s}$CDM model receives inconclusive/weak observational support relative to $Λ$CDM.

Swift heavy ion irradiation of pure CH<SUB>3</SUB>CN ice was investigated to evaluate the influence of the initial ice morphology on its radiolytic evolution under astrophysically relevant conditions. Two deposition protocols were compared: (i) CH<SUB>3</SUB>CN ice deposited and irradiated at 50 K, and (ii) CH<SUB>3</SUB>CN ice deposited at 130 K, subsequently cooled to 10 K prior to irradiation, thereby preserving the structural organization established during deposition. In situ FTIR spectroscopy revealed efficient destruction of CH<SUB>3</SUB>CN and the formation of HCN, HC<SUB>3</SUB>N, CH<SUB>3</SUB>NC, NH<SUB>3</SUB>, and imine-like compounds. The thermally organized ice exhibited a distinct infrared spectral evolution, enhanced destruction, and differences in the stabilization of daughter species compared with the amorphous ice. Destruction cross sections of <mml:math><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mn>2.85</mml:mn><mml:mo>±</mml:mo><mml:mn>0.52</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mo>×</mml:mo><mml:mn>1</mml:mn><mml:msup><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>12</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> and <mml:math><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mn>4.65</mml:mn><mml:mo>±</mml:mo><mml:mn>0.43</mml:mn><mml:mo>)</mml:mo></mml:mrow><mml:mo>×</mml:mo><mml:mn>1</mml:mn><mml:msup><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>12</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> cm<SUP>2</SUP> were determined for the amorphous and thermally organized ices, respectively. These results demonstrate that the thermal history of CH<SUB>3</SUB>CN ice, through its influence on the initial ice morphology, strongly affects radical diffusion, recombination, and product formation during irradiation. The present measurements provide benchmark radiochemical data for acetonitrile and establish a basis for future investigations of more realistic nitrile-bearing astrophysical ice analogues relevant to Titan and other outer Solar System environments.