Current date: 2026-07-28
Setting default datestamp limit: 0
Datestamp limit: 2026-07-28 (0 days ago)
Created/updated limit: 2026-07-21 (7 days ago)
Found keywords_cs.datFound keywords_cis.dat
Suggested sets: physics, physics:astro-ph, physics:gr-qc, physics:physics
Setting default set: physics
OAI-PMH request: http://export.arxiv.org/oai2?verb=ListRecords&from=2026-07-28&until=2026-07-28&set=physics&metadataPrefix=arXiv
Scoring abstracts
Number of records retrieved: 1174
Keyword score statistics
score 11 -- 1 abstracts
score 8 -- 1 abstracts
score 6 -- 4 abstracts
score 5 -- 2 abstracts
score 4 -- 10 abstracts
score 3 -- 15 abstracts
score 2 -- 13 abstracts
in total -- 46 abstracts
Articles that appeared on 2026-07-28
-
[abstract 1 / 46] Wow! (score: 11)
- Title: Constraining cosmological parameters from very-high-energy $γ$-ray attenuation in BLAZAR spectra: Bayesian inference and systematic uncertaintiesAuthors: Patryk Liniewicz, Emmanuel Moulin,Comments: Prepared for submission to JCAPSubjects: astro-ph.HE astro-ph.COCreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
Very-high-energy $γ$ rays from ACTIVE GALACTIC NUCLEi are attenuated through pair production on the extragalactic background light (EBL), providing a probe of cosmic expansion. We develop a Bayesian inference analysis framework that uses an observationally driven, redshift-dependent EBL model and anchors intrinsic source spectra to the FERMI-LAT 3FHL catalogue while marginalising spectral-shape departures and dataset normalisations. The method is validated on realistic mock observations and applied to 241 archival H.E.S.S., MAGIC and VERITAS spectra of 50 AGN compiled in STeVECat. Because the leading opacity depends on the ratio of the EBL normalisation to the reduced Hubble constant, the gamma-ray data primarily constrain this ratio rather than $H_0$ alone. We measure $r=1.723^{+0.096}_{-0.095}$. For a fixed EBL scale, this gives $H_0=58.3^{+3.4}_{-3.0},\mathrm{km,s^{-1},Mpc^{-1}}$; allowing an 18\% EBL-scale uncertainty gives $H_0=60.5^{+10.8}_{-10.0},\mathrm{km,s^{-1},Mpc^{-1}}$. Matched injections recover the input opacity without appreciable bias, and the tested intrinsic-spectrum and EBL-shape perturbations are subdominant except for large infrared-background mismodelling. The predominantly low-redshift sample leaves $Ω\mathrm{M}$ weakly constrained. The measurement is therefore limited by the EBL normalisation rather than statistics; reducing its uncertainty to a few per cent would make gamma-ray opacity a competitive, distance-ladder-independent probe of $H_0$.
[abstract 2 / 46] Wow! (score: 8) - Title: Modeling ultraRELATIVISTIC streaming plasma instabilities under the quasistatic approximationAuthors: P. San Miguel Claveria, Q. Labro, X. Davoine, A. Matheron, M. Tamburini, S. Corde, L. Gremillet, F. Fiuza,Comments:Subjects: physics.plasm-ph astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Plasma streaming instabilities excited by RELATIVISTIC charged particle beams play a pivotal role in astrophysical and laboratory environments. Their numerical study, however, is challenged by the disparity in spatiotemporal scales between the background plasma and beam particles, which can differ by several orders of magnitude for tenuous, ultraRELATIVISTIC beams. Here, we exploit the quasistatic approximation (QSA) to develop a new theoretical framework capable of capturing the full unstable spectrum in the spatiotemporal regime relevant for beams that continuously encounter unperturbed plasma at their leading edge. Within this linear, fully electroMAGNETic model, we uncover a previously unreported spatiotemporal evolution of the current filamentation instability and elucidate its interplay with the oblique two-stream instability, predicting the dominance of filamentation in the vicinity of the beam front. The good agreement between theory, kinetic particle-in-cell (PIC) simulations, and QSA-based PIC simulations validates the robustness of the approach. By pushing QSA-based PIC simulations to extremely dilute electron-positron beams, such as those found in BLAZAR JETs, we demonstrate their unique ability to capture the rich nonlinear dynamics of streaming instabilities in parameter regimes previously inaccessible to kinetic simulations.
[abstract 3 / 46] Yes (score: 6) - Title: On Lorentz Variability of Magnetically Dominated Relativistic OutflowsAuthors: V. I. Berezhiani, N. L. Shatashvili, A. G. Tevzadze,Comments: 16 pages, 2 figures. Accepted for publication in Physica ScriptaSubjects: astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
We show that MAGNETized RELATIVISTIC outflows can exhibit a RELATIVISTIC effect in which Lorentz transformation maps spatially extended MAGNETic field structure into apparent temporal variability in the observer's frame. Using a force-free Beltrami configurations as representative equilibria of MAGNETically dominated outflows, we demonstrate that Lorentz mapping of stationary helical MAGNETic field produces quasi-periodic modulation of observable electroMAGNETic signatures, without invoking intrinsic plasma variability. The same mechanism naturally generates temporal evolution of the observed POLARIZATION properties, producing smooth, generally aperiodic POLARIZATION-angle swings in the observer's frame. This effect may be described as an aberration of force-free MAGNETic fields under Lorentz transformation. The characteristic frequency of the time variability is determined by the helical wave-number of the MAGNETic field, the viewing angle, and the bulk Lorentz factor of the JET outflow, and scales linearly with $Γ$. This establishes a purely kinematic RELATIVISTIC origin of variability and introduces the concept of MAGNETic Lorentz seismology: the inference of MAGNETic field structure in RELATIVISTIC outflows directly from observed temporal variability.
[abstract 4 / 46] Yes (score: 6) - Title: Analytic force-free JET from disk-fed rotating BLACK HOLEsAuthors: Luis Villarin, Ian Vega,Comments: 19 pages, including acknowledgments, appendices, and references; 5 figures total; v3: Accepted for publication in Physical Review DSubjects: gr-qc astro-ph.HECreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
We present a new analytic model of a force-free electroMAGNETic JET launched from a disk-fed rotating BLACK HOLE. The JET solution is force-free to first order in the BLACK HOLE spin and is obtained through a systematic construction based on previously developed analytical methods. The BLACK HOLE JET modeled here exhibits an asymptotically parabolic structure and is parametrized by the location of the current concentration and sign reversal on the thin MAGNETized disk in the equatorial plane. We find that the JET properties show negligible dependence on the disk parameter, suggesting a possible universality of slowly rotating BLACK HOLE JETs with respect to disk structure. Our JET model reproduces the key features expected from the Blandford-Znajek mechanism.
[abstract 5 / 46] Yes (score: 6) - Title: Unification models of Active Galactic NucleiAuthors: Claudio Ricci,Comments: Invited chapter for the Encyclopedia of Astrophysics (edited by I. Mandel, section editor S. McGee) to be published by Elsevier as a Reference ModuleSubjects: astro-ph.GA astro-ph.HECreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
This chapter presents an overview of the unification models for Active Galactic Nuclei (AGN), focusing on the physical structures, classification schemes, and evolutionary processes that characterize accreting supermassive BLACK HOLEs. We introduce the fundamental components of AGN, including the supermassive BLACK HOLE, accretion disk, JETs, outflows, broad-line and narrow-line regions, polar dust and the dusty anisotropic obscurer. The traditional orientation-based unification model is reviewed, with a focus on the role of the covering factor of the obscuring material in shaping observed properties. We introduce the radiation-regulated unification model, which accounts for the influence of radiative feedback on the nuclear environment of SMBHs. We also examine the evolutionary aspects of AGN unification, including the impact of galaxy mergers, host galaxy properties, and redshift-dependent trends. Finally, we discuss changing-look AGN, which challenge conventional unification frameworks by exhibiting dramatic spectral variability.
[abstract 6 / 46] Yes (score: 6) - Title: Radio Jet Properties of the Flaring Gamma-Ray Blazar PKS 0346-27Authors: Máté Krezinger, Sándor Frey, Krisztina É. Gabányi,Comments: 19 pages, 4 figures, accepted for publication in the journal AstronomySubjects: astro-ph.GACreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
The BLAZAR PKS 0346-27 at redshift z=0.991 is among the most distant extragalactic sources detected in very high energy gamma-rays. It underwent a major flare reaching TeV energies in November 2021. Recent modelling of its spectral energy distribution favoured a single-zone proton--SYNCHROTRON-dominated hadronic model with bulk Lorentz factor Gamma=10 over a single-zone leptonic JET model with much higher Gamma. Here we analyse archival radio data to give independent estimates of the JET bulk Lorentz factor. We present high-resolution radio imaging and brightness distribution modelling, as well as flare detection in long-term radio flux density monitoring data, and obtain Gamma<~10 values. This lends support to the hadronic model proposed for the PKS 0346-27 JET. Our results highlight the importance of long-term, very long baseline interferometry and total flux density monitoring in studying BLAZAR JETs.
[abstract 7 / 46] Yes (score: 5) - Title: Reconstructing PTA measurements via early seeding of supermassive BLACK HOLEsAuthors: Sohan Ghodla, Cosmin Ilie,Comments: Accepted as PRD LetterSubjects: astro-ph.CO astro-ph.GA astro-ph.HECreated: 2026-07-26; Updated: 2026-07-28; Datestamp: 2026-07-28
Motivated by recent findings that PTA's nHz signal may be dominated by supermassive BLACK HOLE (SMBH) binaries ($M \gtrsim 10^9 M_\odot$), and high redshift QUASAR observations revealing unexpectedly massive SMBHs, we calculate the implications of early seeded SMBHs for the PTA signal. As an application, we explore two prominent scenarios of high-$z$ SMBHs seeding mechanisms: direct collapse BLACK HOLEs (DCBHs) and collapse of Dark Stars. We show that Dark Star seeded SMBHs, with comoving seed number density of $\mathcal{O}(10^{-3}) \, {\rm Mpc}^{-3}$ can be the dominant contributor to the PTA signal while the DCBH channel may contribute sub-dominantly. We also suggest ways to place an upper bound on the seed number density.
[abstract 8 / 46] Yes (score: 5) - Title: Revisiting early afterglows of GAMMA-RAY BURSTs with finite-thickness ejecta: Implications from XRF 080330 and GRB 080710Authors: Kaori Obayashi, Ryo Yamazaki, Yo Kusafuka, Katsuaki Asano,Comments: 25 pages, 8 figures, 4 tables, JHEAp, in pressSubjects: astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
We revisit the physical origin of the achromatic peaks and breaks observed several thousand seconds after the burst in the multi-wavelength afterglows of XRF 080330 and GRB 080710. Using a numerical afterglow model that consistently incorporates finite ejecta thickness and a generalized external density profile, we perform Bayesian inference to estimate model parameters describing these events. Our analysis shows that the gradual rise and achromatic temporal features in both events are more naturally explained by JET dynamical evolution with finite shell thickness rather than by off-axis viewing effects. The inferred initial radial width of the ejecta is of order $10^{13}$ cm for both bursts, implying a central engine activity timescale significantly longer than that suggested by the prompt gamma-ray duration alone. Taken together, these results demonstrate that early afterglow light curves are strongly influenced by transition dynamics when finite ejecta thickness is properly taken into account, thereby providing a physical link between the prompt and afterglow phases and highlighting limitations of simply applying the thin-shell approximation when interpreting early-time afterglows. Furthermore, Bayesian model comparison favors a generalized circumburst density profile over the canonical uniform or steady-wind models, suggesting that fixing the external density structure to idealized profiles a priori may obscure crucial information about the progenitor's pre-burst activity.
[abstract 9 / 46] Yes (score: 4) - Title: Photon Propagation through Axion Clouds around Magnetized Compact Objects: Time Delays and Polarimetric SignaturesAuthors: M. M. Chaichian, B. A. Couto e Silva, B. L. Sánchez-Vega,Comments: 37 pagesSubjects: hep-ph astro-ph.HE hep-thCreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
Temporal offsets between Gamma-Ray Bursts (GRBs) and high-energy neutrinos probe propagation effects in extreme astrophysical environments. We investigate whether such offsets can be generated by photon propagation through dense axion clouds gravitationally bound to strongly MAGNETized compact objects, such as canonical pulsars. Working within the Euler--Heisenberg effective theory extended by the axion sector, we derive the photon dispersion relations in a strong MAGNETic background permeated by an oscillating axion field. The MAGNETized vacuum is birefringent already at the Euler--Heisenberg level and the axion cloud superimposes density-dependent, time-dependent, and parity-odd structure on this baseline. The resulting geometry-dependent deviations from luminal propagation yield kinematic time delays reaching $Δt_{\perp} \simeq 9.3 \times 10^{-12}$ s for $\mathbf{k} \perp \mathbf{B}$, far too small to account for macroscopic multimessenger offsets, so that propagation through such environments cannot, by itself, rule out Lorentz-invariance violation as an explanation for GRB offsets. In the POLARIZATION sector, we show that the axion-induced circular birefringence is an endpoint effect and therefore does not produce a leading net rotation for a complete vacuum-to-vacuum transit through a localized cloud. For configurations with a nonzero axion-field endpoint contrast, the same parity-odd phase defines a conditional environmental sensitivity benchmark. We find that this mechanism is optimally sensitive in the ultralight regime, yielding a benchmark reach of $g_{aγγ} \lesssim 2.5 \times 10^{-10}\,\mathrm{GeV}^{-1}$ for canonical pulsar fields and axion masses near $m_a \sim 10^{-9}$ eV, and we identify the parity-odd (chiral) birefringence induced by the oscillating cloud as the signature that distinguishes the axion contribution from the calculable QED baseline.
[abstract 10 / 46] Yes (score: 4) - Title: Extreme Variability Reveals How the Eddington Ratio Regulates Coronal Power in Active Galactic NucleiAuthors: Arghajit Jana, Claudio Ricci, Franz E. Bauer, Kriti Kamal Gupta, Benny Trakhtenbrot, Alessia Tortosa, Ruancun Li, Luis C. Ho, Richard Mushotzky, Hsiang-Kuang Chang, Yaherlyn Diaz, Georgios Dimopoulos, Kristína Kallová, Michael J. Koss, Stéphane Paltani, Matthew J. Temple,Comments: 4 figures, accepted for publication in ApJ Letter. Comments are welcomeSubjects: astro-ph.GA astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
The bolometric luminosity ($L_{\rm bol}$) of ACTIVE GALACTIC NUCLEi (AGNs) is a key tracer of accretion physics, but its direct determination is often hindered by limited spectral coverage and contamination of the host galaxy. Bolometric corrections ($κ_λ = L_{\rm bol}/L_λ$) offer a practical means of estimating $L_{\rm bol}$, with the X-ray bolometric correction ($κ_{\rm 2-10}$) being crucial for exploring the coupling between the accretion disk and the X-ray corona. Here we present multi-epoch, multi-wavelength observations of five highly variable, changing-state AGNs that span more than three orders of magnitude in Eddington ratio ($-3.6\lesssim \log λ_{\rm Edd} \lesssim -0.5$). This unique data set reveals a remarkably tight relation between $κ_{\rm 2-10}$ and $λ_{\rm Edd}$, with an intrinsic scatter of only $\sim0.05$ dex. We find that while the sources show bolometric corrections following different tracks in luminosity space that depend on BLACK HOLE mass, they all display the same $κ_{\rm 2-10}-λ_{\rm Edd}$ trend. This shows unambiguously that $λ_{\rm Edd}$ is the primary driver of X-ray bolometric corrections, and points to a tight underlying trend that can be used to obtain reliable estimates of bolometric output from X-ray luminosities. Our results highlight how time-domain, multi-wavelength observations of variable AGN offer unique insights into the accretion flow structure and its radiative output.
[abstract 11 / 46] Yes (score: 4) - Title: Relativistic Chiral MHD with application to the early UniverseAuthors: Deepen Garg, Jennifer Schober,Comments: 14 pagesSubjects: astro-ph.CO astro-ph.HE hep-ph physics.plasm-phCreated: 2026-07-24; Updated: 2026-07-28; Datestamp: 2026-07-28
We present a systematic derivation of the equations of RELATIVISTIC chiral MAGNETohydrodynamics (MHD) for a plasma of charged fermions in an expanding universe. Through a combination of a coordinate transformation and a rescaling of the dynamical variables, we bring the full system to the same form as in the Minkowski metric, with the Hubble expansion surviving only in the chirality-flipping rate and the kinematic viscosity. Retaining all four contributions to both the electric and the axial current yields terms absent from standard chiral MHD: charge-density corrections to the evolution equations for the chemical potentials, and an electric current proportional to the charge chemical potential $μ$ and the bulk velocity. The latter is mandated by current conservation, requires no chirality imbalance, and drives the charge-flow instability studied in a companion paper. For the radiation-dominated era, we evaluate all the coefficients in physical units and use them to estimate the MAGNETic Reynolds number, the attainable MAGNETic field strength, and the minimum temperature at which the chiral dynamo can operate. The resulting equations are cast in a form ready for direct numerical implementation.
[abstract 12 / 46] Yes (score: 4) - Title: Diverse Morphologies of GRB X-Ray Plateaus within a Common Magnetar FrameworkAuthors: Xiao-Fei Dong, Yong-Feng Huang, Nurimangul Nurmamat, Chen Deng, Ze-Cheng Zou, Fan Xu, Abdusattar Kurban, Chen Du, Chen-Ran Hu, Jin-Jun Geng,Comments: 14 pages, 7 figures, 1 table. Submitted. Comments are welcomeSubjects: astro-ph.HECreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
The origin of the X-ray plateau phase in GAMMA-RAY BURSTs (GRBs) remains an open problem. In particular, it is unclear whether GRBs with different temporal morphologies (i.e., with a rising, flat, or decaying plateau) arise from a common underlying mechanism. Although MAGNETar energy injection is a leading explanation, previous studies have primarily inferred MAGNETar properties on a burst-by-burst basis and have not tested the model at the population level. Here we perform the first hierarchical population inference of MAGNETar parameters for a uniform sample of 185 long GRBs with X-ray plateaus within a conditional Poisson point-process framework. It is found that the observed plateau population is well reproduced by physically plausible MAGNETar populations. The inferred parameter distributions show no strong statistical separation among subclasses with different plateau morphologies. Nevertheless, all subclasses show a substantial intrinsic luminosity scatter, $σ_{L,\rm int}\sim0.5$--1.0 dex, whereas the intrinsic duration scatter remains considerably smaller. The results provide a population-level test of the MAGNETar interpretation of GRB X-ray plateaus, showing that the observed diversity of plateau morphologies does not require distinct MAGNETar populations.
[abstract 13 / 46] Yes (score: 4) - Title: Quasistatic modeling of ultraRELATIVISTIC beam-plasma instabilitiesAuthors: P. San Miguel Claveria, L. Gremillet, X. Davoine, Q. Labro, A. Matheron, M. Tamburini, F. Fiuza, S. Corde,Comments:Subjects: physics.plasm-ph astro-ph.HE physics.acc-phCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Relativistic particle beams propagating through dense ambient plasmas are susceptible to streaming instabilities that can govern the system dynamics in various astrophysical and laboratory settings. For an unMAGNETized, collisionless plasma pervaded by a dilute, cold RELATIVISTIC beam, the dominant instabilities are the quasielectrostatic, oblique two-stream (OTSI) and the essentially MAGNETic, current filamentation instability (CFI). While their linear and nonlinear properties have been researched for decades, most treatments assume unbounded, uniform systems and thus predict purely temporal instability growth. This assumption, however, is questionable for realistic configurations where a bounded beam continuously encounters fresh plasma. This feature causes instabilities to grow in a spatiotemporal manner. Whereas spatiotemporal perturbative treatments of streaming instabilities were derived as early as the 1960s, only recently have the spatiotemporal regimes of OTSI and CFI been addressed theoretically. Yet these models are restricted to a specific instability class, and hence cannot describe the competition between spatiotemporal OTSI and CFI. In this work, we present a unified, fully electroMAGNETic quasi-static model of all unstable modes arising throughout the beam. By not adopting the slowly varying envelope approximation (SVEA), we find that a previously unreported spatiotemporal CFI actually prevails near the front, precisely where the SVEA fails, and is only superseded by OTSI further back in the beam. Furthermore, we demonstrate that our model also captures the growth of the self-modulation and hosing instabilities excited by long, narrow beams. Comparisons with particle-in-cell simulations confirm the validity of the quasistatic approach for modeling streaming plasma instabilities triggered by RELATIVISTIC dilute beams.
[abstract 14 / 46] Yes (score: 4) - Title: Testing the theory of colliding winds: the periastron passage of 9 Sagittarii. II. Radio monitoringAuthors: R. Blomme, G. Rauw, D. Volpi, Y. Nazé, R. Prinja,Comments: 8 pages, 4 figures, accepted for publication in A&ASubjects: astro-ph.SR astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Colliding winds in massive-star binaries generate non-thermal radio emission and an increased X-ray emission. We study the radio emission of the non-thermal emitter 9 Sgr, which is a long-period and highly eccentric binary. We conducted a monitoring campaign of 9 Sgr around its 2013 - 2014 periastron passage, obtaining radio, X-ray and optical spectroscopy data. In this paper, we analyse the radio data. The radio data at 3.6, 6 and 20 cm show a maximum near periastron. Other non-thermal radio emitters among O-type binaries have a minimum flux near periastron, because the SYNCHROTRON emission is absorbed by the free-free absorption in the two stellar winds. This is not the case for 9 Sgr, because even at periastron the orbital separation is sufficient to maintain the wind-wind collision and its associated SYNCHROTRON emission outside the effective free-free radius of both stars. Our standard modelling with a local MAGNETic field that decreases inversely proportional to the distance from the stars (1/r) fails to explain the observed fluxes. Instead, we need to adopt a local MAGNETic field that decreases faster than 1/r. While our model provides an acceptably good fit to the data, there is clearly still room for improvement. More advanced modelling should include MAGNETohydrodynamics and more detailed physics of the injection, acceleration and cooling of the RELATIVISTIC electrons. Radio observations at orbital phases away from periastron can put further constraints on the models.
[abstract 15 / 46] Yes (score: 4) - Title: Constraints on the MAGNETic field in the hadronic scenario for the origin of the radio halo in the A1795 galaxy clusterAuthors: P. Marchegiani, V. Vacca, F. Loi, F. Govoni, M. Murgia,Comments: 5 pages, 1 appendix, 4 figures, 1 table; accepted for publication in A&ASubjects: astro-ph.HE astro-ph.COCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
The radio halo in the cool-core galaxy cluster A1795 has recently been proposed to be of hadronic origin, because it extends on a scale of the order of Mpc, where no turbulence is expected to be injected in a relaxed cluster. In this paper we aim to constrain the properties of the non-thermal protons and the cluster MAGNETic field strength under the hypothesis of a hadronic origin of the radio halo at the light of the available gamma ray upper limit in this cluster. We assume a radial profile and several values of the central intensity of the MAGNETic field, and derive the corresponding properties of the non-thermal protons necessary to reproduce the flux density and the surface brightness profile of the radio halo. For the obtained results, we calculate the corresponding gamma ray emission and compare it with the FERMI-LAT upper limit. We obtain that, for a MAGNETic field energy radial profile following the thermal one, MAGNETic field central intensities $B_0<5\,μ$G imply a gamma ray emission similar to or above the FERMI-LAT upper limit. Therefore larger values of the MAGNETic field are necessary in the hadronic scenario. For these values the radial profile of non-thermal protons needs to be slightly decreasing with radius, although more slowly than the thermal one. For smaller values of the MAGNETic field different mechanisms for producing or accelerating the non-thermal electrons are necessary.
[abstract 16 / 46] Yes (score: 4) - Title: Transport Properties of the MRI in Differentially Rotating Neutron StarsAuthors: Harshraj Bandyopadhyay, Peter Hammond, David Radice,Comments:Subjects: astro-ph.HE gr-qcCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
We perform three-dimensional, high-resolution, general-RELATIVISTIC MAGNETohydrodynamics (GRMHD) simulations of the MAGNETorotational instability (MRI) in differentially rotating neutron stars. We consider both high-mass models which collapse either promptly, or due to the outward transport of angular momentum removing rotational support, and lower-mass models, which remain stable even after solid-body rotation has been achieved. We measure effective transport coefficients of the resulting turbulent flow, shear-viscosity $α_{\rm vis}$, mixing-length $\ell_{\rm mix}$, and mean-field dynamo $α_{\rm DYN}$-parameter, and their correlations with mean-flow parameters, such as rest-mass density $ρ$, characteristic wavelength of the MRI $λ_{\rm MRI}$, and vertical Alfvén velocity $v_A$. At saturation, $\ell_{\rm mix}$ and $α_{\rm DYN}$ correlate with $λ_{\rm MRI}$ and $v_A$ respectively, as expected from dimensional analysis. However, both quantities show deviations of roughly an order of magnitude from the values predicted on the basis of these correlations. They are also highly intermittent in space and time. The mixing length is found to be largely independent of density, calling into question the $\ell_{\rm mix}(ρ)$ ansatz used in many general-RELATIVISTIC large-eddy simulations. Our results show that, while the effects of MRI-induced turbulence might be qualitatively reproduced by simulations that employ transport coefficients chosen using dimensional-analysis considerations, fully-resolved GRMHD simulations are needed to make quantitative predictions.
[abstract 17 / 46] Yes (score: 4) - Title: R-process nucleosynthesis from MAGNETar giant flares in neutron star--white dwarf mergers: A unified picture for peculiar long GAMMA-RAY BURSTsAuthors: Shu-Qing Zhong, Long Li, Le Zou, Ji-Gui Cheng, Yan-Zhi Meng, Jia-Hong Gu,Comments: accepted by A&ASubjects: astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Peculiar long GAMMA-RAY BURSTs (GRBs), exemplified by GRBs 211211A and 230307A, exhibit a long-duration multi-component prompt emission, an X-ray plateau in their afterglow, and a kilonova signature. Their origin remains highly debated. In this work, we present a unified picture for these events based on neutron star--white dwarf (NS--WD) mergers involving a pre-merger MAGNETar and a massive WD. In this picture, tidal disruption of the WD forms a constant-entropy accretion disk. Hyperaccretion from this disk onto the NS during the early accretion phase amplifies its toroidal MAGNETic field to strengths sufficient to trigger repeated MAGNETar giant flares (GFs). The main burst (MB) of the prompt emission consists of a ``forest'' of initial spikes from these GFs, while the subsequent MAGNETic propeller phase generates the extended emission (EE) and naturally explains the observed MB--EE trough. Crucially, the $e^{\pm}$-$γ$ fireball associated with each GF initial spike shocks the NS crust, leading to crustal ejection that synthesizes r-process heavy elements via the $α$-rich freeze-out mechanism, thereby resolving the r-process deficit in conventional NS--WD hydrodynamic simulations. The ensemble of such fireballs over the MB duration collectively yields $M_{\rm ej}\gtrsim 10^{-5}-10^{-3}\,M_\odot$ of ejecta, sufficient to power the observed kilonova signature when further boosted by the spin-down of the post-merger MAGNETar. Meanwhile, the spin-down radiation also powers the X-ray plateau. This tidally disrupted NS--WD merger picture provides a self-consistent framework that unifies the prompt emission, afterglow, kilonova, and r-process nucleosynthesis observed in peculiar long GRBs.
[abstract 18 / 46] Yes (score: 4) - Title: Implementation and verification of the avalanche source in a 3D full-f particle-in-cell model of RELATIVISTIC electrons for studies of tokamak disruptionsAuthors: Fiona Wouters, Hannes Bergström, Matthias Hoelzl, Guido T. A. Huijsmans, Jan van Dijk, the JOREK team,Comments:Subjects: physics.plasm-phCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Disruptions threaten tokamak operation not only because of large in-vessel forces and thermal heat loads, but also because some electrons may be accelerated to RELATIVISTIC energies. These so-called runaway electrons (REs) can multiply exponentially via knock-on collisions with thermal electrons. As the resulting RE avalanche is exponentially sensitive to the pre-disruption plasma current, multi-MA RE beams may form in large future devices, risking severe localized wall damage. Detailed understanding of RE beam formation and the particle phase-space distribution requires a self-consistent treatment of the RE avalanche and competing losses in the stochastic fields of MHD-active plasmas. Such simulations including the RE sources in 3D fields are needed to develop viable mitigation scenarios. For this, the 3D nonlinear MHD code JOREK includes a hybrid fluid-kinetic model, describing REs with a full-f RELATIVISTIC particle-in-cell (PiC) approach using full-orbit or drift-kinetic descriptions. In this work, an energy and momentum conserving knock-on collision operator is implemented to enable accurate modeling of the RE phase-space dynamics in 3D electroMAGNETic fields. To make such novel high-fidelity simulations computationally viable, a resampling technique was also implemented to restrict the number of markers. The avalanche model is verified using analytical expressions from literature and applied to a JET-like termination scenario, demonstrating its applicability to realistic 3D MHD active scenarios. Future work on porting to accelerated high-performance computing systems will be needed to cross the long time scales involved, e.g., in periodic termination and re-avalanching that could occur in large devices like ITER.
[abstract 19 / 46] (score: 3) - Title: Circumstellar interaction in the extreme white dwarf merger remnant ZTF\,J1901+1458: A new class of white dwarf merger remnants with X-ray emissionAuthors: Aayush Desai, Ilaria Caiazzo, Stephane Vennes, Adela Kawka, Tim Cunningham, Gauri Kotiwale, Andrei A. Cristea, John C. Raymond, Maria Camisassa, Leandro G. Althaus, J. J. Hermes, Iris Traulsen, James Fuller, Jeremy Heyl, Jan van Roestel, Kevin B. Burdge, Antonio C. Rodriguez, Ingrid Pelisoli, Boris T. Gänsicke, Paula Szkody, Sumit K. Maheshwari, Zachary P. Vanderbosch, Andrew Drake, Lilia Ferrario, Dayal Wickramasinghe, Stephen Justham, Ruediger Pakmor, Kareem El-Badry, Thomas Prince, S. R. Kulkarni, Matthew J. Graham, Ben Rusholme, Russ R. Laher, Josiah Purdum,Comments: 23 pages, Accepted in A&A, comments are welcomeSubjects: astro-ph.SR astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Double degenerate white dwarf (WD) mergers can exhibit extreme MAGNETic fields exceeding $10^{8}$ G and rapid rotation, but their spectral-energy distributions and high-energy emission mechanisms remain poorly characterised. ZTF J1901+1458 stands out as the most compact and strongly MAGNETised object discovered in this class to date. Recent Chandra observations have revealed that the white dwarf is also a source of soft X-ray emission, inconsistent with a photospheric origin. We analyse new phase resolved UV spectroscopy from the HST combined with optical and near-infrared photometry and spectroscopy, with newly developed MAGNETic atmosphere models to determine its effective temperature, radius, mass, average surface MAGNETic field strength, and cooling age. Our results demonstrate that the spectral break at $\approx$3000 Å, observed in several highly MAGNETised WDs, is well-reproduced by our new models, which take into account the effect of MAGNETic opacities on the structure of the atmosphere. Our best-fit parameters for the WD yield an effective temperature ($T_{\rm{eff}}=28,015\pm 20$ K) and larger radius ($2630\pm10$ km) than previously reported. Furthermore, the near-infrared data exclude the presence of a stellar or brown dwarf companion hotter than $\approx$700 K. We also jointly analyse the previously published Chandra data and new XMM-Newton X-ray spectra. The faint X-ray emission, $L_X =(1.3\pm0.2)\times10^{27}$ erg/s is very soft and highly pulsed on the rotation period of the WD. We suggest that the X-rays are powered by accretion or via the interaction of the WD MAGNETosphere with CSM. If the rapidly rotating MAGNETic field could power a weak wind along open field lines, material could be extracted directly from the surface of the WD. Alternatively, accretion of fallback material from the merger or the tidal disruption of a planetary body are possible sources of CSM.
[abstract 20 / 46] (score: 3) - Title: Undermassive Hosts of $z = 4-6 $ AGN from JWST/NIRCam Image Decomposition with CONGRESS, FRESCO, and JADESAuthors: Zheng Ma, Eichi Egami, Yongda Zhu, Fengwu Sun, Jianwei Lyu, Junyu Zhang, Christopher N. A. Willmer, Andrew J. Bunker, Stefano Carniani, Emma Curtis-Lake, Ryan Hausen, Xihan Ji, Zhiyuan Ji, Ignas Juodžbalis, Roberto Maiolino, George H. Rieke, Pierluigi Rinaldi, Yang Sun, Sandro Tacchella, Hannah Übler, Christina C. Williams,Comments: Submitted to ApJSubjects: astro-ph.GACreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
In the local Universe, supermassive BLACK HOLE (SMBH) masses strongly correlate with their host-galaxies' stellar masses ($M_{*}$), but galaxies hosting faint AGN recently found by JWST may deviate from this relation. To constrain the M$_{\text{BH}}$-M$_{*}$ relation at high redshift, we performed AGN-host image decomposition for 17 low-luminosity AGN galaxies at $z$ $\sim$ 4-6 using NIRCam images in the JADES GOODS-N field. These sources are identified as AGNs from broad H$α$ emission lines detected by the CONGRESS and FRESCO surveys. We used galfit+MCMC to fit spatial profiles in 7 wide-band images and detected extended emission in 9 sources out of 17. The close spatial alignment between the extended components and the AGN centers indicates that this emission likely originates from the host galaxies. These sources are extended at 0.9-2.0~$μ$m, suggesting significant host-galaxy light in the rest-frame UV. For the sources with the host detection, the stellar mass inferred based on image decomposition result can be 1-2 dex lower than the results without image decomposition. The BH-to-stellar mass ratio spans $M_{\text{BH}}/M_\ast$ $\sim$ 0.01-1.48, placing them well above the local $M_{\text{BH}}$-$M_\ast$ relation. In contrast, the host-galaxy size-mass relation broadly agrees with previous measurements. Our results suggest that the host galaxies of these faint AGN are either genuinely under-massive compared to their BLACK HOLE masses, or too compact to be spatially resolved.
[abstract 21 / 46] (score: 3) - Title: Searching for DARK MATTER signals with high energy astrophysical neutrinos in IceCubeAuthors: Khushboo Dixit, Gopolang Mohlabeng, Soebur Razzaque,Comments: 18 pages, 9 figures, Accepted for publication in PRDSubjects: astro-ph.HE hep-phCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
High-energy neutrinos provide a potentially powerful and distinctive probe for DARK MATTER (DM) - neutrino interactions, particularly in environments with enhanced DM densities, such as the DM spikes predicted to form around supermassive BLACK HOLEs (SMBHs) at the center of ACTIVE GALACTIC NUCLEi (AGN). Recent results by the IceCube Neutrino Observatory, which reported four significant AGNs, namely TXS 0506+056, NGC 1068, PKS 1424+240, and NGC 4151 as candidate neutrino sources, provide a valuable opportunity to search for signatures of these interactions. In this study, we use IceCube data to derive the most stringent constraints to date on both the energy-dependent and energy-independent DM-neutrino scattering cross-sections. We perform a statistical analysis using data from individual sources as well as a combined (stacked) analysis of all four sources. Our strongest limits arise from the stacking analysis, yielding an upper bound of $σ_{0} \lesssim 8\times 10^{-39}$ cm$^2$ for an energy-independent cross-section and $σ_{0} \lesssim 10^{-39}$ cm$^2$ for a linearly energy-dependent cross-section, both at 90$\%$ confidence level, particularly in scenarios involving the adiabatic growth of BLACK HOLEs.
[abstract 22 / 46] (score: 3) - Title: Critical Behavior of Photon Rings in Kerr-Bertotti-Robinson SpacetimeAuthors: Xi Wan, Zhenyu Zhang, Fang-Stars Wei, Yehui Hou, Bin Chen,Comments: 34 pages, 5 figures. v2: Minor revision. Accepted by PRDSubjects: gr-qc astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
In this work, we investigate the critical behavior of photon rings in the Kerr-Bertotti-Robinson spacetime, describing a rotating BLACK HOLE immersed in a background MAGNETic field. We analyze the radial and angular motions of photons under the small MAGNETic field approximation. Focusing on unstable spherical orbits, we determine three key parameters, $γ$, $δ$, and $τ$, which characterize radial compression, azimuthal advancement, and time delay. We then examine how these parameters depend on the BLACK HOLE spin, MAGNETic field strength, and observer inclination for both on-axis and off-axis observers, and we further analyze the properties of higher-order images through near-critical lens equations. The results show that the MAGNETic field modifies the geodesic structure, and leads to observable changes in the fine structure of photon rings, providing a useful framework for probing MAGNETized BLACK HOLE environments.
[abstract 23 / 46] (score: 3) - Title: Three dimensional, spherically polarized MAGNETic fieldsAuthors: Anna Tenerani, Marco Velli,Comments:Subjects: physics.plasm-ph astro-ph.SRCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Turbulence in the solar wind is characterized by Alfvénic fluctuations that exhibit spherical POLARIZATION, a geometric condition resulting in the nearly constant magnitude of the MAGNETic field. This property persists even during the largest field fluctuations, sometimes leading to local polarity reversals known as switchbacks. A longstanding question is whether three-dimensional smooth MAGNETic fields can simultaneously satisfy the constant-$|{\bf B}|$ constraint, and how such fields can be constructed analytically or numerically. Here we propose a new numerical method that allows to construct a MAGNETic field that is exactly spherically polarized, reproducing key features of solar wind fluctuations. Using this framework, we find evidence that discontinuities are unavoidable for generic three-dimensional configurations. Fundamentally, this implies that field rotations cannot maintain exactly constant $|{\bf B}|$ in an arbitrarily large spatial domain. Rather, field rotations with constant magnitude can exist in limited regions of space. We argue that these finite spatial domains are separated by discontinuities where a local departure from constant $|{\bf B}|$ is expected. These results provide insights into the structure of solar wind turbulence and more generally into the nature of nonlinear MAGNETic fluctuations in plasmas.
[abstract 24 / 46] (score: 3) - Title: Infrared Echoes of Precessing Tidal Disruption EventsAuthors: Hong-Zhou Wu, Shao-Yu Fu, Wen-Long Xu, Chang Zhou, Wei-Hua Lei,Comments: 16 pages,7 figures,accepted by ApJSubjects: astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
A tidal disruption event (TDE) occurs when a star is torn apart by a supermassive BLACK HOLE. The resulting UV/optical flare irradiates parsec-scale dust, producing delayed mid-infrared echoes that persist for years. These echoes provide unique calorimetric probes of the total radiated energy and dust geometry. Existing models usually assume static axisymmetric illumination patterns. However, the TDE accretion disk is likely misaligned and undergoes RELATIVISTIC precession. In this work, we present a theoretical framework for infrared dust echoes from a precessing TDE disk. The precession will lead to highly variable infrared light curves, which can be revealed by high-cadence observations. The overall profile of the infrared light curves shows double-peaked to single-peaked pattern transitions as a result of the changes in the viewing angle or precession angle. The results indicate that infrared echoes are dynamic tracers of the evolving lighting patterns of the central engine.
[abstract 25 / 46] (score: 3) - Title: A Semi-Analytical Loss Cone Theory for Tidal Disruption Event Rates Around Kerr Black HolesAuthors: Wenkang Xin,Comments: 69 pages, 6 figures. MMathPhys dissertation, University of Oxford, Trinity 2026. v2: Added links to supporting code and fixed integration order in producing Figure 3.1(a). Expanded Appendices B and C to include energy diffusion. Main results are unchangedSubjects: astro-ph.HE astro-ph.GA gr-qcCreated: 2026-07-26; Updated: 2026-07-28; Datestamp: 2026-07-28
A tidal disruption event (TDE) occurs when a star is scattered onto a near-radial orbit and is torn apart by a BLACK HOLE (BH)'s tidal field. The angular momentum threshold for disruption is set by general RELATIVISTIC tidal dynamics, while the supply of stars to the disruption zone is governed by Newtonian stellar dynamics. A spinning BH breaks the spherical symmetry of the disruption boundary, so a star's survival depends on both the magnitude and the orientation of its angular momentum. Existing treatments either assume a non-spinning BH or rely on numerical simulations of spinning BHs. We develop the first semi analytical framework that incorporates spin-dependent loss cone boundaries into TDE rate theory. Using a novel tidal tensor formalism, we compute inclination-dependent thresholds for tidal disruption and direct capture by the event horizon. We then revisit the classical one dimensional loss cone problem with nested disruption and capture boundaries, deriving a closed form capture fraction valid across all loss cone regimes. Finally, we formulate a two dimensional Fokker--Planck equation describing simultaneous diffusion in angular momentum magnitude and orientation. Through a perturbative treatment, we demonstrate that while the Kerr disruption boundary induces a first-order bias favouring the disruption of retrograde stars, the global TDE rate is remarkably insensitive to BLACK HOLE spin. This approach offers a tractable route to including spin and orbital inclination in population-level TDE studies.
[abstract 26 / 46] (score: 3) - Title: Beta-Particle Transport and Thermalization in Kilonova Ejecta with Detailed Atomic MicrophysicsAuthors: Zachary L. Andalman, Christopher L. Fryer, Christopher J. Fontes, Matthew R. Mumpower, Ryan T. Wollaeger,Comments: 20 pages main body, 22 pages total, 14 figures. Updated on Jul 27th, 2026 to fix an error in the original manuscript. Submitted to MNRAS on Jul 1st, 2026. Comments welcome. Atomic data is available at https://zandalman.com/publications/Andalman+2026b/Subjects: astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
When two neutron stars collide, they eject material containing heavy nuclei formed by the rapid neutron capture process ($r$-process). As these nuclei decay, they power a bright optical/near-infrared transient known as a kilonova (KN). Modeling KN emission is a complex problem involving atomic opacities, radiation transport, and heating powered by the thermalization of radioactive decay products like $γ$-rays, $α$-particles, and $β$-particles. For heating by $γ$-rays, many KN modeling codes do full radiation transport calculations. However, heating by $α$- and $β$-particles relies on simplified descriptions of collisions and transport, and remains an important source of uncertainty in KN models. In this paper, we study the thermalization and transport of $β$-particles. To study thermalization, we use evaluated atomic physics data to estimate per-species contributions to energy deposition, scattering, and electron impact ionization, which we make available online. To include non-local effects, we develop a fully RELATIVISTIC framework for charged particle transport in a spherically symmetric, homologously expanding ejecta, considering two limiting MAGNETic-field geometries. Non-local energy deposition and escape reduce thermalization efficiency, especially in the innermost and outermost ejecta, lowering the ejecta temperature and ionization state compared to local deposition models. Coulomb scattering partially offsets these effects by trapping particles at intermediate times. Ionization by secondary electrons significantly enhances the overall ionization rate. We provide analytic prescriptions for the spatially dependent thermalization efficiency for use in future light-curve calculations. Our results demonstrate that evaluated atomic data and charged-particle transport should be incorporated into the next generation of KN models.
[abstract 27 / 46] (score: 3) - Title: Speeding up Gravitational Lens Mass Models with Machine Learning: Applications in X-ray AstronomyAuthors: Alex Ostridge, Rafael Martínez-Galarza, Júlia M. Sisk-Reynés, Daniel A. Schwartz, Anna Barnacka,Comments: Accepted for publication in MNRAS on 21 July 2026. 16 pages, 9 figures, 4 tables. The full code pipeline to reproduce the simulations, neural network training and parameter predictions, along with the trained network models and optimisation code, are publicly available on GitHub at https://github.com/aostridge/Grav-Lens-ML. Comments are welcome!Subjects: astro-ph.GA astro-ph.CO astro-ph.HECreated: 2026-07-24; Updated: 2026-07-28; Datestamp: 2026-07-28
Multi-wavelength observations of quadruply lensed QUASARs constitute a powerful probe of cosmology, DARK MATTER substructure along the line of sight, and the structure of X-ray emitting regions in high-redshift QUASARs. These investigations are conditional on acquiring an accurate model for the surface mass density of matter lensing these QUASARs. We propose a simulation-based machine learning method to accelerate parameter inference in real quadruply lensed systems by several orders of magnitude. We simulate a grid of quadruply lensed sources with Singular Isothermal Ellipsoid (SIE) lenses and use the projected positions of the four lensed images to train two fully connected neural networks that predict the mass parameter and ellipticity. For a large fraction of simulated systems, the neural network-initialised mass models converge in time-scales of a few minutes and recover the source position at the <0.''005 level for a broad range of lens masses and ellipticities. We apply our neural networks to seven quadruply lensed QUASARs, lensed by isolated galaxies or a galaxy-perturber pair, which have archival Chandra observations. The final optimised mass models for each QUASAR predict the observed lensed image positions in Gaia Data Release 3. These mass models enable the caustic method, which locates the X-ray-to-optical emission regions to milliarcsecond precision in these otherwise unresolvable systems, improving the effective angular resolution of Chandra at high-z by up to two orders of magnitude. Our approach accelerates this mass modelling by supplying informed initial parameters, enabling application to the many new quadruply lensed systems expected from forthcoming surveys.
[abstract 28 / 46] (score: 3) - Title: A charge-flow instability in plasmas with charge fluctuationsAuthors: Deepen Garg, Jennifer Schober,Comments: 7 pages, 3 figuresSubjects: astro-ph.CO astro-ph.HE physics.plasm-phCreated: 2026-07-24; Updated: 2026-07-28; Datestamp: 2026-07-28
We present a linear instability in MAGNETized plasmas with charge fluctuations. It is driven by an electric current proportional to the charge chemical potential $μ$ and the bulk velocity. This charge-flow (C-flow) instability has hitherto not been considered in standard MAGNETohydrodynamics or its chiral extensions. We derive its dispersion relation and maximum growth rate, and confirm them with direct numerical simulations. We also show that the C-flow instability persists even for zero-mean fluctuations of $μ$, vanishing resistivity, and a MAGNETic Prandtl number of unity.
[abstract 29 / 46] (score: 3) - Title: A QUASAR hatching from a buried red phase at z = 3.7Authors: Zheng Ma, Yongda Zhu, Zhiyuan Ji, Eiichi Egami, Marcia J. Rieke, Xiaohui Fan, Jianwei Lyu, George H. Rieke, Fengwu Sun, Yang Sun, George D. Becker, Andrew J. Bunker, Francesco D'Eugenio, Xiangyu Jin, Ignas Juodžbalis, Weizhe Liu, Roberto Maiolino, Pierluigi Rinaldi, Feige Wang, Christopher N. A. Willmer, Yunjing Wu, Jinyi Yang, Junyu Zhang, Peixin Zhu,Comments: 26 pages, 5 main figures, and 10 Extended Data figures. Submitted, comments are welcomeSubjects: astro-ph.GACreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
We present JADES-GS 209777, previously cataloged as CANDELS J033238.02-274626.2, hereafter "the Hatchling," a red QUASAR at $z=3.711$. While the source has been reported in earlier deep-field catalogs, our multiwavelength analysis reveals a visible active nucleus still embedded in a dense gas- and dust-rich environment. Red QUASAR continua are often attributed to dust attenuation, including non-standard extinction curves, but the highly comprehensive multiwavelength data for this source provide direct constraints on the material being cleared. Using JWST/NIRSpec, NIRCam, MIRI, HST, MUSE, Chandra, ALMA, and VLA data, we detect broad emission lines and strong X-ray emission, showing that the active nucleus is at least partially exposed. We also detect H$α$ and He I absorption, indicating dense gas close to the nucleus. Kinematically disturbed O I, Mg II, Na D, and [O III] features, together with extended Ly$α$ emission over $\gtrsim 20$ kpc, further show that multiphase gas is being accelerated from the nuclear region into the host-galaxy environment. The ALMA detection reveals strong dust emission, with the inferred infrared luminosity placing the system in the ULIRG regime. The continuum is red and sharply declining toward the rest-frame UV, resembling compact red AGNs, and may reflect extreme dust attenuation, gas reprocessing, possible BAL-like absorption, or a combination of these effects. Regardless of which mechanism dominates the continuum shape, the line diagnostics show that the visible nucleus remains partially obscured by nearby material. The Hatchling therefore represents a unique opportunity to explore a poorly known transition phase in which feedback is likely clearing an enshrouded QUASAR and allowing it to emerge toward a more unobscured active nucleus.
[abstract 30 / 46] (score: 3) - Title: Radiation Pressure Effect on the degenerate Electron-Positron Plasma DynamicsAuthors: Irakli Ugulava, Vazha Berezhiani,Comments: 12 pages, 4 figuresSubjects: physics.plasm-phCreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
We investigate the influence of radiation pressure on the collective dynamics of a degenerate electron--positron plasma interacting with an intense radiation flux. Assuming the FERMI energy substantially exceeds the thermal energy, we apply general covariant hydrodynamic equations to demonstrate that in a sufficiently dense plasma, radiation pressure outpaces the increase of RELATIVISTIC inertia, yielding an enhanced terminal bulk Lorentz factor. Furthermore, this process is accompanied by dynamic plasma cooling.
[abstract 31 / 46] (score: 3) - Title: X-ray disc reverberation modelling of the X-ray/UV/optical spectral/timing properties of Fairall 9Authors: M. Polioudakis, M. Papoutsis, I. E. Papadakis, C. panagiotou, E. Kammoun, M. Dovciak,Comments: 13 pages, 7 figures, Accepted for publication in Astronomy & AstrophysicsSubjects: astro-ph.GACreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
Multiwavelength monitoring surveys of ACTIVE GALACTIC NUCLEi (AGN) have revealed correlated variability observed in the X-ray, UV, and optical bands. X-ray reverberation, arising from the absorption of X-rays illuminating the accretion disc, provides a self-consistent physical framework for interpreting these observations and imposing constraints on the geometry and energetics of accretion flows and X-ray coronae. We aim to apply the X-ray disc reverberation framework to the Seyfert 1 galaxy Fairall 9, a well-studied AGN with a clear line of sight to the accretion disc, to investigate whether this physical scenario can simultaneously account for its observed spectral and timing properties, as probed by its mean spectral energy distribution (SED), UV/optical power spectral densities (PSDs), and interband time lags. We used multiwavelength data from the 2018-2021 SWIFT intensive monitoring campaign to construct the mean X-ray/UV/optical SED and to compute PSDs in all bands. We first modelled the broadband average SED using KYNSED, which is a physical X-ray reverberation model assuming lamp-post geometry. The resulting best-fit parameter space was then used to model the UV/optical PSDs and further constrain the physical parameters of the system. Finally, we tested whether the observed interband time lags are consistent with the model predictions for the parameter sets that simultaneously reproduce both the SED and the PSDs. X-ray illumination of the accretion disc can explain the broadband mean SED of Fairall 9. The UV/optical variations are likely driven by the variable X-rays that illuminate the disc, and not by short-timescale disc fluctuations of unknown physical origin. X-ray disc illumination and reverberation can explain the mean energy spectrum, the UV/optical power spectra, and the wavelength-dependent time lags simultaneously for a common set of physical parameters.
[abstract 32 / 46] (score: 3) - Title: Probing an Intermediate-Mass Black Hole Companion of Sagittarius A* with Pulsar TimingAuthors: Zexin Hu, Lijing Shao,Comments: 12 pages, 14 figuresSubjects: astro-ph.HE astro-ph.GA gr-qcCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
An intermediate-mass BLACK HOLE (IMBH) hidden in our Galactic Center (GC) may explain the puzzling observations of the stellar distribution around Sagittarius A* (Sgr A*), the supermassive BLACK HOLE (SMBH) in the GC. Future observations with the next-generation radio telescopes, such as the SKA, are promising to discover pulsars orbiting around Sgr A*, and thus provide the possibility of constraining the hidden IMBH with pulsar timing. We study the detectability of a third-body, the IMBH, in the pulsar-SMBH system based on radio timing observation. We find that the pulsar-SMBH system is very sensitive to such a third-body perturbation and can be used to put stringent constraints on the existence of the IMBH. Even under strong perturbations caused by the complex GC astrophysical environments, timing observation will still complement the existing observational constraints.
[abstract 33 / 46] (score: 3) - Title: Cosmic ray heating of cold streams: Implications for the gas supply and growth of massive galaxiesAuthors: Ellis R. Owen, Nicolas Ledos, Evangelia Ntormousi, Shinsuke Takasao, Kentaro Nagamine, Sebastiano Cantalupo,Comments: 23 pages, 13 figures, 1 table. Submitted to A&ASubjects: astro-ph.GA astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Recent observations have demonstrated the presence of COSMIC RAYs (CRs) in cosmic-web filaments. Cold streams supply gas inflows from these filaments into massive galaxies during the cosmic noon. As these streams are expected to be MAGNETised, external cosmic-web CRs may become entrained with this inflowing gas. We aim to determine whether this externally-supplied CR population can deposit energy to alter or disrupt the supply of cold gas to galaxies. We couple a spectrally-resolved CR transport calculation to a redshift-dependent analytical model of MAGNETised cold streams in galaxy haloes and investigate whether externally-supplied CRs can modify gas supply through this channel. We find CR energy deposition can alter the thermal state of cold streams. Dense stream cores remain largely resilient and only experience weak heating. Their temperature is raised by less than a factor of 10, which is insufficient to overcome radiative cooling at the stream-CGM interface. In more diffuse streams, and in partially mixed interface gas of the most massive haloes near the virial radius, CR heating becomes strong enough that radiative cooling can no longer balance it, and the gas is heated toward or above the mixing-layer temperature. This weakens the stability of the stream, making it more susceptible to disruption. Complete evaporation is possible only in extreme cases. Cold streams are therefore more vulnerable to CR heating at larger galactocentric radii, higher halo masses, and in more diffuse or partially-mixed stream material. By preferentially heating diffuse gas, externally supplied CRs may introduce additional selectivity into cold-gas accretion that modifies the gas supply and growth of massive galaxies. These CRs weaken fragile streams and erode their cold envelope, and may cause surviving cold flow components to appear thinner and more sharply confined far into galaxy haloes.
[abstract 34 / 46] (score: 2) - Title: The MAGNETic sensitivity of the Ca II resonance and subordinate lines in the solar atmosphereAuthors: I. Juanikorena Berasategi, E. Alsina Ballester, T. del Pino Alemán, J. Trujillo Bueno,Comments: 14 pages, 14 figures, 3 appendices. Published in Astronomy&Astrophysics. Improved layout of the manuscript from previous versionSubjects: astro-ph.SRCreated: 2026-07-24; Updated: 2026-07-28; Datestamp: 2026-07-28
Aims: The POLARIZATION of the Ca II resonant doublet (H and K lines) and the subordinate infrared triplet lines are key observables for diagnosing solar chromospheric MAGNETism. It is thus necessary to understand the physical mechanisms that shape their Stokes profiles in MAGNETic environments. Methods: Using the spectral synthesis module of the HanleRT-TIC code, we study the effects of anisotropic radiation pumping with partial frequency redistribution (PRD) and J-state interference (JSI) in a plane-parallel semi-empirical static solar atmospheric model. We also analyze the sensitivity of these lines to MAGNETic fields of varying strengths and orientations, accounting for the combined action of the Hanle and Zeeman effects. Results: Including PRD is crucial to model the POLARIZATION in the core regions of the resonant lines, while JSI strongly affects their far wings. The metastable lower levels of the subordinate lines also influence the scattering POLARIZATION of the K line. With horizontal MAGNETic fields, the resonant lines respond to field strengths from sub-gauss to tens of gauss, whereas the infrared triplet scattering POLARIZATION is mainly sensitive to milligauss fields. At a near-limb line of sight (LOS) with $μ= 0.1$, the Hanle effect modifies the scattering POLARIZATION via a dePOLARIZATION and a rotation in the plane of linear POLARIZATION. At disk center, horizontal fields generate linear POLARIZATION in the 1D model: for the K line, the Hanle effect dominates from sub-gauss to a few tens of gauss, and the Zeeman effect dominates in stronger fields. For vertical fields, the Hanle effect vanishes, but MAGNETo-optical effects affect the linear POLARIZATION wings. Finally, atomic level POLARIZATION impacts the outer circular POLARIZATION lobes of the resonant lines, and the weak-field approximation overestimates the LOS MAGNETic component in this frequency range.
[abstract 35 / 46] (score: 2) - Title: Too shy to spin? Cosmic wallflowers as proto-globular clustersAuthors: Floor van Donkelaar, Lucio Mayer, Pedro R. Capelo,Comments: 9 pages, submitted to MNRASSubjects: astro-ph.GA astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
We investigate the rotational properties of star-forming clusters at $z \sim 7.6$ in the high-resolution simulation MassiveBlackPS, focusing on two formation channels: clusters forming in galactic discs via gravitational instability and isolated circumgalactic systems, referred to as cosmic wallflowers, born out of cosmic filaments. Using stellar kinematics, we compare their rotational velocities, $v_{\rm rot}$, and rotational support, $v/σ$, to study whether formation environment leaves a clear dynamical imprint. We find a clear separation, wherein cosmic wallflowers systematically have lower rotational velocities and span a wide range in $v/σ$, whereas the identified disc clusters are strongly rotation-dominated and extend to higher $v_{\rm rot}$. When combined with stellar surface densities, a subset of the low-$v_{\rm rot}$ cosmic wallflowers lie surprisingly close to the observed globular cluster population in the Milky Way, whereas disc clusters remain offset. Within the cosmic wallflower population, we identify two regimes: lower-density, weakly rotating systems that overlap with these globular cluster properties, and denser, more rotationally supported systems that likely follow a different evolutionary pathway, possibly linking them to the origin of massive BLACK HOLE seeds at high redshift. We further find that the gas content correlates with this behaviour, with gas-rich cosmic wallflowers preferentially occupying this low-rotation regime. This all suggests that environment and baryonic content together play a key role in setting the initial dynamical state and possible fate of clusters. In particular, weakly rotating, gas-rich cosmic wallflowers emerge as natural proto-globular cluster candidates, potentially evolving towards present-day systems through angular momentum loss and dynamical heating.
[abstract 36 / 46] (score: 2) - Title: Energetics of frontogenesis in simple balanced modelsAuthors: Yue Bai, Jörn Callies,Comments:Subjects: physics.ao-phCreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
Submesoscale fronts have been proposed to act as conduits funneling kinetic energy from geostrophically constrained mesoscale eddies down to small scales, where the energy can be dissipated. Realistic primitive-equation simulations suggest that the downscale energy transfer at submesoscales is strongly concentrated in sharpening fronts, with convergence on the cyclonic side playing a dominant role. This study explores how much of this phenomenology can be captured by simple quasi-geostrophic (QG) and semi-geostrophic (SG) theories of frontogenesis. An analysis of the kinetic energy budget of classical strain-induced frontogenesis shows that there is downscale transfer in both QG and SG fronts. In QG frontogenesis, the narrowing JET along the sharpening front is powered by buoyancy production, but geostrophic downscale transfer due to the strain field plays an important role. In SG frontogenesis, where frontal sharpening is accelerated by the ageostrophic cross-frontal circulation, ageostrophic advection enhances this downscale transfer on the cyclonic side of the front, where the surface flow is convergent. On the anticyclonic side, where the ageostrophic circulation is divergent, the ageostrophic scale transfer of kinetic energy is upscale and partially offsets the geostrophic downscale transfer. While matching patterns in realistic primitive-equation simulations, the ageostrophic scale transfers remain important but not dominant in the adiabatic and frictionless theory considered here. This suggests that processes absent from these theories may play an important role. For example, mixed-layer turbulence may enhance the ageostrophic circulation and the associated dipole of scale transfers. The advection of ageostrophic momentum may also be important in some circumstances.
[abstract 37 / 46] (score: 2) - Title: High-resolution spectroscopy of the bipolar proto-planetary nebula Hen 3-1475, the Garden Sprinkler NebulaAuthors: Ana Valeria Beltrán-Sánchez, Miriam Peña, Mudumba Parthasarathy,Comments: Published in RMxAASubjects: astro-ph.SRCreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
A detailed analysis of high-resolution spectra in the optical and near-infrared range of the central zone of the proto-planetary nebula Hen 3-1475, obtained in 2006 and 2024, is conducted. The spectrum primarily revealed stellar emission of H Balmer and Paschen series, lines of iron (Fe I, Fe II, and [Fe II]), and other significant lines of He I, Ca II, [Ca II], and O I. Several multiplets of Fe II, the H Balmer series, Ca II H and K, Na I D and He I lines exhibit P-Cygni profiles and bump-like features, which are clear indicators of strong stellar winds. The terminal velocity of the winds was calculated, reaching values up to ~ 800 km/s. [Fe II] and Fe I lines were used as gas density indicators. In these observations, no photoionized nebular lines of planetary nebulae were identified, suggesting that the central star has not reached the temperature required to photoionize the nebula. A comparison between the observations from 2006 and 2024 reveals some few significant differences, being the most important the probably ejection of a new JET emerging from the central zone and the detection of a broad component adjacent to H α, probably originating from emission associated with a JET at 700 km/s. High-spectral resolution observations of the knot NW1 obtained on August 2024, are also presented. This knot shows a typical spectrum of shocked gas. The emission of this knot has changed, presently not showing [O III] 5007 and other ionized lines that were reported in 2006.
[abstract 38 / 46] (score: 2) - Title: Characterisation of a multistable turbulent wake: application of an improved regime identification with analytical model trainingAuthors: Ariane Barlet, Pierre Bragança, Christophe Cuvier, Joran Rolland,Comments: 43 page 23 figuresSubjects: physics.flu-dynCreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
This article presents the experimental study and the modelling of the multistable JET in the wake of two side by side square bars separated by a distance $G$ at Reynolds number $R=U_\infty H/ν=10000$ (with $U_\infty$ the velocity of the incoming flow, $H$ the bar side and $ν$ the kinematic viscosity). The velocity field downstream of the bars is measured by means of two dimensional two components Particle Image Velocimetry (PIV). We use the weighted transverse position of the JET $Y_m$ and the JET width $w$ to characterise the regimes of multistability as the gap ratio $G/H$ is increased. Three main regimes of multistability are possible: tristability, bistability, and monostability. In our wind tunnel, tristability is observed for $G/H\in [1.15,1.25]$, bistability is observed for $G/H\in [1.5,2.65]$ and monostability is observed for $G/H\in [3.0,3.5]$. Within the first two ranges of $G/H$, there exists gap ratios for which multistability is more complex. In order to analyse the simple and complex multistability regimes as well as the transition from bistable to monostable, we construct an analytical stochastic differential equation (SDE) modelling $Y_m$ for each gap ratio. These SDEs are written with polynomial drift and diffusion. For this matter we use a data based method that finds an trade--off between simplicity of the model (smaller number of monomials) and precision. A first key advantage of the use of the data-based model fitting method is that when the flow is tristable, bistable or monostable, we recover the drifts expected from the theory of bifurcations, but we are now able to correct it with the right multiplicative noise expressed by the diffusion. The second key advantage is that we can also fit atypical drift expressions when the multistability regime is complex that help us make sense of the JET behaviour.
[abstract 39 / 46] (score: 2) - Title: Charge-dependent atmospheric muon flux at 17 GV geoMAGNETic cutoff measured with the mini-ICAL prototypeAuthors: S. Pethuraj, Raj Shah, G. Majumder, J. M. John,Comments: 23 pages, 17 figures, 2 tablesSubjects: hep-exCreated: 2026-07-25; Updated: 2026-07-28; Datestamp: 2026-07-28
The Iron CALorimeter (ICAL) detector at the India-Based Neutrino Observatory (INO) was conceived as an underground experiment designed to measure atmospheric neutrino oscillation parameters. As part of the R\&D programme, a scaled prototype (mini-ICAL), 85\,ton, approximately 1/600$^{\mathrm{th}}$ the mass of the full detector, was constructed at the IICHEP Transit Campus, Madurai (altitude 150\,m; latitude 9.9372$^\circ$\,N; longitude 78.013$^\circ$\,E; geoMAGNETic latitude 1.44$^\circ$\,N; vertical cutoff rigidity 17\,GV) and operated between 2018 and 2022. The prototype enabled measurements of charge-dependent cosmic muon spectra in the vicinity of the geoMAGNETic equator and provided an important validation of detector performance, reconstruction algorithms, and simulation frameworks for the ICAL experiment. Differential fluxes of $μ^{-}$ and $μ^{+}$ were measured over the momentum range $\sim$\,1--5\,GeV/c. The obtained momentum spectra are systematically lower than those reported at sites with smaller geoMAGNETic cutoff rigidities, consistent with the suppression of low- and intermediate-rigidity primary COSMIC RAYs at the 17\,GV cutoff. The measurements are compared with predictions from different hadronic interaction models available in CORSIKA simulations.
[abstract 40 / 46] (score: 2) - Title: Black hole shadow parameters and quasi-normal modes for Weyl-incorporated gravityAuthors: Noraiz Tahir, Mubasher Jamil, Kaynat Fatima, Tajammal Hussain Khokhar,Comments: 24 pages, 7 figures, accepted in the International Journal of Geometric Methods in Modern Physics (IJGMMP)Subjects: gr-qcCreated: 2026-07-26; Updated: 2026-07-28; Datestamp: 2026-07-28
An additional term of the form $λ\mathbf{T} \cdot \mathbf{C} \cdot \mathbf{T}$ in the Einstein-Hilbert Lagrangian was introduced to explain the interaction between matter and pure gravitational field [H. W. Lee and A. Qadir, Motion of test particle for Weyl-interaction gravity, {\it Int. Jour. Mod. Phys. D} {\bf 28}(16) (2019) 2040014], the modified RELATIVISTIC dynamics (MORD). In this paper, we estimate the shadow parameters of BLACK HOLE in a spherically symmetric static spacetime within the MORD framework. As a first approximation, we assume that the BLACK HOLE is surrounded by a constant-density baryonic matter halo. The analysis is then extended by introducing a homogeneous plasma background. We compute the shadow radii for various BLACK HOLE masses and analyze their dependence on the WIG coupling parameter $λ$. In addition, we compute the fundamental quasi-normal mode (QNM) frequencies under test-field approximation, and perform a time-domain integration analysis.
[abstract 41 / 46] (score: 2) - Title: Spectral properties of mesoscale fluctuations in interplanetary coronal mass ejectionsAuthors: Anna-Sofia Jylhä, Simon Good, Emilia Kilpua,Comments: 9 pages, 8 figuresSubjects: astro-ph.SR physics.plasm-ph physics.space-phCreated: 2026-07-26; Updated: 2026-07-28; Datestamp: 2026-07-28
Magnetic fields in interplanetary coronal mass ejections (ICMEs) often display a flux rope structure at large scales and a turbulent cascade of fluctuations at smaller scales. However, the nature of fluctuations at transition scales between the flux rope and turbulence - i.e., at mesoscales - has not been previously examined in detail. Mesoscale fluctuations of the MAGNETic field in 142 ICME intervals with clear flux rope signatures at 1 au have been examined using wavelet power spectra, with "mesoscale" defined here as spacecraft-frame frequencies $10^{-4}\ \text{Hz}
[abstract 42 / 46] (score: 2) - Title: Evidence for Azimuthally Anisotropic MgII Absorption around DESI Luminous Red GalaxiesAuthors: Xuanyi Wu, Cheng Li,Comments: 8 pages, 4 figures, 1 table, submitted to ApJLSubjects: astro-ph.GACreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
We use DESI DR1 luminous red galaxies (LRGs) and background QUASAR spectra to measure the mean MgII equivalent-width field around massive quiescent galaxies as a function of projected radius and azimuth relative to the projected major axis. Our forced-measurement approach assigns a MgII doublet-window EW to every LRG-QUASAR pair, including spectra without individually detected absorbers, and subtracts a redshift-matched random-control signal measured from the same normalized QUASAR spectra. The all-angle profile declines smoothly over $r_\text{p}=0.01$-$1.0$ proper Mpc and shows stronger inner absorption at $0.4
[abstract 43 / 46] (score: 2) - Title: Gravitational wave signatures of MAGNETized Ernst BLACK HOLEAuthors: Fazlay Ahmed, Sanjar Shaymatov, Chengxun Yuan, Salah Nasri,Comments: 11 pages, 8 captioned figuresSubjects: gr-qcCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
We investigate gravitational wave (GW) emission from periodic timelike orbits of a test particle around a MAGNETized Ernst BLACK HOLE and the gravitational waveforms generated by their orbital dynamics. The bound geodesics are systematically classified using the zoom-whirl representation labeled with three integers $(z,w,v)$. Gravitational waveforms are computed within a numerical framework that combines exact geodesic motion with the quadrupole approximation, which is well-suited to extreme mass-ratio inspirals (EMRIs). This analysis is particularly relevant for assessing the capability of future gravitational-wave observations to detect the effects of MAGNETic fields. Our results show that an intrinsic MAGNETic field imprints characteristic features on the GW signal, highlighting GW astronomy as a promising avenue for probing MAGNETized BLACK HOLE spacetimes.
[abstract 44 / 46] (score: 2) - Title: Impact of ion-electron collisions on nonlocal ion heat conduction, viscous stress, and diffusionAuthors: Nicholas Mitchell, David Chapman, Grigory Kagan,Comments:Subjects: physics.plasm-phCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
By applying a first-principles reduced kinetic method, this work demonstrates the impact of ion-electron collisions on ion transport for strongly inhomogeneous plasmas in the nonlocal regime, where collisionality is insufficient to enforce local thermal equilibrium due to sharp gradients. Ion heat conduction and viscous stress in both unMAGNETized and MAGNETized plasmas are considered, as well as inter-species diffusion in multi-species plasmas. Most notably, even for equal ion and electron temperatures, ion-electron collisions are found to substantially modify the peak nonlocal heat flow, whereas nonlocal preheats are strongly suppressed since streaming suprathermal particles are further out in the tail of the cold ion distribution where ion-electron collisions become dominant.
[abstract 45 / 46] (score: 2) - Title: Time-Domain Dust Astrophysics. I. Polarization Flares, Polarization-Angle Reverberation, and Fossil Imprints in Supernova-Illuminated CloudsAuthors: Thiem Hoang,Comments: 12 pages, 6 figuresSubjects: astro-ph.GA astro-ph.HECreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
Cosmic transients can dramatically enhance the local radiation field on timescales of days to months. Using the time-domain TransRAT framework, which self-consistently evolves grain heating, alignment, rotational disruption, and switching of the alignment axis between the MAGNETic field (B-RAT) and the radiation direction (k-RAT), we predict the time-dependent dust POLARIZATION of a dense cloud illuminated by a Type~IIP SUPERNOVA at different distances. We identify four key signatures. First, for $D\lesssim1$ pc, a POLARIZATION flare develops within days to weeks, marked by sharp increases in both thermal dust POLARIZATION and extinction-POLARIZATION efficiency; this is followed by a POLARIZATION dip as radiative torque disruption (RAT-D) destroys the large aligned grains. Second, the peak wavelength of extinction POLARIZATION, $λ_{\rm max}$, shifts blueward as the minimum aligned-grain size decreases, providing a diagnostic largely independent of MAGNETic-field geometry. Third, the transition from B-RAT to k-RAT produces an abrupt POLARIZATION-angle rotation of $45^{\circ}$ in our fiducial geometry. Fourth, as the transient fades, the return to B-RAT generates a POLARIZATION-angle reverberation governed by Larmor precession. This reverberation is the most sensitive probe of grain MAGNETism, with superparaMAGNETic grains recovering more rapidly than paraMAGNETic grains. At $D>1$ pc, SN-induced POLARIZATION properties persist long after the radiation has faded, leaving a fossil imprint. This imprint offers the most practical near-term observational test: clouds near SUPERNOVA remnants younger than the relaxation timescale of $\sim10\,t_{\rm gas}$ with $t_{\rm gas}$ gas damping time, should exhibit elevated POLARIZATION and blueshifted $λ_{\rm max}$ today.
[abstract 46 / 46] (score: 2) - Title: Universal Statistics of Energy and Information Flow in Random ElectroMAGNETic FieldsAuthors: Yuchen Ke, Nandini Bhattacharya, Stefan Rotter, Fabian Maucher,Comments:Subjects: physics.opticsCreated: 2026-07-27; Updated: 2026-07-28; Datestamp: 2026-07-28
We establish a universal statistical description for the local flow of energy and information in random electroMAGNETic fields. The longitudinal Poynting flux, written as a Hermitian quadratic form of the transverse electric and MAGNETic field components, follows a probability distribution that is completely determined by four eigenvalues of an electroMAGNETic covariance matrix. These flux eigenvalues quantify forward transport, optical backflow, and POLARIZATION mixing, and reduce to the known paraxial and isotropic limits in the appropriate regimes -- including strongly nonparaxial fields, where no universal description was known so far. Full-vector simulations of continuous and discrete disordered media confirm this universality. The same framework applies to the recently introduced Fisher-information flux, with the fields replaced by their sensitivity to a parameter, thereby unifying the statistics of local energy and information transport in random light and revealing the reversal of information flow across a parameter-dependent object.
arXiv:2607.23095 [pdf, ps, other]
arXiv:2607.24214 [pdf, ps, other]
arXiv:2512.18323 [pdf, ps, other]
arXiv:2602.21865 [pdf, ps, other]
arXiv:2606.12511 [pdf, ps, other]
arXiv:2607.24333 [pdf, ps, other]
arXiv:2507.06163 [pdf, ps, other]
arXiv:2603.11718 [pdf, ps, other]
arXiv:2604.03945 [pdf, ps, other]
arXiv:2607.19485 [pdf, ps, other]
arXiv:2607.22816 [pdf, ps, other]
arXiv:2607.23114 [pdf, ps, other]
arXiv:2607.24234 [pdf, ps, other]
arXiv:2607.24307 [pdf, ps, other]
arXiv:2607.24397 [pdf, ps, other]
arXiv:2607.24457 [pdf, ps, other]
arXiv:2607.24531 [pdf, ps, other]
arXiv:2607.24602 [pdf, ps, other]
arXiv:2509.03216 [pdf, ps, other]
arXiv:2601.15962 [pdf, ps, other]
arXiv:2602.06121 [pdf, ps, other]
arXiv:2603.25049 [pdf, ps, other]
arXiv:2605.04285 [pdf, ps, other]
arXiv:2606.07072 [pdf, ps, other]
arXiv:2606.18050 [pdf, ps, other]
arXiv:2607.01228 [pdf, ps, other]
arXiv:2607.22812 [pdf, ps, other]
arXiv:2607.22815 [pdf, ps, other]
arXiv:2607.22966 [pdf, ps, other]
arXiv:2607.23217 [pdf, ps, other]
arXiv:2607.23267 [pdf, ps, other]
arXiv:2607.24201 [pdf, ps, other]
arXiv:2607.24461 [pdf, ps, other]
arXiv:2510.19719 [pdf, ps, other]
arXiv:2606.27426 [pdf, ps, other]
arXiv:2607.22970 [pdf, ps, other]
arXiv:2607.23061 [pdf, ps, other]
arXiv:2607.23206 [pdf, ps, other]
arXiv:2607.23330 [pdf, ps, other]
arXiv:2607.23552 [pdf, ps, other]
arXiv:2607.23742 [pdf, ps, other]
arXiv:2607.24071 [pdf, ps, other]
arXiv:2607.24154 [pdf, ps, other]
arXiv:2607.24505 [pdf, ps, other]
arXiv:2607.24517 [pdf, ps, other]
arXiv:2607.24631 [pdf, ps, other]