Current date: 2026-11-05
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Number of records retrieved: 844
Keyword score statistics
score 6 -- 2 abstracts
score 5 -- 4 abstracts
score 4 -- 7 abstracts
score 3 -- 4 abstracts
score 2 -- 25 abstracts
in total -- 42 abstracts
Articles that appeared on 2026-11-05
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[abstract 1 / 42] Yes (score: 6)
- Title: Unveiling the nonthermal environments of NGC 3411 and NGC 5903 through new MeerKAT observationsAuthors: T. Pasini, F. De Gasperin, E. O'Sullivan, M. Brüggen, M. Gaspari, K. Kolokythas, E. Bulbul, Y. E. Bahar,Comments:Subjects: astro-ph.GA astro-ph.COCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Galaxy groups are key laboratories for investigating the interplay between ACTIVE GALACTIC NUCLEus (AGN) outbursts and the dynamical processes of the intra-group medium. We aim to characterize the morphology, spectral properties, and MAGNETic field structure of the diffuse nonthermal radio emission in two peculiar galaxy groups, NGC 3411 and NGC 5903, selected from an originally larger sample, in order to constrain its origin and its connection with the dynamics of the intra-group medium. We present new MeerKAT UHF- and L-band observations of the two groups, complemented by archival Chandra and XMM-Newton data already analyzed in previous works. In NGC 3411, we detect extended radio emission surrounding the central AGN over scales of ~70 kpc, and resolve previously undetected arc-shaped substructures on scales of ~20-30 kpc. This extended component exhibits a relatively uniform steep spectrum ($α$ ~ -1.7). We discuss possible scenarios for its origin, including mini-halos, aged AGN plasma, weak shocks, and the possibility of a RADIO GALAXy observed along the line of sight. In NGC 5903, MeerKAT reveals a complex filamentary morphology, including a previously unknown ring-like structure surrounding the central AGN. Spectral-index mapping shows localized flattening ($α$ ~ -0.9) along the north arc, while POLARIZATION data reveal ordered MAGNETic fields and a patchy rotation measure distribution across the source. Together with the disturbed X-ray morphology, these results support a scenario in which fossil AGN plasma has been redistributed and locally reenergized by group-scale dynamical processes such as turbulence, shear, and weak compression. Our results demonstrate that galaxy groups can host a rich variety of nonthermal phenomena, whose properties can only be fully revealed through the combination of sensitive, high-resolution, and multifrequency radio observations.
[abstract 2 / 42] Yes (score: 6) - Title: Constraining the white-dwarf mass in the intermediate polar IGR J17014-4306 using X-ray and optical spectroscopyAuthors: D. C. Souza, M. P. Diaz, A. S. Oliveira, G. J. M. Luna, C. V. Rodrigues, M. Reynolds, N. Palivanas, I. J. Lima, J. Mikołajewska, M. Orio,Comments:Subjects: astro-ph.HECreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Intermediate polars (IPs), a subclass of MAGNETic cataclysmic variables, often show discrepancies between white-dwarf (WD) mass measurements from X-ray spectral modeling and optical dynamical studies. We investigate the IP IGR J17014-4306. We performed a joint spectral analysis of NUSTAR observations combined with archival XMM-Newton and SWIFT data, modeling the broad-band X-ray spectrum with a multi-temperature cooling-flow model. Additionally, we obtained time-resolved optical spectroscopy with the SOAR telescope to measure the radial velocity of the donor star and constrain the system's orbital parameters. The X-ray spectral analysis reveals a very high post-shock plasma temperature of $kT_{\max}=50_{-8}^{+11}\,\mathrm{keV}$, corresponding to a WD mass of $M_{\mathrm{WD}}=0.94_{-0.07}^{+0.09}\,M_\odot$. We also fitted the NUSTAR spectrum above 10 keV with the ipolar30KK model, obtaining $M_{\mathrm{WD}}=0.88_{-0.12}^{+0.14}\,M_\odot$. Our optical spectroscopy yields a radial-velocity semi-amplitude for the companion star of $K_2=165\pm4\,\mathrm{km\,s^{-1}}$ and an optical mass function of $f(M)=0.249\pm0.018\,M_\odot$. Combined with the eclipse geometry and the WD mass estimate from the X-ray models, these results favor a high mass ratio, $0.76\lesssim q\lesssim0.95$, and a donor-star mass of approximately $0.67\lesssim M_2/M_\odot\lesssim0.89$. In the limiting case of $q=1$, the WD mass has an upper limit of $1.14\,M_\odot$. Together with the X-ray measurements, this indicates a relatively massive WD. The lack of an independent measurement of the WD dynamical mass leaves it unclear whether the dynamical mass is consistent with the X-ray measurements or whether the X-ray mass is underestimated, as has been found for other IPs. Thus, our constraints make IGR J17014-4306 an important system for improving our understanding of IPs.
[abstract 3 / 42] Yes (score: 5) - Title: A unified modeling of X-ray and gamma-ray spectro-polarimetric data: the case of Cygnus X-1Authors: Tristan Bouchet, Thomas Siegert, Victoria Grinberg, Jérôme Rodriguez, Floriane Cangemi, Philippe Laurent, Joern Wilms,Comments: 13 pages plus appendix. Accepted for publication in A&ASubjects: astro-ph.HECreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Recent X-ray and soft gamma-ray spectro-polarimetric observations of BLACK HOLE X-ray binaries, such as Cygnus X-1, reveal discrepancies that challenge current models of accretion and high-energy emission. We present a general framework for broadband spectro-polarimetric modeling that simultaneously fits spectral and POLARIZATION data from independent instruments across different energy bands. The method robustly combines measurements with different energy binning and statistical significance while accounting for energy-dependent POLARIZATION mixing between model components. Applied to Cygnus X-1 over the 2 keV-2 MeV range, it provides an improved characterization of the soft gamma-ray hard-tail and constrains the optically thin SYNCHROTRON cutoff energy to $(2.8^{+0.6}_{-0.8}) \times 10^{2}$ keV. We discuss the implications for non-thermal electron acceleration in the context of Bohm diffusion and SYNCHROTRON cooling, and propose a new explanation for the observed POLARIZATION misalignment based on MAGNETic field helicity and Doppler boosting. The framework is broadly applicable to multi-instrument spectro-polarimetric analyses.
[abstract 4 / 42] Yes (score: 5) - Title: Characterizing Gravitational Wave ElectroMAGNETic Counterparts with the Schmidt Observatory SystemAuthors: Keerthi Kunnumkai, Antonella Palmese, Thomas Wevers, Mattia Bulla, Suvi Gezari, Saul Perlmutter, Liliana Rivera Sandoval, Gudmundur Stefansson, Mickael Rigault, Arpita Roy,Comments:Subjects: astro-ph.HECreated: 2026-11-03; Updated: 2026-11-05; Datestamp: 2026-11-05
The emergence of gravitational wave (GW) multimessenger astronomy, marked by the detection of GW170817 and its associated kilonova, has opened a new window into the physics of compact binary mergers. Building a statistical population of kilonovae remains a challenge, limited by the low neutron star merger detection rates and the rapid evolution of these faint transients. The former problem will be overcome with upcoming LIGO/Virgo/KAGRA (LVK) sensitivity improvements leading to the fifth Observing Run (O5), while the latter will be addressed by the Schmidt Observatory System (including the Argus Array, the Deep Synoptic Array (DSA), and the Lazuli Space Observatory), in addition to ongoing and upcoming surveys (including the Rubin Observatory Legacy Survey of Space and Time). Using simulations of expected kilonovae at LVK O5 sensitivity, we find that Argus and Rubin could detect binary neutron star kilonovae at a rate of 0.3-4.2 yr$^{-1}$ and 0.6-7.0 yr$^{-1}$ respectively. For neutron star-BLACK HOLE mergers, Rubin could detect up to 1 kilonova per year. Lazuli will be able to characterize this kilonova population down to $g \sim 26$ mag as early as 12 hours post merger. Additionally, $\sim35\%$ of these events are expected to exhibit a JET afterglow that will be detectable by DSA. We further characterize kilonova spectra to determine observable features of heavy element production. Finally, we develop an observing strategy that combines high cadence imaging and spectral monitoring, maximizing Lazuli's ability to constrain ejecta properties and composition of GW counterparts with reasonable observing time.
[abstract 5 / 42] Yes (score: 5) - Title: ReveaLLAGN 2: Exploring the Nuclear Gas and Stellar Kinematics of Nearby LLAGNs with JWST/NIRSpec IFUAuthors: Antoine Dumont, Nadine Neumayer, Anil C. Seth, Torsten Böker, Jonelle L. Walsh, Micheal Eracleous, Luis C. Ho, Kameron Goold, David Ohlson, Timothy A. Davis,Comments: Accepted for publication in Astronomy & AstrophysicsSubjects: astro-ph.GACreated: 2026-11-03; Updated: 2026-11-05; Datestamp: 2026-11-05
Low-luminosity ACTIVE GALACTIC NUCLEi (LLAGN) represent the most common mode of BLACK HOLE accretion in the local Universe, yet their nuclear structure, stellar and gas kinematics remain poorly constrained at parsec scales. We investigate the nuclear regions of eight nearby representative LLAGN, the ReveaLLAGN sample: M87, M104, M94, M81, NGC1052, NGC4258, NGC5128 and NGC4395. Using JWST/NIRSpec data, we probe the stellar, molecular hydrogen, hydrogen recombination, and high ionisation coronal lines kinematics and their spatial distribution, exploring how detectability and spatial distributions of these lines vary across different Eddington ratios. The stellar LOSV maps reveal a slowly rotating disk in the nuclei of all our targets, characterised by an anti-correlation with the h3 Gauss-Hermite moment. Across the sample, the stellar velocity dispersion rises toward the central BLACK HOLE. Only in M104 and M94 does the velocity dispersion display a more intricate pattern that departs from a simple disk configuration, indicating the presence of multiple kinematic components in these galaxies. Across the sample, the gas distribution and kinematics exhibit rotation that is frequently decoupled from the stellar rotation, suggesting that the stellar gravitational potential is decoupled from the current accretion state. The gas kinematics are often visually aligned with the radio JET, presenting broader velocity dispersions along the JET direction. Line-ratio maps indicate that the dominant excitation mechanism is photoionisation by the central AGN, with mechanical heating from shocks becoming important only at higher Eddington ratios. Across the sample, we detect coronal lines in all LLAGN when using nuclear-aperture spectra, and we can obtain spatially resolved kinematics only in NGC5128 and NGC4395, the highest Eddington ratio sources.
[abstract 6 / 42] Yes (score: 5) - Title: Can Magnetic Reconnection Accelerate Energetic Particles in the Heliosheath?Authors: Jeongbhin Seo, Teresa Boland, Fan Guo, Xiaocan Li, Giulia Murtas,Comments: 16 pages, 6 figures, Accepted for The Astrophysical JournalSubjects: astro-ph.HE astro-ph.SRCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
The mechanism for accelerating energetic particles in the outer heliosphere is still under debate. The termination shock, turbulence, and MAGNETic RECONNECTion have all been proposed as viable mechanisms. We investigate compression-driven particle acceleration during MAGNETic RECONNECTion in the heliospheric current sheet using the MHD--SDE framework that incorporates energetic-particle feedback into the MHD evolution. For the heliosheath conditions considered here, we find that RECONNECTion-driven acceleration is inefficient downstream of the termination shock, whereas RECONNECTion near the heliopause can generate stronger compression and produce a power-law differential intensity spectrum $J(\varepsilon)\propto\varepsilon^{-5.4}$. However, even the hardest spectrum achieved during MAGNETic RECONNECTion remains much steeper than the typical $J(\varepsilon)\propto\varepsilon^{-1.5}$ spectrum observed in the heliosheath. This indicates that MAGNETic RECONNECTion alone is insufficient to explain the acceleration of energetic particles in the heliosheath.
[abstract 7 / 42] Yes (score: 4) - Title: Investigating the Circumnuclear Medium of Tidal Disruption Events with Radio ObservationsAuthors: Chang Zhou, Wei-Hua Lei, Xiangli Lei, Po Ma, Shao-Yu Fu, Zi-Pei Zhu,Comments: 27 Pages, 8 figuresSubjects: astro-ph.HECreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Tidal disruption events (TDEs) are unique tools for investigating quiescent supermassive BLACK HOLE (SMBH), accretion physics, and circumnuclear medium (CNM) environments. The CNM density profile is of great astrophysical significance, since it provides key diagnostics for the accretion history of dormant SMBH. TDEs can launch outflows that produce radio emission when propagating into the CNM. The SYNCHROTRON radio flux density can be described by a series of power-law segments $F_ν\propto t^{-α} ν^{-β}$. The closure relation (CR), i.e., the relation between the temporal indices $α$ and the spectral indices $β$, are therefore monitoring the CNM density profile. In this work, we first collect 53 TDEs with radio observations to date. We then obtain the predicted CR for arbitrary CNM and different dynamical phases of the outflow, and apply to the radio TDE sample. We constrain the CNM density profile for 26 radio TDEs with good data quality. The results are generally consistent with those estimated with equipatition method, suggesting that CR analysis is efficient in the study of CNM profile for a quiescent SMBH.
[abstract 8 / 42] Yes (score: 4) - Title: Accretion-powered flares from BLACK HOLE-disk collisions in galactic nucleiAuthors: Joaquin Pelle, Kyohei Kawaguchi, Masaru Shibata, Alan Tsz-Lok Lam,Comments: 9 figures. Accepted for publication in MNRASSubjects: astro-ph.HE gr-qcCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Black hole impacts on accretion discs in galactic nuclei can power luminous transients, but predicting their observable signatures is challenging because the post-collision flow is highly time-dependent and inhomogeneous. We present a radiative post-processing framework for RELATIVISTIC hydrodynamics simulations of BLACK HOLE-disc collisions. Using physically motivated prescriptions for shock heating, optical depth via an eikonal solver, and photon escape fractions that account for photon trapping and diffusion, we predict light curves and spectral energy distributions over a range of disc densities and collision velocities. Our results indicate that the emission is dominated by the long-lived accretion flow onto the secondary BLACK HOLE, whose mass supply is highly super-Eddington, rather than by cooling of the unbound ejecta. In the parameter range explored, the luminosity is typically of the order of the Eddington luminosity of the secondary and can reach several times this value, and the emission is generically dominated by soft X-rays. We find that lower velocity collisions produce brighter flares, while the disc surface density mainly controls spectral evolution: low-density discs typically produce $\sim$keV-peaked flares with weak spectral evolution, whereas high-density discs show softer early emission and late-time hardening. A depletion-time estimate calibrated to our results suggests characteristic durations of hours to days for intermediate-mass secondaries, and yields $t_{\rm flare} \propto P_{\rm QPE}$. We discuss implications for QPE-like transients and for the SMBH-binary candidate OJ 287. Our framework does not include radiative feedback on the gas, therefore the luminosities should be interpreted only as baseline estimates of the available power for radiation.
[abstract 9 / 42] 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: 19 pages, 12 figures, first revisionSubjects: physics.plasm-phCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Tokamak disruptions may lead to the acceleration of some electrons 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. In this work, an energy and momentum conserving knock-on collision operator is implemented in the 3D nonlinear MHD code JOREK for the full-f RELATIVISTIC hybrid fluid-kinetic model that describes the REs using the particle-in-cell (PiC) approach both for full-orbit and drift-kinetic markers, which will enable accurate modeling of the RE phase-space dynamics in realistic 3D electroMAGNETic fields. Such a self-consistent treatment of the RE avalanche and competing losses in the stochastic fields of MHD-active plasmas is required to further the understanding of RE transport and phase-space dynamics in self-consistent interaction with the 3D plasma evolution, which is needed for developing reliable predictions as well as reliable mitigation methods. 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 10 / 42] Yes (score: 4) - Title: Correlated Signatures of Plasma Lensing in Fast Radio BurstsAuthors: Paz Beniamini, Pawan Kumar,Comments: Accepted for publication in ApJSubjects: astro-ph.HECreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Plasma lensing has been proposed to explain narrow spectra, multiple burst copies, frequency drifts, interference fringes, and POLARIZATION changes in fast radio bursts (FRBs). Because many of these features are not unique to lensing, a convincing identification requires several correlated observables to be reproduced by one lens model. We derive such relations for a one-dimensional Gaussian plasma lens near a fold caustic. We distinguish the phase separation of the merging images from their observable group-delay difference and identify three regimes: resolved burst copies, overlapping images with negligible mutual coherence, and coherent spectral interference. We connect the magnification, image delay, spectral-envelope width, fringe spacing, differential dispersion, time-frequency caustic curvature, and the brightness and ordering of the third image. We derive separate finite-source constraints from large fold magnification and from fringe visibility, and relate the wave-optics magnification scale to the plasma column of the lens. High-contrast fringes simultaneously constrain the source size and the mutual coherence of the two image fields, which constrains the intrinsic coherence of the FRB radiation once the observed spectrum and instrumental bandpass are accounted for. We also derive the conditions for differential Faraday rotation in MAGNETized lenses. Finally, we show that clean lensing by a volume-filling turbulent screen requires fine tuning between rare strong fluctuations and caustic confusion, suggesting that sparse sheets, filaments, interfaces, or shocked clumps are more promising lensing structures.
[abstract 11 / 42] Yes (score: 4) - Title: Insights on the mass composition of ultrahigh-energy COSMIC RAYs from small-scale anisotropy with large-scale structure simulationsAuthors: Ryo Higuchi, Eiji Kido, Shigehiro Nagataki,Comments:Subjects: astro-ph.HECreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Ultra-high-energy COSMIC RAYs (UHECRs) above 100 EeV provide important clues to the most energetic processes in the Universe. At the highest energies, it is expected that UHECRs originate only from nearby sources because of energy losses during propagation. In such a regime, small-scale anisotropies in arrival directions could appear if the MAGNETic deflections are sufficiently small, for example, for a limited fraction of UHECRs with relatively low electric charge. Using the Pierre Auger Observatory open data, we confirm there is no significant small-scale anisotropy above 100 EeV within 3 degrees, indicating an almost isotropic sky distribution. To interpret this, we consider that heavier nuclei have higher photodisintegration thresholds due to their smaller Lorentz factors, resulting in longer propagation lengths. Combination with the nearly homogeneous distribution of galaxies at such distances can explain the absence of anisotropies above 100 EeV. Based on this idea, we perform mock observations of UHECRs above 100 EeV assuming pure-proton, iron, and uranium compositions. We predict the expected UHECR distributions using the Millennium Run semi-analytic galaxy catalog and turbulent extragalactic MAGNETic fields. By varying the source density and MAGNETic field strength, we evaluate the anisotropy for each case. Without MAGNETic fields, the observed isotropy above 100 EeV excludes the pure-proton and pure-iron cases. The pure-uranium case can reproduce the observed isotropy when the source density is high and the MAGNETic field is turbulent. When the turbulent field is strong, both the iron and uranium cases remain consistent with the data, whereas almost no parameter set can explain the observation for a pure-proton composition. Our results constrain the possible combinations of source density and MAGNETic field strength across different UHECR compositions.
[abstract 12 / 42] Yes (score: 4) - Title: The kinematic Kelvin-Helmholtz instability-driven dynamo: implications for merging compact objectsAuthors: James R. Beattie, Amitava Bhattacharjee, Elias R. Most, Bart Ripperda, Alexander Philippov, Ralf S. Klessen, Salvatore Cielo,Comments: 6 pages, 5 figures main text. 10 pages supplemental materials. 8k VR visualization here: https://youtu.be/t-6yRoGyFhk. Submitted. Comments welcomeSubjects: astro-ph.HE astro-ph.GA astro-ph.SR physics.flu-dynCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Binary neutron star (BNS) mergers excite a Kelvin--Helmholtz instability (KHI) in the shear layer between them. It is parasitized upon by the MAGNETic field to form a powerful MAGNETic dynamo. Using a large ensemble of high-resolution visco-resistive KHI-driven dynamo simulations we construct analytical, asymptotic in Reynolds number ($\rm{Re}$) models for the MAGNETic field growth rates and mean vertical field dynamo onset times. Our models suggest that in the $\rm{Re} \gg 1$ limit, the mean vertical field is seeded immediately, kinematic growth rates become asymptotic in $\rm{Re}$, and the dynamo moves out of the kinematic stage on $\mathcal{O}(0.1\,\rm{ms})$ timescales, readily attaining MAGNETar-strength fields during this transition. This suggests that most global BNS merger simulations are not time-resolving the correct KHI-driven dynamo regime.
[abstract 13 / 42] Yes (score: 4) - Title: Tiny Quiet-Sun EUV Ejections Revealed by High-resolution Multiwavelength ObservationsAuthors: Nengyi Huang, Yuqian Wei, Qin Li, Jeongwoo Lee, Haimin Wang,Comments:Subjects: astro-ph.SRCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
We investigate two successive tiny quiet-Sun EUV ejections on 2022 October 29 using coordinated Solar Orbiter/EUI, IRIS, SDO/AIA, and Goode Solar Telescope observations. We examine their low-lying geometry and the chromospheric and transition-region response before and between the releases. A curved H-alpha thread is present beforehand, and Mg ii and Si iv spectra reveal a compact multithermal precursor 2.6--2.7 min before the first EUV brightening. EUI--AIA stereoscopy places the recurrent compact EUV kernel near 2.2 Mm and the sampled emission at approximately 0.6--4.2 Mm along inclined, locally arched structures. The first ejection shows multithreaded, helical-looking EUV strands; the second shows straighter strands and a decrease in the cross-ridge separation of redshifted and blueshifted Mg ii k3 samples from 1.47'' to 0.89''. Nevertheless, the two peaks have comparable emission-measure increments and estimated event-associated thermal contents of a few 10^26 erg under the same assumptions. Before the second ejection, the regional Si iv and k3 blueshift signals remain enhanced, while the Mg ii central reversal along the activated ridge remains shallower than before the event. Component RECONNECTion between the curved structure and the surrounding field offers a possible explanation. The observations show that JET-like EUV emission can occur in low-lying structures. The second ejection begins before the chromospheric and transition-region spectra have returned to their pre-event states. Its spectral signatures may therefore depend on the atmospheric changes associated with the first ejection as well as on the additional energy input.
[abstract 14 / 42] (score: 3) - Title: A new era for Dual AGN science with SHARPAuthors: P. Severgnini, C. Vignali, A. De Rosa, E. Portaluri, F. Rigamonti, L. Battistini, L. Bertassi, E. Bertola, S. Bianchi, E. Bortolas, C. Cicone, Q. D'Amato, R. Della Ceca, I. Delvecchio, M. Dotti, J. Harms, I. Lamperti, F. Mannucci, M. Parvatikar, B. Sala, M. Scialpi, R. Serafinelli, J. Singh, M. V. Zanchettin,Comments: 8 pages, 2 figures, Published in the New Astronomy Special issue: SHARP science bookSubjects: astro-ph.GACreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
The search for and the characterization of ultra-compact dual ACTIVE GALACTIC NUCLEi (AGN) are among the hottest topics of current extragalactic astrophysics. These systems involve two accreting massive BLACK HOLEs (MBHs) embedded within the same host galaxy, with relative projected separations from a few hundred pc down to a few pc. They are central to understanding hierarchical galaxy formation, BLACK HOLE growth and demographics, and accretion-feedback coupling in the most extreme interaction phases. Even more compellingly, such tight pairs are the most direct precursors of gravitationally bound binary MBHs (sub-pc scale separation), which are among the loudest emitters of gravitational waves (GWs) in the low-frequency ranges. SHARP will deliver the first statistical census and physical characterization of ultra-compact dual AGN up to cosmic distances, finally bridging the observational gap between kpc-scale pairs and sub-pc GW-emitting binaries, and enabling a breakthrough understanding of MBH growth, feedback and co-evolution across cosmic time.
[abstract 15 / 42] (score: 3) - Title: A high-frequency turnover in the persistent radio source of FRB20201124AAuthors: G. Bruni, G. Gianfagna, L. Piro, A. L. Thakur, L. Nicastro, E. Palazzi, A. Rossi, S. Savaglio, A. Gardini, Y. -P. Yang, B. Zhang,Comments: Submitted to A&A LettersSubjects: astro-ph.HE astro-ph.SRCreated: 2026-11-03; Updated: 2026-11-05; Datestamp: 2026-11-05
Persistent radio sources (PRSs) associated with repeating fast radio bursts probe the immediate MAGNETo-ionic environment of their engine and thereby constrain the nature and evolutionary stage of the progenitor. The persistent radio source of FRB20201124A is the most extreme in the current sample, with a spectrum that remains flat or inverted up to 22 GHz. We aim to constrain the centimetre-to-millimetre spectral energy distribution of this source and to test whether its properties are consistent with a young, rotation-powered MAGNETar wind nebula. We analysed archival ALMA Band 3 observations at $\sim100$ GHz and combined them with existing VLA measurements at 6, 15 and 22 GHz. The resulting spectrum was fitted with the Granot--Sari broken power law in the slow-cooling regime using Bayesian nested sampling. The two-parameter model yields a peak frequency $ν_m = 63^{+100}_{-33}$ GHz and a peak flux $F_m = 28\pm9$ $μ$Jy. This solution is consistent with theoretical expectations for a young MAGNETar wind nebula, which predict a peak frequency in the same range and a self-absorption frequency below $\sim0.5$ GHz. With its inverted spectrum extending to tens of gigahertz and the highest peak frequency among known PRSs, the source associated with FRB20201124A is the most extreme in the current sample. Its properties match those expected for a rotation-powered MAGNETar wind nebula, making it a strong candidate for the youngest ($t\lesssim20$ yr) MAGNETar associated with a repeating FRB to date.
[abstract 16 / 42] (score: 3) - Title: Frequent Optical Flares in an M-type Detached Eclipsing Binary TIC 349005337Authors: Xiao Zhou, Liying Zhu, Wei Hu, Gil Nachmani, Jia Zhang, Mikhail Yu. Kovalev, Ergang Zhao,Comments: 20 pages, 11 figures, 9 tables; accepted by ApJSubjects: astro-ph.SRCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
A comprehensive photometric and spectroscopic analysis of TIC 349005337, a highly active M-type detached eclipsing binary with an orbital period of 2.6079133 days, is presented utilizing high-cadence and long-term monitoring photometry from the Transiting Exoplanet Survey Satellite (TESS) and medium-resolution spectroscopy from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). By integrating radial velocity curves with light curves, we determined the fundamental physical parameters for both components. The system consists of an M-dwarf primary ($M_1 = 0.517 \pm 0.009 M_\odot$, $R_1 = 0.518 \pm 0.003 R_\odot$) and a fully convective secondary ($M_2 = 0.298 \pm 0.004 M_\odot$, $R_2 = 0.357 \pm 0.003 R_\odot$). A total of 12 high-energy stellar flares, with the most energetic event reaching $3.87 \times 10^{34}$ erg, is identified, confirming the system is in a state of MAGNETic hyper-activity. The frequent superflares suggest that intense MAGNETic activity and significant starspot coverage play a dominant role in altering the stellar atmospheric structure. As the secondary component falls below the fully convective boundary, these energetic flares provide critical empirical constraints for distributed dynamo models in the low-mass regime. Our results highlight TIC 349005337 as an ideal laboratory for investigating the interplay between binary dynamics, MAGNETic RECONNECTion, and the resulting impact on the atmospheric stability of potential orbiting exoplanets.
[abstract 17 / 42] (score: 3) - Title: Optical linear POLARIZATION of the Be--X-ray pulsar binary LS V +44 17Authors: Anagha P. Nitindala, Andrei V. Berdyugin, Alexandra Veledina, Sergey S. Tsygankov, Vadim Kravtsov, Maria Alejandra Diaz Teodori, Vilppu Piirola, Takeshi Sakanoi, Masato Kagitani, Svetlana V. Berdyugina, Juri Poutanen,Comments: Accepted for publication in A&ASubjects: astro-ph.HE astro-ph.SRCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
We present the optical $BVR$ POLARIZATION measurements for the Be--X-ray pulsar binary LS V +44 17 from its giant outburst in early 2023 and subsequently over three years. We detect a significant POLARIZATION of about $\approx1.1$--$2.1\%$, which includes the interstellar contribution. Polarization evolves significantly with time since the outburst. The interstellar POLARIZATION was found to be $\approx2.5$--$2.9\%$. The obtained intrinsic optical POLARIZATION of LS V +44 17 after correction is between $0.5$--$1.7\%$, perpendicular to the interstellar POLARIZATION direction. We consider various plausible sources of optical POLARIZATION and infer scattering in the Be decretion disk to be the most dominant source based on time and spectral evolution. Changing intrinsic PA with time hints at a plausible precession of the Be disk.
[abstract 18 / 42] (score: 2) - Title: Numerical Study of Jet-Like Outwash from Multi-Rotor eVTOLs and Strategies for Flow MitigationAuthors: Yen-Chen Chen, Chih-Che Chueh,Comments: 29 pages, 11 figures, 1 tableSubjects: physics.flu-dynCreated: 2026-11-03; Updated: 2026-11-05; Datestamp: 2026-11-05
This study presents a comprehensive computational investigation of outwash phenomena generated by electric vertical takeoff and landing (eVTOL) aircraft, with particular emphasis on how rotor geometry and alignment shape hazardous airflow patterns at vertiports. Using nondimensional Reynolds-averaged Navier-Stokes (RANS) simulations with the k-omega SST turbulence model implemented in OpenFOAM, the research systematically characterizes JET-like outwash across a range of multi-rotor configurations. Results demonstrate that propeller count and inter-propeller spacing are primary determinants of outwash intensity, orientation, propagation range, and boundary-layer structure. For power-lift eVTOLs, low propeller counts combined with narrow spacing produce highly directional, intensified JET-like outwash with propagation ranges far exceeding current FAA EB105a safety standards. Conversely, higher propeller counts and larger spacings reduce peak velocities and propagation distances, enabling safer and more compact vertiport layouts. High-propeller-count designs further exhibit vertically stratified and thickened outwash boundary layers, requiring tailored mitigation strategies. Targeted engineering solutions-such as modular blast deflectors aligned with predicted outwash directions-are shown to reduce required vertiport safety areas by up to 82% without compromising operational safety. These findings establish a direct link between aircraft design, regulatory compliance, and infrastructure optimization, offering practical pathways for safe and scalable urban air mobility. The study also provides a foundation for future research on optimal mitigation device geometries and system-level integration of eVTOL operations within urban environments.
[abstract 19 / 42] (score: 2) - Title: Hydroacoustic Attenuation and Amplification by TurbulenceAuthors: Kai-Xin Hu, Yue-Jin Hu,Comments:Subjects: physics.flu-dynCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Acoustic waves propagating through fluid media are significantly influenced by turbulence. This paper experimentally investigates the influence of water turbulence on the propagation characteristics of acoustic waves. It shows that acoustic waves can be obviously attenuated or amplified at frequencies far exceeding the turbulent fluctuation frequency, with no spectral broadening. The amplification factor depends on the wave frequency rather than its amplitude. The study covers two flow conditions: pipe flow and free JET, driven by either a pump or hydraulic head difference, while the wave propagation directions both parallel and perpendicular to the mean flow are considered.Turbulent fluctuations without mean motion can still alter the wave amplitude, while laminar flow has no effect on acoustic signals. Comparison with conventional theories and experiments indicates that mechanisms such as bubbles, resonance, scattering, multipath interference or viscous dissipation cannot explain the observed phenomena. This indicates that there exists an incompletely understood new mechanism in the interaction between turbulence and acoustic waves.
[abstract 20 / 42] (score: 2) - Title: Analysis and simulations of droplet generation regimes in a coaxial microfluidic deviceAuthors: Alessio Innocenti, Andrea Poggi, Simone Camarri, Maria Vittoria Salvetti,Comments: 35 pages. Accepted versionSubjects: physics.flu-dynCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
The generation of microdroplets via segmentation in microfluidic devices is of interest in many applications, from biochemical to pharmaceutical. This technique permits indeed much higher control on the droplet size, uniformity and generation rate than in standard batch generation processes. In this work we have evaluated the suitability of the open-source software Basilisk to accurately predict microdroplet generation by segmentation. We have validated the numerical tool with analytical solutions for the dynamics of droplets in confined flows, namely with Bretherton theory, and by comparison with literature experimental results. We have then performed several campaigns of numerical simulations for a coaxial device, analyzing the different regimes of droplet generation, and evaluating how the physical and flow parameters affect the production mechanisms and {the diameters of the generated droplets}. Finally we have proposed new scaling laws for the prediction of droplet diameters in the dripping and JETting regimes, refining existing ones by taking into account additional physical effects, like the viscosity ratio.
[abstract 21 / 42] (score: 2) - Title: Inside the cocoon: a comprehensive explanation of the spectra of Little Red DotsAuthors: A. Sneppen, D. Watson, J. H. Matthews, G. Nikopoulos, N. Allen, G. Brammer, R. Damgaard, K. E. Heintz, C. Knigge, K. S. Long, V. Rusakov, S. A. Sim, J. Witstok,Comments: 24 pages, 23 figures, 3 tables. Accepted to A&ASubjects: astro-ph.GA astro-ph.HECreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
The James Webb Space Telescope (JWST) has revealed a new population of compact galaxies, the `little red dots' (LRDs), whose nature remains unclear. We assemble grating spectra for 53 LRD-like objects and use self-consistent radiative-transfer calculations to show that a supermassive BLACK HOLE embedded in a dense gas cocoon reproduces the spectra in detail, without requiring a stellar-like photosphere. The near-symmetric, electron-scattering-broadened emission line-shapes can be reproduced by cocoons with comparable inflowing and outflowing mass-fluxes. The same cocoon structure also simultaneously accounts for the continuum shapes, H and He line equivalent widths, and absorption features, and predicts metal-line absorption, X-ray weakness, and muted variability. We predict correlations should exist between Balmer break strength, Balmer line absorption, and scattering line width, and confirm their presence in the observed sample. Typical LRDs have BLACK HOLEs of order $10^{6}$ $\mathrm{M}_\odot$ inside ionised cocoons of tens of $\mathrm{M}_\odot$, likely fed by a much larger cold-gas reservoir.
[abstract 22 / 42] (score: 2) - Title: Accurate waveforms for generic planar-orbit binary BLACK HOLEs: The multipolar effective-one-body model SEOBNRv6EHMAuthors: Aldo Gamboa, Alessandra Buonanno, Lorenzo Pompili, Raffi Enficiaud, Michael Boyle, Lawrence E. Kidder, Oliver Long, Peter James Nee, Harald P. Pfeiffer, Antoni Ramos-Buades, Mark A. Scheel,Comments: 66 pages, 23 figures; v2: matches version accepted at PRDSubjects: gr-qc astro-ph.HECreated: 2026-11-03; Updated: 2026-11-05; Datestamp: 2026-11-05
Accurate and computationally efficient waveform models are required to infer the parameters of compact binaries from their gravitational wave (GW) emission. Among these parameters, orbital eccentricity serves as a smoking gun for dynamical formation channels and must be accounted for to avoid systematic errors in GW analyses. Here, we present SEOBNRv6EHM, a time-domain, multipolar waveform model for binaries on generic planar orbits, calibrated to quasi-circular (QC) numerical-relativity (NR) simulations from the SXS collaboration. In addition to the dominant $(2,2)$ mode, the model provides the $(2,1)$, $(3,3)$, $(3,2)$, $(4,4)$, and $(4,3)$ multipoles for the full inspiral-merger-ringdown process of coalescing binaries, as well as for dynamical captures and scattering encounters. The model is built within the effective-one-body (EOB) framework, and it employs novel resummations of the radiation-reaction force and waveform modes. We validate its accuracy through comparisons against 592 QC, 319 eccentric, one dynamical-capture, and two scattering SXS NR waveforms, and through scattering-angle comparisons against 61 SXS NR simulations. For QC and small-eccentricity binaries, its accuracy is comparable to previous-generation SEOBNRv5 models. For highly eccentric systems, however, SEOBNRv6EHM attains unprecedented accuracy, with waveform mismatches remaining below or close to $ 2\% $ across the total mass range $ 20-200\, \mathrm{M}_\odot $ for eccentricities up to $\sim 0.9$ at 14 periastron passages before merger. Additionally, SEOBNRv6EHM achieves waveform-generation walltimes that are $ 2 - 8 $ times faster than other state-of-the-art EOB eccentric models, enabling efficient and accurate applications in GW astronomy.
[abstract 23 / 42] (score: 2) - Title: MusE GAs FLOw and Wind (MEGAFLOW) XIV: Background-Galaxy Absorption Reveals Kiloparsec-Scale Structure in the Cool Circumgalactic MediumAuthors: Yucheng Guo, Nicolas F. Bouché, Martin Wendt, Timothy Heckman, Joop Schaye, Sanchayeeta Borthakur, Johannes Zabl, Maxime Cherrey, Sowgat Muzahid, Ismael Pessa, Ramona Augustin, Daria Kozlova,Comments: Accepted for publication in A&ASubjects: astro-ph.GACreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
The properties of the cool ($T\sim10^4$~K) gas in the circumgalactic medium (CGM) are closely linked to the physical mechanisms that create and maintain this multiphase medium. The cool CGM is thought to consist of discrete clouds, whose characteristic size is unknown. Here we present a geometric and direct approach to constrain the coherence scale of these cool structures using stacked MgII absorption lines measured against extended background galaxies and effectively point-like background QUASARs, whose sizes are a few kpc and $\lesssim 0.01$pc, respectively. When the background-source size is smaller than the coherence scale of the foreground clouds, incomplete covering lowers the detection fraction and causes the median stacked absorption to differ from the mean. For stacked MgII absorption against background galaxies, the mean and median equivalent width (EW) profiles are broadly consistent. For stacked MgII absorption against background QUASARs, by contrast, the median and mean EW profiles differ significantly, reaching a $\approx10σ$ difference beyond 100 kpc. Furthermore, we find that the median and mean EW profiles are broadly consistent for large background galaxies (median half-light radius $\approx 6.6$ kpc), but differ at the $\approx3σ$ level for small background galaxies ($\approx 1.5$ kpc). This suggests that the MgII-bearing gas has an effective transverse coherence scale of order a few kiloparsecs, broadly consistent with the $\sim$2--7 kpc range probed by the background galaxies. Using a toy model in which the CGM is populated with discrete cool clouds, we show that the observed differences arise naturally from the combination of partial covering and beam averaging. Our results provide a new geometry-based measure of the small-scale structure of cool CGM gas.
[abstract 24 / 42] (score: 2) - Title: IceCube Real-time Searches for High-energy Neutrinos Coincident with LIGO/Virgo/KAGRA Gravitational-Wave Alerts in O4aAuthors: The IceCube Collaboration, R. Abbasi, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, J. M. Alameddine, S. Ali, N. M. Amin, K. Andeen, C. Argüelles, Y. Ashida, S. Athanasiadou, S. N. Axani, R. Babu, X. Bai, A. Balagopal V., S. W. Barwick, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, P. Behrens, J. Beise, C. Bellenghi, S. Benkel, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. Böser, O. Botner, J. Böttcher, J. Braun, B. Brinson, Z. Brisson-Tsavoussis, L. Brusa, R. T. Burley, D. Butterfield, K. Carloni, J. Carpio, N. Chau, Y. C. Chen, Z. Chen, D. Chirkin, S. Choi, A. Chubarov, B. A. Clark, G. H. Collin, D. A. Coloma Borja, A. Connolly, J. M. Conrad, D. F. Cowen, C. De Clercq, J. J. DeLaunay, D. Delgado, T. Delmeulle, S. Deng, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, J. C. Díaz-Vélez, S. DiKerby, T. Ding, M. Dittmer, A. Domi, L. Draper, L. Dueser, D. Durnford, K. Dutta, M. A. DuVernois, T. Ehrhardt, L. Eidenschink, A. Eimer, C. Eldridge, P. Eller, E. Ellinger, D. Elsässer, R. Engel, H. Erpenbeck, W. Esmail, S. Eulig, J. Evans, P. A. Evenson, K. L. Fan, K. Fang, K. Farrag, A. R. Fazely, A. Fedynitch, N. Feigl, C. Finley, D. Fox, A. Franckowiak, S. Fukami, P. Fürst, J. Gallagher, E. Ganster, A. Garcia, M. Garcia, E. Genton, L. Gerhardt, A. Ghadimi, C. Glaser, T. Glüsenkamp, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, S. Griffin, K. M. Groth, D. Guevel, C. Günther, P. Gutjahr, C. Ha, A. Hallgren, L. Halve, F. Halzen, L. Hamacher, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. Häußler, K. Helbing, J. Hellrung, B. Henke, L. Hennig, F. Henningsen, L. Heuermann, R. Hewett, N. Heyer, S. Hickford, A. Hidvegi, C. Hill, G. C. Hill, R. Hmaid, K. D. Hoffman, A. Hollnagel, D. Hooper, S. Hori, K. Hoshina, M. Hostert, W. Hou, M. Hrywniak, T. Huber, K. Hultqvist, K. Hymon, A. Ishihara, W. Iwakiri, M. Jacquart, S. Jain, O. Janik, M. Jansson, M. Jin, N. Kamp, D. Kang, W. Kang, A. Kappes, L. Kardum, T. Karg, A. Karle, A. Katil, M. Kauer, J. L. Kelley, M. Khanal, A. Khatee Zathul, A. Kheirandish, T. Kim, H. Kimku, F. Kirchner, J. Kiryluk, C. Klein, S. R. Klein, Y. Kobayashi, S. Koch, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. Köpke, C. Kopper, D. J. Koskinen, P. Koundal, M. Kowalski, T. Kozynets, A. Kravka, N. Krieger, T. Krishnan, K. Kruiswijk, E. Krupczak, A. Kumar, E. Kun, N. Kurahashi, C. Lagunas Gualda, L. Lallement Arnaud, M. J. Larson, F. Lauber, J. P. Lazar, K. Leonard DeHolton, A. Leszczyńska, C. Li, J. Liao, C. Lin, Q. R. Liu, Y. T. Liu, M. Liubarska, C. Love, L. Lu, F. Lucarelli, W. Luszczak, Y. Lyu, M. Macdonald, E. Magnus, Y. Makino, E. Manao, S. Mancina, A. Mand, I. C. Mariş, S. Marka, Z. Marka, L. Marten, I. Martinez-Soler, R. Maruyama, J. Mauro, F. Mayhew, F. McNally, K. Meagher, A. Medina, M. Meier, Y. Merckx, L. Merten, J. Mitchell, L. Molchany, S. Mondal, T. Montaruli, R. W. Moore, Y. Morii, A. Mosbrugger, D. Mousadi, E. Moyaux, T. Mukherjee, M. Nakos, U. Naumann, L. Neste, M. Neumann, H. Niederhausen, M. U. Nisa, K. Noda, A. Noell, A. Novikov, A. Obertacke, V. O'Dell, A. Olivas, R. Orsoe, J. Osborn, E. O'Sullivan, B. Owens, V. Palusova, H. Pandya, A. Parenti, N. Park, V. Parrish, E. N. Paudel, L. Paul, C. Pérez de los Heros, T. Pernice, T. C. Petersen, J. Peterson, S. Pick, M. Plum, A. Pontén, V. Poojyam, B. Pries, R. Procter-Murphy, G. T. Przybylski, L. Pyras, C. Raab, J. Rack-Helleis, N. Rad, M. Ravn, K. Rawlins, Z. Rechav, A. Rehman, I. Reistroffer, E. Resconi, C. D. Rho, W. Rhode, L. Ricca, B. Riedel, A. Rifaie, E. J. Roberts, S. Rodan, M. J. Romfoe, M. Rongen, A. Rosted, C. Rott, T. Ruhe, L. Ruohan, D. Ryckbosch, J. Saffer, D. Salazar-Gallegos, P. Sampathkumar, A. Sandrock, G. Sanger-Johnson, M. Santander, S. Sarkar, M. Scarnera, M. Schaufel, H. Schieler, S. Schindler, L. Schlickmann, B. Schlüter, F. Schlüter, N. Schmeisser, T. Schmidt, A. Scholz, F. G. Schröder, S. Schwirn, S. Sclafani, D. Seckel, L. Seen, M. Seikh, S. Seunarine, P. A. Sevle Myhr, R. Shah, S. Shah, S. Shefali, N. Shimizu, M. Shin, B. Skrzypek, R. Snihur, J. Soedingrekso, D. Soldin, P. Soldin, G. Sommani, D. Song, C. Spannfellner, G. M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, T. Stezelberger, T. Stürwald, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, A. Thakuri, M. Thiesmeyer, W. G. Thompson, J. Thwaites, S. Tilav, K. Tollefson, J. A. Torres, S. Toscano, D. Tosi, K. Upshaw, A. Vaidyanathan, N. Valtonen-Mattila, J. Valverde, J. Vandenbroucke, T. Van Eeden, N. van Eijndhoven, L. Van Rootselaar, J. van Santen, J. Vara, F. Varsi, M. Velazquez, M. Venugopal, M. Vereecken, S. Vergara Carrasco, S. Verpoest, D. Veske, A. Vijai, J. Villarreal, C. Walck, A. Wang, E. H. S. Warrick, C. Weaver, P. Weigel, A. Weindl, J. Weldert, A. Y. Wen, C. Wendt, J. Werthebach, M. Weyrauch, N. Whitehorn, C. H. Wiebusch, D. R. Williams, L. Witthaus, G. Wrede, X. W. Xu, J. P. Yanez, Y. Yao, E. Yildizci, S. Yoshida, R. Young, F. Yu, S. Yu, T. Yuan, S. Yun-Cárcamo, A. Zander Jurowitzki, A. Zegarelli, A. Zhang, S. Zhang, Z. Zhang, P. Zhelnin, P. Zilberman, C. Zilleruelo Cañas,Comments:Subjects: astro-ph.HECreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Gravitational-wave events from mergers of compact objects are a predicted source of high-energy neutrinos. Using data from the IceCube Neutrino Observatory, we search for neutrinos coincident with 85 significant and 945 low-significance gravitational-wave candidate events from compact binary coalescences published in real-time by the LIGO-Virgo-KAGRA collaboration during the first part of its fourth observing run (O4a) and its preceding engineering run, within a time window of $\pm500$ seconds from the merger time. We report improvements to the online pipelines, including automatic sending of notices, which improved the median IceCube real-time response compared to the previous observing run by a factor of 2.7 times faster. In addition, we search for long-duration neutrino emission from three candidate events: two neutron star-BLACK HOLE mergers and one low-significance gravitational-wave event with a possible subthreshold gamma-ray counterpart. We use two methods, both of which have been previously used to search for neutrinos from gravitational-wave transients: an unbinned maximum likelihood analysis on significant alerts and a Bayesian analysis accounting for astrophysical priors on all alerts. We find no statistically significant emission from any individual gravitational-wave event analyzed. In the unbinned maximum likelihood search, the lowest $p$-value event is S231029y, with $p=0.0079$ ($0.752$ post-trials). In the Bayesian search, the lowest $p$-value for significant events is S230904n, with $p=0.0076$ ($0.9996$ post-trials), and for low-significance events is S231025a, with $p=0.0011$ ($0.678$ post-trials), with an overall population $p$-value of $0.55$. We accordingly set upper limits for each event on the time-integrated flux and energy emitted in neutrinos, assuming isotropic emission.
[abstract 25 / 42] (score: 2) - Title: Thermodynamic topology of MAGNETic GMGHS BLACK HOLEs: the $\overline {W}^{1-}$ subclassAuthors: Dejiang Yin, Qi-Qi Liang, Yu-Die Wan, Li-Yun Zhang,Comments: 11 pages, 3 figures; accepted version by EPJCSubjects: gr-qcCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Thermodynamic topology provides a topological classification of BLACK HOLE states and their branch structures in thermodynamic parameter space. We investigate the thermodynamic topology of the charged nonextremal MAGNETic Gibbons--Maeda family in four-dimensional asymptotically flat Einstein--Maxwell--dilaton gravity, with particular emphasis on its string-theory member at the dilaton coupling $a=1$, the Gibbons--Maeda--Garfinkle--Horowitz--Strominger (GMGHS) BLACK HOLE. An analytic classification over the complete domain of regular outer horizons shows that the dilaton coupling separates the family into three limiting structures of the inverse Hawking temperature. At $a=1$, the GMGHS defect curve approaches a nonzero lower inverse temperature endpoint and contains a single unstable branch. In particular, the MAGNETic GMGHS BLACK HOLE provides an explicit realization of the previously proposed $\overline W^{1-}$ thermodynamic topological subclass within an asymptotically flat Einstein--Maxwell--dilaton solution. This result demonstrates that the global topological number $W$ alone does not completely characterize BLACK HOLE thermodynamic topology. The asymptotic behavior of the inverse Hawking temperature near the boundaries of the physical horizon domain provides an additional criterion for distinguishing thermodynamic topological subclasses with the same $W$.
[abstract 26 / 42] (score: 2) - Title: Electroweak-Scale Cosmic Magnetism: Magnetogenesis, Baryogenesis, Phase Transitions and Gravitational WavesAuthors: Fayez Abu-Ajamieh,Comments: 110 pages, 5 figuresSubjects: hep-phCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Magnetic fields, the baryon asymmetry of the Universe, and stochastic gravitational waves provide complementary probes of physics in the early Universe. Near the electroweak scale, these phenomena are not necessarily independent. The electroweak anomaly allows hyperMAGNETic helicity to exchange charge with chiral fermions, sphalerons can change baryon and lepton number, and first-order phase transitions in extensions of the Standard Model can drive plasma motion, MAGNETogenesis, and gravitational waves. In this review, we explain these connections and examine the literature needed to make quantitative predictions. We begin with the properties of primordial MAGNETic fields and the electroweak plasma, then discuss the mechanisms that produce MAGNETic fields, the conversion between helicity and baryon number, MAGNETic backreaction, and the evolution of the field to the present day. We also review the observational constraints and recent developments, including gauge-invariant descriptions of MAGNETic flux through the crossover and RECONNECTion-controlled field evolution. Particular attention is given to the assumptions behind commonly used formulas and to the distinction between established results and model-dependent estimates. We argue that the most useful way forward is to predict the baryon abundance, present-day MAGNETic-field spectrum, and gravitational-wave signal from the same microscopic model, with consistent treatment of the intervening plasma dynamics.
[abstract 27 / 42] (score: 2) - Title: Unsupervised Neural Operators for Rotating Relativistic Stars: High-Fidelity Equation of State Inference and Pulsar Spin Evolution at ScaleAuthors: Anarya Ray,Comments:Subjects: astro-ph.HE cs.AI cs.LG gr-qcCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Observed populations of rotating neutron stars~(NSs) with millisecond-order periods are powerful probes of fundamental physics. Mass-radius measurements inform poorly constrained properties of degenerate nuclear matter, whereas high-fidelity population synthesis connects unknowns in NS formation and binary evolution to large radio-timing surveys. However, repeated structure calculations are prohibitive due to the computational cost of solving the highly coupled partial differential equations of axisymmetric general RELATIVISTIC hydrostatic equilibrium that govern rotating NS interiors. Non-rotating calculations or approximate rotational corrections can bias equation of state inference and limit the fidelity of population synthesis in tracing the evolutionary history of progenitors and propagating equation of state uncertainties. In this \textit{Letter}, we develop physics-informed neural operators that can solve the axisymmetric problem with high accuracy and negligible computational cost. \textit{Our solvers are trained in a fully unsupervised setting, with the training objective informed solely by the partial differential equations, and achieve a $10^3\times$ speed-up with negligible accuracy loss}. These solvers enable scalable EoS inference that self-consistently accounts for rotation and repeated stellar-structure calculations during binary evolution, making spin predictions that account for rotational structure and EoS uncertainties computationally accessible to population synthesis.
[abstract 28 / 42] (score: 2) - Title: A Laplace-Transform Green's Function for Two-Zone Diffusion with Energy Losses: Application to the Geminga Pulsar HaloAuthors: Furong Li, Wei Liu, Yali Shao, Yiqing Guo,Comments: 18 pages, 6 figuresSubjects: astro-ph.HECreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Extended TeV gamma-ray halos around pulsars are commonly interpreted as evidence for slow diffusion of high-energy electrons and positrons near their sources, with diffusion coefficients about two orders of magnitude below the Galactic average inferred from B/C measurements. A two-zone diffusion picture offers a natural phenomenological resolution: particles are temporarily confined in a slow-diffusion region around the source and subsequently propagate through the outer region with a diffusion coefficient close to the Galactic average. Using a Laplace-transform method, we derive an analytical Green's-function solution to the spherically symmetric two-zone diffusion equation, in which the diffusion coefficient changes discontinuously at r_b. The solution satisfies continuity of both the particle density and the diffusive flux at the boundary and reduces to the standard Gaussian kernel in the one-zone limit. For the parameter set used in our comparison, the spatial kernel and the positron flux at Earth agree numerically with an independent integral solution of the same two-zone problem. Applied to Geminga, the two-zone models examined here produce a more extended outer particle distribution and broader positron spectra than the homogeneous diffusion model, with higher positron fluxes in the TeV range. The adopted injection model further affects the height and shape of the high-energy spectral peak. The predicted gamma-ray surface-brightness profile also reproduces the main radial decline observed by HAWC.
[abstract 29 / 42] (score: 2) - Title: Spontaneous Enhancement of Inward Impurity Pinch during Massive Impurity Injection in Tokamak PlasmasAuthors: L. Zeng, W. Xia, D. Hu, T. Tang, X. Zhu, S. Zhao, T. Shi, D. Chen, Y. Duan, L. Xu, G. Li, G. Zuo, J. Hu, X. Gao, Y. Sun, Z. Gao,Comments:Subjects: physics.plasm-phCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
A spontaneous enhancement of inward impurity pinch is identified prior to the fast quench under massive impurity injection on the EAST tokamak. The transition is marked by a rapid shift of the MAGNETic-island rotation frequency toward the electron diaMAGNETic direction within a few hundred microseconds. An extended KDG model shows that the impurity-induced increase in bulk ion collisionality can drive a transition across banana regime, nonlinearly modifying the parallel viscosity and producing a radial electric field excursion of approximately -10 kV/m, consistent with experiment. The associated self-organized response of the plasma flow and electrostatic potential can modify the parallel friction and further strengthen the neoclassical inward impurity pinch. Projections for ITER disruption mitigation suggest that this mechanism is expected to enhance impurity penetration, thereby improving the overall effectiveness of mitigation.
[abstract 30 / 42] (score: 2) - Title: Shifts in Rossby wave regimes via the change of group velocity with zonal JETsAuthors: Zhixiang Li, Jianhua Lu, Yimin Liu, Tim Woollings,Comments: Submitted to npj Climate and Atmospheric ScienceSubjects: physics.ao-phCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Evidences show it is questionable to use the trends in Rossby wave phase speed (Cpx) to interpret the relation between the changes of extreme events and westerly JETs. We propose, by using 70 years (1954-2023) of ERA5 reanalysis, that the trends in extremes are associated with the shifts of Rossby wave regimes, via the westerly-induced changes in Rossby wave group velocity (Cgx), which are two to three times larger than those in Cpx. We find significant deceleration in the subtropics and polar regions, alongside a salient midlatitude acceleration, of Rossby wave Cgx, especially over the East Asia-Pacific-North America and North Atlantic-Europe sectors. These changes induce robust shifts in spatiotemporal regimes of Rossby waves, from the transient synoptic-scale regime toward the quasi-stationary planetary-scale wave regime where Cgx decelerates, and vice versa. The CESM2 Large Ensemble confirms that the observed pattern over the Eurasia-Pacific-North America sector is a forced response to external forcing, while uncertainties remain over the polar regions and the North Atlantic. We suggest that westerly trends may reshape the regimes of extratropical Rossby wave activity and extreme weather events through the changes in group velocity rather than phase speed of Rossby waves.
[abstract 31 / 42] (score: 2) - Title: First ray-tracing simulations of mode conversion using metaplectic geometrical opticsAuthors: Rui Kai Lee, Valerian H. Hall-Chen, I. Y. Dodin,Comments: 8 pages, 6 figures. Submitted to Physical Review ESubjects: physics.plasm-phCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Advanced scenarios of radiofrequency power deposition into MAGNETically confined fusion plasmas, particularly those using electron Bernstein waves, involve linear mode conversion (energy transfer between separate dispersion branches) in regions where the waves experience reflection. Full-wave simulations of this conversion are time-consuming, and geometrical-optics (GO) modeling is problematic because it is typically restricted to single waves and leads to spurious singularities at cutoffs. Here, we report the first reduced simulations that overcome these limitations without resorting to approximate analytical formulas for the conversion efficiency. The algorithm is based on the recently developed metaplectic geometrical optics (MGO), which eliminates GO's spurious singularities by metaplectic transformations, provided that the symplectic curvature of the rays $R^{-1}$ is small. To prove the concept, we simulate one-dimensional O--X mode conversion caused by the plasma-density gradient near the critical density, a problem for which an approximate analytical solution is available and can be compared with. Numerical MGO demonstrates good agreement with said theory. This opens a way for fast and accurate ray-tracing modeling of any linear mode conversion at $R^{-1} \ll 1$.
[abstract 32 / 42] (score: 2) - Title: Measurements of isolated photon pair production in association with JETs in pp collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detectorAuthors: ATLAS Collaboration,Comments: 56 pages in total, author list starting page 39, 17 figures, 4 tables, submitted to Phys. Rev. D. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2016-12/Subjects: hep-exCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Measurements of integrated and differential production cross section of two isolated photons in events with and without associated hadronic JETs based on the 2012 dataset of 20.3 fb$^{-1}$ integrated luminosity of proton-proton collisions at $\sqrt{s}=8$ TeV collected by the ATLAS experiment are presented. The measurements consider photons with pseudorapidities of $|η^γ|<1.37$ or $1.56<|η^γ|<2.37$ and transverse energy of $E_{T}^γ>22$ GeV. Jets are required to have $p_{T}^{j}>25$ GeV for $|η^{j}|<2.4$ and $p_{T}^{j}>50$ GeV for $2.4<|η^{j}|<4.4$. Events are classified into categories based on the number of JETs and integrated fiducial cross sections of diphoton production in association with inclusive and exclusive number of JETs are presented. Fiducial cross sections, differential in sixteen diphoton, JET, diJET and photon-JET observables, are presented and compared with leading-order Sherpa 1.4.1 predictions in all JET categories, fixed-order next-to-leading-order GoSam and BlackHat calculations in selected categories, and NLO-matched predictions from Sherpa 2.2.14 in all categories. Overall, the NLO predictions provide a reasonable description of the data, with significant discrepancies observed for increasing JET multiplicity, particularly for angular variables, attributable to the absence of higher-order terms in the calculations. The Sherpa 2.2.14 NLO-matched predictions provide the best overall description of the data across all JET categories and observables.
[abstract 33 / 42] (score: 2) - Title: A search for sterile neutrinos at ultrahigh energies at the Pierre Auger ObservatoryAuthors: The Pierre Auger Collaboration, A. Abdul Halim, P. Abreu, M. Aglietta, M. Ahmed, I. Allekotte, K. Almeida Cheminant, R. Aloisio, J. Alvarez-Muñiz, A. Ambrosone, J. Ammerman Yebra, L. Anchordoqui, B. Andrada, L. Andrade Dourado, L. Apollonio, C. Aramo, J. C. Arteaga Velázquez, P. Assis, G. Avila, E. Avocone, A. Bakalova, Y. Balibrea, A. Baluta, F. Barbato, A. Bartz Mocellin, O. Batalla Cruz, J. P. Behler, C. Berat, M. E. Bertaina, M. Bianciotto, P. L. Biermann, V. Binet, K. Bismark, T. Bister, J. Biteau, J. Blazek, J. Blümer, M. Boháčová, D. Boncioli, C. Bonifazi, P. Boril, N. Borodai, J. Brack, P. G. Brichetto Orquera, S. Buitink, A. Bwembya, T. R. Caba Pineda, K. S. Caballero-Mora, S. Cabana-Freire, L. Caccianiga, J. Caraça-Valente, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon, M. Cerda, B. Čermáková, A. Cermenati, K. Cerny, J. A. Chinellato, J. Chudoba, L. Chytka, R. W. Clay, A. C. Cobos Cerutti, R. Colalillo, R. Conceição, G. Consolati, M. Conte, F. Convenga, D. Correia dos Santos, P. J. Costa, C. E. Covault, M. Cristinziani, C. S. Cruz Sanchez, S. Dasso, K. Daumiller, B. R. Dawson, R. M. de Almeida, E. -T. de Boone, B. de Errico, J. de Jesús, S. J. de Jong, J. R. T. de Mello Neto, I. De Mitri, D. de Oliveira Franco, F. de Palma, V. de Souza, E. De Vito, A. Del Popolo, O. Deligny, N. Denner, K. Denner Syrokvas, L. Deval, A. di Matteo, C. Dobrigkeit, J. C. D'Olivo, L. M. Domingues Mendes, T. Dominguez, Y. Dominguez Ballesteros, Q. Dorosti, R. C. dos Anjos, J. Ebr, F. Ellwanger, R. Engel, M. Erdmann, A. Etchegoyen, C. Evoli, H. Falcke, G. Farrar, A. C. Fauth, T. Fehler, F. Feldbusch, A. Fernandes, M. Fernández Alonso, B. Fick, J. M. Figueira, P. Filip, A. Filipčič, B. Flaggs, A. Franco, M. Freitas, T. Fujii, A. Fuster, C. Galea, C. Galelli, B. García, C. Gaudu, P. L. Ghia, U. Giaccari, M. Giammarco, C. Glaser, F. Gobbi, F. Gollan, G. Golup, P. F. Gómez Vitale, J. P. Gongora, N. González, D. Góra, A. Gorgi, M. Gottowik, F. Guarino, G. P. Guedes, Y. C. Guerra, L. Gülzow, S. Hahn, P. Hamal, M. R. Hampel, P. Hansen, A. Haungs, M. Havelka, T. Hebbeker, C. Hojvat, J. R. Hörandel, P. Horvath, M. Hrabovský, T. Huege, A. Insolia, P. G. Isar, M. Ismaiel, P. Janecek, V. Jilek, K. -H. Kampert, L. Karczubová, B. Keilhauer, V. V. Kizakke Covilakam, H. O. Klages, M. Kleifges, A. Klingel, J. Köhler, F. Krieger, M. Kubatova, B. L. Lago, N. Langner, N. Leal, M. A. Leigui de Oliveira, Y. Lema-Capeans, A. Letessier-Selvon, I. Lhenry-Yvon, L. Lopes, P. Magnani, M. Mallamaci, S. Mancuso, D. Mandat, P. Mantsch, A. G. Mariazzi, C. Marinelli, I. C. Mariş, G. Marsella, D. Martello, S. Martinelli, O. Martínez Bravo, A. Martínez-Mendez, M. A. Martins, H. -J. Mathes, J. Matthews, G. Matthiae, E. Mayotte, S. Mayotte, P. O. Mazur, G. Medina-Tanco, D. Melo, A. Menshikov, C. Merx, S. Michal, M. I. Micheletti, L. Miramonti, M. Mogarkar, S. Mollerach, F. Montanet, L. Morejon, K. Mulrey, R. Mussa, W. M. Namasaka, S. Negi, L. Nellen, K. Nguyen, G. Nicora, M. Niechciol, D. Nitz, D. Nosek, A. Novikov, V. Novotny, L. Nožka, A. Nucita, L. A. Núñez, S. E. Nuza, J. Ochoa, M. Olegario, C. Oliveira, L. Östman, M. Palatka, J. Pallotta, G. Parente, T. Paulsen, M. Pech, J. Pękala, R. Pelayo, D. Perez, C. Pérez Bertolli, L. Perrone, S. Petrera, T. Pierog, M. Pimenta, M. Platino, P. Privitera, C. Priyadarshi, M. Prouza, K. Pytel, S. Querchfeld, L. Ramella, J. Rautenberg, D. Ravignani, J. V. Reginatto Akim, M. Z. Rennó, A. Reuzki, J. Ridky, F. Riehn, M. Risse, V. Rizi, B. Rocha-Moldes, E. Rodriguez, G. Rodriguez Fernandez, J. Rodriguez Rojo, M. Roth, E. Roulet, A. C. Rovero, A. Saftoiu, M. Saharan, F. Salamida, H. Salazar, G. Salina, P. Sampathkumar, N. San Martin, J. D. Sanabria Gomez, F. Sánchez, F. M. Sánchez Rodriguez, E. Santos, F. Sarazin, R. Sarmento, R. Sato, P. Savina, V. Scherini, H. Schieler, M. Schimp, D. Schmidt, O. Scholten, H. Schoorlemmer, P. Schovánek, F. G. Schröder, J. Schulte, T. Schulz, S. J. Sciutto, M. Scornavacche, A. Sedoski, S. Sehgal, S. U. Shivashankara, G. Sigl, K. Simkova, F. Simon, R. Šmída, S. Soares Sippert, P. Sommers, S. Stanič, J. Stasielak, P. Stassi, S. Strähnz, M. Straub, T. Suomijärvi, A. D. Supanitsky, Z. Svozilikova, Z. Szadkowski, F. Tairli, A. Tapia, C. Taricco, C. Timmermans, O. Tkachenko, P. Tobiska, C. J. Todero Peixoto, B. Tomé, A. Travaini, P. Travnicek, C. Trimarelli, M. Tueros, M. Unger, R. Uzeiroska-Geyik, L. Vaclavek, M. Vacula, I. Vaiman, J. F. Valdés Galicia, L. Valore, P. van Dillen, E. Varela, V. Vašíčková, D. Veberič, M. A. Vega Caro, I. D. Vergara Quispe, S. Verpoest, V. Verzi, J. Vicha, L. M. A. Victoria, S. Vorobiov, J. B. Vuta, A. A. Watson, A. Weindl, M. Weitz, L. Wiencke, H. Wilczyński, B. Wundheiler, B. Yue, A. Yushkov, E. Zas, D. Zavrtanik, M. Zavrtanik,Comments: 18 pages, 4 figuresSubjects: astro-ph.HE hep-phCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
We investigate the sensitivity of the Pierre Auger Observatory to sterile neutrinos with masses in the MeV-to-100 MeV range. To this end, we consider a minimal $3+1$ framework in which a single sterile state mixes mainly with the $ν_τ$ flavor through an active--sterile mixing angle $θ_N$ to produce a mass eigenstate $N_1$. At ultrahigh energies, $N_1$ neutrinos can traverse substantial chord lengths through the Earth and interact through their active component, producing $τ$ leptons that may emerge near the surface and decay in the atmosphere, thereby generating detectable air showers. We compute the corresponding exposures with a detailed Monte Carlo simulation of neutrino propagation, interactions, $τ$ energy losses and decay, and derive upper limits at $90\%$ confidence level on an isotropic diffuse flux of $N_1$ neutrinos. For an $E^{-2}$ spectrum, we obtain $E^2Φ_N\leq 2\times10^{-9}\sin^{-2}θ_N\,\mathrm{GeV\,cm^{-2}\,sr^{-1}\,s^{-1}}$ over $0.3$--$200$ EeV for $\sin^2θ_N\lesssim10^{-1}$. We further consider $N_1$ neutrinos arising from the decay of a superheavy dark-matter particle. For a benchmark dark-matter mass of $10^{13}$ GeV, we derive constraints on the active--sterile mixing angle and dark-matter lifetime for sterile-neutrino masses of $10$ and $100$ MeV. These results illustrate the potential of the Observatory to probe long-lived weakly interacting particles.
[abstract 34 / 42] (score: 2) - Title: The Environment of High-Energy Transient Host Galaxies at High Redshifts as Observed by SHARPAuthors: L. Izzo,Comments: 4 pages, 3 figures, accepted for publication in the New Astronomy Special issue: SHARP science bookSubjects: astro-ph.HE astro-ph.GACreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
The study of transient events, such as Gamma-Ray Bursts (GRBs) and extreme Supernovae (SNe), provides a unique probe of star-forming environments in the early Universe. Traditional global host galaxy studies often fail to capture the local conditions around the progenitor, leading to potential mischaracterizations due to metallicity gradients and spatial inhomogeneities. Using high spatial resolution integral field unit (IFU) data, such as those obtained with SHARP/VESPER, allows us to spatially resolve the host galaxies and accurately determine the physical properties (metallicity, stellar age, kinematics) at the precise explosion site. Here, we review the need for near-infrared spatially-resolved observations to link progenitor properties, such as the required low metallicity for long GRBs, to their birth environments, and highlight the crucial role of instruments like SHARP in advancing high-redshift transient science, including the characterization of SNe without associated GRBs and Kilonovae hosts.
[abstract 35 / 42] (score: 2) - Title: Probing black bounce spacetime through mass accretion rateAuthors: Xi-Rui Guo, Ya-Peng Hu, Yu-Sen An,Comments: 17 pages, 7 figuresSubjects: gr-qcCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
We study steady, spherically symmetric accretion of a collisionless kinetic gas onto a compact object described by the Simpson--Visser (SV) metric, a one-parameter regularization of the Schwarzschild spacetime. Using the standard RELATIVISTIC Vlasov formalism, we adopt boundary conditions at a finite injection radius $R$ and compute the mass accretion rate $\dot{M}$ for Vlasov gas with both monoenergetic and Maxwell--Jüttner distribution functions. Throughout the computation, we also take into account the influence of particle's angular momentum. We carefully investigate the influence of the black bounce parameter on the mass accretion rate $\dot{M}$. By expanding accretion rate in terms of bounce parameter $a$, we found that the leading-order correction appears at quadratic order in $a$. This work extends the Vlasov accretion framework to a broader class of spherically symmetric spacetimes and quantifies the impact of the geometric modification on the accretion flow. In particular, since the shadows of the SV and Schwarzschild BLACK HOLEs are degenerate, comparing their mass accretion rates may offer a complementary probe for distinguishing these geometries in future astrophysical observations.
[abstract 36 / 42] (score: 2) - Title: A trust layer for fast pedestal-stability surrogates: calibrated error bars, out-of-distribution alarms and few-shot recalibrationAuthors: Amin Vakhshouri,Comments: 9 pages, 6 figuresSubjects: cs.LG physics.plasm-phCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Machine-learning surrogates of linear peeling-ballooning stability now run in milliseconds, but they are mostly deployed as point estimators: they do not say how wrong they may be, or when a query lies outside what they were trained on. For a fusion company designing a new device, every equilibrium of interest is outside the training data of existing surrogates, so this is the case that matters. We describe a model-agnostic trust layer for stability surrogates, made of conformal error bars, out-of-distribution alarms that route doubtful cases to the physics code, and recalibration from a few simulations of a new design, and we test it with pre-registered hypotheses. On a large public dataset of JET-like equilibria with ideal-MHD growth rates, the error bars hold their nominal coverage in distribution and fall short under a shift in plasma shape; a few dozen simulations of the new shape, or routing the cases the alarms flag, restore it. On resistive BOUT++ surrogates, the bars stay calibrated on held-out runs, the alarm flags tokamaks absent from training, and a scenario scan is screened in seconds instead of hours. Across equilibria from the SPARC library and the DIII-D coil set, a surrogate trained on our own graded BOUT++ labels beats the baseline on unseen equilibria, while a surrogate trained elsewhere ranks the same cases backwards and its alarm declines them. Building our own neural-operator surrogate, the harness exposed two input defects whose fix closed its gap to a simple network. For every surrogate tested, the trust layer keeps coverage near target, with a bar width set by that surrogate's own error. Not every pre-registered hypothesis held, and we report those results and the limits of all of them.
[abstract 37 / 42] (score: 2) - Title: Quasi-equilibrium tidal folds of white dwarfs around rotating BLACK HOLEs in shift-symmetric Einstein--scalar--Gauss--Bonnet gravityAuthors: Shoupan Liu, Meilin Liu, Yu Wang, Yunqi Liu,Comments:Subjects: gr-qcCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
We examine how the geometry of rotating BLACK HOLEs in linear, shift-symmetric Einstein--scalar--Gauss--Bonnet (EsGB) gravity changes the limiting tidal equilibria of white dwarfs (WDs). The RELATIVISTIC tidal field is obtained from numerical EsGB backgrounds in a parallel-transported frame and coupled to a compressible affine model. Comparisons with Kerr BLACK HOLEs matched in Arnowitt--Deser--Misner (ADM) mass and angular momentum show a positive shift in the orbital frequency at the tidal fold. At fixed spin the relative correction follows an approximately quadratic dependence on the EsGB coupling, consistent with the leading response of the metric to the scalar field. Over the sampled backgrounds, the relative correction reaches order $10^{-3}$. Black hole rotation also changes the relation between the tidal fold and the innermost stable circular orbit (ISCO): the sampled prograde folds remain outside the ISCO, while retrograde folds move inside it at higher spins. Orbital orientation therefore controls whether tidal equilibrium is lost before the orbital stability limit is reached. For the stellar and BLACK HOLE masses considered here, the characteristic gravitational wave (GW) frequencies fall in the millihertz band relevant to planned space based interferometers. Future GW observations capable of resolving deviations from Kerr predictions could constrain the EsGB coupling.
[abstract 38 / 42] (score: 2) - Title: Born-Infeld BLACK HOLEs in bumblebee gravityAuthors: A. A. Araújo Filho, E. M. Siquieri, N. Heidari, V. B. Bezerra, A. F. Santos,Comments: 51 pages, 18 figuresSubjects: gr-qcCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
We construct exact static and spherically symmetric charged solutions in bumblebee gravity minimally coupled to Born--Infeld electrodynamics, taking into account a spacelike vector norm and a vanishing cosmological constant. An independently varied Lagrange multiplier enforces the norm constraint and acquires a radial profile determined by the transverse electroMAGNETic pressure. The solutions include purely radial configurations and configurations with constant or varying temporal amplitudes. At $ξ=κ/2$, the varying temporal amplitude introduces an independent bumblebee field strength while preserving the metric of the constant temporal configuration. Moreover, the electric field remains bounded, and the temporal configurations admit smooth extensions across a simple future horizon under explicit regularity conditions. We derive the photon sphere and shadow radii for both metric and nonlinear electroMAGNETic propagation. The leading nonlinear corrections enlarge the shadow at fixed geometric charge, whereas the temporal amplitude enters through the charged lapse. Comparisons with observations of Sgr~A$^*$ and M87$^*$ provide conditional bounds on the charge and nonlinear scale. In addition, the adopted planetary perihelion allowances yield an illustrative sensitivity of $|ξ|(b^2+u_0^2)\lesssim2.6\times10^{-12}$ for a neutral solar exterior.
[abstract 39 / 42] (score: 2) - Title: Energetic Nonthermal Electrons within the Above-the-looptop Regions in Solar Flares: Acceleration, Feedback, and Quasi-Periodic PulsationsAuthors: Jeongbhin Seo, Fan Guo, Xiaocan Li, Bin Chen, Chengcai Shen, Hui Li,Comments: 13 pages, 6 figuresSubjects: astro-ph.HE astro-ph.SRCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Solar flares are among the most dramatic events in the solar system, releasing substantial MAGNETic energy and accelerating a large number of electrons to high energies. Notably, in certain events, the above-the-looptop region may contain a significant population of nonthermal electrons, both in number and energy. For the first time, we adopt a novel numerical method that combines MAGNETohydrodynamics with energetic particles incorporating feedback from nonthermal electrons to investigate electron acceleration and transport in solar flares. We find that a large fraction of energetic electrons are accelerated via the current sheet and termination shock regions. Most energetic electrons are concentrated in the above-the-looptop region, carrying a sizable amount of the released energy. We observe that greater feedback of nonthermal electrons leads to steeper energy spectra. The energy density of the nonthermal electrons oscillates due to the periodic impact of MAGNETic islands into the above-the-looptop, which may help explain the observed quasi-periodic pulsations (QPPs). Our simulations provide new insights into the origin of nonthermal electrons and associated emissions in the above-the-looptop region.
[abstract 40 / 42] (score: 2) - Title: Magnetic Properties of Galactic Molecular CloudsAuthors: Philip C. Myers, Ian W. Stephens, Simon Coudé, Nicole Karnath, Howard A. Smith,Comments: 38 pages, 10 figures, accepted by The Astrophysical JournalSubjects: astro-ph.GACreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
The earliest studies of molecular clouds (MCs) showed scaling relations between mass and radius M$\sim$R^s with exponent s $\approx$ 2, known as the third Larson relation. More recent CO surveys indicate 2 < s < 3 in the inner Milky Way (MW) and nearby galaxies. These observations appear consistent with the virial equilibrium (VE) of MAGNETically subcritical clouds, bound by the pressure Pe of the midplane ISM. The VE equations for such clouds are consistent with 2 < s < 3 for MAGNETically subcritical clouds, but not for MAGNETically critical, supercritical, or nonMAGNETic clouds. We fit the subcritical VE equations to M-R trends observed in CO surveys of $\sim$1500 clouds, with correlation coefficients 0.8 - 1. The fits indicate median mass-to-flux ratio lambda $\approx$ 0.7, MAGNETic field strength Btot $\approx$ 60$\mathrm{μG}$, and Pe/k $\approx$ 5 x 10^5 cm^-3 K in the inner MW, with lesser values in M33 and M31. For 18 MW "bones," VE analysis assuming likely values of Pe also indicates subcritical values of lambda, as found from POLARIZATION observations. These results indicate that many giant molecular clouds (GMCs) are consistent with pressure-bound MAGNETically subcritical virial equilibrium. If so, GMCs may have low STAR FORMATION efficiency (SFE) because their relatively strong fields cause filaments, clumps and cores to form slowly, while feedback and turbulence disperse them rapidly. The fields in their clumps and cores are likely weak enough to allow star-forming collapse, according to Zeeman and DCF observations, and according to MHD simulations which predict SFE $\approx$ 0.5-2%.
[abstract 41 / 42] (score: 2) - Title: Magnetohydrodynamics During ReheatingAuthors: Sovan Sau, Subhasis Maiti, Sahel Dey, Alberto Roper Pol, Debaprasad Maity,Comments: 14+6 pages, 24 Figures, Comments and suggestions are most welcomeSubjects: astro-ph.COCreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
Reheating is a crucial phase that connects inflation with the hot Big Bang Universe. During this phase, the nonlinear interactions among the inflaton, the radiation plasma, and the primordial MAGNETic fields can influence the subsequent evolution of cosmic structures we observe today. In this paper, we develop a multifluid framework to investigate the evolution of three dimensional nonlinear MAGNETohydrodynamics (MHD) during the non instantaneous reheating phase driven by the perturbative decay of the inflaton into the radiation plasma. For the present paper, we consider the simplest scenario where the inflaton field homogeneously injects energy into the radiation sector. We study the MHD evolution of the coupled inflaton radiation system during the reheating phase, including the evolution of their individual kinetic energies, the velocity perturbations, vorticity, MAGNETic fields, and gravitational waves. We find that homogeneous energy transfer from the inflaton to the radiation sector increases the radiation and kinetic energy densities but does not significantly amplify the initial MAGNETic field perturbations. Consequently, the MAGNETic spectrum remains largely unchanged with respect to the instantaneous reheating scenario, while the velocity perturbations undergo a scale redistribution that affects the resulting GW spectrum. Our results demonstrate the importance of nonlinear multifluid MHD dynamics in understanding the evolution of primordial fields during reheating and provide a framework for exploring more realistic scenarios involving inhomogeneous decay processes and detailed thermalization effects.
[abstract 42 / 42] (score: 2) - Title: ReveaLLAGN 3: Revealing the Infrared Spectral Energy Distributions of Low Luminosity AGNAuthors: David Ohlson, Anil C. Seth, Kameron Goold, Nischal Acharya, Torsten Böker, Antoine Dumont, Ruby Duncan, Michael Eracleous, Anja Feldmeier-Krause, Juan Antonio Fernández-Ontiveros, Elena Gallo, Andy D. Goulding, Jenny E. Greene, Luis C. Ho, Sera B. Markoff, Mallory Molina, Richard M. Plotkin, Almudena Prieto, Shobita Satyapal, Glenn van de Ven, Jonelle L. Walsh,Comments:Subjects: astro-ph.GACreated: 2026-11-04; Updated: 2026-11-05; Datestamp: 2026-11-05
The spectral energy distributions of ACTIVE GALACTIC NUCLEi (AGN) provide valuable information on the emission mechanisms taking place in their inner regions. Here we use the James Webb Space Telescope to study the near and mid-infrared spectral energy distributions of seven nearby low-luminosity active galaxy nuclei from 1.7 to 24 $μm$. We cleanly separate the AGN spectrum by performing spatial fits of the two-dimensional images across all wavelengths. We then compare these clean unresolved spectra to aperture-based spectra and show that they effectively remove galaxy contamination. Comparing our infrared measurements to X-ray emission, we find that low-luminosity AGN have enhanced near-infrared emission relative to more luminous AGN, a trend that correlates with radio-loudness, while their mid-infrared-to-X-ray ratios are comparable. A majority of our targets show strong compact silicate emission suggesting the presence of warm dust on parsec scales in these systems. We also quantify the near- and mid-infrared power-law slopes and colors of low-luminosity AGN. In the near-infrared we find AGN of all luminosities have similar spectral slopes and colors, however in the mid-infrared, we find low-luminosity AGN typically have steeper slopes and redder colors than more luminous AGN. Both the strong silicate emission and steep mid-infrared slopes disagree with existing models for low-luminosity AGN spectral energy distributions.
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