Current date: 2026-05-26
Setting default datestamp limit: 0
Datestamp limit: 2026-05-26 (0 days ago)
Created/updated limit: 2026-05-19 (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=2026-05-26&until=2026-05-26&set=physics&metadataPrefix=arXiv
Scoring abstracts
Number of records retrieved: 1056
Keyword score statistics
score 9 -- 2 abstracts
score 7 -- 5 abstracts
score 6 -- 3 abstracts
score 5 -- 4 abstracts
score 4 -- 7 abstracts
score 3 -- 12 abstracts
score 2 -- 22 abstracts
in total -- 55 abstracts
Articles that appeared on 2026-05-26
-
[abstract 1 / 55] Wow! (score: 9)
- Title: Observational Properties of Nonthermal Emission from Relativistic Jets Escaping Active Galactic Nucleus DisksAuthors: Ken Chen, Zi-Gao Dai,Comments: 22 pages, 10 figures, accepted for publication in ApJSubjects: astro-ph.HECreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
Relativistic JETs launched from stellar-mass compact objects embedded in the accretion disk of an ACTIVE GALACTIC NUCLEus (AGN) can produce nonthermal emission upon successfully breaking out of the disk. In this paper, we present a comprehensive study of the long-term propagation dynamics and broadband nonthermal radiation signatures of such JETs in a realistic AGN environment, explicitly modeled as wind outflows. Our modeling reveals two distinct features imprinted by the high-density AGN medium: rapid deceleration of the JET ejecta, accompanied by a prompt downshift of the emission spectral energy distribution, and persistently strong SYNCHROTRON self-absorption, giving rise to a prominent quasi-thermal hump in the emission spectrum. Crucially, both GAMMA-RAY BURST JETs and JETs powered by accreting binary BLACK HOLE merger remnants can produce detectable multi-wavelength emissions that substantially outshine the AGN background. Moreover, the short time delays between gravitational wave triggers and these electroMAGNETic counterparts--typically less than $10^6 s$--greatly facilitate secure multi-messenger associations. Besides, our findings highlight that interaction-induced radiation from AGN-embedded JET systems offers a powerful diagnostic probe of the spatial distribution,density structure, and physical properties of the AGN medium.
[abstract 2 / 55] Wow! (score: 9) - Title: X-ray Polarization Signatures from Comptonization by Magnetic Reconnection PlasmoidsAuthors: John Groger, Kun Hu, Henric Krawczynski,Comments: Submitted to ApJLSubjects: astro-ph.HECreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Emission from X-ray binaries in the hard spectral state is dominated by high-energy radiation attributed to the Compton scattering of seed photons. The prevalent model of the Comptonization by hot electrons or pairs faces the problem of rapid radiative cooling of the emitting particles. A proposed alternative mechanism is the Comptonization by scattering off fast plasmoids formed during MAGNETic RECONNECTion. In this work, we simulate a simplified model of the plasmoid chain with Monte Carlo radiation transport and report on spectropolarimetric properties. We find that the Comptonization off trans-RELATIVISTIC bulk plasmoids is not only able to reproduce the 100 keV spectral cutoff, but furthermore produces X-rays that are above 1 keV strongly polarized perpendicular to the RECONNECTion layer. The POLARIZATION is stronger than that from the Comptonization by an isotropic hot plasma owing to the confinement of the motion of the scattering plasmoids in the plane of the RECONNECTion layer. The dependence of POLARIZATION on azimuthal viewing angle is discussed, along with possible locations for the plasmoid chain in an equatorial current sheet or the sheath of the BLACK HOLE's RELATIVISTIC JET.
[abstract 3 / 55] Wow! (score: 7) - Title: Multi Messenger Study of GRB 221009A with VHE Gamma-ray and Neutrino Afterglow from a Gaussian Structured JetAuthors: T. Mondal, S. Razzaque, Jagdish C Joshi, S. Majumder, D. Bose,Comments: 16 pages, 10 figuresSubjects: astro-ph.HECreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Recent detections of very-high-energy (VHE; $\gtrsim 100~{\rm GeV}$) emission from GRB afterglows, most notably the unprecedented brightness of GRB~221009A observed by LHAASO, reveal components beyond the standard electron SYNCHROTRON model. The multi-TeV photons motivate SYNCHROTRON self-Compton and possible hadronic contributions, while the non-detection of coincident neutrinos by IceCube/KM3NeT/GRAND200k constrains the microphysical parameters, JET kinetic energy, and ambient-medium density. We model the VHE afterglow of GRB~221009A with an external forward shock from a Gaussian structured JET in a uniform-density medium. This angular structure reproduces the extreme TeV output at an off-axis angle but without demanding large energies as in a top-hat JET. We compute the corresponding $pγ$ neutrino flux in the PeV-EeV range and derive a time-integrated upper limit using the effective areas of IceCube-Gen2 and GRAND200k. This provides insight into the contribution of individual GRBs to neutrino events. The predicted neutrino flux for GRB~221009A, using parameters inferred from the multi-wavelength spectral energy distribution, lies below the sensitivities of these detectors. Even our correlation analysis, optimized for neutrino searches with the upcoming GRAND200k, indicates that the expected number of events from this GRB is of order $\sim 0.1$ under a highly optimistic microphysical parameter regime. We also compare neutrino-flux variations from on-axis and off-axis viewing geometries and find an approximately order of magnitude difference in the signal. Thus, our study concludes that a brighter burst closer than GRB~221009A would be crucial for neutrino detection by upcoming telescopes. Future GRB detections by the Cherenkov Telescope Array will provide important constraints on their geometry, radiation mechanisms, and possible associated neutrino signals.
[abstract 4 / 55] Wow! (score: 7) - Title: Hadronic Processes, Plasma Evolution and Neutrino Emission in Magnetic Towers of Neutron-Star Merger RemnantsAuthors: Rostom Mbarek, Jiaxi Wu, Elias R. Most,Comments: Under ReviewSubjects: astro-ph.HECreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
Binary neutron star mergers can form short-lived MAGNETar-like remnants whose MAGNETically dominated polar towers reach $B\sim10^{15}$--$10^{16}\,\mathrm{G}$, but the microphysical composition of these outflows remains poorly understood. Combining tower geometries from GRMHD simulations with an analytic treatment of QED and hadronic processes, we argue that MAGNETic RECONNECTion is the most viable particle acceleration channel in this strongly radiative regime, where the current sheets thin to collisionless scales. Purely leptonic pair loading -- including resonant inverse Compton scattering of soft photons -- is bottlenecked by rapid pitch-angle damping and the tendency of one-photon MAGNETic conversion to populate low Landau levels. Once protons reach mildly RELATIVISTIC energies ($γ_p\gtrsim1.3$), however, inelastic proton-proton ($pp$) collisions inject large-pitch-angle pions that drive $π^0\to2γ\to e^\pm$ cascades with multiplicity $\mathcal{M}_{\rm cas}\simeq4$ at $B=10^{15}\,\mathrm{G}$, supplying the perpendicular momentum the leptonic channel cannot maintain. This hadronic route dominates pair loading and channels most of the dissipated MAGNETic energy into the $e^\pm$ population that could power the nonthermal emission emerging at larger radii. Charged-pion decay, modulated by $π^\pm$ SYNCHROTRON cooling, further seeds a nonthermal neutrino tail up to $\sim 300\,(σ_p/5)\,\mathrm{MeV}$, spectrally distinct from the thermal cooling burst and detectable from sources within $\sim 100\,\mathrm{kpc}$
[abstract 5 / 55] Wow! (score: 7) - Title: The Lumina Project: The Demographics of Active Galactic Nuclei from Quasars to Little Red Dots at $z\geq 3$Authors: Xuejian Shen, Oliver Zier, Aaron Smith, Rongrong Liu, Rahul Kannan, Teodora-Elena Bulichi, Sonja M. Koehler, Volker Springel, Mark Vogelsberger, Lars Hernquist, Rohan P. Naidu, Anna de Graaff, Elia Pizzati, David M. Alexander, Luis C. Ho, Vasily Kokorev, Gene Leung, Anna-Christina Eilers, Ryan C. Hickox,Comments: 30 pages, 21 figures. To be submitted. Comments are welcomed!Subjects: astro-ph.GA astro-ph.CO astro-ph.HECreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
High-redshift ACTIVE GALACTIC NUCLEi (AGN) serve as powerful probes of early black-hole growth, galaxy formation, and the evolving intergalactic medium (IGM). In this work, we use Lumina, a cosmological radiation-hydrodynamic simulation spanning the epochs of hydrogen and helium reionization, which combines a large $(500\,{\rm cMpc})^3$ volume with $2\times 6000^3$ resolution elements, to explore high-redshift AGN. The simulation self-consistently follows hundreds of millions of galaxies and supermassive BLACK HOLEs (SMBHs), together with their impact on the ionization and thermal state of the IGM. We exploit this uniquely large dynamic range to predict multi-band AGN luminosity functions (LFs) at $z \geq 3$, from hard X-rays to the mid-infrared. These predictions encompass both moderately luminous QUASARs and the faint ``Little Red Dots'' (LRDs) uncovered by JWST. We develop an empirical model that maps simulated SMBHs onto observed AGN using bolometric and extinction/absorption corrections for canonical AGN and LRDs, and in which SMBHs with $M_{\rm BH}\leq 10\,M_{\rm seed} \sim 10^{7}\,{\rm M}_{\odot}$ stay in the LRD phase with a duty cycle of $30\%$. This simple framework reproduces the observed LFs and clustering of LRDs. Meanwhile, the pre-JWST QUASAR LF constraints are recovered, although we find that a $\sim 0.3$ dex log-normal scatter in bolometric luminosity is required to reproduce the bright end. We place the simulated AGN population in the cosmological context by quantifying the redshift evolution of AGN and LRD number densities, and their contributions to the integrated BH mass densities. The same AGN population is the dominant driver for the HeII reionization modelled self-consistently in Lumina. This empirical AGN model paves the way for general population-synthesis models of high-redshift AGN, including LRDs, in a unified cosmological framework.
[abstract 6 / 55] Wow! (score: 7) - Title: The XRISM measurements of the black-hole spin in Cyg X-1 are highly model-dependentAuthors: Andrzej A. Zdziarski, Swadesh Chand, Michal Szanecki, Gulab Dewangan, Barbara De Marco,Comments: Submitted to ApJ, comments are welcomeSubjects: astro-ph.HECreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
We study the persistent BLACK HOLE X-ray binary Cyg X-1, recently observed by XRISM Resolve and simultaneously by NICER and NUSTAR in its hard spectral state. We confirm the result of Draghis et al.\ that fits of the Resolve data alone with the simplest available RELATIVISTIC reflection model, relxill, yield a BLACK HOLE spin parameter close to the maximum, $a_* = 0.99$. However, fitting with an improved, Comptonization-based model, relxillCp, yields a low $a_*=0.0^{+0.17}$. A similarly low range is obtained with another Comptonization-based model, reflkerrD. Then, fits to the combined data require two Comptonization models but are consistent with any spin value. We conclude that the spin value of Cyg X-1 is strongly model-dependent. However, low spin values are consistent with the constraints from gravitational waves. All of the models constrain the inner disk radius to be <10 gravitational radii, which is consistent with a recent finding of the weakness of thermal reverberation in Cyg X-1. The implied source geometry is that of an outflowing disk corona, which was also proposed to explain the X-ray POLARIZATION observed from this source.
[abstract 7 / 55] Wow! (score: 7) - Title: Shear Particle Acceleration in Structured Gamma-Ray Burst Jets: IV. Thermal {\em vs.} Non-thermal Emission of the Jet CocoonAuthors: Zi-Qi Wang, Xiao-Li Huang, Hai-Ming Zhang, En-Wei Liang,Comments: 9 pages, 4 figures, 2 tables, Accepted for publication in ApJSubjects: astro-ph.HECreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
A distinct thermal or quasi-thermal spectral component is occasionally observed in GAMMA-RAY BURST (GRB) prompt emission spectra. Taking GRB 090902B as a case study, we investigate its origin within a structured JET framework, in which the outflow consists of an ultra-RELATIVISTIC uniform core surrounded by a structured cocoon. In the weak-scattering regime with inefficient shear acceleration, electrons pre-energized in the thin JET-cocoon interaction layer are further heated in the mixed JET-cocoon (MJC) region, forming a quasi-thermal electron distribution. Parameterizing the radial temperature profile of electrons as a power law with index $q_T$, we demonstrate that both the peak flux and spectral width of the thermal component are sensitive to maximum temperature $T_{\max}$ and $q_T$. Combined with the SYNCHROTRON emission of shock-accelerated electrons in the JET core, our model reproduces both the quasi-thermal component in the keV-MeV range and the broadband non-thermal emission observed in the time-integrated and time-resolved spectra of GRB 090902B. A comparative analysis of GRB 240825A within a shear-acceleration dominated (strong-scattering) scenario shows that shear-accelerated electrons produce broader spectra than thermalized electrons in the weak-scattering regime. These results indicate that GRB spectral diversity likely arises from the additional emission component originating in the MJC region under different physical conditions.
[abstract 8 / 55] Yes (score: 6) - Title: BASS LV. Connecting X-ray variability with AGN physical properties and a new path to Cosmological distancesAuthors: Matilde Signorini, Federica Ricci, Alessia Tortosa, Stefano Bianchi, Fabio La Franca, Franz E. Bauer, Fiona A. Harrison, Kohei Ichikawa, Arghajit Jana, Michael J. Koss, Tingting Liu, Kyuseok Oh, Alessandro Peca, Meredith Powell, Claudio Ricci, David B. Sanders, Roberto Serafinelli, Daniel Stern, Benny Trakhtenbrot, Ezequiel Treister, Megan Urry,Comments: accepted for publication in A&A - final versionSubjects: astro-ph.GA astro-ph.CO astro-ph.HECreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
X-ray variability is a well-established characteristic of ACTIVE GALACTIC NUCLEi (AGN), known to correlate inversely with both the supermassive BLACK HOLE mass and luminosity, although the degree of each remains a topic of debate. The potential of X-ray variability as a proxy for MBH or for intrinsic LX has led to proposals to use AGN as standard candles to test cosmological models. However, the large intrinsic dispersion in these relations has limited their practical applications. In this work, we investigate the dependence of X-ray variability on AGN physical properties using a sample of 134 Seyfert 1 galaxies from the BAT AGN Spectroscopic Survey (BASS), which is the largest sample to date, more than three times larger than those used in previous studies. Contrary to earlier findings, we observe that X-ray variability correlates with luminosity just as strongly as with MBH. Furthermore, we still do not find evidence for the expected anti-correlation between variability and Eddington ratio, even when using refined bolometric luminosities from SED fitting to compute the Eddington ratio. From a cosmological perspective, the increased sample size reduces the scatter in the log(L)-log(exvar) relation to ~0.63 dex - a significant improvement over previous results, but still too large to serve as competitive standard candles, when compared to SNIa (uncertainties on distances of ~5-10%) or the L(X)-L(UV) relation in QUASARs (uncertainties of 10-12%). We tested including the width of broad emission lines as additional parameters, but found that this does not significantly lower the observed dispersion, contrary to previous studies on smaller samples. Finally, we discuss how future X-ray missions such as AXIS and NewAthena will improve this scenario by enabling precise variability measurements for thousands of AGN up to redshift z~3, thereby enabling it as a new cosmological probe.
[abstract 9 / 55] Yes (score: 6) - Title: A Three-Decade VLBI Study of the Nucleus in the Lobe-Dominated Quasar 3C207Authors: D. H. Hough, J. P. Linick, E. L. Danielson, S. M. Escobedo, H. D. Ibaroudene, B. D. Sadler, N. A. Polito, R. C. Vermeulen, C. E. Aars, C. L. Newton, T. A. Rector,Comments:Subjects: astro-ph.GACreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
We present results from very-long-baseline-interferometry (VLBI) observations of the nucleus in the lobe-dominated QUASAR 3C207. These observations were completed at 8.4 or 10.7 GHz (X-band) from 1981 to 2010, spanning 29 years. The nucleus of 3C207 is the strongest and most variable in the 3CR complete sample of LDQs, which is under study to test RELATIVISTIC JET models over a wide range of JET orientation angles. Images have typical resolutions of ~0.5-1.0 milliarcseconds (mas) and sensitivities of ~0.1-0.2 mJy beam^{-1}. The VLBI core region has flux density outbursts at mean intervals of ~7 yr; two of these are multiple outbursts from a stationary "true: core that feeds a "swinging component" ~0.5 mas to the east. The position angle (PA) of the swinging component shows a long-term increase of ~40°, with a short-term reversal of ~10°. A one-sided, curved VLBI JET extends ~25 mas eastward, with components spanning a PA range of ~25°. The JET components have average apparent transverse velocities ~10c. One component shows apparent acceleration from 7c to 14c at 2-3 mas from the true core, where the flow is redirected toward PA ~90°. Another component shows marginal evidence for apparent deceleration. Individual JET components expand until reaching the recollimation zone. Our results are consistent with a physical model in which 3C207 has quasi-periodic outbursts, JET precession by ballistic components on a conical surface with a small opening angle, and a recollimation process that modifies component motions and narrows the conical geometry on a scale of ~100 pc.
[abstract 10 / 55] Yes (score: 6) - Title: Inverse Compton scattering occurring in a reverse-shock scenario involving a kilonova: A channel of TeV gamma-ray photonsAuthors: Nissim Fraija, Jorge Alexis Montes, Sara Fraija-Castellanos, María Magdalena González,Comments: 23 pages, 9 figures. Accepted for publication in MNRASSubjects: astro-ph.HECreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
Gamma-ray bursts (GRBs) are among the most luminous transients in the Universe and constitute prime targets for multimessenger studies, particularly in connection with gravitational-wave events. The detection of very-high-energy (TeV) photons from GRBs would provide valuable constraints on the physical conditions in the outflow, including the bulk Lorentz factor, circumburst density, radiation processes, and microphysical parameters. The possible detection of TeV emission temporally associated with an optical-infrared kilonova (KN), as suggested for GRB 160821B, presents a challenge to standard SYNCHROTRON self-Compton scenarios. In this work, we explore an alternative mechanism in which TeV photons are produced during the afterglow phase via external inverse Compton (EIC) scattering. In this scenario, electrons accelerated in the reverse shock upscatter seed photons originating from the KN. We derive the corresponding EIC light curves and spectra for a reverse shock evolving in the thin-shell regime within a constant-density medium, and apply the model to GRB 160821B. We further constrain the parameter space for TeV detectability by incorporating the high KN luminosity observed in AT2017gfo, as well as flux upper limits reported by H.E.S.S. and HAWC. We find that TeV emission is more likely under conditions of very low MAGNETic energy fraction, $ε_{\rm B_r} \lesssim 10^{-6}$, combined with a bright KN and relatively low redshift. This mechanism predicts TeV photons on timescales of hours to a few days after the burst.
[abstract 11 / 55] Yes (score: 5) - Title: IGR J12580+0134: A Possible Repeated Partial Tidal Disruption Event Inferred from Late-Time Radio Re-brighteninAuthors: Po Ma, Shao-Yu Fu, Linhui Wu, Wei-Hua Lei, Qiang Yuan,Comments: 17 pages, 6 figures, 2 tables, submitted to ApJSubjects: astro-ph.HECreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Repeating partial tidal disruption events (pTDEs) provide a direct probe of stellar orbits and episodic mass loss around supermassive BLACK HOLEs, but robust identification requires multi-band and multi-epoch evidence. %consistent with a single physical origin. We investigate whether the late-time radio rebrightening of the nuclear transient IGR~J12580+0134 in NGC~4845 can be explained as a repeating pTDE, using multi-epoch Karl G.\ Jansky VLA observations together with X-ray constraints from \textit{SWIFT}/XRT and \textit{NICER}. \textbf{Through a systematic analysis of the radio data, we identify two well-defined radio flares and a possible third late-time rebrightening flare.} \textbf{Modeling the second flare with a SYNCHROTRON afterglow framework using Markov Chain Monte Carlo fitting is consistent with a sub-RELATIVISTIC outflow with a characteristic velocity of order $\mathbf{v \simeq 0.3c}$, an isotropic-equivalent kinetic energy of order $\mathbf{10^{50}}$ erg, and an approximately constant-density circumnuclear medium}. No significant contemporaneous brightening is detected by \textit{SWIFT}/XRT during the 2016 radio flare, while faint \textit{NICER} flares in 2023 suggest intermittent low-level accretion. \textbf{We also considered several possible interpretations for the late-time radio rebrightening, and found that the repeated pTDE scenario provides a more natural overall explanation for the observed phenomenology. Given the currently sparse data coverage, continued sensitive radio and X-ray monitoring will be essential to test this interpretation and to search for future reactivations.
[abstract 12 / 55] Yes (score: 5) - Title: A 4.5-s Quasiperiodic Spectral Oscillation in GRB 230307A: Evidence for Free Precession of a Post-Merger Magnetar?Authors: Run-Chao Chen, Jun Yang, Bin-Bin Zhang, Chen-Wei Wang, Wen-Jun Tan, Shao-Lin Xiong, Bing Zhang,Comments: 20 pages, 5 figures; author's accepted manuscript; accepted for publication in ApJLSubjects: astro-ph.HECreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Millisecond MAGNETars, rapidly rotating neutron stars with ultra-strong MAGNETic fields, have long been proposed as central engines of GAMMA-RAY BURSTs (GRBs). For GRBs produced by neutron star mergers, the survival of a long-lived MAGNETar remnant remains uncertain, as the merger remnant may rapidly collapse into a BLACK HOLE. In GRB 230307A, multiwavelength observations together with a previously reported 909-Hz periodic signal consistent with millisecond spin in its prompt emission provide strong evidence that such a post-merger MAGNETar may power the burst. Here we report the discovery of a quasiperiodic modulation with a characteristic period of 4.5 s in the spectral evolution of GRB 230307A, detected consistently across multiple gamma-ray instruments. The modulation is manifested as a coherent, energy-dependent variation of the spectral shape, with the strongest signature in the evolution of the peak energy. Within the MAGNETar-engine framework, such a low-frequency modulation can be interpreted as a manifestation of large-scale periodic variations associated with the central engine. If interpreted in terms of free precession, the observed timescale implies a stellar ellipticity of $ε\gtrsim 2.4 \times 10^{-4}$, corresponding to an internal MAGNETic field strength of $B_t \gtrsim 1.6 \times 10^{16}$ G, alongside a dipole field of $B_p \approx 5.6 \times 10^{15}$ G inferred from the early X-ray emission. These results suggest that such systems may provide potential sources of post-merger gravitational waves (GWs), motivating targeted searches following GRB triggers.
[abstract 13 / 55] Yes (score: 5) - Title: On the maximum neutrino flux of BLAZARs in the one-zone leptohadronic modelAuthors: Wei-Jian Li, Rui Xue, Ze-Rui Wang, Dingrong Xiong,Comments: 36 pages, 21 figures, 2 tables, accepted by ApJSubjects: astro-ph.HECreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
The origin of extragalactic high-energy neutrinos remains a major mystery in astrophysics, with BLAZARs as leading candidate sources. The widely adopted one-zone leptohadronic JET model, however, faces severe challenges from stringent X-ray observational constraints. In this work, we present an analytical approach that derives the maximum neutrino flux as a function of the observed X-ray flux and the corresponding physical parameters attainable within the one-zone leptohadronic framework. Applying this approach to a sample of neutrino candidate BLAZARs, we further perform numerical modeling and find agreement between analytical and numerical results. Both approaches consistently show that the model-predicted neutrino fluxes do not significantly exceed those obtained in previous one-zone studies and remain below the flux levels inferred from IceCube observations, suggesting that the one-zone scenario alone is unlikely to fully account for high-energy neutrino-BLAZAR associations. This highlights the importance of considering multi-zone models or alternative production sites (e.g., JET base, hot corona) to better explain high-energy neutrino origins in BLAZARs.
[abstract 14 / 55] Yes (score: 5) - Title: GRB 260310A / SN 2026fgk: A Multi-Wavelength Study of a Nearby Underluminous Long GRB and SN with a Complex AfterglowAuthors: Ramandeep Gill, Rosa L. Becerra, Antonio de Ugarte Postigo, Christina C. Thöne, Alan M. Watson, Noémie Globus, Jean-Grégoire Ducoin, Peter Veres, Stanley E. Kurtz, Asuka Kuwata, Antonio Martín-Carrillo, Luca Izzo, Christophe Adami, Enrique Moreno Méndez, Nikos Mandarakas, Camila Angulo-Valdez, Stéphane Basa, William H. Lee, Edilberto Aguilar-Ruiz, Dalya Akl, Margo F. Aller, Miguel Ángel Aloy, Jie An, Sarah Antier, Jean-Luc Atteia, Nathaniel R. Butler, Krittapas Chanchaiworawit, Philipe V. De La Parra, Damien Dornic, Francis Fortin, Shaoyu Fu, Johan P. U. Fynbo, Lluis Galbany, Leonardo García-García, Stefan Geier, Marion Guelfand, Linbo He, Shuaiqing Jiang, Emeric Le Floc'h, Massimiliano Lincetto, Xing Liu, Gianluca Lombardi, Diego López-Cámara, Daniele Bjørn Malesani, Francesco Magnani, Kanthanakorn Noysena, Margarita Pereyra, Ny Avo Rakotondrainibe, Anthony C. S. Readhead, Delphine Russeil, Fredd Sánchez-Álvarez, Benjamin Schneider, Tirth D. Surti, Nial R. Tanvir, Samaporn Tinyanont, Dong Xu, Zipei Zhu,Comments: Submitted to MNRASSubjects: astro-ph.HECreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
We present a comprehensive multi-wavelength study of GRB 260310A / SN 2026fgk, a nearby ($z=0.153$), long-duration GAMMA-RAY BURST (GRB) with an exceptionally underluminous prompt $γ$-ray emission and a Comptonized spectrum. It is located at the edge of a blue host galaxy with a projected distance of 15 kpc, which is one of the largest offsets reported for a long GRB. The bright optical afterglow, with dense coverage from COLIBRÍ, likely peaked at a few to several hours post-burst, followed by a shallow decay not expected from canonical afterglow models. Both the optical and X-ray light curves show a brief chromatic plateau from $4-7$ days and a more standard decay thereafter only terminated with a rebrightening at $\sim20$ days. We demonstrate that this feature is best described by a combination of emission from the Ic-BL SUPERNOVA, as identified in GTC spectra, and a late-time refreshed shock. The broadband optical to X-ray spectral energy distribution is well described by SYNCHROTRON emission from the forward shock, while the radio observations demand an additional emission component. We model the afterglow using (a) an on-axis uniform JET from a dirty fireball with late-time energy injection and (b) a misaligned JET with power-law angular structure, both having material emitting along our line-of-sight (LOS) moving with an initial Lorentz factor of $Γ_0\sim20-35$. Had this GRB occurred at a more typical redshift ($z\gtrsim0.5$), its prompt emission would likely have remained undetected by current $γ$-ray monitors while its optical afterglow would still have been readily detectable, placing it observationally among orphan afterglows or gamma-ray quiet fast X-ray transients.
[abstract 15 / 55] Yes (score: 4) - Title: Identification of periodicities with arbitrary shapes in AGN light curvesAuthors: Lorenzo Bertassi, Maria Charisi, Riccardo Buscicchio, Fabio Rigamonti, Jessie Runnoe, Massimo Dotti,Comments: 14 pages, 15 figures, Accepted by A&ASubjects: astro-ph.GACreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
Massive BLACK HOLE binaries are expected to be observable as periodic AGN in time-domain photometric surveys. Periodicities may originate from different physical processes, including the intermittent gas feeding of the BLACK HOLEs caused by the time-varying non-axisymmetric binary potential, the Doppler boosting of the flux emitted by individual accretion discs bound to the orbiting BHs, and the gravitational lensing of the accretion disc of one BLACK HOLE due to the presence of the other. Only the Doppler boost scenario applied to circular binaries with non-modulated accretion predicts a sinusoidal light curve, while in the general case, binary signals are expected to show more complex periodic patterns. Current searches for massive BLACK HOLE binaries rely on techniques tailored to quasi-sinusoidal light curves, but fail to identify the more complex periodicities predicted. We present an alternative method that leverages Gaussian processes, making use of a generic periodic kernel flexible enough for the identification of arbitrary periodicities in unevenly sampled light curves with realistic QUASAR noise. We demonstrate that it outperforms previously proposed strategies in identifying general periodicities by analysing mock light curves with different baselines. Specifically, we find that our analysis can detect non-sinusoidal periodicities (e.g., sawtooth-shaped) and retrieves a higher fraction of true periodicities when compared to periodogram analysis or Gaussian processes analysis with less flexible periodic kernels. Furthermore, by comparing the retrieved fraction of periodicities between mock PTF light curves and mock LSST light curves, we find that our analysis is most sensitive to the number of observed cycles. The application of this analysis has the potential to greatly increase the scientific return of current and upcoming large time-domain photometric surveys.
[abstract 16 / 55] Yes (score: 4) - Title: Stochastic Particle Acceleration during Pressure-Anisotropy-Driven Magnetogenesis in the Pre-Structure UniverseAuthors: Ji-Hoon Ha,Comments: 20 pages, 6 figures, Accepted for publication in Astroparticle PhysicsSubjects: astro-ph.HECreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
We investigate whether stochastic acceleration associated with pressure-anisotropy-driven MAGNETogenesis can generate a dynamically significant population of COSMIC RAYs (CRs) prior to nonlinear structure formation. As MAGNETic fields amplify in the early Universe, the associated increase in gyrofrequency enhances pitch-angle scattering, potentially shortening the stochastic acceleration time. We derive an analytic criterion for efficient cosmological acceleration by comparing the acceleration timescale with the Hubble time, which defines a critical MAGNETic field and a corresponding CR turn-on redshift $z_{\rm on}$. For representative parameters, we find $z_{\rm on}\sim1.7$. To quantify the resulting particle population, we solve a Fokker-Planck equation for the isotropic ion (proton) distribution in the redshift interval $z=10\rightarrow z_{\rm on}$, including Coulomb energy losses in a fully ionized intergalactic medium. Throughout most of this epoch, adiabatic expansion dominates over stochastic energization, and Coulomb cooling efficiently thermalizes low-energy particles, introducing an effective low-energy threshold at energies of order ${\mathcal O}(10)$ keV. As a result, the distribution remains close to a cooling Maxwellian, and the formation of a suprathermal tail is strongly suppressed even in the presence of a pre-existing nonthermal component. Even under optimistic assumptions corresponding to the strong-scattering limit, the maximum attainable ion energy reaches at most $\mathcal{O}(10^2)$ GeV. These results indicate that efficient CR production in the intergalactic medium is intrinsically tied to the onset of structure-formation shocks, while earlier microinstability-driven stochastic processes can provide at most a modest pre-acceleration.
[abstract 17 / 55] Yes (score: 4) - Title: Radiative MHD Studies of Solar Spicules: Driving Mechanisms and the Role of Background Magnetic FieldAuthors: Jin Li, Lei Ni, Robertus Erdélyi, Jun Lin, Xiaoli Yan, Guanchong Cheng,Comments:Subjects: astro-ph.SRCreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
We conduct 2.5D radiative MAGNETohydrodynamic (MHD) simulations to investigate the driving mechanisms of the solar spicules in coronal holes and how the different background MAGNETic fields affect their formation. The simulation model includes the upper convection zone, photosphere, chromosphere, and lower corona. We run several cases with different background MAGNETic fields to primarily explore the effects of MAGNETic field strength and inclination on the characteristics of the formed spicules, such as the maximum height, lifetime, maximum upward velocity, and deceleration. According to the results, we find that a weaker background MAGNETic field tends to cause solar spicules that exhibit higher heights, longer lifetimes and faster maximum upward velocities. Additionally, when the background MAGNETic field inclines, the generated spicules incline accordingly; compared with those in a vertical MAGNETic field, the spicules in the inclined MAGNETic field are relatively longer, with smaller decelerations, longer lifetimes and lower maximum upward velocities. Meanwhile, by tracking and analyzing the formation processes of the spicules in two cases with different MAGNETic field strengths, we find that most of the spicules are mainly driven by shock waves induced by convective and turbulent motions around the solar surface, while less than one third of the spicules are primarily driven by high-velocity RECONNECTion outflows. These results provide a more in-depth basis for the theoretical understanding of the driving mechanisms and formation processes of solar spicules.
[abstract 18 / 55] Yes (score: 4) - Title: Pulse Modulation as a Signature of the Asteroid-Neutron Star Collision Model for High-Energy TransientsAuthors: Partha Bagchi, Biswanath Layek, Dheeraj Saini, Anjishnu Sarkar, Ajit M. Srivastava, Deepthi Godaba Venkata,Comments:Subjects: astro-ph.HECreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
Asteroid-neutron star collision models have been proposed as possible sources of high-energy transients, such as GAMMA-RAY BURSTs (GRBs) and fast radio bursts (FRBs). The sequence of events following the impact of the asteroid and finally dissolving into the neutron star can have several other observable consequences. We propose that due to the development of the off-diagonal moment of inertia (MI) components, the merger's aftermath can lead to the wobbling of the pulsar (assuming the neutron star happens to be a pulsar). Using sample values of various parameters, viz., size, shape, the locations of the deposits, and the pre-existing pulsar deformation parameter ($η$), we calculate the detailed pulse profile modulation of the pulsar. We observe a distinct pattern of pulse profile modulation on a characteristic timescale enhanced by a factor of $1/η$ compared to the pulse timing. Importantly, even small changes in the MI components, of order $ε$, can produce large pulse profile modulations of order $ε/η$ (depending on the relative location of asteroid material deposition). Thus, if an asteroid-neutron star collision is responsible for a high-energy transient, the associated pulse profile modulation may serve as a falsifiable observational signature of such an event.
[abstract 19 / 55] Yes (score: 4) - Title: Radio Study of G76.9+1.0 Pulsar Wind NebulaAuthors: Haotian Qiu, Yunlei Huang, C-Y. Ng, Lili Yang, Sujie Lin, Yihan Liu,Comments: 8 pages, 7 figures, submitted to A&ASubjects: astro-ph.HECreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
Pulsar Wind Nebulae (PWNe) are key astrophysical laboratories for high energy phenomena. Specifically, radio observations and related polarimetry are essential probes to understand acceleration and transport, as well as PWN interaction with environment. We aim to better study the multi-wavelength morphology and MAGNETic geometry of \gname\ PWN (a system between early and middle ages). We conduct high resolution VLA observations at 3 cm (X band), 6 cm (C band), and 13 cm (S band) and compare them with the archival Chandra X-ray data. We also performed spectral analysis and radio polarimetry based on our radio observations. Our new VLA observations reveal a north-south double-lobed PWN bracketing a bridge-like feature, with the pulsar clearly resolved at C and S bands. The POLARIZATION fraction reaches 30\% across all bands, with the bridge region showing ordered north-south MAGNETic fields aligned with the X-ray torus elongation, while the southern outer lobe exhibits fields not following such a direction and the northern lobe displays a more chaotic configuration. Notably, we detect a significant radio-X-ray anti-correlation near the pulsar, with bright radio emission appearing just beyond the compact X-ray PWN boundary, multiwavelength spectral analysis suggest distinct particle populations. The radio PWN spectral index steepens from $α\sim-0.3$ in the inner bridge to $<-1.0$ in the outer lobes, yet we suggest it is less likely related to SYNCHROTRON cooling. We tried to use a thick torus model with toroidal $B$-field to reproduce observed features; the result implies possible particle deceleration in the radio PWN. The equipartition MAGNETic field strength is estimated to be $\sim$15.3\,$μ$G.
[abstract 20 / 55] Yes (score: 4) - Title: Discovery of Short-Term γ-Ray Pulsed Radiation Variations Following a Glitch in PSR J0205+6449Authors: Wen-Tao Ye, Ming-Yu Ge, Shi-Jie Zheng, Xiang Ma, Yu-Jia Zheng, Han-Long Peng, Xue-Zhi Liu, Li-Ming Song, Shuang-Nan Zhang, Fang-Jun Lu,Comments: 10 pages, 3 figures, 1 table; accepted by ApJLSubjects: astro-ph.HECreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
Rotation-powered pulsars exhibit stable emission characteristics most of the time. However, their radiative state can vary with the sudden changes of rotational state such as glitches. To date, pulsed radiation changes associated with glitches have only been detected in the radio band. Since the emission regions of radio and $γ$-ray may differ, searching and investigating whether glitches can induce changes in high-energy radiation would further deepen our understanding of how glitches affect the MAGNETosphere of pulsars. We report successive variations in the $γ$-ray pulsed radiation of PSR J0205+6449 following the glitch at MJD 54904 observed by the {\sl FERMI}/LAT. The amplitude ratio of the two peaks showed a hint of an increase during MJD 54905--54940 initially, followed by a recovery to the mean level and a significant ($>5\,σ$) decrease in the separation between the two peaks over MJD 54940--55000. The amplitude ratio of the two peaks increased ($\sim3\,σ$) again in MJD 55000--55160, accompanied by a marginal flux variation. Finally, the pulsed radiation reverted to its normal state. This is the first significant detection of pulsed radiation variation associated with a glitch in $γ$-ray pulsars. We attribute this to MAGNETospheric reconfiguration triggered by localized crustal breaking and associated elastic displacement near the polar cap following the glitch.
[abstract 21 / 55] Yes (score: 4) - Title: Legacy analysis of Milky Way dwarf spheroidal satellite galaxies: an updateAuthors: A. Circiello, M. Di Mauro, M. Ajello, C. Karwin, A. Drlica-Wagner, M. Á. Sánchez-Conde,Comments:Subjects: astro-ph.HECreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Studies of FERMI-Large Area Telescope (LAT) data coincident with dwarf spheroidal satellite galaxies (dSphs) of the Milky Way (MW) have put the most stringent constraints on models of annihilating DARK MATTER (DM) with candidate masses in the GeV-TeV range. Recent results found the presence of small, local significance excesses from these targets, at the 2-3 sigma level. However, these excesses disagree on the predicted properties of the DM candidate, and their significance vanishes when considering the correction factors for the number of trials. In this work, we apply key improvements to the analysis of the dSphs. We use stricter cuts on the data, implement a method to adaptively model the background, and assume an updated framework for DM annihilation. We find that our improved background modeling leads to a better agreement between the model and the data. This produces an increase in the local and global significance of the dSphs excess compared to previous studies. Finally, we find that the DM properties obtained in this work are less dependent on the sample of dSphs being considered compared to previous studies, while remaining in agreement with the predictions from the Galactic center excess observed by the FERMI-LAT and the antiproton excess observed by the Alpha Magnetic Spectrometer (AMS-02). Considering our improvements, a future significant increase in the number of dwarfs may lead to a definitive confirmation or exclusion of the DM interpretation of the Galactic center excess.
[abstract 22 / 55] (score: 3) - Title: Turbulence in Magnetised Neutron StarsAuthors: William Cook, Raj Kishor Joshi, Sebastiano Bernuzzi, Brynmor Haskell, Jacob Fields,Comments: 11 pages, 7 figures. Extended discussion of helicity. Updated to match published version in MNRASSubjects: astro-ph.HE gr-qcCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
The MAGNETic field configuration in the interior of neutron stars and its stability are open problems and may be impacted by the influence of a turbulent cascade within the star. Assessing the impact of turbulent flow with numerical simulations requires incredibly high resolution as well as long lived simulations covering multiple Alfven times. We present a series of simulations of MAGNETised neutron stars with resolution up to 29m and lasting at their longest 1.2s to assess this issue, the longest lasting and highest resolution such simulations to date. At the highest resolution we find evidence for a turbulent cascade absent in an unMAGNETised star which cannot be captured with lower resolution simulations, consistent with Kolmogorov power law scaling. The presence of turbulence triggers an inverse cascade of helicity, while at late times the net helicity appears to vanish, suggesting that a twisted-torus is not formed in the MAGNETic field. We find that the presence of the MAGNETic field excites a characteristic quadrupolar oscillation of the density profile at 145 Hz, consistent with Alfvenic modes proposed as the source of quasi-periodic oscillations observed in MAGNETars.
[abstract 23 / 55] (score: 3) - Title: Systematic Effects of Chaotic Magnetic Fields on Neutron Star Tidal Deformability: Implications for Gravitational Wave Constraints on Dense MatterAuthors: Debarshi Mukherjee,Comments: This manuscript is being withdrawn by the author because it does not meet the scientific standards the author wishes to maintain in the permanent literature. The results and presentation are considered preliminary and should not be citedSubjects: astro-ph.HE gr-qcCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
We investigate the effects of strong MAGNETic fields on the equation of state (EoS) of neutron star matter and the resulting implications for tidal deformability measurements in binary neutron star (BNS) mergers. A critical issue with previous MAGNETized neutron star studies is the treatment of MAGNETic field anisotropy in the Tolman-Oppenheimer-Volkoff (TOV) equations. To address this fundamental problem, we employ the chaotic MAGNETic field approximation, which allows for a self-consistent treatment of MAGNETic pressure while maintaining isotropy. Using a RELATIVISTIC mean field approach with properly implemented MAGNETic field corrections, we compute mass-radius relations and tidal deformability parameters for neutron stars with MAGNETic field strengths ranging from $10^{15}$ to $10^{16}$ G. Our systematic study reveals that MAGNETic fields induce increases in both stellar radii (0.8--2.3\%) and tidal deformabilities (4.2--18.1\%) compared to field-free cases, with effects scaling approximately as $B^{1/2}$. These modifications, while modest, are potentially detectable with current and next-generation gravitational wave detectors. For a canonical $1.4\,M_\odot$ neutron star, the tidal deformability increases from $Λ_{1.4} = 678 \times 10^6$ in the absence of MAGNETic fields to $Λ_{1.4} = 803 \times 10^6$ for $B = 10^{16}$ G. We demonstrate that MAGNETic field effects must be considered when constraining the neutron star equation of state using gravitational wave observations, particularly for populations including highly MAGNETized neutron stars. Our results suggest that the current GW170817 constraint on tidal deformability may require systematic corrections when accounting for MAGNETic field effects. We provide scaling relations for MAGNETic field corrections and discuss the implications for population studies of neutron star mergers with next-generation detectors.
[abstract 24 / 55] (score: 3) - Title: First detection of X-ray POLARIZATION from the long-period X-ray pulsar 4U 1954+319Authors: Alexander Salganik, Lingda Kong, Sofia V. Forsblom, Menglei Zhou, Honghui Liu, QingChang Zhao, Sergey S. Tsygankov, Andrea Santangelo, Juri Poutanen,Comments: Accepted to A&A. 7 pages, 7 figures, 3 tablesSubjects: astro-ph.HECreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
We report the first detection of X-ray POLARIZATION with the Imaging X-ray Polarimetry Explorer from the X-ray pulsar (XRP) 4U 1954$+$319. The source belongs to an extremely rare class of systems in which a slowly rotating neutron star accretes from the dense wind of a red supergiant companion. We detect coherent pulsations at $P_{\rm spin}=5.49\pm0.05$ h, which is one of the longest spin periods known among XRPs. While the phase-averaged analysis shows no significant POLARIZATION, with a 99% confidence minimum detectable POLARIZATION (MDP$_{99}$) of 4.9% in the 2-8 keV band, the phase-resolved analysis shows a single interval at pulse maximum in which the POLARIZATION degree (PD) exceeds the MDP$_{99}$, yielding ${\rm PD}=10.2_{-3.0}^{+3.1}$%. The POLARIZATION angle (PA) exhibits a smooth $\approx150^{\circ}$ rotation over the pulse, and a joint evaluation of all phase bins yields an overall detection significance of $3.3σ$. Using the rotating vector model, we identify a geometric solution that reproduces the observed PA variation. From this model, we infer a phase-independent ${\rm PD}$ of $6.1\pm1.1$% in the 2-8 keV band.
[abstract 25 / 55] (score: 3) - Title: Little Red Dot $-$ Host Galaxy $=$ Black Hole Star: A Gas-Enshrouded Heart at the Center of Every Little Red DotAuthors: Wendy Q. Sun, Rohan P. Naidu, Jorryt Matthee, Anna de Graaff, John Chisholm, Jenny E. Greene, Pascal A. Oesch, Alberto Torralba, Raphael E. Hviding, Gabriel Brammer, Robert A. Simcoe, Sownak Bose, Rychard Bouwens, Pratika Dayal, Anna-Christina Eilers, Qinyue Fei, Lukas J. Furtak, Rashmi Gottumukkala, Andy Goulding, Kasper E. Heintz, Michaela Hirschmann, Vasily Kokorev, Joel Leja, Zhaoran Liu, Priyamvada Natarajan, Andrew D. Santarelli, David J. Setton, Aaron Smith, Sandro Tacchella, Marta Volonteri, Fabian Walter, Andrea Weibel, Christina C. Williams,Comments: Published in the Open Journal of Astrophysics. Main results in Figs. 5 (BH* stack), 12 (explanation of the LRD SED), and 15 (hidden BH*s in blue galaxies). Comments warmly welcomed!Subjects: astro-ph.GA astro-ph.CO astro-ph.HECreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
The central engines of Little Red Dots (LRDs) may be ``BLACK HOLE stars" (BH*s), early stages of BLACK HOLE growth characterized by dense gas envelopes. So far, the most direct evidence for BH*s comes from a handful of sources where the host galaxy is completely outshone as suggested by their remarkably steep Balmer breaks. Here we present a novel scheme to disentangle BH*s from their host galaxies assuming that the [OIII]5008Å line arises exclusively from the host. Using a sample of 98 LRDs ($z$~$2-9$) with high quality NIRSpec/PRISM spectra, we demonstrate that the host-subtracted median stack displays a Balmer break $>2\times$ stronger than massive quiescent galaxies, with the rest-optical continuum resembling a blackbody-like SED ($T_{\rm{eff}}$~$4050$ K, $\log(L_{\rm{bol}})$~$43.9$ erg s$^{-1}$, $R_{\rm{eff}}$~$1300$ au). We measure a steep Balmer decrement (H$α$/H$β>10$) and numerous density-sensitive features (e.g., FeII, HeI, OI). These are hallmark signatures of dense gas envelopes, providing population-level evidence that BH*s indeed power LRDs. In the median LRD, BH*s account for $\sim20\%$ of the UV emission, $\sim50\%$ at the Balmer break, and $\sim90\%$ at wavelengths longer than H$α$ with the remainder arising from the host. BH*s preferentially reside in low-mass galaxies ($M_{\rm{\star}}$~$10^{8}\,{\rm M}_{\rm{\odot}}$) undergoing recent starbursts, as evidenced by extreme emission line EWs (e.g., [OIII]5008Å~$1100$Å, CIII]~$12$Å), thereby favoring BH* origins linked to star-formation. We show V-shaped LRD selections are biased to high BH*/host fractions ($\gtrsim60\%$ at 5500Å) -- less dominant BH*s may be powering JWST's blue broad-line AGN. We find BH*s are so commonplace and transient (duty cycle $\sim1\%$, lifetime $\sim10$ Myrs) that every massive BLACK HOLE may have once shone as a BH*.
[abstract 26 / 55] (score: 3) - Title: Dynamic Alignment as a Statistical Survival EffectAuthors: Amir Jafari,Comments:Subjects: physics.plasm-ph astro-ph.SR physics.space-phCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Dynamic alignment in MAGNETohydrodynamic (MHD) turbulence is usually taken to mean that Elsässer fluctuations become increasingly aligned at smaller inertial-range scales. We show that this is not the correct physical interpretation of standard weighted measurements: the measured small angles result from statistical selective survival rather than from a volume-filling tendency toward alignment. Our framework separates angular statistics from Elsässer-amplitude weighting and describes amplitude--angle populations through selective retention. Large-amplitude large-angle events deplete faster than large-amplitude small-angle events, so the latter are overrepresented in weighted measurements although the typical folded angle shows no progressive scale dependence. The aligned strong-event population need not be produced more efficiently; it can dominate second-order amplitudes because it has a longer residence time. Thus retention allows effective Elsässer-increment scaling shallower than \(\ell_\perp^{1/3}\), without scale-dependent alignment of the typical angle. We test this using JHTDB MHD data and Wind observations. In JHTDB, the unweighted folded angle remains moderately below the random baseline, while weighted diagnostics sample intense Elsässer-increment events whose amplitudes correlate with smaller folded angles. The measured retention balance produces effective Elsässer-increment scaling close to \(\ell_\perp^{1/4}\), giving \(k_\perp^{-3/2}\) rather than Kolmogorov--Richardson \(k_\perp^{-5/3}\), while the typical folded angle shows no progressive scale-dependent alignment. Wind shows the same angle--amplitude hierarchy and negative covariance. Dynamic alignment, as usually measured, is thus better understood as selective survival of small-angle intense fluctuations, with a nearly scale-independent typical angle and a \(k_\perp^{-3/2}\)-type effective spectrum.
[abstract 27 / 55] (score: 3) - Title: Timing and Spectral Studies of PSR J2022+3842 with NICER and NUSTARAuthors: Jia-Ning Hu, Xiang-Hua Li, Xian-Ao Wang, Han-Long Peng, Shi-Qi Zhou, Wen-Tao Ye, Shi-Jie Zheng, Ze-Jun Jiang, Ming-Yu Ge,Comments:Subjects: astro-ph.HECreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
We report on the long-term timing analysis of PSR J2022+3842 using observations from the Neutron Star Interior Composition Explorer (NICER), along with spectral properties derived from joint observations with NICER and the Nuclear Spectroscopic Telescope Array (NUSTAR). Two large glitches are identified around MJD 58335 with $Δν=25.35(2)\times10^{-6}$ Hz and MJD 58875 with $Δν=52.078(6)\times10^{-6}$ Hz. Furthermore, phase-resolved spectroscopy reveals that the X-ray emission is well described by a power-law model across different phase intervals. The phase-integrated X-ray spectrum (1-79 keV) has a photon index of $Γ=1.22(7)$, yielding an unabsorbed 0.5-10 keV flux of $8.9(6)\times10^{-13}$ erg cm$^{-2}$ s$^{-1}$. The main pulse spectrum (1.2-79 keV) and the inter-pulse spectrum (1-70 keV) are harder with $Γ=1.17(4)$ and $Γ=1.03^{+0.07}_{-0.06}$ separately, producing an unabsorbed 0.5-10 keV flux of $33.2(2)\times10^{-13}$ erg cm$^{-2}$ s$^{-1}$ and $29(3)\times10^{-13}$ erg cm$^{-2}$ s$^{-1}$. Investigation of the pulse profile evolution with time shows that no significant variations were observed.
[abstract 28 / 55] (score: 3) - Title: QPEs from Warped Disk Collisions with EMRIs: Brightness-Recurrence Diagram and Gravitational-Wave Follow-upAuthors: Bo-An Chen, Bei You, Giovanni Miniutti, Ning Jiang, Zhen Pan, Tao Yang, Xi-Long Fan, Kai Liao, Xu-Heng Ding, Zong-Hong Zhu, Shuai-Kang Yang, Sai-En Xu, Han He, Xiao Fan,Comments: 8 pages, 4 figures, submittedSubjects: astro-ph.HE astro-ph.CO astro-ph.GA gr-qcCreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
Quasi-Periodic Eruptions (QPEs) display correlated long/short and strong/weak patterns that remain unexplained by existing flat-disk collision models. We propose that these features arise from an extreme-mass-ratio inspiral (EMRI) colliding with a warped accretion disk, likely formed after a tidal disruption event. The warp modulates both recurrence time and burst energy, encoding the disk geometry -- and thus the spin of the central supermassive BLACK HOLE (SMBH) -- into the X-ray light curve. We introduce the Brightness-Recurrence Diagram (BRD) to visualize this correlation, where QPE bursts trace an elliptical trajectory driven by the EMRI's apsidal precession; the tilt of this ellipse encodes whether the EMRI is prograde or retrograde relative to the SMBH spin. Applying this model to the prototypical QPE source GSN 069 successfully reproduces the observed patterns. The data are consistent with either a prograde stellar secondary or a retrograde stellar-mass BLACK HOLE. In the stellar-mass BLACK HOLE scenario, ongoing orbital decay could render the EMRI detectable by LISA within a few decades, facilitating gravitational-wave follow-up and independent multimessenger constraints on the system.
[abstract 29 / 55] (score: 3) - Title: ElectroMAGNETic Signatures of Kinetic Alfvén Wave Turbulence at Ion Inertial Scales in Earth's High-$β$ MagnetosheathAuthors: Mani K Chettri, Rupak Mukherjee, Hemam D. Singh,Comments:Subjects: physics.plasm-phCreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
We present a multi-diagnostic electroMAGNETic study of kinetic Alfvén wave (KAW) activity in Earth's MAGNETosheath using burst-mode measurements from the Magnetospheric Multiscale (MMS) mission. We apply this analysis to a well-characterized dayside MAGNETosheath interval on 2015 December 28 at unusually high plasma $β_i \approx 14$. The identification relies on four simultaneous criteria: the normalized electric-to-MAGNETic field ratio $\dEperp / (\dBperp \vA)$ exceeding the ideal MHD limit (median 2.55), the presence of a finite parallel electric field $\dEpar$ (peak $3.2$~mV~m$^{-1}$), a spectral break at the ion inertial scale $\kperp d_i \approx 1$ (where $d_i = 45.0$~km is the ion inertial length, the theoretically expected transition scale at $β_i \gg 1$), and a kinetic-range MAGNETic compressibility $C_B = 0.31$ within the KAW-predicted range $[0.10, 0.40]$. All four criteria are satisfied in the same interval, providing a consistent electroMAGNETic identification of KAWs that does not require particle distribution measurements. A key result of this analysis is the clear identification of $d_i$ rather than the ion gyroradius $\rhoi = 170.4$~km as the relevant spectral break scale. At $β_i = 14.4$, the two scales differ by a factor of 3.79, making this distinction observationally testable in a way that is not possible at the more typical MAGNETosheath $β\sim 1$--$5$.
[abstract 30 / 55] (score: 3) - Title: Discovery of Molecular and Atomic Gas associated with HESS J1646-458 (Westerlund 1): Spatial TeV Gamma-Ray and Interstellar Proton CorrespondenceAuthors: H. Sano, Y. Fukui, S. Fujimori, T. Murase, R. Z. E. Alsaberi, M. D. Filipović, G. Rowell, M. Aruga, Y. Asano, R. G. Bhuvana, F. Demachi, S. Einecke, N. Fukaya, R. Hamada, H. Inoue, T. Kamazaki, S. Lazarević, T. Minamidani, Z. J. Smeaton, H. Sudou, K. Tachihara, H. Takaba, K. Tsuge, R. I. Yamada,Comments: 18 pages, 9 figures, accepted for publication in The Astrophysical Journal (ApJ)Subjects: astro-ph.HE astro-ph.GACreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
We report CO and HI studies of molecular and atomic gas toward the TeV gamma-ray source HESS J1646$-$458, widely considered to be associated with the young massive cluster Westerlund 1 (Wd1). We found that molecular clouds at $V_\mathrm{LSR} \sim$$-32$ km s$^{-1}$ coincide with arc-like structures seen at 8 $μ$m, likely illuminated by strong FUV radiation from Wd1. $^{12}$CO($J$ = 3-2) emission at the same velocity reveals a cavity-like structure with an expansion velocity of $\sim$$5$ km s$^{-1}$ toward the central region of Wd1, suggesting a recently formed wind-blown bubble driven by the cluster. We also identify a complementary spatial distribution between the $V_\mathrm{LSR} \sim$$-55$ and $\sim$$-32$ km s$^{-1}$ clouds, connected by an intermediate-velocity component at $V_\mathrm{LSR} \sim$$-44$ km s$^{-1}$. These characteristics are consistent with signatures of triggered STAR FORMATION through a cloud-cloud collision and imply that both clouds are physically associated with Wd1. On larger scales, the total interstellar proton column density at $V_\mathrm{LSR}$ $\sim$$-36$-$-23$ km s$^{-1}$ shows a moderate spatial correspondence with the TeV gamma-ray shell. Together with this correlation, a substantial gas mass of $\sim$$1.6 \times 10^6$ $M_\odot$, and the absence of bright SYNCHROTRON X-rays, the TeV gamma-ray emission surrounding Wd1 is consistent with the hadronic origin. The present finding allows us to calculate the total energy of accelerated cosmic-ray protons to be $\sim$$6 \times 10^{49}$ erg.
[abstract 31 / 55] (score: 3) - Title: Reassessing high-energy emission correlations in GAMMA-RAY BURSTs using a large, homogeneous sample of X-ray afterglowsAuthors: A. A. Vigliano, F. Longo, Ž. Bošnjak,Comments: A&A, acceptedSubjects: astro-ph.HE astro-ph.IMCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Gamma-ray bursts (GRBs) show diverse X-ray afterglow light-curves, including breaks and plateaus, whose physical origins remain debated. Previous claims linked high-energy ($E \ge 100$ MeV) detection to X-ray afterglow complexity or plateau incidence, but they were often based on small or heterogeneous samples. We present a large-scale, uniform, model-independent analysis of the complete SWIFT-XRT GRB afterglow catalog, including more than 1400 events. Our automated pipeline performs flare removal and segmented power-law fitting consistently across the sample. We find that both light-curve complexity and plateau incidence are strongly governed by the XRT observation start time, $t_{XRT}$. Apparent correlations between high-energy emission and X-ray morphology arise when $t_{XRT}$ is ignored, but vanish when the sample is stratified or controlled for this variable. X-ray complexity and plateaus are therefore not directly coupled to high-energy detectability, and early X-ray morphology is not predictive of high-energy emission. These results resolve conflicting claims in the literature and show that controlling for $t_{XRT}$ is essential in large-sample GRB studies. The automated pipeline provides a reproducible basis for future analyses of GRB afterglows from SWIFT and upcoming missions such as SVOM, Einstein Probe, and THESEUS.
[abstract 32 / 55] (score: 3) - Title: Extreme color-magnitude variability: connection to changing-look AGNsAuthors: Litao Zhu, Zhongxiang Wang, Alok C. Gupta, P. U. Devanand, Ruoheng Yang, Qiangmeng Huang, Man Lang, Jiawen Li,Comments: 15 pages, 17 figures, 3 tables, submitted to A&ASubjects: astro-ph.GACreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Context. Changing-look ACTIVE GALACTIC NUCLEi (CL-AGNs) challenge the unified model of AGNs and offer key insights into the physics of the accretion processes of super-massive BLACK HOLEs. While systematic spectroscopic comparisons have successfully identified large samples of CL-AGNs, photometric selection based on variability features provides an efficient alternative. Methods. We use the colour--magnitude (CM) variability method to continue our identification of the CL transition in AGNs, which utilizes the slope ($k$) of the CM variations to identify strong bluer-when-brighter behavior, while the variation amplitudes in optical and mid-infrared bands are also considered. The candidates thus selected from the Type-2 AGNs given in the Sloan Digital Sky Survey catalog are spectroscopically observed using the 3.6-m DOT and the 2-m HCT. Results. We confirm seven turn-on CL-AGNs among 12 candidates. Comparing them with both the general AGN populations and the spectroscopically identified CL-AGN sample, the CL-AGNs showed larger optical and MIR variations and $k$ values. The extreme CM variabilities of these sources (with optical magnitude changes $>$ 0.9) occurred recently. For four sources, flare-like brightening episodes were temporally associated with the turn-on transitions within 3--7 years, suggesting that these flares may trace short-timescale accretion enhancement, central brightening, and BLR re-illumination. Conclusions. The extreme CM variability serves as a highly efficient criterion for finding CL-AGNs. The properties of the CL-AGNs thus found suggest that they may represent AGNs at a pivotal state, which likely occur CL transitions due to enhanced accretion activity, while the cause of the accretion activity, determined to have a time scale of several years, remains to be investigated.
[abstract 33 / 55] (score: 3) - Title: Diversity of morphology of type II spicules in MURaM-ChE simulationsAuthors: Sanghita Chandra, Robert Cameron, Damien Przybylski, Sami K. Solanki,Comments: 15 pages, 14 figures. Accepted for publication in A&ASubjects: astro-ph.SRCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Spicules are ubiquitous, small-scale features in the solar atmosphere, exhibiting a JET-like appearance most clearly identified by their apparent motion in off-limb observations. While they are often interpreted as narrow, thread-like structures, their true three-dimensional (3D) structure remains unknown. We aim to uncover the 3D morphology and dynamics of fast-evolving spicules (type II) using a MURaM-ChE simulation. We use a H$α$ proxy that has been developed using non-equilibrium (NE) hydrogen populations in MURaM-ChE. The proxy, modelled as an escape probability, is synthesised to isolate on-disc as well as off-limb H$α$ wing features. The 3D structure of these features is investigated using the 3D information on opacity in H$α$. We identify type II spicules, with unique 3D morphologies: the dominant being thread-like and slab-like. The appearance of spicules as slabs or threads is a function of time and Doppler velocity. The spicules extending above the spicule-forest (2Mm -3Mm above the surface) tend to be located at quasi-separatrix layers (QSLs). We find that the spatially resolved contributions to the opacity of spicules are often similar for spicules synthesised in the horizontal direction, and their on-disk rapid blueshifted excursion (RBE) synthesised in the vertical direction at the same Doppler velocity of 37km/s. This confirms that RBEs are indeed the on-disc counterparts of spicules. Furthermore, our analysis indicates that cross-field motions can significantly contribute to spicule dynamics. Spicules exhibit a range of morphologies, including both slab-like and thread-like structures. Their observed appearance depends strongly on line-of-sight projection and Doppler sampling. Spicules are preferentially located at QSLs, highlighting the role of MAGNETic topology in driving spicular dynamics.
[abstract 34 / 55] (score: 2) - Title: Thermodynamic topology of dyonic AdS BLACK HOLEs with quasitopological electroMAGNETism in Einstein-Gauss-Bonnet gravityAuthors: Hao Chen, Meng-Yao Zhang, Hassan Hassanabadi, Bekir Can Lütfüoğlu, Zheng-Wen Long,Comments: 13 pages, 24 figuresSubjects: gr-qcCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
In this study, we investigate the thermodynamic topology of the high-dimensional dyonic AdS BLACK HOLEs with quasitopological electroMAGNETism in the Einstein-Gauss-Bonnet background. We first examine the topological charge connected to the critical point and find that the two conventional critical points $CP_{1},CP_{2}$ of the BLACK HOLE are physical critical point, and the novel critical point $CP_{3}$ that lacks the capability to minimize the Gibbs free energy ($α=0.5$). The critical points $CP_{1}$ and $CP_{2}$ are observed to occur at the maximum extreme points of temperature in the isobaric curve, while the critical point $CP_{3}$, emerges at the minimum extreme points of temperature. Furthermore, the number of phases at the novel critical point exhibits an upward trend, followed by a subsequent decline at the conventional critical points. With the increase of the coupling constant ($α= 1$), although the system has three critical points, only the conventional $CP_{1}$ is a (physical) critical point, and the conventional $CP_{2}$ serves as the phase annihilation point. This means that the coupling constant $α$ has significant impact on the phase structure. Additionally, we regard dyonic AdS BLACK HOLEs as a topological defect within the thermodynamic space, our findings indicate that alterations in pressure can result in the system exhibiting distinct points of generation and annihilation. However, the total topological number of BLACK HOLEs in different dimensions is $1$, the system shares a similar topological classification as the charged RN-AdS BLACK HOLEs. The discovery we have made provides a crucial component in understanding the thermodynamic topology of dyonic AdS BLACK HOLEs.
[abstract 35 / 55] (score: 2) - Title: Experimental investigation relating free-surface features to sub-surface turbulenceAuthors: Omer M. Babiker, Jørgen R. Aarnes, Ali Semati, Amélie Ferran, Yi Hui Tee, R. Jason Hearst, Simen Å. Ellingsen,Comments:Subjects: physics.flu-dynCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Turbulent flows beneath a free surface play a central role in the Earth system, yet their coupling to observable surface features remains incompletely understood. Recent studies using Direct Numerical Simulations (DNS) have reported strong correlation between observable surface features and surface divergence as well as velocity statistics directly beneath, but were limited to Reynolds numbers ($Re$) far below those typical of natural flows, and do not carry the inherent challenges of measurement and flow fidelity that real flows present. We present a laboratory study in which free-surface topology and sub-surface turbulent velocity are measured simultaneously in a JET-stirred tank, extending these numerical results to the physical domain. Using a novel combination of particle-image velocimetry (PIV) and free-surface profilometry, we access $Re$ up to two orders of magnitude higher than in the DNS. A computer vision method developed for identifying turbulent imprints on the free surface is successfully applied to experimental data, enabling direct comparison with the DNS. The correlation between time series of mean-square surface divergence and surface features is found to persist as strongly at higher Reynolds numbers, despite the increased disparity of turbulent scales. Beyond the thin viscous layer, all surface-to-bulk correlations scale with the integral length scale across both experimental and numerical cases. The normalized cross-correlation between mean-square horizontal velocity divergence and surface area covered by structures decreases linearly with depth and remains significant even two integral scales beneath the surface, unlike point-to-point correlations which decay fast, illustrating how correlations are near-instantaneous but spatially non-local. These results demonstrate that visible surface features provide considerable... [truncated due to arXiv length constraint]
[abstract 36 / 55] (score: 2) - Title: Exact Black Hole Solutions in Bumblebee Gravity with Lightlike or Spacelike VEVSAuthors: Jia-Zhou Liu, Shan-Ping Wu, Shao-Wen Wei, Yu-Xiao Liu,Comments:Subjects: gr-qcCreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
Motivated by recent developments in Lorentz-violating theories of gravity, we obtain new BLACK HOLE solutions within the framework of bumblebee gravity, where the bumblebee vector field possesses two independent nonzero components and acquires either a lightlike or spacelike vacuum expectation value. Within this framework, we derive new Schwarzschild-like and Schwarzschild-(A)dS-like BLACK HOLE solutions. By further incorporating a nonminimally coupled electroMAGNETic field, we generalize these to new charged BLACK HOLE solutions. These solutions extend previous results by including additional Lorentz-violating parameters. A key finding is that even for lightlike vacuum expectation values, the BLACK HOLE solutions exhibit distinct corrections from Lorentz violation. Furthermore, we present a preliminary analysis of their thermodynamic properties. Similar to previous studies that reported a discrepancy between the BLACK HOLE entropy and the Wald entropy in bumblebee gravity with spacelike vacuum expectation values, our solutions in the spacelike case exhibit the same behavior. In contrast, for the lightlike case considered here, the two entropies coincide.
[abstract 37 / 55] (score: 2) - Title: A Universal Framework for Horizon-Scale Tests of Gravity with Black Hole ShadowsAuthors: Wentao Liu, Yang Liu, Di Wu, Yu-Xiao Liu,Comments: 10 pages, 10 figures; accepted for publication as a Letter in PRDSubjects: gr-qcCreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
In this Letter, we have developed a numerically efficient framework for evaluating parameters in metric theories of gravity, and applied it to constrain the horizon-scale MAGNETic field in the Kerr-Bertotti-Robinson (Kerr-BR) spacetime using the latest EHT observations. The method's adaptive ray-tracing strategy achieves near-linear computational efficiency without loss of numerical accuracy. Owing to this efficiency, the framework enables high precision shadow modeling at minimal computational cost and, for the first time, supports statistically robust inference of BLACK HOLE parameters from horizon-scale observations for arbitrary stationary BLACK HOLEs. The above framework is applied to the recently obtained Kerr-BR BLACK HOLE, an exact MAGNETized and rotating solution to the Einstein field equations. We have evaluated the horizon-scale MAGNETic fields of M87* and Sgr A*, with the latter showing a field strength of $93.3^{+14.7}_{-23.8}G$, consistent with the equipartition estimate of $71G$ from polarized ALMA observations, thereby supporting Einstein's gravity.
[abstract 38 / 55] (score: 2) - Title: Tamm-Rubilar branch diagnostics for Drummond-Hathrell photon propagation: Schwarzschild calibration and a Kerr weak-lensing benchmarkAuthors: José Rodal,Comments: 27 pages, 1 figure, 1 table. Major replacement of arXiv:2603.21352v1-v2: title and scope changed; prior ansatz-dependent warp-drive screening claim removed as a main result and retained only as an appendix-level test. Refocused on Tamm-Rubilar diagnostics, DH calibration, and Kerr weak-lensing. Ancillary code bundle includedSubjects: gr-qcCreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
This paper develops a local Tamm-Rubilar branch diagnostic for supplied nondispersive, pair-symmetric constitutive tensors and uses it as a preprocessing layer for POLARIZATION-resolved ray transport. The diagnostic constructs the local quartic Fresnel polynomial, checks real ADM-oriented roots and root margins, and separates algebraic branch stability from the separate effective-field-theory question of when a Drummond-Hathrell low-frequency surrogate is applicable. For constitutive tensors with a reflection isometry, the adapted bivector matrix has an exact parity block form. The full parity-invariant Tamm-Rubilar polynomial is a quartic with coefficients even in the transverse momentum, while a restricted meridional SSSW-frame quartic is retained only as a compact analytic benchmark and root-margin test. In Schwarzschild, the Ricci-flat Drummond-Hathrell curvature sector factorizes and reproduces the standard radial no-shift and orbital POLARIZATION-split result. The rotating-spacetime benchmark is an infinity-to-infinity weak-lensing calculation in the linearized Kerr field. In a transported Born screen, the local slow-Kerr MAGNETic-Weyl eigenbasis tilt has zero leading endpoint mismatch, while the branch-delay split has a spin-odd term proportional to the angular momentum projected along the lens-plane normal. The resulting phase retardance is far below near-term detectability for representative compact-object grazing rays, so the Kerr calculation is presented as a reproducible scale-setting benchmark for the diagnostic and transport framework rather than as an observational claim.
[abstract 39 / 55] (score: 2) - Title: Irregular Repeating Tidal Disruption Events due to Diffusive TidesAuthors: Shu Yan Lau, Ethan McKeever, Hang Yu,Comments: 13 pages, 5 figuresSubjects: astro-ph.HECreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
A repeating partial tidal disruption event (rpTDE) is typically modeled as a star on a bound orbit that is partially disrupted by a massive BLACK HOLE (MBH) at each pericenter passage. For disruption to occur, the pericenter distance must be close to or within the characteristic tidal radius, such that the tidal field overcomes the star's binding force and triggers mass loss. However, a binary with a pericenter distance several times the tidal radius can build up its tidal perturbation over multiple orbits via a diffusive process, eventually triggering a nonlinear instability that ejects mass and powers an eruption. This leads to repeated, stochastic disruptions. In this Letter, we propose that such a mechanism can produce a subclass of rpTDEs with large variations in recurrence time (e.g., J0456-20), which we dub ``diffusive-tide rpTDEs''. We show that diffusive tidal growth can occur for a white dwarf or main-sequence star orbiting a MBH when the pericenter distance is a few times the tidal radius, provided that the orbital period is shorter than the tidal energy dissipation timescale. These diffusive-tide rpTDEs may account for a significant fraction of the rpTDE population.
[abstract 40 / 55] (score: 2) - Title: Transport of electrons in tangled MAGNETic fieldsAuthors: Daniel Verscharen, Natasha Jeffrey, Anton Artemyev, Jesse T. Coburn, Matthew W. Kunz, Oreste Pezzi, Mario Riquelme, Ida Svenningsson, Lynn B. Wilson,Comments: 84 pages, 16 figures; accepted for publication in Space Science Reviews This version of the article has been accepted for publication, after peer review but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s11214-026-01303-9Subjects: physics.space-ph astro-ph.GA astro-ph.SR physics.geo-ph physics.plasm-phCreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
Cosmic MAGNETic fields are typically inhomogeneous and often highly tangled due to large-scale plasma flows, turbulence, and instabilities. If the variations in the MAGNETic field occur on scales that are large compared to the gyro-radius of the plasma electrons, the electrons are primarily confined to gyro-centre trajectories along the field lines. Therefore, in-situ electron measurements help us map out the connectivity of the MAGNETic field in space plasmas. Gyro-centre drifts, wave-particle interactions, trapping, and cross-field diffusion are processes related to field inhomogeneities and fluctuations; they have the potential to modify or even disrupt the transport of electrons along field lines. We introduce the basic principles of electron transport in tangled MAGNETic fields and review the creation of tangled fields through turbulence and instabilities as well as the modulation of parallel electron transport through kinetic instabilities. We then describe trapping and de-trapping effects in inhomogeneous MAGNETic fields, as well as electron diffusion and energisation across the MAGNETic field. The transport of electrons in tangled fields results from a complex interplay of plasma processes that occur on a broad range of scales. A combination of in-situ plasma measurements, remote-sensing plasma observations, and plasma theory and simulations is required to resolve this contemporary challenge to the fields of heliophysics and astrophysics.
[abstract 41 / 55] (score: 2) - Title: Pfirsch-Schlüter CurrentAuthors: Allen H Boozer,Comments:Subjects: physics.plasm-phCreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
The Pfirsch-Schlüter current is a current that flows along the MAGNETic field lines in a toroidal plasma equilibrium that is required to make the plasma current density divergence free in the presence of a plasma-pressure gradient. A distortion in the plasma shape is caused by the Pfirsch-Schlüter current, and it is desirable to minimize both the strength and the distance this current flows along the MAGNETic field lines. The Pfirsch-Schlüter current is localized within a half period of a stellarator when $d\ell/B$ integrated over the half period is the same for all lines in the MAGNETic surface. It is shown that within parts in a thousand this is the same condition as the distance $\ell_{p/2}$ required for a field line to cross the half period being the same for all lines in the surface. To make the $\ell_{p/2}$'s the same, the lines started on the small major radius side of the plasma must undergo wiggles to make their $\ell_{p/2}$ as long as those started on the outboard side. This is achievable either using modular coils with a large helical component on the small major radius side or with a central column carrying a helical current.
[abstract 42 / 55] (score: 2) - Title: A formation scenario of BLACK HOLE-envelope systems --viscous hydrodynamics simulation in general relativity--Authors: Alan Tsz Lok Lam, Masaru Shibata, Kenta Hotokezaka, Carlo Musolino,Comments: 13 pages, 10 figuresSubjects: astro-ph.HE astro-ph.GACreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
By performing a viscous hydrodynamics simulation in general relativity for super-Eddington accretion flows onto massive BLACK HOLEs of mass $M=10^5$--$10^7M_\odot$, we discuss a formation scenario for BLACK HOLE-envelope systems. We consider the mass accretion rate of $a^3/G \approx 1.5 \times 10^{25} (a/10\,\mathrm{km\,s^{-1}})^3$\,g/s, comparable to the Eddington mass accretion rate of a $10^7M_\odot$ BLACK HOLE, assuming that the gas temperature of the infalling matter is $\lesssim 10^4$\,K. Here, $a$ and $G$ denote the sound speed and gravitational constant. For the accretion flow, we set up a quasi-spherical Bondi-type flow in which radial inflow dominates over angular momentum in the distant region. It is found that (i) for low-mass BLACK HOLEs with $M \lesssim 10^6M_\odot$, a photon-trapped region forms in the inner region, and a significant viscous outflow driven near the polar region overcomes the ram pressure of the mass inflow, leading to an inflow-outflow structure; (ii) for massive BLACK HOLEs of $M \gtrsim 3 \times 10^6M_\odot$, the outflow is not launched, and a convective envelope around the BLACK HOLE gradually develops; and (iii) irrespective of the black-hole mass, the mass accretion rate onto the BLACK HOLE is of order 10\% of the Eddington accretion rate for reasonable values of the viscous coefficient. As the mass accretion rate onto the BLACK HOLEs is much lower than the mass growth rate of the envelope for low-mass BLACK HOLEs with $M\lesssim 10^6M_\odot$, the envelope mass is likely to increase until the total viscous heating rate exceeds the Eddington luminosity of the system, if the mass accretion rate is preserved to be high for $\gtrsim 10^8 (M/10^7M_\odot)$\,yrs.
[abstract 43 / 55] (score: 2) - Title: Pitch-Angle Scattering of Cosmic Rays: Confronting Theory with ObservationsAuthors: Huirong Yan, Siqi Zhao, Ming Zhang,Comments: 8 pages, 3 figuresSubjects: astro-ph.HE astro-ph.SRCreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
Cosmic ray (CR) propagation is controlled by scattering in turbulent MAGNETic fields in space. In general, diffusive propagation is governed by pitch-angle diffusion in phase space. In this study, pitch-angle diffusion in the local interstellar medium (LISM) deduced from the analysis of {the CR small scale anisotropy data} from the Tibet AS$γ$ experiment is compared with theoretical predictions. While it is difficult to reconcile the inferred LISM pitch angle diffusion coefficient with conventional theoretical results of particle scattering by Alfvénic turbulence, we find {very good} agreement with the prediction from particle scattering in quasi-slab fast modes shaped by the damping in the warm ionized medium. These findings offer direct evidence that CR scattering is predominantly governed by fast-mode turbulence. Furthermore, the comparison between experimental and theoretical results imposes strong constraints on plasma and MAGNETic field parameters within the local bubble, indicating that the LISM is in a low $β\simeq 0.1$ condition. The turbulence in the LISM should be compressible with a fast mode component of amplitude approximately $δB/B_0 \approx 0.5$.
[abstract 44 / 55] (score: 2) - Title: Quasi-DNS with chemical kinetics for near blow-out dynamics of a single multi-injection burner element for future gas turbine applicationsAuthors: Kazuki Abe, Youhi Morii, Kaoru Maruta,Comments: 19 pages, 11 figuresSubjects: physics.flu-dynCreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
Gas turbine combustors increasingly operate close to lean blow-out (LBO) limits, where small changes in fuel-air mixing or flow structure can destabilize the flame and alter near-blow-out dynamics. Conventional design practice relies mainly on Reynolds-averaged Navier-Stokes (RANS) simulations, which often overpredict turbulent mixing and cannot resolve unsteady flame anchoring and local extinction near burner hardware. We develop a Quasi-DNS workflow with detailed methane-air chemistry for a single element of a multiple-injection burner, modeled as a coaxial burner with a mixing tube and downstream combustion chamber, as a methodological basis for near-blow-out analysis. The workflow is implemented in OpenFOAM and comprises: (i) a simplified three-dimensional sector geometry with a 30-degree domain to capture circumferential vortices at the mixing tube outlet, (ii) boundary conditions and inlet profiles reproducing coaxial JET and preheated air conditions, (iii) a reduced Yang-Pope mechanism validated against GRI 3.0 using Cantera laminar flame speed, ignition delay, and counterflow diffusion flame calculations, (iv) grid generation and convergence checks based on flame structure and scalar dissipation rate, and (v) diagnostics including methane- and CO-based flame indices to classify local combustion modes. We demonstrate the workflow for a partially premixed methane flame at an overall equivalence ratio of phi = 0.45 and a perfectly premixed reference at the same phi. The Quasi-DNS results show limited mixing inside the mixing tube and strong vortical mixing at the outlet, leading to extended and structured heat-release regions that differ markedly from the smoother, more compact flames predicted by RANS. The methodology provides a reusable framework for analyzing flame structure, stabilization, and LBO-relevant dynamics in coaxial burners with mixing tubes.
[abstract 45 / 55] (score: 2) - Title: Evidence for mass-dependent spin subpopulations in GWTC-4Authors: Asad Hussain, Maximiliano Isi, Aaron Zimmerman,Comments:Subjects: astro-ph.HECreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
While the origin of merging black-hole binaries observed in gravitational waves remain uncertain, different formation channels are expected to leave distinct imprints on their observed mass and spin distributions. In this work, we focus on the mass dependence of the spin magnitudes $(χ_1,χ_2)$, allowing for multiple spin subpopulations whose relative fraction varies with mass. Using the binaries from the fourth LIGO--Virgo--KAGRA gravitational wave transient catalog (GWTC-4), we find strong evidence for two subpopulations, with a log Bayes factor of $\log_{10} \mathcal B = 4^{+6}_{-2}$. The data support a picture in which low-mass systems are composed almost entirely of slowly spinning BLACK HOLEs ($χ\lesssim 0.2$), while high-mass systems are dominated by a broader component with moderate to rapid spins, peaking at $(χ_1,χ_2)\approx(0.7,0.7)$ and retaining a non-negligible tail toward asymmetric spins $(χ_1,χ_2)\approx(0.7,0)$. The transition between these regimes spans a broad range from $m_1 \approx 35^{+20}_{-20} \,M_\odot$ to $m_1 \approx 70^{+90}_{-25}\,M_\odot$. For the low-mass, slowly-spinning regime, a flexible model of spin orientations does not allow us to exclude identically vanishing spins, $χ_1 = χ_2 = 0$. Meanwhile, the high-mass, rapidly-spinning population does not neatly display the spin-magnitude asymmetry expected from hierarchical mergers, although the data do not exclude that. This kind of localized structure is generally difficult to access with standard Monte-Carlo likelihood estimators, which we replace with a regularized representation in terms of truncated Gaussian mixtures. Taken together, our results provide a new target for formation models, which should reproduce not only the mass and effective spin distributions, but also the mass-dependent structure of the individual component-spin magnitudes.
[abstract 46 / 55] (score: 2) - Title: Stress-Energy Tensor for Modified General Relativity with Quantum-Deformed Metric in Riemann SpacetimeAuthors: A. Tawfik, Saleh O. Allehabi, A. A. Alshehri, M. Nasar, M. Maher,Comments: 26 pages, 0 figure, and 0 table accepted for publication in International Journal of Modern Physics ASubjects: gr-qcCreated: 2026-05-22; Updated: 2026-05-26; Datestamp: 2026-05-26
The generalized noncommutative Heisenberg algebra, which is based on the generalized uncertainty principle, imposes a minimal length uncertainty on quantum mechanics (QM), on one hand. On the other hand, the quantum-induced spacetime which is based on quantum-deformed metric through geometric quantization is proposed as additional curvatures on the RELATIVISTIC tangent bundle on Finsler manifold. An additional term that incorporates minimal length discretization along with second-order derivatives of tangent covectors, thereby suggesting an approach to reconcile the principles of QM with General Relativity (GR), is utilized for the construction of a torsion-free quantum-deformed metric on Riemann manifold. Consequently, it is proposed that quantum-induced revisions to the symmetric stress-energy tensor, source of spacetime curvature, along with the current density related to the gauge transformations of gravity, ought to be taken into account in the matter Lagrangian with electroMAGNETic and scalar components. Vanishing covariant derivative of the quantum-induced stress-energy tensor suggests that the corresponding continuity equation implies that the gravitational fields do work on the classical and quantum matter and vice versa and the non-gravitational energy and momentum are no longer entirely conserved. For vanishing tangent covector derivatives and/or minimal length uncertainty, the classical formulations of the Einstein stress-energy tensor are retained and accordingly that of GR and QM. We conclude that the proposed quantum-induced formulation of the stress-energy tensor is fundamentally suitable for both classical and quantum-induced field equations.
[abstract 47 / 55] (score: 2) - Title: Changing-look Active Galactic Nuclei from SDSS, LAMOST and DESI SurveyAuthors: Guohai Chen, Wenxin Yang, Xuhong Ye, Zhiqiang Chen, Zhiyuan Pei, Hubing Xiao, Junhui Fan,Comments: 16 pages, 5 figures, submitted to ApJSSubjects: astro-ph.GACreated: 2026-05-23; Updated: 2026-05-26; Datestamp: 2026-05-26
Although more than 1000 optical changing-look ACTIVE GALACTIC NUCLEi (CLAGNs) have been reported to date, their physical origin remains unclear, and repeating CLAGNs (RCLAGNs) are still rare. Expanding the CLAGN sample, especially RCLAGNs, is therefore important for constraining the underlying mechanism. We systematically search for CLAGNs by cross-matching spectroscopic observations from the Sloan Digital Sky Survey (SDSS) and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), and further use spectra from the Dark Energy Spectroscopic Instrument (DESI) to investigate repeating CL behavior. We identify 45 CLAGNs, including 40 newly reported sources. The sample is dominated by turn-off events, with 43 turn-off and 2 turn-on sources, possibly because Type 2 AGNs either lack a detectable broad-line region or have their broad emission lines obscured by circumnuclear dust. Using DESI as a third spectroscopic epoch, we identify 12 RCLAGNs. This high detection rate of repeated CL behavior suggests that CL transitions may arise from recurrent physical processes, such as accretion-rate fluctuations or disk instabilities. In the log MBH - log(Lbol/LEdd) plane, RCLAGNs further show a clear high-low-high accretion-state evolution, supporting a close link between CL behavior and recurrent changes in accretion power. Finally, the rest-frame upper limits on the transition timescales are about 10 yr for the first transition and about 4 yr for the second, reflecting different survey time baselines rather than intrinsic differences in physical transition timescales.
[abstract 48 / 55] (score: 2) - Title: The Evolution of Cataclysmic Variables Under Various MagneticAuthors: Wen-Shi Tang, Xiang-Dong Li, Zhe Cui, Zhu-Ling Deng, Wei-Min Gu,Comments: 15 pages, 7 figures, accepted by ApJSubjects: astro-ph.HECreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
Recent studies revealed discrepancies between observations and the predictions of the standard MAGNETic braking (MB). Although alternative models have been broadly discussed in neutron star binaries, they have not been systematically tested in cataclysmic variables (CVs). In this work, we investigate the performance of four MB models in CVs: the standard MB, the Convection And Rotation Boosted (CARB) model, the $τ$-boosted model, and the saturated, boosted, and disrupted (SBD) model. We find that both the CARB and $τ$-boosted models appear too strong so that it fails to reproduce the location of the period gap in CVs, indicating that they are not appropriate for CVs. Furthermore, we present a comparison between the standard MB and the SBD models. Compared with the standard model, although the SBD model can better reproduce some observational features, it also exacerbates certain discrepancies between theory and observations. We also find that different prescriptions for the convective turnover timescale have a significant impact on the results in the non-standard MBs. Finally, we discuss the impact of the SBD model on the formation and evolution of AM CVn.
[abstract 49 / 55] (score: 2) - Title: Impact of non-equilibrium radiation in a high-enthalpy inductively coupled plasma wind tunnelAuthors: Sanjeev Kumar, Sung Min Jo, Alessandro Munafò, Marco Panesi,Comments:Subjects: physics.plasm-phCreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
High-power inductively coupled plasma (ICP) wind tunnels are widely used to reproduce high-enthalpy environments relevant to atmospheric entry and hypersonic testing. Despite their importance, radiative heat transfer in ICP facilities is commonly neglected or modeled using simplified optically thin assumptions, and the impact of non-equilibrium radiation on plasma dynamics remains poorly quantified. In this work, a loosely coupled, multi-physics framework is developed to systematically investigate radiative cooling effects in the 350 kW Plasmatron X facility at the University of Illinois Urbana-Champaign. The approach self-consistently couples a MAGNETohydrodynamic plasma framework with a spectral radiative transport solver, eliminating the need for optically thin or empirical models. Simulations are performed for nitrogen and air plasmas over a wide range of operating pressures (1-101 kPa) and powers (100-350 kW). The results reveal a strong pressure dependence of radiative losses, with radiation contributing negligibly at low pressures, but becoming a dominant energy sink at elevated pressures. At atmospheric pressure, radiative losses account for up to approximately 32% and 22% of the input power for nitrogen and air plasmas, respectively, leading to substantial reductions in core plasma temperatures. Nitrogen plasmas consistently exhibit higher radiative losses than air as a result of increased concentrations of radiatively active species and higher electron number densities. Pressure-power maps of radiative heat loss relative to input power are constructed to quantify combined operating effects and to provide guidance for facility operation and modeling fidelity. Finally, an assessment of self-absorption demonstrates that the Plasmatron X torch operates predominantly in an optically thin regime, even at the highest power and pressure conditions considered.
[abstract 50 / 55] (score: 2) - Title: Cyclotron breaking: a mechanism for parallel ion cyclotron waves to heat the fast solar windAuthors: Evan L. Yerger, Benjamin D. G. Chandran, Vincent David, Trevor A. Bowen, Stuart D. Bale,Comments: 16 pages, 4 figures, submitted to Journal of Plasma PhysicsSubjects: astro-ph.SR physics.plasm-ph physics.space-phCreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
The $\textit{Parker Solar Probe}$ ($\textit{PSP}$) mission has observed near-continuous power in parallel ion cyclotron waves (PICWs) in the young, fast solar wind. These waves are unlikely to be directly produced by the turbulent cascade and are likely born of a local instability; yet, they are observed to both cool -- and heat -- the plasma. We propose that these observations can be self-consistently explained as the natural consequence of PICWs propagating in the inhomogeneous solar wind after they have been driven unstable. In this work, we argue that strong proton heating by a turbulent cascade of oblique ICWs will result in PICWs being driven unstable in a process known as quasi-linear focusing. Because the power in the turbulent cascade is concentrated at scales above the turbulent transition region, PICWs will be driven unstable within a range of wave numbers parallel to the background MAGNETic field, $k_\parallel$, that is bounded from above by $k_{\parallel\rm P}^*$, corresponding to the start of the transition region. As unstable PICWs propagate away from the sun to regions of lower proton density, their $k_\parallel$, multiplied by the proton inertial length $d_{\rm p}$, increases. Eventually, the $k_\parallel d_{\rm p}$ of the PICWs becomes larger than $k_{\parallel\rm P}^*d_{\rm p}$ and the waves damp, heating the solar wind. We call this effect `cyclotron breaking', in analogy with ocean waves breaking on the shore. We then discuss the testable predictions of the theory, including a distinct heating signature in which PICWs cool fast protons and heat slow protons at any given heliocentric distance $r$. Finally, we conjecture that cyclotron breaking can lead to net heating by PICWs if the power emitted as PICWs decreases sufficiently rapidly with $r$ that local emission of PICWs is overwhelmed by the local damping of PICWs generated closer to the sun.
[abstract 51 / 55] (score: 2) - Title: Computing weak-strong uniqueness of a Mach 2000 astrophysical JETAuthors: Stephan Simonis, Gauthier Wissocq,Comments:Subjects: math.NA cs.MS cs.NA physics.comp-ph physics.flu-dynCreated: 2026-05-24; Updated: 2026-05-26; Datestamp: 2026-05-26
The simulation of extreme Mach astrophysical flows is traditionally viewed through the lens of deterministic positivity-preserving schemes. However, due to phenomena such as Kelvin--Helmholtz instabilities and shock anomalies, the multi-dimensional Euler equations admit a plethora of non-unique entropy solutions in turbulent regimes. For the first time, we computationally explore the weak-strong uniqueness of a Mach 2000 JET by defining the statistical solution as the pushforward of a probability measure through a vectorial lattice Boltzmann method (VLBM) operator. Utilizing highly optimized CUDA kernels, we compute an ensemble of 1000 Monte Carlo samples across a sequence of unprecedentedly refined spatial grids of up to 3.2 million cells, and subsequently post-process the empirical measures via memory-mapped CPU streaming. We contrast the strong sample-wise $L^1$ error divergence with the convergence of the probability measure in the 1-point Wasserstein distance via empirical Cauchy rates. Our mathematical results demonstrate that while individual flow realizations physically diverge due to chaotic shear-layer instabilities, the macroscopic statistical solution converges to a well-defined limit measure at a rate of 0.5. Conclusively, we provide the first numerical verification of statistical solution stability in the extreme compressible regime.
[abstract 52 / 55] (score: 2) - Title: Optimized design of a Penning ion source for sealed neutron tubeAuthors: Shiwei Jing, Jia Song, Shengduo Liu, Weiyang Zhang, Sijia Zhou, Hailong Xu, Zebin Li, Tin Zhang, Zhihu Gao, Guofeng Qu,Comments:Subjects: physics.plasm-phCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Sealed neutron tubes have a wide range of applications, and the ion source is their core component. Penning ion sources commonly suffer from issues such as uneven MAGNETic field distribution and a low proportion of monoatomic ions. Improving the performance of the ion source can effectively address the problems of low neutron flux and short operational lifespan. This study aims to optimise the MAGNETic field configuration and discharge parameters of the ion source, thereby increasing the proportion of monoatomic and enhancing discharge stability, and to provide a design basis for high-performance sealed neutron tubes. Develop a MAGNETic field-plasma coupling model to compare and analyze the MAGNETic field distribution patterns of traditional MAGNETic block structures and soft iron-reinforced structures, and investigate the mechanisms by which operating pressure and anode voltage affect plasma density and ion composition using COMSOL multiphysics simulation methods. Simulation results indicate that the soft iron structure significantly enhances the axial MAGNETic field strength and uniformity within the discharge region; under conditions of 0.06 Pa gas pressure and 1500 V anode voltage, the proportion of monoatomic ions increased from the conventional 9% to 30%.
[abstract 53 / 55] (score: 2) - Title: ElectroMAGNETic emission from a black-to-white hole transition -- Photospheric emissionAuthors: Mattia Villani,Comments: Accepted for the publication in General Relativity and GravitationSubjects: gr-qcCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
We calculate the gamma ray emission from a black-to-white hole transition. We put forward a model for the prompt emission phase, based on the photospheric emission model with the underlying idea that the number of photons and leptons emitted by the white hole will be larger than the baryon content. We calculate the spectrum of the emitted radiation and give an estimate of the total energy emitted. Finally, we estimate the cosmological density of lunar mass primordial BLACK HOLEs.
[abstract 54 / 55] (score: 2) - Title: Reversible-jump MCMC reveals binary BLACK HOLE subpopulations with distinct redshift evolutionAuthors: April Qiu Cheng, Alexandre Toubiana, Sylvia Biscoveanu, Jonathan Gair,Comments: main body 17 pages, total 47 pages, 8 main figures + 4 extended figuresSubjects: astro-ph.HE astro-ph.GA gr-qcCreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
Analyses of the growing catalog of binary BLACK HOLE (BBH) mergers observed by the LIGO-Virgo-KAGRA detectors are beginning to resolve features in their population-level mass, spin, and redshift distributions, revealing imprints of the astrophysical processes driving their formation and evolution. We present a novel method to search for subpopulations in the data using reversible-jump Markov chain Monte Carlo, providing interpretable results while making minimal prior assumptions. We find evidence for three subpopulations: a narrow subpopulation in primary mass at $\sim 10~M_\odot$ with preferentially aligned spins and unequal masses, consistent with isolated binary evolution; a subpopulation broadly distributed around $\sim 30~M_\odot$ with isotropically-distributed spins and a strong preference for equal mass ratios, consistent with dynamical formation in clusters; and a high-spin subpopulation spanning the continuum in mass, which we interpret as the confluence of multiple subdominant formation channels. When we allow for the independent redshift evolution of each subpopulation, we find that the subpopulation encompassing the $10~M_\odot$ peak evolves more quickly than the $30~M_\odot$ subpopulation, with implications for the delay-time distribution and metallicity-dependent BBH formation efficiency. Our work lays the foundation for a novel data-driven framework to infer the formation mechanisms of BBHs.
[abstract 55 / 55] (score: 2) - Title: Interstellar extinction, POLARIZATION efficiency, and grain alignment in the direction towards bright-rimmed clouds and cometary globulesAuthors: Saikhom Pravash,Comments: 25 Pages, 12 Figures, 1 Table. Accepted for publication in the Research in Astronomy and Astrophysics JournalSubjects: astro-ph.GACreated: 2026-05-25; Updated: 2026-05-26; Datestamp: 2026-05-26
The POLARIZATION of starlight and thermal dust emission, resulting from non-spherical grains aligned with the interstellar MAGNETic field (B-field), act as a powerful tool to trace the B-field morphologies and strengths in molecular clouds and constrain the grain alignment mechanisms and grain properties. The exact alignment mechanisms of grains is not yet fully clear. However, the leading theory is the alignment induced by RAdiative Torques (RATs), known as RAT theory. In this work, we use optical POLARIZATION observations of background stars projected towards nine of Bright-Rimmed Clouds (BRCs) and Cometary Globules(CGs) to study the POLARIZATION efficiencies and the alignment mechanisms of the grains in the direction towards the outer diffuse envelopes of these clouds. We use distance and extinction data of the stars from Gaia EDR3 and StarHorse 2 Catalogue. We study the variations of the degree and position angle of POLARIZATION, and the extinction, as functions of distance of the stars. For some of the clouds, we find discrete enhancement of the extinction at certain distances along with an increase in POLARIZATION degree, signifying the presence of polarizing dust layers. We estimate the POLARIZATION efficiency of grains towards each of the clouds. We find that it decreases with increasing extinction, and also shows a slight increase with dust temperature for some clouds associated with more ordered MAGNETic field orientations, providing an implication for the alignment of grains by RATs. Whereas, for some other clouds, the decrease in the POLARIZATION efficiency with extinction may be caused by more fluctuations in the MAGNETic field orientations.
arXiv:2605.10557 [pdf, ps, other]
arXiv:2605.26065 [pdf, ps, other]
arXiv:2511.13633 [pdf, ps, other]
arXiv:2605.24083 [pdf, ps, other]
arXiv:2605.24112 [pdf, ps, other]
arXiv:2605.24664 [pdf, ps, other]
arXiv:2605.25147 [pdf, ps, other]
arXiv:2602.20315 [pdf, ps, other]
arXiv:2605.24746 [pdf, ps, other]
arXiv:2605.25209 [pdf, ps, other]
arXiv:2602.22040 [pdf, ps, other]
arXiv:2604.06828 [pdf, ps, other]
arXiv:2605.24107 [pdf, ps, other]
arXiv:2605.26091 [pdf, ps, other]
arXiv:2512.13688 [pdf, ps, other]
arXiv:2603.05032 [pdf, ps, other]
arXiv:2605.24374 [pdf, ps, other]
arXiv:2605.24886 [pdf, ps, other]
arXiv:2605.24936 [pdf, ps, other]
arXiv:2605.25205 [pdf, ps, other]
arXiv:2605.25586 [pdf, ps, other]
arXiv:2506.08037 [pdf, ps, other]
arXiv:2509.12246 [pdf, ps, other]
arXiv:2512.08195 [pdf, ps, other]
arXiv:2601.20929 [pdf, ps, other]
arXiv:2605.11305 [pdf, ps, other]
arXiv:2605.24591 [pdf, ps, other]
arXiv:2605.24905 [pdf, ps, other]
arXiv:2605.25199 [pdf, ps, other]
arXiv:2605.25467 [pdf, ps, other]
arXiv:2605.25644 [pdf, ps, other]
arXiv:2605.25689 [pdf, ps, other]
arXiv:2605.25886 [pdf, ps, other]
arXiv:2403.14730 [pdf, ps, other]
arXiv:2510.03732 [pdf, ps, other]
arXiv:2510.16731 [pdf, ps, other]
arXiv:2511.06017 [pdf, ps, other]
arXiv:2603.21352 [pdf, ps, other]
arXiv:2603.27132 [pdf, ps, other]
arXiv:2605.04293 [pdf, ps, other]
arXiv:2605.21637 [pdf, ps, other]
arXiv:2605.24087 [pdf, ps, other]
arXiv:2605.24143 [pdf, ps, other]
arXiv:2605.24226 [pdf, ps, other]
arXiv:2605.24281 [pdf, ps, other]
arXiv:2605.24282 [pdf, ps, other]
arXiv:2605.24429 [pdf, ps, other]
arXiv:2605.24820 [pdf, ps, other]
arXiv:2605.25060 [pdf, ps, other]
arXiv:2605.25117 [pdf, ps, other]
arXiv:2605.25282 [pdf, ps, other]
arXiv:2605.25668 [pdf, ps, other]
arXiv:2605.25709 [pdf, ps, other]
arXiv:2605.25980 [pdf, ps, other]
arXiv:2605.26030 [pdf, ps, other]