Current date: 2025-10-15
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Scoring abstracts
Number of records retrieved: 659
Keyword score statistics
score 10 -- 1 abstracts
score 6 -- 2 abstracts
score 5 -- 2 abstracts
score 4 -- 6 abstracts
score 3 -- 11 abstracts
score 2 -- 19 abstracts
in total -- 41 abstracts
Articles that appeared on 2025-10-15
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[abstract 1 / 41] Wow! (score: 10)
- Title: Ultra-long MeV transient from a RELATIVISTIC JET: a tidal disruption event candidateAuthors: Gor Oganesyan, Elias Kammoun, Annarita Ierardi, Alessio Ludovico De Santis, Biswajit Banerjee, Emanuele Sobacchi, Felix Aharonian, Samanta Macera, Pawan Tiwari, Alessio Mei, Shraddha Mohnani, Stefano Ascenzi, Samuele Ronchini, Marica Branchesi,Comments: Accepted for publication in A&A (Letter)Subjects: astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
On July 2, 2025, the Gamma-ray Burst Monitor (GBM) onboard the FERMI Gamma-ray space telescope detected three short-duration MeV transients with overlapping sky locations. These events, named as GRB 250702D, B, and E (collectively referred to as DBE), triggered the detector with delays of approximately 1-2 hours between each burst. Follow-up observations of this unusually long MeV transient (lasting >3 hours) by the Neil Gehrels SWIFT Observatory and the Nuclear Spectroscopic Telescope Array over a period of 10 days revealed a steep temporal decline in soft X-rays ($\propto t^{-1.9 \pm 0.1}$). The time-averaged spectra during the outbursts are well described by a single power law $dN_γ/dE \propto E^{-1.5}$, while upper limits above 100 MeV imply a spectral cutoff between 10 MeV and 100 MeV. Using standard gamma-ray transparency arguments, we derive a lower limit on the bulk Lorentz factor. Combined with the steep decline in X-rays, these constraints point to a RELATIVISTIC JET origin. The properties of DBE are inconsistent with established GRB spectral-energy correlations, disfavoring classical long GRB progenitors. Instead, the basic characteristics of DBE resemble those of previously reported JETted tidal disruption events (TDEs), though alternative progenitor channels cannot be excluded. In the RELATIVISTIC TDE scenario, DBE is the first one with detected MeV gamma-ray emission. We argue that the observed emission is most likely produced by SYNCHROTRON radiation from sub-TeV electrons.
[abstract 2 / 41] Yes (score: 6) - Title: 1FLAT: a Firmamento-based catalog of AGN in FERMI-LAT high Galactic latitude γ-ray sourcesAuthors: P. Giommi, M. Doro, M. Gouvêa, L. Fronte, F. Metruccio, F. Arneodo, U. Barres de Almeida, S. Di Pippo, T. Kerscher, A. Macció, B. Mazzon, M. Morrone, E. Prandini, A. Rodríguez, A. Ruina, N. Sahakyan, L. Silveri, D. Tripathi,Comments: Accepted for publication in ApJS. 1FLAT can be accessed here: https://huggingface.co/datasets/micheledoro/1FLAT.fitsSubjects: astro-ph.HE astro-ph.IMCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
We present a systematic reassessment of 5,062 high-Galactic latitude gamma-ray sources from the FERMI-LAT 4FGL-DR4 catalog using Firmamento, a web-based platform for multi-frequency source discovery and analysis. Our goal is to provide an independent evaluation of LAT gamma-ray source associations through alternative spectral and spatial methods that combine recent and legacy survey data, supplemented by human supervision of spectral energy distributions (SEDs), source morphology, flux variability, and template-based comparisons. Firmamento confirms the 4FGL-DR4 and 4LAC-DR3 counterparts or unassociated sources in 4,493 cases (88.8%), demonstrating the robustness of both approaches. Beyond this general agreement, we identify 421 new BLAZAR counterparts among previously unassociated sources, thereby reducing the fraction of unidentified extragalactic FERMI-LAT sources from 25% to 17%. In addition, in 64 cases we find alternative BLAZAR associations, while in 49 instances we do not confirm the 4FGL-DR4 association. For all confirmed BLAZAR counterparts we provide homogeneous estimates of SYNCHROTRON peak frequency and peak flux using machine-learning and template-based methods; these agree with 4LAC-DR3 values in most cases, though significant discrepancies appear for a few dozen sources, often due to improved X-ray coverage. The primary outcome of this work is the 1st Firmamento LAT AGN table (1FLAT), made publicly available through the Firmamento platform (https://firmamento.nyuad.nyu.edu), where all related multi-wavelength data and images are available. The project involved extensive manual validation and benefited from the active participation of graduate and undergraduate students, highlighting the platform's value for both research and education.
[abstract 3 / 41] Yes (score: 6) - Title: New Tests of Low-Scale Quantum Gravity with Cosmic-Ray CollisionsAuthors: Manuel Ettengruber, Gonzalo Herrera,Comments:Subjects: hep-ph astro-ph.HE gr-qc hep-thCreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
Cosmic ray collisions at high center of mass energy could enable graviton and BLACK HOLE production as expected in theories of low-scale quantum gravity, such as extra-dimensions, many species, or some versions of string theory. Here we propose three novel phenomenological tests of these theories. We first consider the collision of COSMIC RAYs with ambient protons, electrons and photons in Active Galactic Nuclei (AGN), finding that high-energy neutrino data from the BLAZAR TXS 0506+056 places a constraint on the fundamental scale of gravity of $M_f \gtrsim 0.3$ TeV, and future high-energy neutrino data could raise this bound to $M_f \gtrsim 200$ TeV. We then point out that collisions of pairs of COSMIC RAYs could occur at a sizable rate in AGN where the accelerated COSMIC RAYs are not collimated, or on supermassive BLACK HOLE binaries. This consideration could potentially let us test unprecedented large fundamental scales of $M_f \gtrsim 2$ PeV. We further compute the corresponding thermal neutrino emission arising from the Hawking evaporation of BLACK HOLEs produced in COSMIC RAY collisions, finding a spectrum that clearly differs from that expected in meson decays. Finally, we speculate with an scenario which would produce high-energy neutrino and gamma-ray emission from regions in the sky where no multi-wavelength counterparts would be expected, via graviton propagation from a different brane, which then decays in our Universe.
[abstract 4 / 41] Yes (score: 5) - Title: Cross-correlation of Luminous Red Galaxies with ML-selected AGN in HSC-SSP III: HOD Parameters for Type I and Type II QuasarsAuthors: Rodrigo Córdova Rosado, Andy D. Goulding, Jenny E. Greene, Nickolas Kokron, Andrina Nicola, Michael A. Strauss, Ryan C. Hickox,Comments: 28 pages, 12 figures, submitted to ApJSubjects: astro-ph.GACreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
Understanding the DARK MATTER (DM) halo environment in which galaxies that host ACTIVE GALACTIC NUCLEi (AGN) reside is a window into the nature of supermassive BLACK HOLE (SMBH) accretion. We apply halo occupation distribution (HOD) modeling tools to interpret the angular cross-correlation functions between $1.5\times10^6$ luminous red galaxies (LRGs) and our $\sim28,500$ Hyper Suprime-Cam + Wide-field Infrared Survey Explorer-selected (and $L_{6 μm}$-limited) AGN to infer the halo properties of distinct QUASAR samples at physical scales $s>0.1\,{\rm Mpc}$, for $z\in0.7-1.0$. We find that Type I (unobscured) and Type II (obscured) AGN cluster differently, both on small and large physical scales. The derived HODs imply that Type I AGN reside, on average, in substantially ($\sim3\times$) more massive halos ($M_h \sim 10^{13.4} M_\odot$) than Type II AGN ($M_h \sim 10^{12.9} M_\odot$) at $>5σ$ significance. While Type II AGN show one-halo correlations similar to that of galaxies of their average halo mass, the Type I AGN intra-halo clustering signal is significantly shallower. We interpret this observation with HOD methods and find Type I AGN are significantly less likely ($f_{sat}\sim0.05^{+1}_{-0.05}\%$) to be found in satellite galaxies than Type II AGN. We find reddened + obscured AGN to have typical satellite fractions for their inferred average halo mass ($\sim10^{13} M_\odot$), with $f_{sat} \sim 20^{+10}_{-5}\%$. Taken together, these results pose a significant challenge to the strict unified AGN morphological model, and instead suggest that a QUASAR's spectral class is strongly correlated with its host galaxy's DARK MATTER halo environment. These intriguing results have provided a more complex picture of the SMBH -- DM halo connection, and motivate future analyses of the intrinsic galaxy and accretion properties of AGN.
[abstract 5 / 41] Yes (score: 5) - Title: Rotation of Polarization Angle in Gamma-Ray Burst Prompt Phase. III. The Influence of the Magnetic Field OrientationAuthors: Xing-Yao Wang, Jia-Sheng Li, Mi-Xiang Lan,Comments: 9 pages, 2 figures, 1 table, ApJ acceptedSubjects: astro-ph.HECreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
Polarization is very sensitive to the configuration of the MAGNETic field in the radiation region. In addition to POLARIZATION curve and POLARIZATION spectrum, studies of POLARIZATION angle (PA) rotation spectrum is also crucial. In this paper, we use a simple parametric MAGNETic RECONNECTion model with a large-scale aligned MAGNETic field in the radiation region to study the effects of field orientation on the PA rotations. Under different field orientations, variations of the PA rotation with parameters and the PA rotation spectra are studied. We find that the conclusions obtained in our previous works are almost independent of the field orientations. The area of the parameter space with $Δ$PA $>10^\circ$ will shrink as the value of field orientation ($δ$) increases for $0^\circ<δ<90^\circ$. The $Δ$PA values would be the same for two complementary field orientations. For two particular MAGNETic field orientations ($δ=0^\circ$ and $90^\circ$), the $Δ$PA would also only be $0^\circ$ or $90^\circ$ within the burst duration.
[abstract 6 / 41] Yes (score: 4) - Title: The redshift distribution of Einstein Probe transients supports their relation to GAMMA-RAY BURSTsAuthors: Brendan O'Connor, Paz Beniamini, Eleonora Troja, Malte Busmann, Simone Dichiara, Ramandeep Gill, Jonathan Granot, Michael Moss, Xander Hall, Antonella Palmese, Niccolo Passaleva, Yu-Han Yang,Comments: Revised Version for ApJLSubjects: astro-ph.HECreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
The launch of the \textit{Einstein Probe} unleashed a new era of high-energy transient discovery in the largely unexplored soft X-ray band. The \textit{Einstein Probe} has detected a significant number of fast X-ray transients that display no gamma-ray emission, complicating their robust association to more common GAMMA-RAY BURSTs. To explore their possible connection, we analyzed the redshift distribution of both \textit{Einstein Probe} fast X-ray transients and long duration GAMMA-RAY BURSTs. A comparative analysis of their cumulative redshift distributions using non-parametric two-sample tests, namely the Kolmogorov-Smirnov and Anderson-Darling tests, finds no statistically significant difference. These tests favor that their redshifts are drawn from the same underlying distribution. This empirical connection between \textit{Einstein Probe} transients and long GAMMA-RAY BURSTs is further supported by their agreement with the so-called ``Amati relation'' between the spectral peak energy and the isotropic-equivalent energy. Together, these results indicate that most extragalactic \textit{Einstein Probe} fast X-ray transients are closely related to long GAMMA-RAY BURSTs and originate from a massive star (collapsar) progenitor channel. Our findings highlight the role of the \textit{Einstein Probe} in uncovering the missing population of failed JETs and dirty fireballs that emit primarily at soft X-ray wavelengths.
[abstract 7 / 41] Yes (score: 4) - Title: The Gravitational Wave Memory from Binary Neutron Star MergersAuthors: Jamie Bamber, Antonios Tsokaros, Milton Ruiz, Stuart L. Shapiro, Marc Favata, Matthew Karlson, Fabrizio Venturi Piñas,Comments: 8 pages, 5 figures. Movies and additional visualizations available at https://tinyurl.com/shapiromoviesSubjects: gr-qc astro-ph.HECreated: 2025-10-10; Updated: 2025-10-15; Datestamp: 2025-10-15
The gravitational wave signal produced by the merger of two compact objects includes both an oscillatory transient and a non-oscillatory part, the so-called memory effect. This produces a permanent displacement of test masses and has not yet been measured. We use general RELATIVISTIC MAGNETohydrodynamic simulations, including neutrinos, with several representative viable equations of state, to quantify--for the first time--the effects of the neutron star MAGNETic field, neutrino emission, and the ejected mass on the linear and nonlinear displacement memory in binary neutron star mergers. We find that the additional contributions due to the emission of electroMAGNETic radiation, neutrinos and baryonic ejecta can be ~15% of the total memory for moderate MAGNETic fields and up to ~50% for extreme MAGNETic fields. The memory is most affected by changes in the equation of state, the binary mass, and the MAGNETic field. In particular, for moderate premerger field strengths, the dominant impact of the electroMAGNETic field is the change in the gravitational wave luminosity, and the associated gravitational wave null memory, due to the unstable growth of the MAGNETic field and the resulting redistribution of angular momentum it induces in the remnant. While the direct electroMAGNETic contribution to the null memory is additive, the change in the gravitational wave null memory can--in some cases--result in the total memory being smaller than that from the corresponding nonMAGNETized binary. Furthermore, in contrast to binary BLACK HOLE mergers, the growth of the memory in binary neutron star mergers is extended due to the long emission timescale of electroMAGNETic fields, neutrinos, and ejecta. These results necessitate the consideration of the MAGNETic field, as well as the equation of state, for accurate parameter estimation in future analyses of gravitational wave memory data.
[abstract 8 / 41] Yes (score: 4) - Title: MESA-QUEST: Tracing the formation of direct collapse BLACK HOLE seeds via quasi-starsAuthors: Andrew D. Santarelli, Claire B. Campbell, Ebraheem Farag, Earl P. Bellinger, Priyamvada Natarajan, Matthew E. Caplan,Comments: 14 pages, 3 figures, presented at Simons Foundation SCEECS Annual Meeting in Feb. 2025 and comprised a portion of author A.D.S's Masters thesisSubjects: astro-ph.HE astro-ph.CO astro-ph.GACreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
The origin of the first supermassive BLACK HOLEs (SMBHs) observed at redshifts $z\geq 9$ remains one of the most challenging open questions in astrophysics. Their rapid emergence suggests that massive ``heavy seeds'' must have formed early, possibly through the direct collapse of pristine gas clouds in the first galaxies. We present MESA-QUEST, a new framework built upon the Modules for Experiments in Stellar Astrophysics (MESA) code, designed to model the structure and evolution of quasi-stars -- massive, radiation-supported envelopes hosting accreting BLACK HOLEs at their cores -- believed to be the progenitors of direct-collapse BLACK HOLE (DCBH) seeds. Our implementation introduces flexible boundary conditions representing both Bondi accretion and saturated-convection regimes, and explores the impact of several stellar wind and mass-loss prescriptions, including Reimers, Dutch, and super-Eddington radiation-driven winds. We find that quasi-stars can grow central BLACK HOLEs to $\geq 10^3\,M_{\odot}$ under favorable conditions, with saturated-convection models yielding BH-to-total mass ratios up to 0.55$M_*$ -- five times higher than Bondi-limited cases. However, strong radiation-driven winds can dramatically curtail growth, potentially quenching heavy-seed formation unless balanced by sustained envelope accretion. Our results delineate the physical limits under which quasi-stars can remain stable and produce heavy seeds capable of evolving into the earliest SMBHs detected by JWST and Chandra. Future extensions will incorporate rotation, MAGNETic fields, and GR-radiation hydrodynamics to refine accretion physics and constrain the viability of the quasi-star pathway for early SMBH formation.
[abstract 9 / 41] Yes (score: 4) - Title: Impact of Cosmic Ray Acceleration on the Early Evolution of Bow Shocks around Massive Runaway StarsAuthors: Keito Watanabe, Stefanie Walch, Tim-Eric Rathjen, Jonathan Mackey, Pierre Nürnberger, Philipp Girichidis,Comments: 25 pages, 26 figures (7 figures in Appendix). Submitted to A&ASubjects: astro-ph.HECreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
Bow shocks generated from the interaction of winds from massive runaway stars with the interstellar medium have been shown to be prominent particle accelerators through recent $γ$-ray and radio SYNCHROTRON observations. Here, we study particle acceleration from bow shocks by conducting 3D ideal COSMIC RAY MAGNETohydrodynamic simulations in the advection-diffusion limit. We use the Eulerian grid-based code FLASH, where stellar winds are injected through tabulated wind velocities and mass loss rates. We implement a gradient-based shock detection algorithm to resolve the shocked regions where the CRs are injected dynamically. Simulations are performed for different values of the CR diffusion coefficient and star velocities within an ISM-like environment up to 180 kyr to showcase the impact of dynamical CR injection on the early evolution of the wind-driven bow shock. With a simplified spectral model in post-processing, we calculate the expected upper limits of $γ$-ray and SYNCHROTRON emission and compare with those from current observations. We observe that variations of CR diffusion rates can strongly dictate the morphology of the bow shock and the overall $γ$-ray and radio SYNCHROTRON luminosity due to the balance between the CR injection efficiency and diffusion. Our results yield qualitatively comparable results with current observations, primarily attributed to the high-energy protons and electrons contributing to non-thermal emission from efficient acceleration at the forward shock through the approximations and assumptions in the injection algorithm. We conclude that CR acceleration, with varying CR diffusion rates, may substantially affect the morphology of wind-driven bow shocks and their non-thermal emission, if there is efficient particle acceleration in the forward shock. [abridged]
[abstract 10 / 41] Yes (score: 4) - Title: A Possible Shutting-Down Event of Mass Accretion in An Active Galactic Nucleus at z~1.8Authors: Tomoki Morokuma, Malte Schramm, Toshihiro Kawaguchi, Josefa Becerra González, Jose Antonio Acosta-Pulido, Nieves Castro-Rodríguez, Kana Morokuma-Matsui, Shintaro Koshida, Junko Furusawa, Hisanori Furusawa, Tsuyoshi Terai, Fumi Yoshida, Kotaro Niinuma, Yoshiki Toba,Comments: 15 pages, 7 figures, 1 table. Accepted for publication in PASJSubjects: astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
We present the discovery of a large gradual apparent fading event in optical and near-infrared wavelengths in a QUASAR at z=1.767 by a factor of 20-30 (in optical) over a period of ~20 years in the observed frame. This pronounced fading trend in brightness was first identified by comparing the magnitudes measured in the Subaru/Hyper Suprime-Cam (HSC) images with those in the Sloan Digital Sky Survey (SDSS) images for ~3x10^4 QUASARs spectroscopically identified by SDSS. We performed follow-up observations, including optical imaging and spectroscopy as well as near-infrared imaging, with >4m-class telescopes such as Subaru, GTC, Keck, and SOAR telescopes. We combine these new data with the archival data to examine the variability behavior over ~20 years in detail and even the longer-term trend of the variability over ~70 years in the observed frame. We find that (i) the AGN component likely faded by a factor of ~50 from the early 2000s to 2023 and (ii) the observed brightness decline is best explained by a substantial decrease in accretion rate rather than time-varying line-of-sight dust obscuration. These findings are derived from multi-component (time-varying AGN + constant galaxy) spectral energy distribution fitting over multi-epochs, which is well consistent with the optical spectra. The Eddington ratio decreases by a factor of ~50, from ~0.4 to ~0.008 if we use the BLACK HOLE mass measured with the SDSS spectrum, which could be highly uncertain because of the very large variability. The total brightness is dominated by the host galaxy in the rest-frame optical wavelength rather than the AGN as of 2023.
[abstract 11 / 41] Yes (score: 4) - Title: Modeling gamma-ray signatures of particle acceleration in stellar clusters from GeV to PeVAuthors: A. Inventar, S. Gabici, E. Peretti,Comments: 8 pages, 3 figures, ICRC proceedingSubjects: astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Young massive stellar clusters (YMSCs) have recently regained interest as PeVatron candidates, potentially accounting for the cosmic-ray (CR) knee as alternatives to isolated SUPERNOVA remnants (SNRs). LHAASO's unique capability to detect photons above 0.1 PeV, hence tracing multi-PeV CRs, can provide critical constraints on galactic acceleration models when combined with H.E.S.S. and FERMI-LAT data. We investigate the transport of particles from YMSCs acceleration sites, namely wind termination shocks (WTS) or embedded SNRs, to nearby dense molecular clouds where proton-proton interactions produce high-energy gamma rays. We determine the necessary conditions, such as the distance between the acceleration site and the target, or the cluster's power and age, for detectable gamma-ray excesses and identify viable systems through parameter space exploration. By comparing with observations, we can constrain key physical parameters including WTS efficiency, diffusion coefficient and injection slope. Our analysis also examines whether some of LHAASO's unidentified sources might correspond to such cluster-cloud systems.
[abstract 12 / 41] (score: 3) - Title: Value Added Catalog of physical properties of more than 1.3 million galaxies from the DESI SurveyAuthors: M. Siudek, R. Pucha, M. Mezcua, S. Juneau, J. Aguilar, S. Ahlen, D. Brooks, C. Circosta, T. Claybaugh, S. Cole, K. Dawson, A. de la Macorra, Arjun Dey, Biprateep Dey, P. Doel, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, G. Gutierrez, K. Honscheid, C. Howlett, M. Ishak, R. Kehoe, D. Kirkby, T. Kisner, A. Kremin, A. Lambert, M. Landriau, L. Le Guillou, M. Manera, P. Martini, A. Meisner, R. Miquel, J. Moustakas, J. A. Newman, G. Niz, Z. Pan, W. J. Percival, C. Poppett, F. Prada, G. Rossi, A. Saintonge, E. Sanchez, D. Schlegel, D. Scholte, M. Schubnell, H. Seo, F. Speranza, D. Sprayberry, G. Tarle, B. A. Weaver, H. Zou,Comments: resubmitted after addressing minor referee comments; fixing eq. 3Subjects: astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Aims. We present an extensive catalog of the physical properties of more than a million galaxies within the Dark Energy Spectroscopic Instrument (DESI), one of the largest spectroscopic surveys to date. Spanning over a full variety of target types, including emission line galaxies and luminous red galaxies as well as QUASARs, our survey encompasses an unprecedented range of spectroscopic redshifts, stretching from 0 to 6. Methods. The physical properties, such as stellar masses and STAR FORMATION rates, are derived via the CIGALE spectral energy distribution (SED) fitting code accounting for the contribution coming from ACTIVE GALACTIC NUCLEi (AGN). Based on the modeling of the optical-mid-infrared (grz complemented by WISE photometry) SEDs, we study galaxy properties with respect to their location on the main sequence. Results. We revise the dependence of stellar mass estimates on model choices and availability of the WISE photometry. The WISE information is mandatory to minimize the misclassification of star-forming galaxies as AGN. The lack of WISE bands in SED fits leads to elevated AGN fractions for 68% of star-forming galaxies identified using emission line diagnostic diagram but does not significantly affect their stellar mass nor STAR FORMATION estimates.
[abstract 13 / 41] (score: 3) - Title: A Time-Dependent Solution for GSN 069 Disk Evolution and the Nature of Long-Lived Tidal Disruption EventsAuthors: M. Guolo, A. Mummery, A. Ingram, M. Nicholl, S. Gezari, E. Nathan,Comments: 25 pages, 13 Figs, +Appendix. Published ApJ. Accepted versionSubjects: astro-ph.HE astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
We present the implementation of a fully time-dependent RELATIVISTIC disk model-based on the light curve fitting package FitTeD-into the X-ray spectral fitting environment, pyXspec. This implementation enables simultaneous fitting of multi-epoch and multi-wavelength spectral data, where the only free parameters are those describing the BLACK HOLE and the initial conditions, while the subsequent evolution is governed by the dynamical equations of an evolving accretion flow. We use it fit seven epochs of X-ray spectra and two epochs of UV spectra of the 'long-lived' tidal disruption event (TDE) and quasi-periodic eruption (QPE) source GSN 069, from 2010 through late-2019. Our results show that such 'long-lived', X-ray-bright TDEs-of which GSN 069 is a prime, but not unique, example-can naturally be explained within the same framework as events with shorter-lived X-ray emission, like ASASSN-14li and AT2019dsg. Their distinction lies in the `viscous' timescale parameter-tied to the disk's angular momentum transport efficiency-which should be treated as a free parameter when modeling the disk evolution of transient events. We examine the implications for QPE models by tracking the time evolution of disk properties such as mass surface density and accretion rate. We argue that existing QPE models may not be able to reproduce the observed connection between the presence (2018) or absence (2014) of eruptions and the disk properties. In the context of orbiter-disk collision models, the change in mass surface density appears insufficient to explain the needed variation in the eruption's temperature. The absence of eruptions in GSN 069 in 2014 remains a challenge for QPE models.
[abstract 14 / 41] (score: 3) - Title: A Comprehensive Analytical Model of the Dynamic Z-PinchAuthors: Alejandro Mesa Dame, Eric S. Lavine, David A. Hammer,Comments: 10 pages, 14 figuresSubjects: physics.plasm-phCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
We present an analytical 1D axisymmetric model describing the evolution of the dynamic z-pinch. This model is capable of predicting the trajectories of the imploding sheath's MAGNETic piston and preceding shock front, along with the velocity, pressure, density, and MAGNETic field profiles, for any time-dependent current, spatially-varying initial density profile, and weak initial axial field. The implosion is divided into stages, with each stage described by a set of coupled ordinary differential equations derived from the ideal MHD equations. Comparison with experimental data from the COBRA pulsed-power facility is quite promising and implies this model could prove useful in designing and analyzing future pulsed-power experiments.
[abstract 15 / 41] (score: 3) - Title: The Relation Between AGN and Host Galaxy Properties in the JWST Era: II. The merger-driven evolution of Seyferts at Cosmic NoonAuthors: Nina Bonaventura, Jianwei Lyu, George H. Rieke, Andrew J. Bunker, Chris J. Willott, Christopher N. A. Willmer,Comments:Subjects: astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
In Paper I, we exploited the unsurpassed resolution and depth of JWST/NIRCam imagery to investigate the relationship between AGN and host-galaxy properties in the JWST era, finding a correlation between the level of spatial disturbance (as measured by shape asymmetry, $A_S$) and obscuration ($N_H$). Here in Paper II, we report an expansion of our X-ray and infrared analysis of Seyfert-luminosity host galaxies with four additional metrics to the single-metric morphology analysis of Paper I, as well as new samples of inactive control galaxies. This expanded study of one of the largest and most complete, multi-wavelength samples of AGN detected at $0.6
[abstract 16 / 41] (score: 3) - Title: On three dimensional steady super-Alfvénic MAGNETohydrodynamics shocks with aligned fieldsAuthors: Shangkun Weng, Wengang Yang,Comments:Subjects: math.AP physics.plasm-phCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
The coupled motion between the hydrodynamic flow and MAGNETic field introduces significant complexity into the structure of the MAGNETohydrodynamic (MHD) equations. A key factor contributing to this complexity is the presence of Alfvén waves, which critically influences the character of the flow and makes the problem considerably more challenging. Within the framework where the MAGNETic field is everywhere parallel to the flow velocity, we give an effective decomposition of the steady MHD equations in terms of the deformation tensor and the modified vorticity, where the modification in the vorticity is to record the effect of the Lorentz force on the velocity field. The existence and structural stability of the super-Alfvénic cylindrical transonic shock solutions for the steady MHD equations are established under three-dimensional perturbations of the incoming flow and the exit total pressure (kinetic plus MAGNETic).
[abstract 17 / 41] (score: 3) - Title: Comparison of MHD and gyrokinetic simulations of linear instabilities at the q = 1 surfaceAuthors: F. N. Antlitz, X. Wang, M. Hoelzl, G. T. A. Huijsmans, H. Zhang, J. Puchmayr, Ph. Lauber, T. Hayward-Schneider, B. F. McMillan, A. Mishchenko, E. Poli, Z. X. Lu, JOREK team,Comments:Subjects: physics.plasm-phCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Accurate modeling of core instabilities in tokamak plasmas is essential to understand the underlying physical mechanisms and their impact on plasma confinement. The ideal stability of the internal kink mode and the m = 1 collisionless tearing mode are analyzed numerically both with gyrokinetic and MHD codes. We compare the different models implemented in the codes and show that the gyrokinetic equations without collisions inherently contain the ideal MHD limit. The simulation results show that the stability of the internal kink mode strongly depends on the choice of several setup parameters like the inclusion of parallel MAGNETic field fluctuations, the tokamak aspect ratio, the drift- or gyrokinetic treatment of the ions and the electron mass. Furthermore, we demonstrate the stabilization of the instabilities by diaMAGNETic effects. Our results indicate that gyrokinetic and MHD models can be reconciled in the description of the internal kink mode by careful consideration of the simulation setup and model assumptions, but instabilities like the collisionless tearing mode require a more advanced treatment beyond MHD.
[abstract 18 / 41] (score: 3) - Title: Enhanced Localization of Dark Lensed Gravitational Wave Events Enables Host Galaxy Identification and Precise Cosmological InferenceAuthors: Zhiwei Chen, Qingjuan Yu, Youjun Lu, Xiao Guo,Comments: 23 pages, 8 figures, accepted for publication in Astrophysical Journal LettersSubjects: astro-ph.CO astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Lensed gravitational wave (GW) events are expected to be powerful new probes of cosmology, contingent on redshift measurement by electroMAGNETic observations. Host galaxy identification is thus crucial but challenging due to poor localization by GW signal alone. In this paper, we show that the third-generation ground-based GW detectors will detect a population of lensed events with three or more detectable images (including the central one), each arriving at distinct times and Earth locations in the space, forming an effective network that reduces the typical localization area to $\sim0.01$ deg$^2$. For at least $90\%$ (or $50\%$) of these events, the localization improves by more than a factor of $10$ (or $30$) comparing with unlensed cases. Such precise localization and multiple-image detections enable robust host-galaxy identification and, through lens modelling, further yield sub-arcsecond position. As ``dark lensed sirens", these events become powerful probes of cosmological parameters. Using simulated lensed compact-binary mergers, we show that two-year or longer observations with third-generation GW detectors can measure the Hubble constant to $\lesssim1$\% precision via ``dark lensed sirens" (even when relying solely on lensed stellar-mass binary BLACK HOLE events), while simultaneously constraining other cosmological parameters. This approach will provide an independent, complementary avenue for measuring cosmological parameters.
[abstract 19 / 41] (score: 3) - Title: DIPLODOCUS II: Implementation of transport equations and test cases relevant to micro-scale physics of JETted astrophysical sourcesAuthors: Christopher N. Everett, Marc Klinger-Plaisier, Garret Cotter,Comments: 26 pages, 24 figures, submitted to Physical Review DSubjects: astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
DIPLODOCUS (Distribution-In-PLateaux methODOlogy for the CompUtation of transport equationS) is a novel framework being developed for the general transport of particle distribution functions through the seven dimensions of phase space, including forcing terms and interactions between particles. Following Paper I, which details the background analytic framework, this second paper provides an overview of the numerical implementation in the form of the code package Diplodocus.jl, written in Julia, including the description of a novel Monte-Carlo sampling technique for the pre-computation of anisotropic collision integrals. In addition to the discussion of numerical implementation, a selection of test cases are presented to examine the package's capabilities. These test cases focus on micro-scale physical effects: binary collisions, emissive interactions and external forces that are relevant to the modelling of JETted astrophysical sources, such as Active Galactic Nuclei and X-Ray Binaries.
[abstract 20 / 41] (score: 3) - Title: Formation of protostars and the launching of stellar core outflows with moving-mesh radiation non-ideal MAGNETohydrodynamicsAuthors: Alexander C. Mayer, Rüdiger Pakmor, Thorsten Naab, Oliver Zier, Alexei V. Ivlev, Tommaso Grassi, Paola Caselli, Volker Springel,Comments: 16 pages, 12 Figures; submitted to MNRASSubjects: astro-ph.SR astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
We present an implementation of radiative transfer with flux-limited diffusion (FLD) for the moving-mesh code {\small AREPO} and use the method in a physical model for the formation of protostars with non-ideal radiation-MAGNETohydrodynamics (RMHD). We follow previous work in splitting the additional terms to the hydrodynamical equations arising from the inclusion of radiation into terms to be integrated explicitly and implicitly, as the diffusion and coupling terms would impose very restrictive timestep criteria. We validate the scheme with standard test problems for radiation diffusion, matter-gas coupling, and radiative shocks from the literature. Our implementation is compatible with local timestepping, which often presents problems for implicit schemes, and we found very good agreement with results obtained with global timesteps. We present an example application of the new implementation to the collapse of a $1\,{\rm M}_\odot$ molecular cloud core to a second Larson core modelled with radiation non-ideal MAGNETohydrodynamics. A high-velocity JET with v$_{\rm rad}> 10\, {\rm km\,s^{-1}}$ is self-consistently launched from the second core, nested within the first core, which produces a lower-velocity MAGNETorotational outflow. We observe MAGNETic field amplification up to more than $\vert \mathbf{B}\vert_{\rm max}>10^5$~G in the second core, which is surrounded by a small ($<0.5$~au) disk. This application demonstrates the robustness of our scheme in multi-scale and high-resolution simulations on arbitrary meshes and, as such, the model can be readily used for further simulations of protoSTAR FORMATION at high resolution.
[abstract 21 / 41] (score: 3) - Title: Interacting galaxies in the IllustrisTNG simulations - IX: Mini mergers trigger AGN in cosmological simulationsAuthors: Shoshannah Byrne-Mamahit, Sara L. Ellison, David R. Patton, Scott Wilkinson, Leonardo Ferreira, Connor Bottrell,Comments: 15 pages, 13 figures, accepted for publication in Monthly Notices of the Royal Astronomical SocietySubjects: astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Galaxy mergers are transformative events that can cause gaseous inflows capable of triggering ACTIVE GALACTIC NUCLEi (AGN). Previous studies of AGN in simulations have mainly focused on major interactions (i.e. between approximately equal mass galaxies), which produce the strongest inflows and, therefore, would be the most likely to trigger AGN activity. However, minor interactions are far more common and may still enhance accretion onto supermassive BLACK HOLEs. We present an analysis of post-merger galaxies from the IllustrisTNG simulation with stellar mass ratios of $μ>$1:100. We select post-mergers from the TNG50-1 simulation, from redshifts $0\leq z< 1$, with stellar masses greater than $10^{10}M_{\odot}$. We find an AGN excess in post-mergers with a stellar mass ratio as low as 1:40. The AGN excess is mass ratio and luminosity dependent, with 1.2-1.6 times more AGN found in post-mergers of 1:40$\leq μ< $1:4 than in matched non-merger controls, and as many as 6 times more AGN found in major $μ\geq$1:4 post-mergers. The AGN excess is long lived, between 500 Myr to 1 Gyr post-coalescence, across all of the mass ratio regimes. We demonstrate that the most luminous AGN in the simulation overwhelmingly occur in either post-mergers or pairs (with $μ\geq $1:40). Finally, we demonstrate that mini mergers are likely to be overlooked in observational studies due to the weakness of features usually associated with recent merger activity, such as tidal streams and shells, making it challenging to completely account for merger-induced AGN activity even in deep galaxy surveys.
[abstract 22 / 41] (score: 3) - Title: Mapping the Perseus Galaxy Cluster with XRISM: Gas Kinematic Features and their Implications for TurbulenceAuthors: Congyao Zhang, Irina Zhuravleva, Annie Heinrich, Elena Bellomi, Nhut Truong, John ZuHone, Eugene Churazov, Megan E. Eckart, Yutaka Fujita, Julie Hlavacek-Larrondo, Yuto Ichinohe, Maxim Markevitch, Kyoko Matsushita, François Mernier, Eric D. Miller, Koji Mori, Hiroshi Nakajima, Anna Ogorzalek, Frederick S. Porter, Ayşegül Tümer, Shutaro Ueda, Norbert Werner,Comments: 15 pages, 17 figures, submitted to A&ASubjects: astro-ph.HE astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
In this paper, we present extended gas kinematic maps of the Perseus cluster by combining five new XRISM/Resolve pointings observed in 2025 with four Performance Verification datasets from 2024, totaling 745 ks net exposure. To date, Perseus remains the only cluster that has been extensively mapped out to ~0.7$r_{2500}$ by XRISM/Resolve, while simultaneously offering sufficient spatial resolution to resolve gaseous substructures driven by mergers and AGN feedback. Our observations cover multiple radial directions and a broad dynamical range, enabling us to characterize the intracluster medium kinematics up to the scale of ~500 kpc. In the measurements, we detect high velocity dispersions ($\simeq$300 km/s) in the eastern region of the cluster, corresponding to a nonthermal pressure fraction of $\simeq$7-13%. The velocity field outside the AGN-dominant region can be effectively described by a single, large-scale kinematic driver based on the velocity structure function, which statistically favors an energy injection scale of at least a few hundred kpc. The estimated turbulent dissipation energy is comparable to the gravitational potential energy released by a recent merger, implying a significant role of turbulent cascade in the merger energy conversion. In the bulk velocity field, we observe a dipole-like pattern along the east-west direction with an amplitude of $\simeq\pm$200-300 km/s, indicating rotational motions induced by the recent merger event. This feature constrains the viewing direction to ~30$^\circ$-50$^\circ$ relative to the normal of the merger plane. Our hydrodynamic simulations suggest that Perseus has experienced at least two energetic mergers since redshift z~1, the latest associated with the RADIO GALAXy IC310. This study showcases exciting scientific opportunities for future missions with high-resolution spectroscopic capabilities (e.g., HUBS, LEM, and NewAthena).
[abstract 23 / 41] (score: 2) - Title: Cosmic Ray Muon Polarization to Facilitate Atmospheric Neutrino PhysicsAuthors: Ming-Chen Sun, Shi-Han Zhao, Rui-Xuan Gao, He-Sheng Liu, Ai-Yu Bai, Jian Tang,Comments: 9 pages; 9 figuresSubjects: hep-exCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Atmospheric neutrinos (ATNs) offer a paradigm for understanding neutrino properties, while it is critical to quantify uncertainties in flux modeling. Since ATNs are produced simultaneously with COSMIC RAY muons, precision measurements of COSMIC RAY muons, including arrival direction, energy spectra, and spin POLARIZATION, will help reduce ATN production uncertainties and facilitate atmospheric neutrino physics. This letter proposes using an array strategy to measure the spin POLARIZATION of COSMIC RAY muons, thereby strengthening the emergent synergies between COSMIC RAY and atmospheric neutrino physics. Constraints on long-standing atmospheric neutrino flux uncertainties at the percentage level in a few-GeV energy range are achievable within one year using a $O(10)~\text{m}^2$ array of Cosmic-Ray muon Spin POLARIZATION detectoRs (CRmuSRs). With the resulting reduction in flux uncertainties, oscillation analysis of atmospheric neutrinos in a liquid scintillator detector with an exposure of 1500 $\text{kt}\cdot\text{yr}$ will break the octant degeneracy and achieve the precision measurement of $θ_{23}$ with the uncertainty smaller than $5$° at 3$σ$ confidence level irrespective of the mass ordering.
[abstract 24 / 41] (score: 2) - Title: DIPLODOCUS I: Framework for the evaluation of RELATIVISTIC transport equations with continuous forcing and discrete particle interactionsAuthors: Christopher N. Everett, Garret Cotter,Comments: 16 pages, 7 figures; submitted to Physical Review D; typos corrected, references addedSubjects: astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
DIPLODOCUS (Distribution-In-PLateaux methODOlogy for the CompUtation of transport equationS) is a novel framework being developed for the mesoscopic modelling of astrophysical systems via the transport of particle distribution functions through the seven dimensions of phase space, including continuous forces and discrete interactions between particles. This first paper in a series provides an overview of the analytical framework behind the model, consisting of an integral formulation of the RELATIVISTIC transport equations (Boltzmann equations) and a discretisation procedure for the particle distribution function (Distribution-In-Plateaux). The latter allows for the evaluation of anisotropic interactions, and generates a conservative numerical scheme for a distribution function's transport through phase space.
[abstract 25 / 41] (score: 2) - Title: Small Progenitors, Large Couplings: Type Ic Supernova Constraints on Radiatively Decaying ParticlesAuthors: Francisco R. Candón, Damiano F. G. Fiorillo, Hans-Thomas Janka, Bart F. A. van Baal, Edoardo Vitagliano,Comments: 7+7 pages, 2+5 figuresSubjects: hep-ph astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Supernova (SN) 1987A is a celebrated laboratory in searches for gamma-ray flashes produced by the radiative decay of sub-GeV particles such as axion-like particles (ALPs), sterile neutrinos, and novel gauge BOSONs. At large couplings, however, particles decay rapidly inside the stellar envelope, which results in a suppression of the signal. Focusing on the prototypical example of ALPs with a photon coupling, we show that core-collapse SNe of Type Ic are much less affected by this attenuation, thanks to the compactness of their progenitors ensuing from the loss of their envelope. While FERMI-LAT may miss the brief gamma-ray flash from a single Type Ic SN, their high rate allows for a statistical approach: by stacking many events, we can obtain constraints that significantly surpass those from SN 1987A at large couplings. Our approach can be extended to any feebly interacting particle featuring a decay channel into photons.
[abstract 26 / 41] (score: 2) - Title: Resonant W and Z Boson Production in FSRQ Jets: Implications for Diffuse Neutrino FluxesAuthors: J. -H. Ha, I. Alikhanov,Comments: 21pages, 7 figures, 1 table, submitted to JCAPSubjects: astro-ph.HE hep-phCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Blazars, particularly Flat Spectrum Radio Quasars (FSRQs), are well-known for their ability to accelerate a substantial population of electrons and positrons, as inferred from multiwavelength radiation observations. Therefore, these astrophysical objects are promising candidates for studying high-energy electron--positron interactions, such as the production of $W^{\pm}$ and $Z$ BOSONs. In this work, we explore the implications of electron--positron annihilation processes in the JET environments of FSRQs, focusing on the resonant production of electroweak BOSONs and their potential contribution to the diffuse neutrino flux. By modeling the electron distribution in the JET of the FSRQ 3C~279 during a flaring state, we calculate the reaction rates for $W^{\pm}$ and $Z$ BOSONs and estimate the resulting diffuse fluxes from the cosmological population of FSRQs. We incorporate the FSRQ luminosity function and its redshift evolution to account for the population distribution across cosmic time, finding that the differential flux contribution exhibits a pronounced peak at redshift $z \sim 1$. While the expected fluxes remain well below the detection thresholds of current neutrino observatories such as IceCube, KM3NeT, or Baikal-GVD, the expected flux from the $Z$ BOSON production could account for approximately $10^{-3}$ of the total diffuse astrophysical neutrino flux. These results provide a theoretical benchmark for the role of Standard Model electroweak processes in extreme astrophysical environments and emphasize the interplay between particle physics and astrophysics, illustrating that even rare high-energy interactions can leave a subtle but quantifiable imprint on the diffuse astrophysical neutrinos.
[abstract 27 / 41] (score: 2) - Title: Revisiting the limits on DARK MATTER annihilation cross-section and decay lifetime in light of electron and positron fluxesAuthors: Nagisa Hiroshima, Kazunori Kohri, Partha Kumar Paul, Narendra Sahu,Comments: 8 pages, 4 captioned figuresSubjects: hep-ph astro-ph.CO astro-ph.HECreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
We revisit the upper bound on the annihilation cross-section, $\langleσv\rangle$ of a stable DARK MATTER (DM) of mass $5\times10^2-10^{14}$ GeV by considering five different channels: $W^+W^-$, $b\bar{b}$, $μ^+μ^-$, $τ^+τ^-$, and $e^+e^-$. We use the observed electron and positron fluxes from CALET, DAMPE, HESS, positron flux from AMS-02, and gamma-ray flux from HAWC, GRAPES-3, CASA-MIA to constrain the annihilation cross-section. We also consider unstable DM of mass $10^3-10^{16}$~GeV decaying to $W^+W^-$, $b\bar{b}$, $μ^+μ^-$, $τ^+τ^-$, and $e^+e^-$ and derive the corresponding lower bound on the DM lifetime, $τ_{\rm DM}$. We find that the latest data from CALET gives a stringent constraint on $\langleσv\rangle$ in the low DM mass regime. For a typical DM mass of 1 TeV, we show that $\langleσv\rangle_{{\rm DM~DM}\rightarrowμ^+μ^-}\gtrsim\mathcal{O}(10^{-24})~\rm cm^3/s$ is disfavored. On the other hand in the low mass regime, the AMS-02 gives a much stringent limit on the DM lifetime, excluding $τ_{\rm DM\rightarrowμ^+μ^-}\lesssim\mathcal{O}(10^{27})$ s for a 1 TeV mass of DM. In the high mass regime, typically $M_{\rm DM}\gtrsim\mathcal{O}(10^5)$ GeV, HAWC and CASA-MIA give the strongest constraints on $\langleσv\rangle$ and $τ_{\rm DM}$.
[abstract 28 / 41] (score: 2) - Title: Quasinormal modes from numerical relativity with Bayesian inferenceAuthors: Richard Dyer, Christopher J. Moore,Comments: Main text: 14 pages, 10 figures. Appendix: 6 pages, 10 figuresSubjects: gr-qc astro-ph.HECreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
Numerical relativity (NR) enables the study of physics in strong and dynamical gravitational fields and provides predictions for the gravitational-wave signals produced by merging BLACK HOLEs. Despite the impressive accuracy of modern codes, the resulting waveforms inevitably contain numerical uncertainties. Quantifying these uncertainties is important, especially for studies probing subdominant or nonlinear effects around the merger and ringdown. This paper describes a flexible Gaussian-process model for the numerical uncertainties in all the spherical-harmonic waveform modes across a state-of-the-art catalog of NR waveforms and a highly efficient procedure for sampling the posteriors of quasinormal mode models without the need for expensive Markov chain Monte Carlo. The Gaussian-process model is used to define a likelihood function which allows many Bayesian data analysis techniques - already widely used in the analysis of experimental gravitational wave data - to be applied to NR waveforms as well. The efficacy of this approach is demonstrated by applying it to the analysis of quasinormal modes in Cauchy-characteristic evolved waveforms.
[abstract 29 / 41] (score: 2) - Title: False Alarm Rates in Detecting Gravitational Wave Lensing from Astrophysical Coincidences: Insights with Model-Independent Technique GLANCEAuthors: Aniruddha Chakraborty, Suvodip Mukherjee,Comments: 18 pages, 10 figures (including appendices)Subjects: gr-qc astro-ph.CO astro-ph.GA astro-ph.HECreated: 2025-10-13; Updated: 2025-10-15; Datestamp: 2025-10-15
The strong lensing gravitational waves (GWs) due to intervening massive astrophysical systems between the source and an observer are an inevitable consequence of the general theory of relativity, which can produce multiple GW events in overlapping sky localization error. However, the confirmed detection of such a unique astrophysical phenomenon is challenging due to several sources of contamination, arising from detector noise to astrophysical uncertainties. Robust model-independent search techniques that can mitigate noise contamination were developed in the past. In this study, we explore the astrophysical uncertainty associated with incorrectly classifying a pair of unlensed GW events as a lensed event, and the associated False Alarm Rate (FAR) depending on the GW source properties. To understand the effect of unlensed astrophysical GW sources in producing false lensing detections, we have performed a model-independent test using the pipeline GLANCE on a simulated population of merging binary-BLACK HOLEs (BBHs). We find that $\sim$ 0.01\% of the event pairs can be falsely classified as lensed with a lensing threshold signal-to-noise ratio of 1.5, appearing at a time delay between the event pairs of $\sim$ 1000 days or more. We show the FAR distribution for the parameter space of GW source masses, delay time, and lensing magnification parameter over which the model-independent technique GLANCE can confidently detect lensed GW pair with the current LIGO detector sensitivity. In the future, this technique will be useful for understanding the FAR of the upcoming next-generation GW detectors, which can observe many more GW sources.
[abstract 30 / 41] (score: 2) - Title: Polar Filaments Capture High Latitude Solar Poloidal Field Interactions and can Foretell the Future Sunspot Cycle Amplitude before Polar Field PrecursorsAuthors: Srinjana Routh, Shaonwita Pal, Dibyendu Nandy, Subhamoy Chatterjee, Dipankar Banerjee, Mohd. Saleem Khan,Comments: Accepted for publication in The Astrophysical Journal Letters (ApJL)Subjects: astro-ph.SR physics.plasm-ph physics.space-phCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Polar fields at the minimum of a sunspot cycle -- which are a manifestation of the radial component of the Sun's poloidal field -- are deemed to be the best indicator of the strength of the toroidal component, and hence the amplitude of the future sunspot cycle. However, the Sun's polar MAGNETic fields are difficult to constrain with ground-based or space-based observations from near the plane-of-ecliptic. In this context, polar filaments -- dark, elongated structures that overlie polarity inversion lines -- are known to offer critical insights into solar polar field dynamics. Through investigations of the long-term evolution of polar filament areas and length acquired from the Meudon Observatory and complimentary solar surface flux transport simulations, here we establish the common physical foundation connecting the Babcock-Leighton solar dynamo mechanism of solar polar field reversal and build-up with the origin and evolution of polar filaments. We discover a new relationship connecting the residual filament area of adjacent solar cycles with the amplitude of the next sunspot cycle -- which can serve as a new tool for solar cycle forecasts -- advancing the forecast window to earlier than polar field based precursors. We conclude that polar filament properties encapsulate the physics of interaction of the poloidal MAGNETic field of the previous and current sunspot cycles, the resultant of which is the net poloidal MAGNETic field at the end of the current cycle, thus encoding as a precursor the strength of the upcoming solar cycle.
[abstract 31 / 41] (score: 2) - Title: Spatio-Temporal Evolution of the March 2022 ICME Revealed by Multi-Point Observations of Forbush DecreasesAuthors: Gaku Kinoshita, Beatriz Sanchez-Cano, Yoshizumi Miyoshi, Laura Rodoriguez-Garcia, Emilia Kilpua, Benoit Lavraud, Mathias Rojo, Marco Pinto, Yuki Harada, Go Murakami, Yoshifumi Saito, Shoichiro Yokota, Daniel Heyner, David Fischer, Nicolas Andre, Kazuo Yoshioka,Comments: 21 pages, 11 figuresSubjects: astro-ph.SR astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Interplanetary coronal mass ejections (ICMEs) cause Forbush Decreases (FDs) effects, which are local decreases in background galactic COSMIC RAYs (GCR). Even though FDs can be observed with simple particle instruments, their amplitude and shape provide physical profiles of passing ICMEs. However, in some cases, previous statistical studies of the heliocentric distance dependence of FD changes associated with ICME propagation have found no strong correlation. We need the criteria for evaluating the relationship between ICMEs structure and FD, necessary for FDs statistical analysis. This study investigates the effect of evolutions and interactions of ICMEs on FDs profiles in the inner Solar System, using multipoint comparisons. We focus on multipoint ICME observations by Solar Orbiter, BepiColombo, and near-Earth spacecraft from March 10-16, 2022, when these spacecraft were ideally located for studying the radial and longitudinal evolutions of ICME and accompanying FDs. We compared GCR variations with the multiple in-situ data and ICME model, clarifying the correspondence between the evolution of each ICME structure in radial and azimuthal directions and the depth and gradients of the FD. The radial comparison revealed decreases in FD intensities and gradients associated with the expansion of the ICME. The longitudinal difference found in FD intensity indicates longitudinal variations of the ICMEs shielding effect. These results suggest that accurate multi-point FD comparisons require determining the relationship between the observers position and the inner structure of the passing ICMEs.
[abstract 32 / 41] (score: 2) - Title: Fe XVIII-XXIV K beta Inner-shell Absorption Lines in the X-ray Spectra of Neutron Star and Black Hole Binaries with XRISMAuthors: Masahiro Tsujimoto, Daiki Miura, Hiroya Yamaguchi, Ehud Behar, Chris Done, Maria Diaz Trigo, Chamani M. Gunasekera, Peter A. M. van Hoof, Stefano Bianchi, Maryam Dehghanian, Gary J. Ferland,Comments: 4 pages, 6 figures, accepted for publication in Plasma and Fusion ResearchSubjects: astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
The advent of the X-ray microcalorimeter spectrometer Resolve onboard the XRISM space telescope opened a new era for high-resolution X-ray spectroscopy of astrophysical plasmas. Many spectral features were newly detected, including the K alpha and K beta inner-shell transition lines of mildly ionized (F- to Li-like) Fe at 6-8 keV in the spectra of X-ray binaries and ACTIVE GALACTIC NUCLEi. The widely used atomic databases contain information on the K alpha but not K beta lines of these ions. We conducted the atomic structure calculation using FAC to derive the Fe K alpha and K beta lines and verified the result against ground experiments and other calculations of the Fe K alpha lines. We then implemented the Fe K beta lines in a radiative transfer code (cloudy) and compared the synthesized and observed spectra with XRISM. A reasonably good agreement was obtained between the observation and the ab initio calculations. This exemplifies the need to expand the atomic databases to interpret astrophysical spectra.
[abstract 33 / 41] (score: 2) - Title: Optically thick winds of very massive stars suppress intermediate-mass BLACK HOLE formationAuthors: Stefano Torniamenti, Michela Mapelli, Lumen Boco, Filippo Simonato, Giuliano Iorio, Erika Korb,Comments: 10 pages, 7 figures. Comments welcomeSubjects: astro-ph.HE astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Intermediate-mass BLACK HOLEs (IMBHs) are the link between stellar-mass and supermassive BLACK HOLEs. Gravitational waves have started unveiling a population of IMBHs in the $\sim 100-300 \, \mathrm{M_{\odot}}$ range. Here, we investigate the formation of IMBHs from very massive stars (VMSs, $>100\,{} \mathrm{M_{\odot}}$). We calculate new VMS models that account for the transition from optically thin to optically thick winds, and study how this enhanced mass loss affects IMBH formation and the BLACK HOLE mass function at intermediate and high metallicity ($Z=10^{-4}-0.02$). We show that optically thick winds suppress the formation of IMBHs from direct VMS collapse at metallicities $Z>0.001$, one order of magnitude lower than predicted by previous models. Our models indicate that the stellar progenitors of GW231123 must have had a metallicity $Z<0.002$, if the primary BLACK HOLE formed via direct VMS collapse.
[abstract 34 / 41] (score: 2) - Title: Jets in Low-Mass ProtostarsAuthors: Somnath Dutta,Comments: 26 pages, 7 figures, A review on protostellar jets, published in the Universe (MDPI) journalSubjects: astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Jets and outflows are key components of low-mass STAR FORMATION, regulating accretion and shaping the surrounding molecular clouds. These flows, traced by molecular species at (sub)millimeter wavelengths (e.g., CO, SiO, SO, H$_2$CO, and CH$_3$OH) and by atomic, ionized, and molecular lines in the infrared (e.g., H$_2$, [Fe II], [S I]), originate from protostellar accretion disks deeply embedded within dusty envelopes. Jets play a crucial role in removing angular momentum from the disk, thereby enabling continued mass accretion, while directly preserving a record of the protostar's outflow history and potentially providing indirect insights into its accretion history. Recent advances in high-resolution, high-sensitivity observations, particularly with the James Webb Space Telescope (JWST) in the infrared and the Atacama Large Millimeter/submillimeter Array (ALMA) at (sub)millimeter wavelengths, have revolutionized studies of protostellar JETs and outflows. These instruments provide complementary views of warm, shock-excited gas and cold molecular component of the JET-outflow system. In this review, we discuss the current status of observational studies that reveal detailed structures, kinematics, and chemical compositions of protostellar JETs and outflows. Recent analyses of mass-loss rates, velocities, rotation, molecular abundances, and MAGNETic fields provide critical insights into JET launching mechanisms, disk evolution, and the potential formation of binary systems and planets. The synergy of JWST's infrared sensitivity and ALMA's high-resolution imaging is advancing our understanding of JETs and outflows. Future large-scale, high-resolution surveys with these facilities are expected to drive major breakthroughs in outflow research.
[abstract 35 / 41] (score: 2) - Title: The double neutron star PSR J1946+2052 I. Masses and tests of general relativityAuthors: Lingqi Meng, Paulo C. C. Freire, Kevin Stovall, Norbert Wex, Xueli Miao, Weiwei Zhu, Michael Kramer, James M. Cordes, Huanchen Hu, Jinchen Jiang, Emilie Parent, Lijing Shao, Ingrid H. Stairs, Mengyao Xue, Adam Brazier, Fernando Camilo, David J. Champion, Shami Chatterjee, Fronefield Crawford, Ziyao Fang, Qiuyang Fu, Yanjun Guo, Jason W. T. Hessels, Maura MacLaughlin, Chenchen Miao, Jiarui Niu, Ziwei Wu, Jumei Yao, Mao Yuan, Youlin Yue, Chengmin Zhang,Comments: 12 figures and 3 tables, accepted for publication in A&ASubjects: astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
We conducted high-precision timing of PSR J1946+2052 to determine the masses of the two neutron stars in the system, test general relativity (GR) and assessed the system's potential for future measurement of the moment of inertia of the pulsar. We analysed seven years of timing data from the Arecibo 305-m radio telescope, the Green Bank Telescope (GBT), and the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The data processing accounted for dispersion measure variations and RELATIVISTIC spin precession-induced profile evolution. We employed both DDFWHE and DDGR binary models to measure the spin parameters, kinematic parameters and orbital parameters. The timing campaign has resulted in the precise measurement of five post-Keplerian parameters, which yield very precise masses for the system and three tests of general relativity. One of these is the second most precise test of the radiative properties of gravity to date: the intrinsic orbital decay, $\dot{P}_{\rm b,int}=-1.8288(16)\times10^{-12}\rm\,s\,s^{-1}$, represents $1.00005(91)$ of the GR prediction, indicating that the theory has passed this stringent test. The other two tests, of the Shapiro delay parameters, have precisions of 6\% and 5\% respectively; this is caused by the moderate orbital inclination of the system, $\sim 74^{\circ}$; the measurements of the Shapiro delay parameters also agree with the GR predictions. Additionally, we analysed the higher-order contributions of $\dotω$, including the Lense-Thirring contribution. Both the second post-Newtonian and the Lense-Thirring contributions are larger than the current uncertainty of $\dotω$ ($δ\dotω=4\times10^{-4}\,\rm deg\,yr^{-1}$), leading to the higher-order correction for the total mass.
[abstract 36 / 41] (score: 2) - Title: Spectroscopic Reverberation Mapping for SARM: The Case of Mrk 1048 and Mrk 618Authors: Shivangi Pandey, Suvendu Rakshit, S. Muneer, Jincen Jose, Ashutosh Tomar, Yan-Rong Li, Jian-Min Wang, C. S. Stalin, Jong-Hak Woo, Romain G. Petrov, James Leftley, Sebastian F. Hönig, Amit Kumar Mandal, Tushar Ubarhande, Shu Wang, Michael Brotherton, Archana Gupta,Comments: Accepted for Publication in ApJ, 9 figures, 5 tables, 22 pagesSubjects: astro-ph.GACreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
Robust extragalactic distance measurements are crucial for resolving the persistent discrepancy in the value of the Hubble constant (H$_0$)). Active Galactic Nuclei (AGNs), through their compact and variable broad-line regions (BLRs), enable the determination of geometric distances when reverberation mapping (RM) is combined with spectroastrometry(SA). We report results from a spectroscopic RM campaign (October 2022 to March 2023) targeting two narrow-line Seyfert 1 galaxies, Mrk 1048 and Mrk 618, using 3.6-m DOT and 2-m HCT. High-cadence spectro-photometric monitoring was carried out using onboard instruments such as ADFOSC, HFOSC, and TANSPEC, resulting in well-sampled continuum and emission line light curves. The observed fractional variability ($F_{\mathrm{var}}$) ranged from 4% to 14% across the $g$-band, H$β$, and H$α$ light curves. The time lags were measured using the interpolated cross-correlation function (ICCF), PyI$^{2}$CCF, and \textsc{JAVELIN} methods. In the rest frame, the ICCF analysis yields H$β$ lags of $10.5^{+2.6}_{-4.2}$ days for Mrk 1048 and $10.2^{+3.4}_{-2.9}$ days for Mrk 618, while the corresponding H$α$ lags are $18.7^{+5.3}_{-5.4}$ and $14.4^{+4.6}_{-10.5}$ days, respectively. The emission-line widths, measured from the rms spectra using $σ_{\mathrm{line}}$, give virial BLACK HOLE mass estimates of $6.3^{+2.0}_{-2.1} \times 10^7\,M_\odot$ for Mrk 1048 and $1.2^{+0.4}_{-0.6} \times 10^7\,M_\odot$ for Mrk 618. These results will serve as a basis for absolute geometric distance calibration when combined with VLTI/GRAVITY spectro-astrometric measurements, thereby contributing to the development of AGNs as standardizable cosmological probes.
[abstract 37 / 41] (score: 2) - Title: Low Reynolds number flow in a packed bed of rotated barsAuthors: Wojciech Sadowski, Christin Velten, Maximilian Brömmer, Hakan Demir, Kerstin Hülz, Francesca di Mare, Katharina Zähringer, Viktor Scherer,Comments: submitted to Chemical Engineering & TechnlogySubjects: physics.flu-dynCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
The present study focuses on the gas flow through an experiment-scale modular packed bed reactor consisting of square bars, arranged in layers. Each layer is rotated by $30^\circ$ resulting in a complex shape of the void spaces between the bars. Particle Image Velocimetry measurement results inside and on top of the studied system are presented for particle-based Reynolds numbers of 100 and 200, and used as validation data for two sets of particle-resolved numerical simulations, using boundary conforming meshing strategy and treating the solid boundaries via the blocked-off method. The flow inside the bed is largely independent from the Reynolds number and seems to be determined by the geometry of the void spaces. The flow in the freeboard is dominated by the presence of slowly dissipating JETs downstream of the bed, which are characterized by unsteady oscillations at the higher Reynolds number. The numerical results obtained with both methods are in good agreement with the measurements, both inside and above the bed. However, stronger deviations between the results can be observed in the freeboard and can be traced to numerical properties of the current simulation approaches.
[abstract 38 / 41] (score: 2) - Title: JWST and Keck Observations of the Off-Nuclear TDE AT 2024tvd: A Massive Nuclear Star Cluster and Minor-Merger Origin for its Black HoleAuthors: Kishore C. Patra, Ryan J. Foley, Nicholas Earl, Kyle W. Davis, Enrico Ramirez-Ruiz, V. Ashley Villar, Sebastian Gomez, K. Decker French, Kirsty Taggart, Prasiddha Arunachalam, Phillip Macias, Ravjit Kaur, Samaporn Tinyanont,Comments: 22 pages, 9 figures, comments welcomeSubjects: astro-ph.HE astro-ph.GA astro-ph.SRCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
We present JWST/NIRSpec and NIRCam observations of the first optically selected off-nuclear tidal disruption event (TDE), AT 2024tvd, along with Keck/KCWI integral field unit spectroscopy. The spectra show broad H and He emission lines that are characteristic of a TDE. Stellar kinematics show smooth host-galaxy morphology and ordered bulge rotation, with no evidence of disturbances in velocity, dispersion, age or metallicity space. We construct the first quasi-simultaneous spectral-energy distribution (SED) from X-rays to infrared for a TDE and decompose it into three components: the TDE accretion flow, an unresolved nuclear star cluster (NSC), and heated dust emission. The accretion component implies a BLACK HOLE mass of $\log(M_\bullet/M_\odot) = 5.50\pm 0.04$, an instantaneous super-Eddington accretion rate of $\log (\dot{M}/M_{\odot} yr^{-1}) = -1.22 \pm 0.04$, and an outer disk photosphere radius of $\log(r_{out}/r_{g}) = 3.8 \pm 0.1$. The dust emission is well described by a blackbody with $T_{dust} = 873\pm 15$ K and peak luminosity $\log (L_{dust}/erg$ $s^{-1}) = 40.80\pm 0.01$, consistent with a dust echo near the sublimation radius. The SED is best fit when including additional stellar emission above the galaxy background at the TDE location, corresponding to $\log(M_{\star}/M_\odot) = 7.97^{+0.16}_{-0.26}$, which we interpret as a massive NSC or an ultra-compact dwarf galaxy. These results support a minor-merger origin for the MBH responsible for the TDE over scenarios involving gravitational recoil or dynamical ejection from the nucleus.
[abstract 39 / 41] (score: 2) - Title: OCTOPUS: A Versatile, User-Friendly, and Extensible Public Code for General-Relativistic Ray-Tracing in Spherically Symmetric and Static SpacetimesAuthors: Shiyang Hu, Shijie Tan, Dan Li, Lina Zhang, Chen Deng, Wenfu Cao,Comments: 49 pages, 24 figures, comments are welcomeSubjects: gr-qcCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
This paper presents OCTOPUS, a RELATIVISTIC ray-tracing algorithm developed within a Fortran-based, OpenMP-accelerated framework, designed for asymptotically flat, spherically symmetric curved spacetimes. The code efficiently and accurately computes key RELATIVISTIC features -- including the BLACK HOLE event horizon, photon rings, critical curves, and innermost stable circular orbits -- and simulates BLACK HOLE shadows, redshift factor distributions, accretion disk images, toroidal images, as well as gravitational lensing, light curves, and gravitational radiation from hot-spots. OCTOPUS provides an automated, modular solution for qualitative studies of BLACK HOLE observables and multi-messenger correlations between electroMAGNETic and gravitational signals in curved spacetime. Its implementation requires only the metric potential and its first-, second-, and third-order radial derivatives as input, ensuring low user barriers while remaining highly extensible and adaptable. Using a Schwarzschild BLACK HOLE surrounded by a Dehnen-type DARK MATTER halo, we thoroughly validate the algorithm's precision, efficiency, and functionality, and investigate how DARK MATTER halo parameters affect observational signatures. Our results demonstrate that increasing the scale and density of the DARK MATTER halo strengthens the spacetime's gravitational field, an effect clearly reflected in BLACK HOLE images and supported by hot-spot light curve signatures. A future version of OCTOPUS, with expanded capabilities for axisymmetric spacetimes, is planned for release.
[abstract 40 / 41] (score: 2) - Title: High-energy photons from Gamma-Ray Bursts, but no neutrinosAuthors: A. De Rújula,Comments: 8 pages, 13 figuresSubjects: hep-ph astro-ph.HECreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
The Cannon-Ball model of Gamma-Ray Bursts and their afterglows--described in the text and in innumerable previous occasions--is extremely successful and predictive. In a few intrinsically bright GRBs, gamma-rays with energies in the TeV range have been observed. The CB model, I argue, has no difficulty in describing the origin and approximate properties of these high-energy gamma rays and the extreme difficulty of observing their accompanying neutrinos.
[abstract 41 / 41] (score: 2) - Title: Energy calibration of LHAASO-KM2A using the COSMIC RAY Moon shadowAuthors: Ali Raza, Huihai He, Faisal Akram, The LHAASO Collaboration,Comments: 12 pages, 13 figures, 2 tablesSubjects: astro-ph.HE astro-ph.IMCreated: 2025-10-14; Updated: 2025-10-15; Datestamp: 2025-10-15
We present a precise measurement of the westward, rigidity-dependent shift of the Moon's shadow using three and a half years of cosmic-ray data collected by the Kilometer Square Array (KM2A) of the Large High Altitude Air Shower Observatory (LHAASO). These measurements enable us to calibrate the detector energy response in the range 20-260 TeV, with results showing excellent agreement with the response derived from Monte Carlo (MC) simulations of the KM2A detector. We also measure a best-fit parameter $ε= 0.015 \pm 0.08$, corresponding to a 95% confidence interval of [-14%, +17%] for the energy-scale estimation. This result establishes the exceptional accuracy of the KM2A-MC in simulating the detector's response within this energy range.
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