Current date: 2026-11-13
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Datestamp limit: 2026-11-13 (0 days ago)
Created/updated limit: 2026-11-06 (7 days ago)
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Scoring abstracts
Number of records retrieved: 1300
Keyword score statistics
score 9 -- 3 abstracts
score 8 -- 2 abstracts
score 6 -- 6 abstracts
score 5 -- 4 abstracts
score 4 -- 8 abstracts
score 3 -- 15 abstracts
score 2 -- 24 abstracts
in total -- 62 abstracts
Articles that appeared on 2026-11-13
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[abstract 1 / 62] Wow! (score: 9)
- Title: Flare genesis in RELATIVISTIC JET: Disentangling the drivers of variability in the BLAZAR 4C +27.50Authors: Joysankar Majumdar, Sakshi Maurya, Raj Prince,Comments: Accepted for publication in ApJSubjects: astro-ph.HE astro-ph.GACreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
Recently, BLAZAR 4C +27.50 was found to be flaring in gamma-rays since its detection with FERMI-LAT in 2008. For the first time, a dedicated temporal and spectral study of the BLAZAR 4C +27.50 has been performed in this work to understand the nature of this object. We used the Bayesian block algorithm to identify four flaring states and one quiet state in the 4-year-long FERMI-LAT light curve. Simultaneous broadband flaring episodes have been observed, and a significant correlation is seen between optical and $γ$-ray emission, suggesting the co-spatial origin of the broadband emission. The variation of fractional variability amplitude with respect to frequency shows a nearly double hump structure similar to broadband SED. The fastest flux doubling time in the 1-day binned $γ$-ray light curve is found to be about 7.8 hours. A curvature in $γ$-ray spectra has been observed, possibly caused by a stochastic particle acceleration process rather than radiative cooling. No evident correlation was found in the $γ$-ray flux-index plot, but a clear harder-when-brighter trend is observed in the X-ray flux-index plot. A one-zone leptonic model has been implemented to understand broadband emission during the quiet and flaring states, and the variation of the JET parameters has been investigated. Broadband SED modeling suggested that an enhancement in the MAGNETic field and particle energy density, together with a harder particle spectrum, might have caused the flaring events, while the bulk Lorentz factor shows no systematic change.
[abstract 2 / 62] Wow! (score: 9) - Title: Very High-Energy GRB Afterglow Fits with Neural-Network Emulation and Bayesian inferenceAuthors: Edilberto Aguilar-Ruiz, Jessica Saldívar Talavera, Ramandeep Gill, Sundar Srinivasan,Comments: Accepted in MNRASSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The very high-energy ($E > 100$ GeV) afterglow emission in GAMMA-RAY BURSTs (GRBs) can be explained by SYNCHROTRON self-Compton (SSC). Modeling this emission accurately requires fully numerical codes that solve the time-dependent coupled particle--photon kinetic equations while accounting for Klein--Nishina suppression. However, their substantial computational cost makes them impractical for traditional parameter inference techniques such as Markov Chain Monte Carlo (MCMC) sampling. In this work, we present a highly efficient surrogate model based on artificial neural networks (ANNs) that emulates a one-zone kinetic SSC radiation code. To train our ANN, we use a multi-dimensional model parameter grid that constitutes a sample of 100,800 spectra produced by an infinitely thin spherical blast wave propagating inside a constant density interstellar medium (ISM). The ANN reproduces the numerical spectra well, with the median relative error generally below 2 per cent across the full frequency domain. Using this surrogate framework, we perform Bayesian parameter posterior estimation via MCMC and fit the broadband GRB afterglow observations of GRB 190114C from X-rays to TeV $γ$-rays at different epochs. We find an energetic JET with isotropic-equivalent kinetic energy of $E_{\rm k,iso}\simeq7.2\times10^{54}$ erg moving with a coasting bulk Lorentz factor of $Γ\gtrsim500$ into an ISM with density $n\simeq0.1\,{\rm cm^{-3}}$. The deviation of our model light curve from observations on long timescales suggests that an ISM environment is inconsistent, and instead favours a radially stratified external medium.
[abstract 3 / 62] Wow! (score: 9) - Title: Double Blandford: Resistive GRMHD simulations of accreting BLACK HOLEs simultaneously launch winds and JETsAuthors: J. Speicher, O. Porth, N. Degenaar,Comments: 21 pages, 18 figures, submitted to MNRASSubjects: astro-ph.HECreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
Magnetic fields can launch outflows through the Blandford-Znajek (BZ) or the Blandford-Payne (BP) mechanism in accreting BLACK HOLE systems. Despite the dominant launching mechanism still being unclear, the BP process has been insufficiently studied in general-RELATIVISTIC MAGNETohydrodynamic (GRMHD) simulations due to difficulties in generating and maintaining the required large-scale MAGNETic field geometry. Here, we set up six resistive GRMHD simulations of thin accretion disks with BHAC. The accretion disks in two simulations become MAGNETically arrested, while the others stay in the standard and normal evolution (SANE) regime. All simulations form JETs and winds. The JETs are parabolic and collimated by the outer sub-RELATIVISTIC disk wind; a power law relating the JET width $x$ to the height $z$ as $x\propto z^\mathcal{K}$ yields exponents between 0.52 and 0.64. Among the SANE simulations, the setup with spin parameter $a_* = -0.9375$ has the strongest and most efficient JET, as it accumulates the most MAGNETic flux at the BLACK HOLE horizon. For a highly spinning BLACK HOLE with $a_*=0.9375$, the BZ JET power is $\gtrsim3$ times greater than the disk wind power. The simulated wind regions consist of a highly MAGNETized region, where the MAGNETization parameter $σ\gg1$, and a less MAGNETized region. A fast outflow with the potential to reach Lorentz factors up to $Γ_\infty\approx25$ propagates in the former region, but because the Lorentz force acts against the disk, it cannot remove a measurable amount of mass from the disk. In the less-MAGNETized region, a centrifugally driven slower wind efficiently carries away disk material.
[abstract 4 / 62] Wow! (score: 8) - Title: General Relativistic and Non-Inertial Effects on Magnetic Reconnection RatesAuthors: Jake Willard, Yi-Hsin Liu,Comments: 26 pages, 14 figuresSubjects: astro-ph.HE astro-ph.SR physics.plasm-ph physics.space-phCreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
We develop a gauge-independent theory of MAGNETic RECONNECTion beyond the standard special-RELATIVISTIC framework of inertial systems in flat spacetime. Our definitions of RECONNECTion and its rate are independent of reference frame and coordinate system, allowing physical effects of gravity and net linear acceleration to be distinguished from coordinate effects. We extend the mesoscale theory of Liu et al. [PRL 118, 085101 (2017)], in which the RECONNECTion rate depends on physics both within the diffusion region and in an upstream ideal, force-free region. The theory identifies three non-inertial and curved-spacetime (NICS) effects, including gravitationally induced MAGNETic tension: gravitational distortion of the RECONNECTion plane changes the curvature of MAGNETic field lines. Applying the theory to a simplified accretion plasma near )a compact object, we find that (1) whether gravity increases or decreases the RECONNECTion rate depends on the system's orientation relative to the gravitational source, with the greatest increase occurring when the outflow JET points toward or away from the source; and (2) the magnitude of the gravitational effect scales with the dimensionless parameter $\barκ \equiv r_sΔy^2/r^3$, where $r$ is the Schwarzschild radial coordinate, $r_s$ is the source's Schwarzschild radius, and $Δy$ is the mesoscale length.
[abstract 5 / 62] Wow! (score: 8) - Title: Jet energetics and remnant MAGNETism in short GAMMA-RAY BURSTs from binary neutron-star mergers: A statistical study via broadband afterglow modelingAuthors: Changwen Zeng, Zhiwei Chen, Youjun Lu, Hui Sun, Jihui Zhang,Comments: 24 pages, 14 figures; accepted for publication in A&ASubjects: astro-ph.HECreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
Short GAMMA-RAY BURSTs (sGRBs) are believed to originate from compact binary mergers, particularly binary neutron star (BNS) mergers, providing a probe of JET energetics and merger remnants. We compile broadband afterglow observations of 40 sGRBs and perform forward-shock modeling with off-axis Gaussian JETs, excluding data potentially affected by additional energy injection. We derive distributions of beaming-corrected JET kinetic energy $E_k$ and radiative efficiency $η_γ$, and combine these with binary population synthesis and numerical simulations to infer remnant BLACK HOLE (BH) MAGNETic fields assuming the Blandford-Znajek (BZ) JET-launching mechanism. For the 15 strictly constrained bursts, we find a median $E_k\simeq3.8\times10^{49}$ erg and $η_γ\simeq0.35$, with respective 68% intervals of $[5.1\times10^{48},1.9\times10^{50}]$ erg and [0.09, 0.79]. The inferred MAGNETic field supplied by the accretion disk and threading the BH horizon is approximately $7\times10^{15}$ G, with a 68% credible interval of $[2.3\times10^{15},2.4\times10^{16}]$ G, depending slightly on the neutron star equation of state. The full sample yields a higher median field of approximately $2\times10^{16}$ G, with the high-energy and high-field tails predominantly contributed by less well-constrained bursts. These results provide statistical constraints on sGRB JET energetics and suggest characteristic BH MAGNETic fields of order $10^{16}$ G. Comparison with pre-merger neutron star MAGNETic fields indicates a characteristic amplification factor of $η_B\sim10^3$, providing an observational constraint on MAGNETic field amplification during BNS mergers and subsequent BH formation.
[abstract 6 / 62] Yes (score: 6) - Title: Wind-Fed Magnetic Flux and the Emergence of X-ray Coronae in Active Galactic NucleiAuthors: Rostom Mbarek,Comments: Accepted to MNRASSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We propose a scenario for the onset of radiatively efficient Active Galactic Nuclei (AGN) in which circumnuclear stellar and SUPERNOVA-driven winds supply mass and partially ordered MAGNETic flux to a compact disk reservoir around a supermassive BLACK HOLE. A coherent poloidal component surviving advection to small radii strengthens inward, lowering the gas plasma beta until mean Maxwell stresses overtake MRI turbulence, compress the disk vertically, and open a MAGNETically dominated wedge above it. Within a quasi-force-free description of this wedge, the field self-organizes toward a critical twist at which the net radial transport changes sign, defining a MAGNETic saturation radius $r_c\sim10\,r_g$. The MAGNETic squeezing of the disk fixes the pressure balance at the interface between the disk and wedge, confining the accumulated flux at $r_c$: flux advected toward this boundary is preferentially shed, fixing $B_r\propto r^{-2}$ in the interior. From the field topology alone we then derive a normalized saturation flux $ϕ\sim 50$, consistent with the MAD plateau of GRMHD simulations. The resulting compact, time-dependent saturation region is a natural candidate for the AGN X-ray corona, being collisionless, MAGNETized, and, at high compactness, plausibly pair-rich, with hadronic pair injection providing a conditional additional channel. Its size, variability, and spectral hardness are controlled by $r_c$, the compactness, and the MAGNETization. We connect these scalings to observed coronal sizes, variability, and the power partition between the corona and JET. We further propose that Little Red and Blue Dots could represent a disk-reservoir phase preceding luminous AGN activity.
[abstract 7 / 62] Yes (score: 6) - Title: Cosmic Colliders in Binary Blazars Probing Ultra-High-Energy Particle PhysicsAuthors: Giorgio Galanti,Comments: Substantially revised version with updated results, 33 pages, 15 figuresSubjects: hep-ph astro-ph.HE hep-thCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
While terrestrial COLLIDERs and fixed-target cosmic-ray interactions are bounded at center-of-mass (CM) energies $\sqrt{s} \lesssim \mathcal{O}(10^5)\,\text{GeV}$, we demonstrate that sub-parsec binary BLAZARs form broad-band hadronic ``Cosmic Colliders'', overcoming this limitation. In the compressed overlap region of two nearly aligned JETs ($θ_{\rm mis} \sim 1^\circ - 5^\circ$), RELATIVISTIC proton populations collide at CM energies reaching $\sqrt{s} \sim 10^{10}\,\text{GeV}$ -- six orders of magnitude above the Large Hadron Collider. Operating in an optically thin regime ($τ_{pp} \ll 1$), the system performs a continuous CM energy scan, probing asymptotic QCD scaling, gluon saturation, and Froissart unitarity, while opening a possible high-sensitivity window into physics beyond the Standard Model. Secondary TeV-EeV neutrinos and GeV-TeV $γ$-rays fall within the reach of current and planned observatories such as LHAASO, CTAO, IceCube, and GRAND, establishing binary BLAZARs as laboratories for physics at the ultimate energy limit.
[abstract 8 / 62] Yes (score: 6) - Title: Flux Variation of the Crab Pulsar Observed Using FERMI LAT and NUSTARAuthors: Koothodil Abhijith Augustine, Hsiang-Kuang Chang,Comments: 3 figures. 6 pages main text readingSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The flux of pulsed emission from the Crab pulsar, just like most of other pulsars, is considered to be steady over time scales much larger than the pulsation period, except for a smooth, secular decrease related to the aging of pulsars. Such a steady assumption prevails in all theoretical investigations of pulsar emission models. However, here we report the discovery of stochastic variation in the flux and photon index of the Crab pulsar gamma-ray and hard X-ray emissions utilizing archival data of FERMI LAT (0.1 -- 100 GeV, spanning 17 years) and of NUSTAR (3.0 -- 79.0 keV, spanning 13 years) observations. Furthermore, the flux variation is found to be anti-correlated with variation of the spectral photon index, that is, harder when brighter, in both gamma ray and hard X-ray bands. The origin of such variation is intriguing. Some possibilities are discussed.
[abstract 9 / 62] Yes (score: 6) - Title: Detection of 2 MeV spectral bump and ~40 MeV emission line from GRB 221009AAuthors: Zhi-Qiang Ding, Zhenxia Zhang, Yanqiu Zhang, Rui-Ze Shi, Xinqiao Li, Zhuo Li, Zhenghua An, Shaolin Xiong, Roberto Battiston, Shuangnan Zhang, Hua Feng, Dali Zhang, Yanbing Xu, Ping Wang, Xiaoyun Zhao, Yuqian Ma, Hong Lu, Xiangyang Wen, Yongjie Zhang, Xuhui Shen, Shigeng Yuan, Siquan Yang, Rongxue Kang, Chao Zheng, Yan Huang, Wen Su, Shengli Liu, Hui Wang, Xiaohua Liang, Jinzhou Wang, Ke Gong, Xiaojing Liu, Yaqing Liu, Sheng Yang, Zeren Zhima, Jianping Huang, Wei Chu, Na Zhou, Roberto Iuppa, Francesco Maria Follega, Marco Cristoforetti, Wangchen Xue, Lu Wang, Jiaqi Zheng, Jiacong Liu, Chenwei Wang, Wenjun Tan, Zhenghang Yu, Shujie Li, Hao Hong,Comments: 40 pages; accepted for publication in The Astrophysical Journal LettersSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Gamma-ray bursts (GRBs) are the most energetic transients in the Universe, but prompt MeV--sub-GeV observations remain challenging with current gamma-ray observatories. Here, using unsaturated HEPP-H measurements on board CSES-01 and cross-calibrating with likewise unsaturated GECAM-C data, we reconstruct the continuous spectral evolution of GRB 221009A over 2--255 MeV. We identify an unusual spectral bump at $\sim$2 MeV in the first light-curve peak. We also confirm a narrow emission line whose energy decreases from $\sim$40 MeV following a $t^{-1}$ evolution, and whose flux shows a ``rise-then-fall'' profile, implying weak emission from the central JET. These findings hint that a MAGNETically dominated, central-empty JET exists in the BOAT.
[abstract 10 / 62] Yes (score: 6) - Title: Energetic Particle Confinement In Black Hole Accretion DisksAuthors: Daniele Villa, Frank Rieger, Frank Jenko, James Stone,Comments: Accepted for publication in ApJ as of 10 Nov 2026Subjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Using tracer particles propagating in the environment provided by general RELATIVISTIC MAGNETohydrodynamic simulations, this paper addresses fundamental questions related to the confinement and acceleration properties in accretion disks around compact objects. By varying the spin parameter of the central BLACK HOLE and the accretion regime of the disk, a comprehensive picture is obtained for particles whose Larmor radius is comparable to the gravitational radius of the system. It is found that such particles can escape the system at the outermost boundary of the simulations, though, depending on the accretion regime, the time it takes them to escape, and the energetic dynamics along the trajectory can vary significantly. Dynamics near the BLACK HOLE are even more sensitive to environmental details as BLACK HOLEs with higher spin values generate stronger MAGNETic fields, which influence particle motion in non-trivial ways. The primary acceleration mechanism is identified as turbulent scattering, with the JET-sheath emerging as the dominant site for particle energization
[abstract 11 / 62] Yes (score: 6) - Title: Self-Regulated Cosmic-Ray Electron Acceleration in High-Mach-Number MHD-PIC ShocksAuthors: Alisa Galishnikova, Siddhartha Gupta, Anatoly Spitkovsky, Xiaochen Sun,Comments: 14 pages, 8 figures. Submitted to ApJSubjects: astro-ph.HE physics.plasm-phCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Shock waves in SUPERNOVA remnants are thought to accelerate COSMIC RAYs (CRs) via diffusive shock acceleration (DSA). If acceleration is efficient, CR-modified shock models and nonlinear DSA predict smoothly decelerated precursors and concave spectra that harden with energy. These predictions are in tension with observations, which favor spectra closer to the test-particle form, $4 πf(p) p^{4} = {\rm const}$ or steeper. We use one- and two-dimensional MAGNETohydrodynamic-particle-in-cell simulations to follow the long-term nonlinear coupling of the thermal plasma and CR electrons in non-RELATIVISTIC quasi-parallel, high-Mach-number shocks. We choose electrons over ions for their larger charge per unit mass, probing the limits of current-driven feedback. We vary the supplied CR-electron mass fraction to measure the shock's response. Our injection model determines the effective injection and acceleration from particle trajectories through the evolving upstream turbulence, rather than a prescribed shock injection fraction. The reflected CR-electron current excites Bell-type non-resonant turbulence. The resulting MAGNETic structures scatter and isotropize the current-carrying particles, limiting the coherent upstream current and suppressing the formation of a spatially extended CR-pressure precursor. Across the CR-electron mass supply explored, the saturated upstream MAGNETic energy and far-upstream CR current converge to similar levels. In 1D, the downstream high-energy spectrum approaches the test-particle DSA shape across the resolved momentum range, with nonthermal pressure reaching a few tens of percent of the upstream ram pressure. These results suggest that, once injection is sufficient to sustain strong current-driven turbulence, SUPERNOVA-remnant shocks can approach a common regulated state largely insensitive to the details of CR injection.
[abstract 12 / 62] Yes (score: 5) - Title: Revisiting the distance to 4U 1543-475 through X-ray dust-scattering ringsAuthors: B. Vaia, G. Mastroserio, T. Darie, A. Tiengo,Comments: Accepted for publication in A&ASubjects: astro-ph.HE astro-ph.GACreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
We derived a geometrical distance of the black-hole X-ray binary 4U 1543-475 based on X-ray dust-scattering rings associated with its 1992 and 2002 outbursts. We analyzed archival ROSAT and XMM-Newton observations and identified an X-ray dust-scattering ring in each observation, produced by two different dust layers along the line of sight. By combining the angular radii of the rings with the independently determined distances of the scattering dust layers and the epochs of the corresponding outbursts, we derive a best-constrained distance to 4U 1543-475 of 4.6 $\pm$ 0.2 kpc. This value is substantially smaller than the distance of 7.5 kpc commonly adopted in the literature and has important implications for the inferred physical properties of the system. In particular, the revised distance favors the presence of a low-mass extended-horizontal-branch donor star over a main-sequence star, calling for a reassessment of the dynamical parameters of the binary and, consequently, of the black-hole mass. The smaller distance also affects the inferred properties of the RELATIVISTIC JET and the estimate of black-hole spin derived from the spectral continuum-fitting.
[abstract 13 / 62] Yes (score: 5) - Title: Revisiting the Neutrino Emission and Physical Parameter Constraints from Time-Resolved Spectra of Gamma-Ray BurstsAuthors: Yang-Dong-Jun Ou, Hou-Jun Lü, Hao-Yu Yuan, Si-Xue Ren, Xue-Zhao Chang, Yan-Qiu Zhang, Shao-Lin Xiong, En-Wei Liang,Comments: 16 pages, 3 table, 5 figures. Accepted for publication in ApJSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The non-detection of neutrinos associated with GAMMA-RAY BURSTs (GRBs) has placed significant constraints on the physical parameter space of GRB JET models. However, most of these constraints have been derived using the time-integrated spectra. In this paper, we adopt time-resolved spectra, which provide a more detailed description of the prompt emission spectral structure, to calculate the neutrino emission, and investigate how they affect the constraints on GRB physical parameters. By selecting three GRBs (i.e., GRBs 090902B, 110721A and 080916C) whose spectra are composed of different components (e.g., thermal, thermal + non-thermal, and non-thermal), we find that the expected neutrino event numbers from the summed time-resolved spectra are lower than those from the time-integrated approach in the region of relatively low dissipation radius $R$ and bulk Lorentz factor $Γ$, while the opposite trend is found at high $R$ and high $Γ$. Moreover, we also use GECAM-C data to calculate the neutrino emission of the brightest GRB 221009A, and find that the expected number of neutrino events calculated from the summed time-resolved spectra is approximately three times that from the time-integrated spectra in the high-$R$ and high-$Γ$ regime. More details of constraints on the physical parameters are also discussed. These results highlight the importance of time-resolved spectra for future GRB neutrino studies.
[abstract 14 / 62] Yes (score: 5) - Title: Frequency-dependent time delays in Sgr A* from a broadband VLA observationAuthors: Noemi La Bella, Heino Falcke, Christiaan Brinkerink, Jesse Vos,Comments: 8 pages, 5 figuresSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Frequency-dependent radio time delays have been measured in Sgr A* light curves, with higher-frequency emission generally leading lower-frequency emission. These lags have been interpreted in terms of an organized JET-like outflow, expanding plasma components, or MAGNETic-flux eruptions, although their origin and recurrence remain uncertain. We aim to search for and quantify frequency-dependent radio time delays in a new high-cadence Karl G. Jansky Very Large Array (VLA) observation of Sgr A*. Using the improved broad 12-37 GHz frequency coverage, we measured the timing of the dominant variability feature and compared the resulting lag-wavelength slope with previous measurements. Sgr A* was observed with the VLA on 28 May 2022 in the Ku, K, and Ka bands over a 6-hour track. We extracted both band-averaged and 2 GHz subband light curves and measured the delays using a peak-time method and a locally normalized cross-correlation function. The light curves show one broad variability feature, with the maximum occurring progressively later at lower observing frequencies. Both timing methods recover a positive lag-wavelength relation, with a slope of order 40 min/cm. This value agrees with time lag results reported over more than 15 years from the first VLA observations at 22-43 GHz to later multifrequency VLA and ALMA campaigns. The sign and magnitude of the estimated delay are consistent with outward propagation through an optically thick SYNCHROTRON-emitting region. The recurrence of comparable delays over almost two decades suggests that frequency-dependent radio lags are a persistent feature of Sgr A* variability. Broadband, multi-epoch VLA monitoring of Sgr A* provides a useful probe of its radio variability, but robust lag measurements require high cadence and improved (u,v) coverage of both Sgr A* and the surrounding extended emission such as by combining different VLA configurations.
[abstract 15 / 62] Yes (score: 5) - Title: EP250226a: A fast X-ray transient associated with GRB 250226A and its multiwavelength afterglow propertiesAuthors: Rui-Zhi Li, Jirong Mao, Aishwarya Linesh Thakur, Chen-Wei Wang, Jie An, Fei-Fan Song, Yodgor Rajabov, Dong Xu, Shuai-Qing Jiang, Bo-Ting Wang, Tong Zhao, Yujia Song, Hong-Zhou Wu, Yuan Liu, Samaporn Tinyanont, Rungrit Anutarawiramkul, Pathompong Butpan, Zhou Fan, Shaoyu Fu, Xing Liu, Ning-Chen Sun, Zi-Pei Zhu, Benjamin Schneider, Nial R. Tanvir, Daniele B. Malesani, Susanna D. Vergani, Andrew Levan, Giovanna Pugliese, Andrea Saccardi, Luca Izzo, Jesse T. Palmerio, Patrizia Barria, James Craig Rodi, Giulia Gianfagna, Lorenzo Natalucci, Luigi Piro, Nidhal Guessoum, Thomas Hussenot-Desenonges, Ernazar Abdikamalov, D. Turpin, Nelio Sasaki, A. Takey, E. G. Elhosseiny, Y. H. M. Hendy, Ting-Wan Chen, Amar Aryan, Albert K. H. Kong, D. Andrew Howell, Curtis McCully, Joseph R. Farah, Moira Andrews, Kathryn Wynn, Yuan Qi Ni, Wen-Xiong Li, Hu Zou, Yun-Ao Xiao, Wei-Jian Guo, Niu Li, A. S. Pozanenko, A. S. Moskvitin, O. I. Spiridonova, Xingzhu Zou, Brajesh Kumar, Xiaowei Liu, Hui Sun, Xue-Feng Wu, Weimin Yuan,Comments: 32 pages, 17 figures, and 5 tables. The revised manuscript has been submitted to A&ASubjects: astro-ph.HECreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
Recent advances in fast X-ray transient studies have been driven by the wide-field, sensitive soft X-ray monitoring capabilities of the Einstein Probe (EP), enabling the prompt detection and localization of previously underexplored events. EP observations offer new opportunities to investigate the origins, emission mechanisms, and population properties of newly discovered fast X-ray transients. We present multiwavelength observations of EP250226a, an extragalactic fast X-ray transient associated with GRB 250226A. We jointly analyze the prompt emission from soft X-rays to gamma rays and the X-ray afterglow spectra. We collect optical photometric data, perform empirical and afterglow model-based analyses, and present optical-to-infrared spectroscopy, measuring the equivalent widths of absorption lines. The spectroscopic redshift is $z = 3.314$, and the isotropic-equivalent gamma-ray energy is $E_\mathrm{iso}\simeq7.32\times10^{53}$ erg. Its location in the Amati diagram is consistent with a massive-star core-collapse origin (Type II GRB). The fluence ratio $\rm{S}(25-50\,\rm{keV})/\rm{S}(50-100\,\rm{keV})=0.57\pm0.06$ supports its classification as a classical GRB. The X-ray and optical afterglows show achromatic behavior. Among the models considered, a top-hat JET propagating into a uniform interstellar medium best describes the multiwavelength afterglow. This model suggests a highly collimated, nearly on-axis JET, with an isotropic-equivalent kinetic energy of $E_\mathrm{k,iso}\simeq4.07\times10^{55}$ erg, a gamma-ray radiative efficiency of $η_γ\simeq 1.77\%$, and a low MAGNETic-field energy fraction of $\log ε_\mathrm{B,FS} \simeq -6.52$. EP250226a exhibits typical long-duration GRB properties, with the first soft X-ray peak coinciding with the gamma-ray prompt emission, while the soft X-ray emission lasts significantly longer than the gamma-ray emission.
[abstract 16 / 62] Yes (score: 4) - Title: Polarized image of SYNCHROTRON radiations of hotspots in Schwarzschilld-Melvin BLACK HOLE spacetimeAuthors: Yuheng Du, Hu Zhu, Sijie Gao, Minyong Guo,Comments: 21 pages, 11 figuresSubjects: gr-qcCreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
We revisit the innermost stable circular orbits (ISCOs) of charged particles and study the polarized images of SYNCHROTRON radiations emitted from such orbiting hotspots on the equatorial plane in {Schwarzschild}-Melvin BLACK HOLE spacetime. We obtain a constraint on the MAGNETic field for the existence of charged-particle circular orbits. In particular, we identify a critical value for the strength of the MAGNETic field $B_c$ that the circular orbits can have positive and negative angular momentums {below} $B_c$ while only the negative angular momentum branch survives above} $B_c$. Furthermore, we investigate and discuss the primary and secondary images of circularly orbiting charged hotspots carrying the information of POLARIZATION directions observed by distant observers. {We also find that the observed POLARIZATION angle varies rapidly with source azimuth when the emitted photon direction is nearly aligned with the local MAGNETic field, and explain the origin of this behavior.
[abstract 17 / 62] Yes (score: 4) - Title: The Synthetic Absorption Line Spectral Almanac (SALSA)Authors: Dylan Nelson, Celine Peroux, Philipp Richter, Matthew M. Pieri, Sebastian Lopez, Rongmon Bordoloi, Siwei Zou, Joseph N. Burchett, Rebecca L. Davies, Rahul Ramesh, Matthew C. Smith, Sanchayeeta Borthakur, Christopher W. Churchill,Comments: https://www.tng-project.org/spectraSubjects: astro-ph.GA astro-ph.COCreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
We create the first large-scale mock spectroscopic survey of gas absorption sightlines traversing the interstellar medium (ISM), circumgalactic medium (CGM), and intergalactic medium (IGM) surrounding galaxies of virtual Universes. That is, we create mock, or synthetic, absorption spectra by drawing lines-of-sight through cosmological hydrodynamical simulations, using a new mesh-free Voronoi ray-tracing algorithm. The result is the Synthetic Absorption Line Spectral Almanac (SALSA), which is publicly released on our online science platform. It spans a diverse range of ions, transitions, instruments, observational characteristics, modeling assumptions, redshifts, and numerical simulations. These include, but are not limited to: (ions) HI, OI, CI, MgI, MgII, FeII, SiII, CaII, ZnII, SiIII, SiIV, NV, CII, CIV, OVI; (instruments) SDSS-BOSS, KECK-HIRES, UVES, COS, DESI, 4MOST, WEAVE, XSHOOTER; (model choices) with/without dust depletion, noise, QUASAR continua, foregrounds; (redshift) from z=0 to z~6; (ancillary data) integrated equivalent widths, column densities, distances and properties of nearby galaxies; (simulations) IllustrisTNG including TNG50, TNG-Cluster, EAGLE, and SIMBA. We also provide Faraday rotation measure (RM) probing MAGNETic fields, and dispersion measure (DM) as traced by fast radio bursts (FRBs). The resulting dataset is generic and broadly applicable, enabling diverse science goals such as: (i) studies of the underlying physical gas structures giving rise to particular absorption signatures, (ii) galaxy-absorber and halo-absorber correlations, (iii) virtual surveys and survey strategy optimization, (iv) stacking experiments and the identification of weak absorption features, (v) assessment of data reduction methods and completeness calculations, (vi) inference of physical properties from observables, and (vii) apples-to-apples comparisons between simulations and data.
[abstract 18 / 62] Yes (score: 4) - Title: Prospects for probing supermassive binary BLACK HOLEs in strongly lensed ACTIVE GALACTIC NUCLEi via microlensing effectsAuthors: Zekun Li, Changshuo Yan, Youjun Lu, Zhiwei Chen,Comments: 10 pages, 8 figuresSubjects: astro-ph.GA astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Gravitational microlensing in strongly lensed ACTIVE GALACTIC NUCLEi (AGNs) provides a powerful probe of accretion-disk structure and may offer a unique opportunity to identify sub-parsec supermassive binary BLACK HOLEs (SMBBHs) through distinctive signatures. Upcoming wide-field surveys are expected to discover a large sample of strongly lensed AGNs, a fraction of which may host SMBBHs detectable via microlensing. In this paper, we employ semi-analytic models to assess the detection prospects of sub-parsec SMBBHs in lensed AGNs, focusing on systems with resolvable multiple images suitable for microlensing analysis. Accounting for galaxy-scale strong-lensing statistics, and including the cluster-lensing contribution as an optimistic statistical extension, we estimate that up to approximately 87 such systems could be spatially resolved by individual upcoming surveys, including the Vera C. Rubin Observatory (Rubin), Euclid, China's Space Survey Telescope (CSST), and the Roman. For the Rubin WFD survey, we estimate that periodic oscillations in microlensing light curves could identify $\sim0.12-0.68$ short-period ($<5$\,yr) binaries, whereas diagnostics based on the reconstructed size-wavelength relation apply to a broader population, potentially identifying $\sim0.4-5.3$ systems, depending on the model assumptions. CSST, Euclid, and Roman may also reveal up to $10.6$, $8.9$, and $1.2$ systems exhibiting size-wavelength features, and $2.3$, $1.9$, $0.3$ systems showing periodic oscillations, which should be regarded as imaging-selected candidates whose microlensing-based identification requires adequate time-domain follow-up, including cadence, monitoring baseline, photometric precision, and reliable time-delay measurements. Our results show that strongly lensed AGNs provide a promising, though observationally demanding, pathway for finding candidate SMBBHs via microlensing.
[abstract 19 / 62] Yes (score: 4) - Title: Cosmic Ray Reacceleration and Gamma-Ray Emission via the Cloud-Wind Interaction in the Galactic HaloAuthors: Ryohei Inamoto, Jiro Shimoda, Katsuaki Asano,Comments: 13 pages, 13 figures, submitted to ApJSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The interaction between COSMIC RAYs (CRs) and multiphase gas in the Galactic halo may play an important role in shaping the hard gamma-ray spectrum of the FERMI bubbles. We investigate the interaction between a hot Galactic wind and a cold, dense gas clump with a relative velocity of $300\ {\rm km\,s^{-1}}$ using two-dimensional hydrodynamic simulations coupled with momentum-dependent CR transport. The system produces a bow shock and wind reacceleration region downstream, where the wind flow is faster than the initial velocity. For a CR pressure comparable to the gas pressure (CR-rich), the wind acceleration and turbulence behind the clump are enhanced. When CR pressure is dynamically weak, strong gas compression leads to significant CR spectral hardening. In contrast, for the CR-rich case, CR pressure gradients weaken the gas compression and suppress further CR reacceleration. We estimate the gamma-ray intensity from CRs, and find that reaccelerated CRs penetrate the dense clump and enhance hadronic gamma-ray emission. The gamma-ray intensity reaches $\sim 10^{-8}\,\mathrm{erg\,cm^{-2}\,s^{-1}\,sr^{-1}}$ in the 1--10 GeV band, and the gamma-ray spectra become significantly harder, consistent with the FERMI bubbles' emission. These results suggest that an ensemble of dense gas clumps interacting with the Galactic wind may contribute to the gamma-ray emission of the FERMI bubbles.
[abstract 20 / 62] Yes (score: 4) - Title: Astrometric effects of anisotropic gravitational wave backgroundsAuthors: Petar D. Dimitrov, Deyan P. Mihaylov,Comments: 37 pages, 10 figuresSubjects: gr-qcCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Precise astrometric observations of distant objects such as stars and QUASARs can be used to probe gravitational wave signals at nanohertz frequencies. A stochastic gravitational wave background (SGWB) produces correlated apparent motions of pairs of objects on the sky. That correlation as a function of their angular separation is the astrometric analog of the Hellings-Downs curve in the context of pulsar timing measurements. Upper limits on the SGWB have been obtained from very-long baseline interferometry and Gaia astrometry, and future Gaia data releases are expected to improve them. An astrophysical background from inspiraling supermassive BLACK HOLE binaries is expected to be significantly anisotropic. In this work, we compute the astrometric correlation functions for an anisotropic SGWB, known as the generalized overlap reduction functions, for all six gravitational wave POLARIZATIONs. We present closed-form expressions in all cases where the distant-light source limit can be applied, following the approach used for pulsar timing arrays. We find that the correlations differ qualitatively between the tensor, vector, and scalar POLARIZATIONs. Finally, we discuss the applicability of these results in future astrometry searches for arbitrarily polarized anisotropic gravitational wave backgrounds.
[abstract 21 / 62] Yes (score: 4) - Title: Origin of the Fe K$α$ red excess in IC 4329A with XRISM and multi-wavelength spectroscopyAuthors: Misaki Mizumoto, Yuya Nakatani, Satoshi Yamada, Yoshihiro Ueda, Taiki Kawamuro, Shoji Ogawa, Yuto Mochizuki, Kanta Fujiwara, Fumihide Iwamuro, Shogo Otsubo, Noriyuki Matsunaga, Daisuke Taniguchi, Hideyo Kawakita,Comments: 15 pages, 9 figures, accepted for publication in ApJSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We present high-resolution X-ray spectroscopy of the bright local Seyfert 1 galaxy IC 4329A obtained with \textit{XRISM}/Resolve, supported by simultaneous \textit{NUSTAR} data and quasi-simultaneous optical/near-infrared (NIR) spectroscopy. Resolve separates the Fe K$α$ line into a narrow core and a broad component exhibiting a red excess. We examined three scenarios for this red excess: (1) a redshifted X-ray broad line region (xBLR), (2) RELATIVISTIC disk reflection, and (3) an unshifted xBLR partially absorbed by a mildly ionized absorber. All three models reproduce the X-ray spectra equally well. Our optical (H$β$) and NIR (Pa$β$) spectroscopy shows that the broad lines are redshifted by $v \sim +640\text{--}1050\text{ km s}^{-1}$, close to the solution of the redshifted xBLR model ($v_{\rm shift} = +1700_{-800}^{+1700}\text{ km s}^{-1}$). Motivated by this, we constructed a hybrid model in which the xBLR shares the velocity structure of the optical/NIR BLR and the remaining red excess is attributed to a RELATIVISTIC disk line, which also provides an acceptable fit. The inferred xBLR radius is $R_{\rm BLR} \sim (3\text{--}6) \times 10^3\ R_g$ ($\sim 12\text{--}22$ light-days). From the narrow Fe K$α$ core in the hybrid model (${\rm FWHM} = 870_{-280}^{+260}\text{ km s}^{-1}$), we estimate a torus distance of $R_{\rm torus} \sim 0.9_{-0.4}^{+1.0}$ pc ($\sim 1100$ light-days), close to the dust sublimation radius. Furthermore, two ultra-fast outflow (UFO) absorption features are identified with $v_{\text{wind}} \sim -0.30c$ and $-0.24c$, both confirmed at $>99\%$ confidence.
[abstract 22 / 62] Yes (score: 4) - Title: The Role of Precursors and MHD Instabilities in Distinguishing Confined and Eruptive Solar FlaresAuthors: Wen He, Ju Jing, Jeongwoo Lee, Haimin Wang,Comments: 10 pages, two tables, accepted by ApJSubjects: astro-ph.SR physics.space-phCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Identifying pre-flare MAGNETic conditions that determine whether a flare will be eruptive (associated with a coronal mass ejection) or confined remains a major challenge in solar physics. Motivated by previous statistical results showing that some eruptive flares occur under ideal MHD-stable conditions, we investigate the roles of kink instability (KI), torus instability (TI), preflare RECONNECTion traced by precursor brightenings (PBs) and MAGNETic nonpotentiality in solar eruptiveness using an expanded sample of 68 flares above GOES class M4 from 2011--2024. To characterize the nonpotentiality of each active region (AR), we calculate the relative helicity $H_R$, current-carrying helicity $H_J$ and free MAGNETic energy. We find that, (1) 17 of 18 TI-unstable events and 12 of 19 KI-unstable events are eruptive, indicating that the TI parameter outperforms the KI parameter (2) although PBs are more commonly found in the MHD-unstable regime, only 3 of the 12 eruptive events in the TI/KI-stable regime show PBs, suggesting that preflare RECONNECTion may play a secondary role compared with other factors. (3) The strongest indicator of eruptiveness is obtained by combining the TI parameter with MAGNETic nonpotentiality. Specifically, 24 of 36 eruptive flares satisfy $\sqrt{\left| H_J \right|}/ϕ\geq 0.1$ or $n \geq 1.13$, whereas 24 of 25 confined flares satisfy $\sqrt{\left| H_J \right|}/ϕ\le 0.1$ and $n \le 1.13$, where $ϕ$ is the total unsigned MAGNETic flux and $n$ is the decay index. These results suggest that the overall MAGNETic environment of ARs may play a significant role in determining the eruptiveness, in addition to the effect of MHD instability and RECONNECTion.
[abstract 23 / 62] Yes (score: 4) - Title: Exploring a Correlation Between AGN Black Hole Mass and X-ray LuminosityAuthors: Wordsworth K. K. Chu, A. Kathy Romer, Paul Giles, Jessica E. Pilling, Julian A. Mayers,Comments: 5 pages, 1 figureSubjects: astro-ph.GA astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The traditional method to measure Type-1 Active Galactic Nuclei central BLACK HOLE masses ($M_{BH}$) is the reverberation mapping (RM) technique. Motivated by the desire to find a less observationally expensive method (than RM) to estimate $M_{BH}$, we have explored a purported correlation between X-ray luminosity and $M_{BH}$. For this we have compiled a sample of 35 AGN with RM $M_{BH}$ estimates that were detected in the eROSITA All-Sky Survey public data release. Using a sample that is larger than that of J. A. Mayers et al. 2018 and has a cleaner selection function, we confirm their XMM-Newton based result of a positive correlation. However, the scatter on the scaling relation remains too high ($σ_\mathrm{int}=0.50^{+0.08}_{-0.06}$) to make this a practical method to predict $M_{BH}$ for a given X-ray detected Type-1 AGN. That said, our findings can be used to improve mock X-ray skies generated from large volume hydrodynamical cosmological simulations. Such mocks are a necessary ingredient for cluster cosmology and preparation for future missions such as NewAthena.
[abstract 24 / 62] (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: Accepted for publication in PRD. 12 pages, 8 figuresSubjects: astro-ph.HE astro-ph.CO astro-ph.GA gr-qcCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
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 25 / 62] (score: 3) - Title: Quasinormal modes and tidal responses of BLACK HOLEs in generic anisotropic matter environmentsAuthors: Yu-Qian Zhao, Paolo Pani,Comments: 14 pages, 3 figures, matched the Physical Review D accepted versionSubjects: gr-qc astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We develop a perturbative framework for a BLACK HOLE embedded in a generic, possibly anisotropic, matter environment under spherical symmetry. Our approach extends previous analyses restricted to vanishing radial pressure or to perturbative matter configurations. Within this framework, we derive an analytical generalization of the Einstein cluster that incorporates a polytropic radial pressure, and we investigate the properties of this solution. We show that both the geodesic structure and the axial quasinormal-mode spectrum remain predominantly governed by an overall gravitational redshift effect, while the radial pressure systematically enhances the environmental corrections. In contrast, the tidal Love numbers are substantially more sensitive, and can exhibit order-unity deviations, including vanishing and negative strictly static MAGNETic Love numbers for sufficiently large anisotropy. We present the full linearized equations, which can be applied to various extensions, including ringdown analysis and extreme-mass-ratio inspirals.
[abstract 26 / 62] (score: 3) - Title: Probing for anisotropies at different angular scales in the arrival directions of the COSMIC RAYs detected at the Pierre Auger ObservatoryAuthors: The Pierre Auger Collaboration, A. Abdul Halim, P. Abreu, M. Aglietta, M. Ahmed, I. Allekotte, K. Almeida Cheminant, R. Aloisio, J. Alvarez-Muñiz, A. Ambrosone, J. Ammerman Yebra, L. Anchordoqui, B. Andrada, L. Andrade Dourado, L. Apollonio, C. Aramo, J. C. Arteaga Velázquez, P. Assis, G. Avila, E. Avocone, A. Bakalova, Y. Balibrea, A. Baluta, F. Barbato, A. Bartz Mocellin, O. Batalla Cruz, J. P. Behler, C. Berat, M. E. Bertaina, M. Bianciotto, P. L. Biermann, V. Binet, K. Bismark, T. Bister, J. Biteau, J. Blazek, J. Blümer, M. Boháčová, D. Boncioli, C. Bonifazi, P. Boril, N. Borodai, J. Brack, P. G. Brichetto Orquera, S. Buitink, A. Bwembya, T. R. Caba Pineda, K. S. Caballero-Mora, S. Cabana-Freire, L. Caccianiga, J. Caraça-Valente, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon, M. Cerda, B. Čermáková, A. Cermenati, K. Cerny, J. A. Chinellato, J. Chudoba, L. Chytka, R. W. Clay, A. C. Cobos Cerutti, R. Colalillo, R. Conceição, G. Consolati, M. Conte, F. Convenga, D. Correia dos Santos, P. J. Costa, C. E. Covault, M. Cristinziani, C. S. Cruz Sanchez, S. Dasso, K. Daumiller, B. R. Dawson, R. M. de Almeida, E. -T. de Boone, B. de Errico, J. de Jesús, S. J. de Jong, J. R. T. de Mello Neto, I. De Mitri, D. de Oliveira Franco, F. de Palma, V. de Souza, E. De Vito, A. Del Popolo, O. Deligny, N. Denner, K. Denner Syrokvas, L. Deval, A. di Matteo, C. Dobrigkeit, J. C. D'Olivo, L. M. Domingues Mendes, T. Dominguez, Y. Dominguez Ballesteros, Q. Dorosti, R. C. dos Anjos, J. Ebr, F. Ellwanger, R. Engel, M. Erdmann, A. Etchegoyen, C. Evoli, H. Falcke, G. Farrar, A. C. Fauth, T. Fehler, F. Feldbusch, A. Fernandes, M. Fernández Alonso, B. Fick, J. M. Figueira, P. Filip, A. Filipčič, B. Flaggs, A. Franco, M. Freitas, T. Fujii, A. Fuster, C. Galea, C. Galelli, B. García, C. Gaudu, P. L. Ghia, U. Giaccari, M. Giammarco, C. Glaser, F. Gobbi, F. Gollan, G. Golup, P. F. Gómez Vitale, J. P. Gongora, N. González, D. Góra, A. Gorgi, M. Gottowik, F. Guarino, G. P. Guedes, Y. C. Guerra, S. Hahn, P. Hamal, M. R. Hampel, P. Hansen, D. Harari, V. M. Harvey, A. Haungs, M. Havelka, T. Hebbeker, C. Hojvat, J. R. Hörandel, P. Horvath, M. Hrabovský, T. Huege, A. Insolia, P. G. Isar, M. Ismaiel, P. Janecek, V. Jilek, K. -H. Kampert, L. Karczubová, B. Keilhauer, V. V. Kizakke Covilakam, H. O. Klages, M. Kleifges, A. Klingel, J. Köhler, F. Krieger, M. Kubatova, B. L. Lago, N. Leal, M. A. Leigui de Oliveira, Y. Lema-Capeans, A. Letessier-Selvon, I. Lhenry-Yvon, L. Lopes, P. Magnani, M. Mallamaci, S. Mancuso, D. Mandat, P. Mantsch, A. G. Mariazzi, C. Marinelli, I. C. Mariş, G. Marsella, D. Martello, S. Martinelli, O. Martínez Bravo, A. Martínez-Mendez, M. A. Martins, H. -J. Mathes, J. Matthews, G. Matthiae, E. Mayotte, S. Mayotte, P. O. Mazur, G. Medina-Tanco, D. Melo, A. Menshikov, C. Merx, S. Michal, M. I. Micheletti, L. Miramonti, M. Mogarkar, S. Mollerach, F. Montanet, L. Morejon, K. Mulrey, R. Mussa, W. M. Namasaka, S. Negi, L. Nellen, G. A. Neves, K. Nguyen, G. Nicora, M. Niechciol, D. Nitz, D. Nosek, A. Novikov, V. Novotny, L. Nožka, A. Nucita, L. A. Núñez, S. E. Nuza, J. Ochoa, M. Olegario, C. Oliveira, L. Östman, M. Palatka, J. Pallotta, G. Parente, T. Paulsen, M. Pech, J. Pękala, R. Pelayo, D. Perez, C. Pérez Bertolli, L. Perrone, S. Petrera, T. Pierog, M. Pimenta, M. Platino, P. Privitera, C. Priyadarshi, M. Prouza, K. Pytel, S. Querchfeld, L. Ramella, J. Rautenberg, D. Ravignani, J. V. Reginatto Akim, A. Reuzki, J. Ridky, F. Riehn, M. Risse, V. Rizi, B. Rocha-Moldes, E. Rodriguez, G. Rodriguez Fernandez, J. Rodriguez Rojo, M. Roth, E. Roulet, A. C. Rovero, A. Saftoiu, M. Saharan, F. Salamida, H. Salazar, G. Salina, P. Sampathkumar, N. San Martin, J. D. Sanabria Gomez, F. Sánchez, F. M. Sánchez Rodriguez, E. Santos, F. Sarazin, R. Sarmento, R. Sato, P. Savina, V. Scherini, H. Schieler, M. Schimp, D. Schmidt, O. Scholten, H. Schoorlemmer, P. Schovánek, F. G. Schröder, J. Schulte, T. Schulz, S. J. Sciutto, M. Scornavacche, A. Sedoski, S. Sehgal, S. U. Shivashankara, G. Sigl, K. Simkova, F. Simon, R. Šmída, S. Soares Sippert, P. Sommers, S. Stanič, J. Stasielak, P. Stassi, S. Strähnz, M. Straub, T. Suomijärvi, A. D. Supanitsky, Z. Svozilikova, Z. Szadkowski, F. Tairli, A. Tapia, C. Taricco, C. Timmermans, O. Tkachenko, P. Tobiska, C. J. Todero Peixoto, B. Tomé, A. Travaini, P. Travnicek, C. Trimarelli, M. Tueros, M. Unger, R. Uzeiroska-Geyik, L. Vaclavek, M. Vacula, I. Vaiman, J. F. Valdés Galicia, L. Valore, P. van Dillen, E. Varela, V. Vašíčková, D. Veberič, M. A. Vega Caro, I. D. Vergara Quispe, S. Verpoest, V. Verzi, J. Vicha, L. M. A. Victoria, S. Vorobiov, J. B. Vuta, A. A. Watson, A. Weindl, M. Weitz, L. Wiencke, H. Wilczyński, B. Wundheiler, B. Yue, A. Yushkov, E. Zas, D. Zavrtanik, M. Zavrtanik, M. Zeferino Rennó,Comments: 19 pages, 7 figuresSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Studies of the arrival-direction distribution of ultra-high-energy COSMIC RAYs are crucial for revealing their origin. In this work, we investigate the distribution of the arrival directions of events detected with the Pierre Auger Observatory over different angular scales. To do this, we adopt a novel method where we use a von Mises--Fisher distribution to model the excesses with respect to isotropic expectations. This method allows us to study the distribution of arrival directions over different angular scales consistently and simultaneously. We consider the events in different energy bins above 4 EeV detected from 1$^\text{st}$ January 2004 to 31$^\text{st}$ December 2022, i.e. during the entire Phase~I of the Pierre Auger Observatory, with a total exposure of $123{,}000$ km$^2$ sr yr. The most significant excess in the bins considered is a dipolar modulation in the energy range (8--16) EeV, which is compatible with previous findings of the Pierre Auger Collaboration. A dipolar modulation appears to be present for the higher energies considered as well, and at the highest energies, i.e. above 32 EeV, we find indications of its coexistence with an overdensity of intermediate angular scale, located in the Centaurus region.
[abstract 27 / 62] (score: 3) - Title: A self-shadowing BLACK HOLE accretion disk at sub-Eddington luminositiesAuthors: M. Armas Padilla, T. Muñoz-Darias, J. Sánchez-Sierras, M. Shidatsu, D. Mata Sánchez, V. A. Cúneo, E. A. Saavedra, A. Ambrifi, M. C. Baglio, J. Casares, J. M. Corral-Santana, R. P. Fender, J. A. Fernández-Ontiveros, G. Ponti, D. M. Russell, M. A. P. Torres, Y. Ueda, F. M. Vincentelli, I. Yanes-Rizo,Comments: 24 pages, 10 figures. Published in Nature AstronomySubjects: astro-ph.HECreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
Accretion onto BLACK HOLEs powers some of the most energetic sources in the Universe, yet its behaviour across the luminosity range remains poorly understood. Specifically, as the luminosity approaches the Eddington limit ($L_{\rm Edd}$), the inner accretion disk is expected to depart from the standard thin-disk solution, becoming vertically extended. The luminosity threshold and observational signatures of this transition remain, however, uncertain. We present multiwavelength spectroscopy obtained during the decay of a BLACK HOLE X-ray binary outburst. At the peak ($\sim 0.2\,L_{\rm Edd}$), a cool optical and near-infrared spectrum dominated by strong recombination lines of hydrogen and He I is observed. However, as the luminosity decreases, it switches to a hot, highly irradiated, nearly featureless spectrum. This puzzling behavior reveals the emergence of a vertically extended inner disk at the outburst peak, shielding the outer regions from high-energy radiation produced near the BLACK HOLE; a scenario supported by contemporaneous X-ray spectra. Observations of similar systems suggest that this phenomenon may be common among BLACK HOLE accretion disks. Self-shadowing structures at luminosities well below $L_{\rm Edd}$ have major implications for BLACK HOLE accretion flows and their observational properties, affecting inferred BLACK HOLE spins, X-ray POLARIZATION measurements, and the physical conditions of the outer disk and its associated outflows.
[abstract 28 / 62] (score: 3) - Title: The Gaia-alerted 2024--2025 brightening of V346 NorAuthors: Á. Kóspál, D. J. Lengyel, P. Ábrahám, B. M. Marosi, F. Cruz-Sáenz de Miera, E. Fiorellino, T. Giannini, S. Kraus, A. Labdon, P. W. Lucas, Th. Moore, Zs. Nagy, M. Siwak, A. Udalski,Comments: 12 pages, 7 figues, 6 pages of appendix. Accepted for publication in A&ASubjects: astro-ph.SRCreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
Young stellar objects (YSOs) build their final mass through a highly unsteady, episodic accretion process, often accompanied by outflow and ejection events. Objects undergoing episodic high-accretion states are known as eruptive YSOs. V346 Nor is an embedded eruptive YSO that underwent a sudden optical brightening in 2024 July that triggered an alert from the Gaia Photometric Science Alert system. With the aim of characterizing the physical processes behind this recent brightening event, we analyze new and archival photometric and spectroscopic monitoring data. We study how the brightness, colors, and spectral features changed with time in the past decade. We also fitted an accretion disk model to the observations in which the stellar mass--accretion rate product $M_{\star}\dot{M}$ and the line-of-sight extinction $A_V$ are free parameters. The accretion rate in V346 Nor has been higher ($M_{\star}\dot{M} \sim 10^{-4}\,M_{\odot}^2\,$yr$^{-1}$) since 2021 than during any previous historical peak, although it was relatively constant during the 2025 February-May brightness maximum, which was driven instead by a drop in extinction from $A_V \approx 20$\,mag to $10$\,mag. V346 Nor has accreted about 2\% of the stellar mass since its outburst. A P Cygni profile in H$α$ indicates a strong outflowing wind reminiscent of classical FUors. The variability of the CaII infrared triplet lines and transient CO bandhead emission point to a highly unstable inner disk and accretion region. The persistence of forbidden line emission indicates ongoing JET activity. The brightness and color variations of V346 Nor are the result of a superposition of changes in the accretion rate and the line-of-sight extinction. With record-high accretion levels and strong wind and JET activity, V346 Nor is in one of its most active phases since its original outburst in the 1970s.
[abstract 29 / 62] (score: 3) - Title: A Failed Filament Eruption and Associated Active Region Heating Driven by External Magnetic ReconnectionAuthors: Yudi Ou, Yuandeng Shen, Dongxu Liu, Reetika Tiwari,Comments: 21, page, 9 figures, accepted for publication in ApJSubjects: astro-ph.SRCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We investigate a failed filament eruption and associated coronal heating in NOAA Active Region 12353 on 2015 May 23, focusing on the relationship between MAGNETic confinement and external RECONNECTion. Coordinated observations from the Goode Solar Telescope and the Solar Dynamics Observatory, together with nonlinear force-free field extrapolations, allow us to trace the event from the merging of two low-lying filamentary structures to the failed eruption of the resulting elongated filament. Before the rapid rise, the modeled flux rope had entered a regime susceptible to kink instability, while low-atmospheric internal RECONNECTion had already occurred; both may have contributed to the initial acceleration. The rising flux rope remained below the torus instability threshold and was confined by a strong, asymmetric overlying field that compressed it against the overlying loops. An elongated interface brightening, bidirectional plasmoid-like motions, newly brightened loop systems, and progressive weakening of the filament are consistent with external RECONNECTion that changed the MAGNETic connectivity, removed MAGNETic flux from the rope, and disrupted its coherent structure. Differential emission measure analysis indicates that the external RECONNECTion heated the active region loop system. A transient, localized structure with high-temperature emission was observed at the interaction interface, consistent with the expected location of a current sheet associated with external RECONNECTion. These results suggest that the strong confining field halted the filament eruption and sustained the interface compression required for current sheet formation, enabling external RECONNECTion to disrupt the flux rope and heat the active region loop system.
[abstract 30 / 62] (score: 3) - Title: Moving Beyond the DRW Model: Learning Quasar Variability with Generative ModelsAuthors: Nadav Bojan Sellam, Kevin Park, Alex Bronstein, Zoltán Haiman,Comments:Subjects: astro-ph.GA cs.AICreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The optical continuum variability of QUASARs is often described by a damped random walk (DRW) model, with characteristic damping timescales $τ_{\rm DRW}$ of hundreds of days and amplitudes $σ_{\rm DRW}$ of $\mathcal{O}(0.1)$ magnitudes. This model has been widely used as a null hypothesis to assess the significance of periodic signals in QUASAR light curves in the search for supermassive BLACK HOLE binaries, the significance of extreme QUASAR variability like tidal disruption events (TDEs) and changing-look (CL) QUASARs, or to model time lags in reverberation mapping. However, the DRW model is known to be incomplete, and an incorrect null hypothesis can lead to biased significance estimates. We investigate the impact of such null-hypothesis mis-specification on the detection of periodic signals in synthetic QUASAR light curves and introduce the generative model Nullasar, capable of learning QUASAR variability directly from time-series data. We demonstrate that Nullasar, trained with flow matching, can learn delicate statistical properties of stochastic light-curve variability without explicitly assuming any noise model. We further demonstrate that Nullasar can learn correlated distributions of noise parameters and generate new light-curve realizations from a range of deviations from the Gaussian DRW noise model, approximating parametric descriptions of stochastic processes. When used as a null hypothesis for detecting periodic signals in synthetic light curves, Nullasar performs comparably to fitting the correct DRW model to each light curve, and outperforms parametric fitting when the variability follows a more flexible AR(2) model. Finally, we identify practical limitations, including sensitivity to contamination of the training set by non-null signals, and show that projecting the conditioning vector of the model onto its leading principal components largely mitigates it.
[abstract 31 / 62] (score: 3) - Title: On the MeV Nuclear De-excitation Line Emission from the Vela Supernova Remnant RegionAuthors: Y-Z. Shen, B. Liu, Y. Chen,Comments: 22pages,5 figures. Accepted by PRDSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We investigate the potential nuclear de-excitation $γ$-ray line emission from low-energy COSMIC RAYs (LECRs) in the Vela SNR region, one of the nearest and most angularly extended core-collapse SUPERNOVA remnant (SNR) complexes. We calculate the MeV line emission from Vela, Vela Jr., and Puppis A using the TALYS nuclear reaction code, considering both direct and inverse interactions between the accelerated particles and the nuclei interior to the SNRs. The proton spectra are constrained by GeV--TeV $γ$-ray observations under the hadronic assumption, while a broad range of spectral indices is explored to account for the poorly constrained LECR population. We find that Vela dominates the predicted line flux among the three SNRs. The integrated fluxes of the prominent 1.63 MeV $^{20}$Ne, 4.44 MeV $^{12}$C and 6.13 MeV $^{16}$O lines are approximately $1.3\times10^{-10}$ -- $1.2\times10^{-6}$, $3.2\times10^{-10}$ -- $5.6\times10^{-7}$ and $1.6\times10^{-10}$--$2.6\times10^{-7}$ $\rm ph\,cm^{-2}\,s^{-1}$, respectively, over the explored proton spectra. We compare the predicted line emission with both the diffuse Galactic MeV continuum and local source-related continuum emission. In our background estimate, diffuse Galactic emission is the dominant component, while inverse Compton emission from pulsar wind nebula Vela X constitutes an additional local continuum component. The relatively low diffuse background toward Vela compared with the Galactic Center makes this region a promising target for future MeV $γ$-ray observations. Such observations could provide direct constraints on the LECR population and particle acceleration in this complex SNR region.
[abstract 32 / 62] (score: 3) - Title: Magnetically Deformed Neutron Stars and Gravitational WavesAuthors: Remo Ruffini, Sang Pyo Kim, Yu Wang, Shurui Zhang,Comments: 27 pages, 10 figures, comments welcomedSubjects: astro-ph.HE astro-ph.SR gr-qcCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We study the geometric figures of neutron stars and MAGNETars with spin periods from milliseconds to seconds and MAGNETic fields from $10^{12}$-$10^{15}$ G to hypothetical values near the Chandrasekhar-FERMI virial scale, $10^{18}$ G. In Newtonian theory, we find the equilibrium figure of a rotating incompressible fluid with a current-free uniform interior MAGNETic field matched to an exterior dipole field by surface currents. For aligned axes, an oblate spheroid is obtained by minimizing the total gravitational, rotational and MAGNETic energy at fixed mass, volume, angular momentum and frozen MAGNETic flux. Its ellipticity is the sum of rotational and MAGNETic contributions, recovers the Ferraro limit for a weak MAGNETic field, and has a MAGNETic weight that depends on the eccentricity for large deformation. For misaligned MAGNETic and spin axes, we introduce a quadrupolar shape tensor and diagonalize it to find a triaxial ellipsoid whose principal axes are tilted by MAGNETic pressure. The tilt angle and eccentricities are computed analytically as functions of the rotational and MAGNETic eccentricities and the misalignment angle. The MAGNETic energy of the misaligned configuration is obtained in closed form in oblate spheroidal harmonics for arbitrary eccentricity and obliquity. Its weak-field deformation, up to $10^{15}$ G, is proportional to $P_2(\cosα)$, which fixes the MAGNETic forcing tensor, and its finite-eccentricity form gives a generalized Ferraro-Maclaurin relation for rotation-dominated misaligned stars. In the weak-field regime, the triaxial eccentricity is determined by the Ferraro eccentricity and the harmonic mean of order 2 of the rotational and MAGNETic eccentricities. The deformation parameters give the quadrupole moments and hence the continuous gravitational-wave amplitudes, luminosity and spin-down torque of the triaxial configuration.
[abstract 33 / 62] (score: 3) - Title: Low effective-temperature diminution of H$α$ emission from metallic centrifugal MAGNETospheres fed by ion-runaway windsAuthors: Stanley P. Owocki, Jiri Krticka, M. E. Shultz, Asif ud-Doula,Comments: 10 pages, accepted for publication in MNRASSubjects: astro-ph.SRCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Main-sequence B-stars with a strong MAGNETic field and moderately rapid rotation form centrifugal MAGNETospheres (CMs), which often exhibit distinct H$α$ line emission, as well as circularly polarized radio. For CMs of early-type B-stars with $T_{\rm eff} \gtrsim 17$ kK, the onset and strength of the H$α$ emission is well explained in terms of a centrifugal breakout (CBO) model, in which mass fed into the CM by the star's radiatively driven stellar wind builds up to a density that is sufficient for centrifugal forces to overwhelm MAGNETic confinement. The analysis here now argues that the observed diminution and disappearance of the H$α$ emission for CM B-stars with $T_{\rm eff} \lesssim 17$ kK can be explained by the failure of their lower luminosity to drive hydrogen-rich winds; instead they develop an ion runaway of heavier metal ions that are the seat of line-driving, which thus feed a metallic CM (mCM) for which the requisite hydrogen is diminished or even absent. For mid-B-type stars in a narrow transition range of effective temperature $T_{\rm eff} \approx (16.8 \pm 0.3)$ kK, hydrogen can still be driven to a sufficient speed to coast into the inner CM, which we show can explain the reduced strength and width of H$α$ line emission in the transition CM star $ρ$ Oph C. But even in regions with no hydrogen, the build-up of metal density to CBO levels can still drive the MAGNETic RECONNECTion needed to produce the observed radio. We discuss whether such build-up of metals could give rise to direct observational signatures.
[abstract 34 / 62] (score: 3) - Title: LHAASO's Peanut source is a laboratory for studying MAGNETic fields in the Milky WayAuthors: Maksim Kleimenov, Yuan Li, Gwenael Giacinti, Dmitri Semikoz,Comments: 21 pages, 11 figuresSubjects: astro-ph.HE astro-ph.GACreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Recently, the LHAASO Collaboration reported gamma-ray emission from the Peanut-shaped source (Peanut), which extends over $4.5^\circ$ parallel to the Galactic plane at $b=-17.5^\circ$. The source is associated with the millisecond pulsar PSR J0218+4232, located at the eastern edge of the Peanut, at a distance of 3 kpc from the Earth and 0.9 kpc from the Galactic plane. Its location and bright gamma-ray emission above 25 TeV make it a natural laboratory for studying the Galactic MAGNETic field (GMF) in the transition region between the Galactic plane and halo. We interpret the observed emission as inverse-Compton scattering of CMB photons by electrons propagating along the large-scale GMF, accounting for turbulence through two models: Kolmogorov and Goldreich-Sridhar (GS). These models correspond to diffusive and ballistic particle propagation, respectively. While the GS case naturally provides conditions for one-sided gamma-ray emission, in the Kolmogorov case assumptions of one-sided particle injection and MAGNETic mirror at the source are necessary. We find that, in the Kolmogorov scenario, the Peanut's hotspots are likely associated with MAGNETic bottling, whereas in the GS scenario, they are related to MAGNETic field line geometry. Both models yield constraints on the GMF at the location of the Peanut.
[abstract 35 / 62] (score: 3) - Title: Population inference of eccentric binary BLACK HOLEs using asymptotic constants of motionAuthors: Chiara Anselmo, Giulia Fumagalli, Davide Gerosa,Comments: 11 pages, 6 figuresSubjects: gr-qc astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
In standard gravitational-wave population analyses of compact binaries, source parameters are defined at a reference frequency. For quantities that evolve during the inspiral, this means constructing a population of systems at different evolutionary stages, which complicates the astrophysical interpretation of the results. The past-time infinity, or zero-frequency, limit provides a mathematically well-defined reference where all sources enter the population fit on equal footing. This approach was first proposed for spin tilts, which evolve due to spin precession but converge to constant values as binaries are back-propagated. The orbital eccentricity also evolves throughout the inspiral and approaches unity in the zero-frequency limit for all binaries, making it unsuitable as a common reference point for population analyses. On the other hand, the Newtonian orbital angular momentum is an asymptotic constant of motion of the RELATIVISTIC two-body problem and remains finite in this limit. In this paper, we make use of this known asymptotic behavior to reformulate eccentric population inference in terms of orbital angular momentum rather than eccentricity and demonstrate this approach on simulated gravitational-wave data. Our work constitutes the first example of eccentric population inference using only asymptotic constants of motion. Importantly, after the inference has been performed using this consistent reference, the results can be propagated to any preferred frequency for comparison with astrophysical predictions.
[abstract 36 / 62] (score: 3) - Title: Identification of extragalactic radio sources in the VISTA survey of the Magellanic Clouds using an unsupervised machine learning algorithmAuthors: Clara M. Pennock, Jacco Th. van Loon, Mohammed Iddrisu Nlowie, Elizabeth Joy Leese, Maja Nowaczyk, Heinz Andernach, Duncan Farrah, Valentin D. Ivanov, Michał J. Michałowski, Joana M. Oliveira, Jahang Prathap, Syed F. Rahman, Mara Salvato, Tayyaba Zafar,Comments: MNRAS acceptedSubjects: astro-ph.GA astro-ph.IMCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The Magellanic Clouds benefit from a wealth of data across the electroMAGNETic spectrum, but extracting extragalactic sources from these crowded fields is a less than straightforward endeavour. We used an unsupervised machine learning algorithm (t-distributed stochastic neighbourhood embedding; t-SNE) to classify 6,652 and 1,356 sources in the Large and Small Magellanic Clouds, respectively, that were detected in the VISTA Survey of the Magellanic Clouds (VMC) and the Evolutionary Map of the Universe (EMU) survey with the Australian Square Kilometre Array Pathfinder (ASKAP). Multi-wavelength photometry and colours from optical to radio were used as features to cluster similar sources together in 2D space on a t-SNE map. We used previously classified sources to separate the clusters into five classes: AGN, low-redshift galaxies, BLAZARs, dusty stellar objects (e.g. young stellar objects, planetary nebulæ etc) and high proper-motion stars. Previous photometric classifications from the literature match with specific clusters identified, as well as provide insight on areas of the t-SNE map for which there are no previous classifications. This work shows that the combination of unsupervised machine learning with photometry from optical to radio has proven adept at separating the stellar from the extragalactic, and the AGN from the galaxies. Our associated new spectroscopy with SALT includes new discoveries of AGN up to redshift 3.3 and Magellanic emission-line objects.
[abstract 37 / 62] (score: 3) - Title: Euclid Data Release 1 (DR1). Euclid Lens Identification Pipeline and Scientific Exploration (ECLIPSE) A: Strong lens catalogue overviewAuthors: Euclid Collaboration, N. E. P. Lines, P. Holloway, T. Li, T. E. Collett, S. Schuldt, S. H. Vincken, J. W. Nightingale, A. Nersesian, M. Fogliardi, A. Verma, C. J. Storfer, A. Manjón-García, J. Wilde, W. J. R. Enzi, J. A. Acevedo Barroso, A. Sonnenfeld, K. Rojas, E. Baeten, P. Bergamini, C. Cornen, F. Courbin, H. Degaudenzi, G. Despali, R. Gavazzi, C. Macmillan, R. B. Metcalf, D. J. Bowden, R. Cañameras, J. H. -H. Chan, L. R. Ecker, M. Grespan, Q. He, D. P. Johnson, C. Krawczyk, N. Massari, A. Melo, L. A. Moustakas, C. Olave, A. Paulino-Afonso, C. Saulder, D. Sluse, G. Smadja, H. Srivastava, D. Stern, T. T. Thai, C. Tortora, N. Wielders, I. T. Andika, A. Angress, D. J. Ballard, M. Bradac, D. Delley, P. Fleury, A. Galan, G. Granata, T. Harvey, N. B. Hogg, K. Jahnke, K. Kuijken, T. Li, P. J. Marshall, M. Meneghetti, A. More, B. C. Nagam, D. O'Ryan, J. Pearson, H. Qu, D. Ryczanowski, T. Saifollahi, S. Serjeant, C. Spiniello, L. Trobbiani, X. Xu, M. Zumalacarregui, A. L. Faisst, B. Altieri, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, A. Balestra, S. Bardelli, P. Battaglia, R. Bender, A. Biviano, M. Bolzonella, E. Branchini, M. Brescia, S. Camera, G. Cañas-Herrera, V. Capobianco, C. Carbone, V. F. Cardone, J. Carretero, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, A. Costille, H. M. Courtois, M. Cropper, G. De Lucia, C. Dolding, H. Dole, F. Dubath, X. Dupac, S. Dusini, S. Escoffier, M. Farina, R. Farinelli, F. Faustini, S. Ferriol, S. Fotopoulou, M. Frailis, E. Franceschi, M. Fumana, L. Gabarra, S. Galeotta, K. George, B. Gillis, C. Giocoli, J. Gracia-Carpio, A. Grazian, F. Grupp, S. Gwyn, W. G. Hartley, S. V. H. Haugan, S. Hemmati, H. Hoekstra, W. Holmes, I. M. Hook, F. Hormuth, A. Hornstrup, M. Jhabvala, B. Joachimi, S. Kermiche, A. Kiessling, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, A. M. C. Le Brun, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, M. Magliocchetti, G. Mainetti, D. Maino, O. Mansutti, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. J. Massey, N. Mauri, E. Medinaceli, M. Melchior, E. Merlin, G. Meylan, P. Monaco, A. Mora, M. Moresco, C. Moretti, L. Moscardini, R. Nakajima, C. Neissner, R. C. Nichol, S. -M. Niemi, C. Padilla, S. Paltani, F. Pasian, W. J. Percival, V. Pettorino, A. Pezzotta, G. Polenta, M. Poncet, L. A. Popa, L. Pozzetti, F. Raison, R. Rebolo, A. Renzi, J. Rhodes, G. Riccio, I. Risso, F. Rizzo, E. Romelli, M. Roncarelli, B. Rusholme, R. Saglia, Z. Sakr, D. Sapone, B. Sartoris, M. Schirmer, P. Schneider, T. Schrabback, A. Secroun, E. Sihvola, P. Simon, C. Sirignano, G. Sirri, L. Stanco, J. -L. Starck, P. Tallada-Crespí, A. N. Taylor, H. I. Teplitz, I. Tereno, N. Tessore, S. Toft, R. Toledo-Moreo, F. Torradeflot, A. Tsyganov, I. Tutusaus, J. Valiviita, T. Vassallo, Y. Wang, J. Weller, A. Zacchei, G. Zamorani, F. M. Zerbi, E. Zucca, M. Ballardini, S. Borgani, E. Bozzo, C. Burigana, R. Cabanac, A. Cappi, F. Caro, T. Castro, J. A. Escartin Vigo, J. García-Bellido, T. Gasparetto, V. Gautard, C. M. Gutierrez, J. Macias-Perez, R. Maoli, M. Pöntinen, E. Sarpa, V. Scottez, M. Sereno, M. Tenti, M. Tucci, M. Wiesmann, Y. Akrami, G. Angora, S. Anselmi, M. Archidiacono, G. Aricò, F. Atrio-Barandela, M. Baes, L. Bazzanini, D. Bertacca, M. Bethermin, F. Beutler, L. Blot, M. L. Brown, S. Bruton, A. Calabro, B. Camacho Quevedo, C. S. Carvalho, F. Cogato, S. Conseil, A. R. Cooray, P. Corcho-Caballero, B. Csizi, O. Cucciati, H. Dannerbauer, T. de Boer, F. De Paolis, G. Desprez, A. Díaz-Sánchez, S. Di Domizio, J. M. Diego, P. -A. Duc, V. Duret, M. Y. Elkhashab, A. Enia, Y. Fang, A. Farina, A. Finoguenov, A. Franco, Y. Fu, K. Ganga, E. Gaztanaga, Z. Ghaffari, F. Giacomini, F. Gianotti, G. Gozaliasl, A. Gruppuso, M. Guidi, A. Hall, C. Hernández-Monteagudo, T. Heuberger, H. Hildebrandt, J. Hjorth, M. Jauzac, J. J. E. Kajava, Y. Kang, V. Kansal, D. Karagiannis, J. Kim, C. C. Kirkpatrick, A. Kovács, I. Kova{č}i{ć}, K. Koyama, S. Kruk, M. C. Lam, M. Lattanzi, L. Legrand, G. Leroy, G. F. Lesci, J. Lesgourgues, L. Linke, S. J. Liu, G. Maggio, E. A. Magnier, F. Mannucci, F. R. Marleau, C. J. A. P. Martins, M. Migliaccio, M. Miluzio, G. Morgante, S. Nadathur, K. Naidoo, P. Natoli, A. Navarro-Alsina, S. Nesseris, L. Nicastro, M. Oguri, F. Oppizzi, F. Pace, D. Paoletti, F. Passalacqua, K. Paterson, L. Patrizii, C. Pattison, A. Pisani, D. Potter, G. W. Pratt, S. Quai, M. Radovich, G. Rodighiero, W. Roster, S. Sacquegna, M. Sahlén, D. B. Sanders, J. Schaye, A. Schneider, D. Sciotti, E. Sellentin, F. Shankar, L. C. Smith, M. Talia, K. Tanidis, C. Tao, G. Testera, R. Teyssier, S. Tosi, A. Troja, C. Uhlemann, C. Valieri, A. Venhola, D. Vergani, G. Vernardos, P. Vielzeuf, E. Vilenius, S. Vinciguerra, M. von Wietersheim-Kramsta, N. A. Walton, L. Wang, A. H. Wright, D. Scott,Comments: 28 pages. Submitted to A&A as part of the Special Issue "Euclid First Data Release"Subjects: astro-ph.GA astro-ph.COCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We present 15 072 high-confidence strong lens candidates in Euclid Data Release 1 (DR1), spanning 2000 deg$^2$. These comprise 6073 grade A ('sure lens') and 8999 grade B ('probable lens') systems, which we publish alongside a further 9010 grade C ('possible lens') candidates. With more high-confidence candidates than all previous catalogues combined, this sample establishes a large, homogeneous data set of galaxy-scale strong lenses with high-resolution imaging, transforming strong lensing from a field of rare discoveries to a robust statistical tool for astrophysics and cosmology. Of the roughly 900 million sources in DR1, we searched the 68 million passing our catalogue selection using a bespoke discovery pipeline that synthesises scores from five machine-learning models with visual classifications from around 7000 citizen scientists and 67 strong lensing experts. Beyond classical Einstein rings, our catalogue includes 84 candidate double-source-plane lenses and over 1000 candidate disc lenses, two exotic classes with few previously known examples, as well as several hundred candidate lensed AGN and QUASARs. We deliver automated lens models for the combined grade A+B systems, and photometric redshifts and stellar population properties for the deflector galaxies, providing immediate science-ready data products. We find that the majority of the deflector galaxies are massive and quiescent, with stellar masses of $\log_{10}(M_\ast /M_\odot) = 11.39^{+0.29}_{-0.33}$ (Salpeter initial mass function; 16th-84th percentile range). The deflector galaxies span a range of photometric redshifts ($z=0.68 ^{+0.33}_{-0.29}$), extending to higher redshifts than previous ground-based lens samples, and the lenses have a typical Einstein radius of $0.85 ^{+0.44}_{-0.24}$ arcsec. Extrapolating by area, we expect over 100 000 high-confidence strong lens candidates in the Euclid Wide Survey.
[abstract 38 / 62] (score: 3) - Title: Sailing with the winds of HL Tau: the JWST viewAuthors: T. Nony, F. Bacciotti, C. Dougados, M. G. Navarro, B. Nisini, P. Kavanagh, A. Banzatti, V. Delabrosse, L. Podio, S. Cabrit, A. Caratti o Garatti, D. Coffey, T. P. Ray, F. Massi, D. Fedele, E. Whelan, A. Garufi, S. Antoniucci,Comments: 20 pages, 16 figures, accepted by A&ASubjects: astro-ph.SR astro-ph.GACreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Studying protostellar ejections is crucial to understanding the formation of young stars and planetary systems. The Class I/II star HL Tau, with its ringed disk and prominent bipolar outflows, is a benchmark system for these studies. We provide a first overview of our Cycle 3 JWST program targeting HL Tau, focusing on the morphology and kinematics of the various wind components as well as on the water emission lines excited in the inner disk. Our observations cover the 1.66-28 $μ$m spectral range, combining NIRSpec and MIRI MRS mosaics to map the inner 10" of the red-shifted lobe of the outflow and the base of the blue-shifted lobe. In the red-shifted lobe we observe a stratified wind of three nested layers: a fast, highly collimated atomic JET structured in a chain of eight knots and with radial velocities of 160 km/s; a wide-angle H$_2$ wind with velocities of 45 km/s exhibiting complex arc-like substructures; and a warm gas shell, of radial velocity of 35 km/s, visible in low-excitation transitions of CO ($ν$=1-0). This CO shell appears co-spatial with the CO (J=2-1) emission detected by ALMA with velocities from 3 to 25 km/s. In the first 1" of the blue-shifted lobe we detect a similar stratification, but the JET is faster and less collimated. The observed stratification and kinematics of the flow may support a MAGNETically driven disk-wind scenario in which the distinct components originate in the disk at progressively larger distances from the star. However, while the external components observed in CO have the laminar and regular appearance predicted for such winds, the knots in the inner JET and the arcs in the wind could be the manifestation of a pulsed ejection mechanism. Additionally, in MIRI spectra taken at the star position we detect a forest of water lines dominated by cold-to-warm (< 500 K) gas. Their distribution suggests an extended reservoir of sublimated ices.
[abstract 39 / 62] (score: 2) - Title: Magnetars MAGNETic field evolution with ambipolar diffusionAuthors: Monika Sinha, Manoj Kumar Ghosh, Yogeesh N,Comments: 15 pages, 8 figures, Appendix addedSubjects: astro-ph.HE hep-phCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The MAGNETic field associated with neutron stars is generally believed to be threaded inside the star. In the presence of a MAGNETic field, plasma in the interior of the star undergoes a series of processes that result in MAGNETic field evolution. It is believed that MAGNETar activities like X-ray, GAMMA-RAY BURSTs, and giant flares (which release more energy in a few sec than Sun in 10 years), are mainly due to field decay. The most important process of field decay inside the core of the star is the ambipolar diffusion of the charged particles present in the interior plasma. The decay rate due to ambipolar diffusion is directly connected to the ambipolar velocity of the charged particles under the influence of the present MAGNETic field. The ambipolar velocity of the charged particles depends on the internal dynamics of the particles. We outline a general method to solve the particle dynamics in the presence of a MAGNETic field to have a MAGNETohydrodynamics equation from ambipolar velocity. The equation is general and applicable to all possible surrounding conditions temperature, matter states like normal or superfluid, etc.
[abstract 40 / 62] (score: 2) - Title: Chaotic Dynamics around a Hairy Black Hole in Horndeski GravityAuthors: Yang Yu, Ruo-Ting Chen, Shulan Li, Dan Zhang, Jian-Pin Wu,Comments: 47 pages, 16 figuresSubjects: gr-qcCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We investigate the chaotic dynamics of a spinning test particle in a static, spherically symmet- ric hairy BLACK HOLE (BH) in Horndeski gravity, using the Mathisson-Papapetrou-Dixon equations closed by the Tulczyjew-Dixon condition. Bound orbits are identified by fixing the angular momen- tum and setting the energy according to the effective potential, so that the accessible parameter range is bounded by a critical hair parameter, hcrit, which varies non-monotonically with the spin. We analyze the resulting chaotic behavior using Lyapunov exponents, Poincare sections, and re- constructed attractors. We find that the response of these indicators to scalar hair is orbit- and spin-dependent rather than universally monotonic. An analysis of orbital frequency ratios shows that, at physically maximal spin (S = 1), an approaching 2:1 azimuthal resonance overlapping a persistent 1:1 polar lock amplifies chaos, while the hair-driven erosion of potential saddles tends to suppress it. At non-physical spin (S = 1.5), the Lyapunov exponent decreases monotonically. Gravitational waveforms constructed via the quadrupole formula inherit the same state-specific pattern: the correlation between the two POLARIZATION modes varies non-monotonically with h, in step with the Lyapunov exponent. These results show that chaotic indicators respond to scalar hair in an orbit- and resonance-dependent manner rather than through simple monotonic suppres- sion, and identify the spin-dependent resonance structure as an essential ingredient for interpreting chaos around hairy BLACK HOLEs.
[abstract 41 / 62] (score: 2) - Title: Uncertainty-Aware Deep Learning for the Ly$α$ Forest: CNN-Based Absorber Detection and CharacterizationAuthors: Paryag Sharma, Vikram Khaire, Ting-Yun Cheng, Hum Chand, Prakash Gaikwad,Comments: Accepted for publication in MNRASSubjects: astro-ph.GACreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The Ly$α$ forest is a powerful probe of the intergalactic medium and small-scale matter distribution, but deriving absorber properties traditionally requires computationally expensive Voigt-profile fitting. We present a convolutional neural network (CNN) that identifies and characterizes H I Ly$α$ absorbers directly from QUASAR spectra. The model is trained on synthetic spectra generated from the IllustrisTNG simulation and fitted with the VIPER Voigt-profile fitting code to provide training labels. The network simultaneously predicts absorber presence, column density ($N_{\rm HI}$), Doppler parameter ($b_{\rm HI}$), and line centroid. On simulated spectra, the CNN reproduces the viper reference catalogue with an F1 score of $\sim$0.8, with mean absolute errors of $\sim$0.18 in $\log N_{\rm HI}$ and $\sim$0.10 in $\log b_{\rm HI}$. It reproduces the H I column density distribution function and the $b_{\rm HI}$--$N_{\rm HI}$ relation obtained from viper, recovering similar CDDF slopes and a lower-envelope relation with an RMS difference of only 0.36 km s$^{-1}$. Applied to UVES spectra, performance decreases to an F1 score of $\sim$0.5, with mean absolute errors of $\sim$0.35 in $\log N_{\rm HI}$ and $\sim$0.22 in $\log b_{\rm HI}$. Latent-space analysis reveals a significant domain shift between the simulated and UVES spectra, contributing to the reduced performance. Nevertheless, the CNN reproduces the observed CDDF and $b_{\rm HI}$--$N_{\rm HI}$ distributions obtained from the viper catalogue, yielding CDDF slopes consistent with VIPER and a lower-envelope RMS difference of 3.20 km s$^{-1}$ relative to viper. Monte Carlo dropout is implemented during inference to quantify predictive uncertainties. Together with its computational efficiency, the method provides a scalable and uncertainty-aware framework for Ly$α$ forest analysis in upcoming spectroscopic surveys.
[abstract 42 / 62] (score: 2) - Title: $r$-Process as Production of Lanthanides from Compact Object MergersAuthors: Li-Ming Zhuo, Hou-Jun Lü, Xiao-Xuan Liu, Meng-Hua Chen, En-Wei Liang,Comments: 16 pages, 1 table, 8 Figures. Matched with the published verisonSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The relative contributions of binary neutron star (BNS) and BLACK HOLE-neutron star (BH-NS) mergers to the Galactic enrichment from the rapid neutron-capture process ($r$-process) remain an open question in nuclear astrophysics. In this paper, we present end-to-end numerical simulations of binary population synthesis, nucleosynthesis, and Galactic chemical evolution (GCE) via Compact Object Mergers: Population Astrophysics and Statistics (COMPAS), SkyNet network, and a stochastic multizone model, respectively. By considering five equations of state (EOSs) of NS and different spins of BH for BNS and BH-NS mergers, it is found that the averaged abundance seems not to be significantly dependent on the EOS of the neutron star (NS) and the spin of the BH for the BNS and BH-NS mergers. For the given EOSs of NS, the abundance of BNS is higher than that of BH-NS mergers before the second peak (for mass number $A\sim$130), but it is lower when the mass number is greater than 130. Moreover, the lighter $r$-process elements ($A<$130) are predominantly produced by the disk wind, while the heavier elements ($A>$130) originate mainly from the dynamical ejecta. The purely BNS mergers, on the other hand, are the dominant contributors to the production of lanthanides like europium (Eu) at the later stage of GCE, but BH-NS mergers make only a small contribution of heavy $r$-process elements for the $\rm Eu/Fe$ evolutionary tracks in the Milky Way.
[abstract 43 / 62] (score: 2) - Title: SuSy and CoDy Radiation from Evaporating Black HolesAuthors: Giacomo Cacciapaglia, Francesco Sannino, Paola Simone, Vania Vellucci,Comments: 49 pages, 11 figuresSubjects: hep-ph astro-ph.HE gr-qcCreated: 2026-11-06; Updated: 2026-11-13; Datestamp: 2026-11-13
We investigate the interplay between physics beyond the Standard Model and modified spacetime geometries in shaping the photon and neutrino spectra from evaporating BLACK HOLEs. We implement three representative supersymmetric (SuSy) benchmarks and a composite dynamics (CoDy) scenario in BlackHawk. We consider both Schwarzschild BLACK HOLEs and regular BLACK HOLEs geometries, namely polymerized, Hayward, and Simpson--Visser BLACK HOLEs. New degrees of freedom at the TeV scale become accessible at Hawking temperatures corresponding to BLACK HOLE masses of approximately $M_{\rm BH}\sim 10^{10}\,\mathrm{g}$. We show that physics beyond the Standard Model produces distinctive signatures in both the instantaneous secondary-photon and neutrino spectra. Radiative decays generate narrow spectral features with approximately temperature-independent relative amplitudes, while multistep decay cascades produce broad enhancements that become increasingly pronounced at higher temperatures. In contrast, compressed mass spectra exhibit no localized features. Crucially, we show that the effects of new particle physics and modified spacetime geometries can become intertwined in specific energy regimes, altering the resulting spectral signatures. Our results demonstrate that photon and neutrino spectra provide complementary probes of new particle physics and BLACK HOLE geometry, with predicted spectral enhancements extending into the energy ranges accessible to current and future high-energy observatories.
[abstract 44 / 62] (score: 2) - Title: Spins do not add: why rotating stars do not help spin-up BLACK HOLEs in binariesAuthors: Filippo Camilloni, Konrad Topolski, Keneth Miler, Luciano Rezzolla,Comments: v1: Letter, 5 pages + 2 End Matter + 2 Supplemental Material, 9 Figures in total, 1 table;Subjects: gr-qc astro-ph.HECreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
It is well-known that in the merger of a black-hole binary with spins aligned with the orbital angular momentum, the spin of the final BLACK HOLE always increases with the spin of the components. We show that this very intuitive behavior is violated in BLACK HOLE--neutron star binaries, where the spin of the final BLACK HOLE actually decreases as the spin of the neutron star increases. Using a large set of binaries with different spins and mass ratios, we identify the mechanism behind this surprising result in the nonlinear dynamics of the tidal disruption, which drives a substantial loss of angular momentum via dynamical ejecta, in some cases comparable to that radiated via gravitational waves. Our results highlight that the spin evolution of stellar-mass BLACK HOLEs involved in binary mergers is different from what normally assumed, far more complex, and interesting.
[abstract 45 / 62] (score: 2) - Title: Post-adiabatic effects sourced by radiation reaction for inspiraling, eccentric binaries in post-Newtonian theoryAuthors: Rohit S. Chandramouli, Nijaid Arredondo, Lidia J. Gomes Da Silva, Nicolás Yunes,Comments: 30 pages, 15 figures, 1 supplemental mathematica file, comments welcomedSubjects: gr-qc astro-ph.HECreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
The adiabatic approximation, in which eccentric binaries evolve under orbit-averaged fluxes, is widely used in gravitational-wave and astrophysical modeling. We use resummed multiple-scale analysis, which is closely related to near-identity averaging transformations, to derive post-adiabatic corrections from leading-order radiation reaction and explain how the accuracy of the adiabatic approximation depends on the initial orbital phase. While the secular evolution equations for the eccentricity and semi-major axis receive no explicit first post-adiabatic corrections, their solutions acquire such corrections through the initial conditions. We also derive the change in the functional form of the gravitational-wave POLARIZATIONs that cancels the gauge dependence of the orbital elements at first post-adiabatic order, ensuring agreement between waveforms evaluated at the same physical event in different coordinates. At a radial turning point, the first post-adiabatic oscillations of the semi-major axis and eccentricity vanish, so the initial osculating energy and angular momentum agree with their orbit-averaged values up to second post-adiabatic corrections. When initialized elsewhere along the orbit, the adiabatic approximation can accumulate significant dephasing, which the first post-adiabatic approximation can substantially reduce. Both dephasings can change sign across parameter space, consistent with competing contributions from successive orders. Accounting for initialization is therefore essential for assessing the accuracy of these approximations, particularly for long-lived, highly eccentric binaries.
[abstract 46 / 62] (score: 2) - Title: Natal Kicks of Compact Binaries: I. Population Synthesis Framework and Illustrative ExamplesAuthors: Cordelia Dashwood Brown, Poshak Gandhi, Christian Knigge, Yue Zhao, Phil Charles, Pornisara Nuchvanichakul, Katelyn Breivik, Akarsh Sahay, Siddharth Malu,Comments: Approved for publication in Monthly Notices of the Royal Astronomical SocietySubjects: astro-ph.HECreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
The natal kicks imparted to neutron stars and BLACK HOLEs at birth are critical for understanding massive-star evolution, compact-object formation, and compact binary merger rates. However, constraining these kicks is challenging, since they cannot be directly observed. Here, we outline a framework for inferring natal kick probability distributions for compact binaries. Our method embeds the rapid binary-population code COSMIC in a Monte-Carlo workflow that evolves ensembles of simulated binaries. From those which host compact objects, we can select subsets that match the observational characteristics of any given system (e.g. component masses, orbital period, mass-transfer status, systemic velocity). As a proof-of-concept, we apply this framework to six compact binaries spanning a wide range of companion masses and compact-object types. For each system, we identify the evolutionary channel(s) that could have led to the current observational characteristics, and isolate regions of allowed natal kicks and progenitor parameter space. We reconfirm that at least one BLACK HOLE system, XTE J1118+480, must have received a natal kick $v_{\rm NK} > 100$ km s$^{-1}$. The neutron-star system, GX 301-2, is also inferred to have received an impulsive kick exceeding 280 km s$^{-1}$. We discuss the strengths and limitations associated with population-synthesis-based inference methods and explore the effects of adopting different prescriptions for critical binary evolution phases. We provide a detailed demonstration of the non-linear relationship between $v_{\rm NK}$ and $v_{\rm sys}$, highlighting the shortcomings of relying on observations alone to measure natal kicks. The inferred kick velocity distributions across our benchmark sample are generally consistent with previous constraints.
[abstract 47 / 62] (score: 2) - Title: Comparison of the flamelet progress variable and thickened flame models for LES of turbulent combustionAuthors: Ashray Mohit, Margaret Wooldridge, Jesse Capecelatro,Comments: 14 Pages, 15 Figures, To be submitted to Combustion and FlameSubjects: physics.flu-dynCreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
Large-eddy simulation (LES) of turbulent combustion requires closure models for unresolved flame structures and chemical processes. Two widely used but fundamentally different approaches are the flamelet/progress-variable approach (FPVA) and the dynamically thickened-flame model (TFM). Here, both are applied to methane-air combustion within a common numerical framework and evaluated for the Sandia D flame and a JET-in-crossflow representative of a non-assist waste-gas flare across a range of crosswind-to-JET velocity ratios. For the predominantly diffusion-controlled Sandia-D flame, FPVA and TFM exhibit similar accuracy, while FPVA is substantially less computationally expensive and converges faster under mesh refinement. More detailed chemical kinetics improve agreement with experimental measurements, with little additional cost for FPVA but a substantial increase for TFM. For the JET-in-crossflow, both approaches reproduce the experimentally observed reduction in combustion efficiency with increasing crosswind, but their predictions progressively diverge as the crosswind strength increases. This divergence coincides with the emergence of a locally premixed reaction branch captured by TFM but not represented by FPVA, whereas predictions in diffusion-dominated regions remain broadly similar. In TFM, the locally premixed branch is associated with elevated scalar dissipation and greater residual methane downstream, indicating that highly strained premixed combustion contributes to differences in predicted flare performance. These results show that FPVA and TFM can provide similar predictions in diffusion-dominated flames but differ substantially when crossflow induces locally premixed, highly strained combustion near the nozzle.
[abstract 48 / 62] (score: 2) - Title: Plasma simulations with adaptive mesh and algorithm refinementAuthors: Vladimir I. Kolobov, Robert R. Arslanbekov,Comments:Subjects: physics.comp-ph physics.plasm-phCreated: 2026-11-10; Updated: 2026-11-13; Datestamp: 2026-11-13
Adaptive Mesh and Algorithm Refinement (AMAR) combines adaptive Cartesian meshes with automatic selection of kinetic or fluid solvers. It was introduced for rarefied gas dynamics and later extended to gas mixtures, particle and lattice-Boltzmann solvers, computational electroMAGNETics, and multi-phase flows. In weakly ionized plasmas, the species differ by orders of magnitude in mass, velocity, and time scale. This paper describes PAMAR, a plasma extension of AMAR in which electrons, ions, neutral species, and fields can have independent adaptive-mesh solvers, each with its own phase-space dimensionality, refinement criteria, and time step, coupled through a field solver in one executable built on the Basilisk framework. We present two demonstrations. A transient capacitively coupled plasma in argon is simulated with two-stream kinetic solvers for electrons and ions on independent adaptive quadtrees in $(x,v)$. The simulations resolve three electron groups and the time scales of electron and ion kinetics without statistical noise, at a cost between particle-in-cell simulations and fast kinetic models. A sphere at floating potential in a collisionless or weakly collisional plasma is computed with octree solvers in $(r,v,μ)$ for both species and compared with an exact method-of-characteristics solution. Per-species meshes resolve the cold ions at a tenth of the uniform-mesh cost. Both demonstrations also select the model cell by cell. In the capacitive discharge, a hybrid ion solver is kinetic in the sheaths and fluid in the bulk. Around the sphere, a hybrid electron solver confines the kinetic solver to the loss-cone layer and uses a Fokker-Planck model in position and total energy elsewhere. It conserves particles exactly across the interface and uses 1.6 to 5.3 times fewer cells. We discuss the next steps toward parallel, implicit simulations of higher-dimensional problems.
[abstract 49 / 62] (score: 2) - Title: Influence of Alfven wave turbulence dissipation in stellar winds of the Sun and M dwarfsAuthors: Kaito Suzuki, Takaaki Yokoyama, Munehito Shoda,Comments: 14 pages, 4 figures; accepted for publication in ApJSubjects: astro-ph.SRCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The physics of M-dwarf stellar winds is increasingly being investigated within the framework of wave-driven models. In the case of the solar wind, Alfven-wave turbulence (AWT) is believed to play a crucial role in heating and accelerating the plasma. In this study, we perform one-dimensional MAGNETohydrodynamic simulations of the solar and M-dwarf winds using a model that incorporates shock heating generated by mode conversion and treats AWT as an optional component. For the solar wind, we confirm that including AWT reproduces the observed predominance of outwardly propagating Alfven waves, supporting the role of turbulent dissipation in driving the wind. We further validate this AWT-driven solar wind directly against Parker Solar Probe observations, finding good agreement in both the location of the Alfven point and the level of the normalized cross helicity in the fast solar wind. In M-dwarf simulations, we find that AWT dominates the overall heating budget within the investigated parameter range. A parameter survey of coronal MAGNETic field strength reveals that the dependence of the mass-loss rate on Bcor differs qualitatively between cases with and without AWT, highlighting the importance of chromospheric dissipation. In the absence of AWT, the resulting mass-loss rates are broadly consistent with previous studies and observations. In contrast, when AWT is included, the mass-loss rate is significantly reduced because turbulent dissipation decreases the Alfven-wave (Poynting) flux entering the corona. These results suggest that the effects of chromospheric turbulence play a crucial role in modeling M-dwarf winds.
[abstract 50 / 62] (score: 2) - Title: Discovery of a likely supermassive neutron star in a remarkably wide binaryAuthors: Xinlin Zhao, Song Wang, Guang-Yao Xiao, Meng Sun, Roberto Soria, Kyle Akira Rocha, Seth Goggage, Pengfei Wang, Hongliang Yan, Xuan Mao, Yang Huang, Maosheng Xiang, Shuai Liu, Dan Qiu, Meng Zhang, Xue Li, Fabo Feng, Xihong Luo, Xiaohong Yang, Jifeng Liu,Comments: 88 pages, 15 figures, accepted for publication in Science AdvancesSubjects: astro-ph.HE astro-ph.SRCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Supermassive neutron stars ($M \gtrsim 2\ M_{\odot}$) provide stringent constraints on the equation of state of dense matter. We report the discovery of a wide binary system composed of a red giant star and an invisible companion with an orbital period $P\approx 1218\pm3$ days and a comparatively low eccentricity $e\approx 0.09\pm0.01$ (with $1 σ$ uncertainty). By combining radial velocity measurements from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope and the Apache Point Observatory Galactic Evolution Experiment (APOGEE) with astrometric data from {\it Gaia} DR2 and DR3 catalogues, we derive a Keplerian orbit with an inclination angle $i\approx73^{\circ}\pm11^{\circ}$. The unseen companion has a mass in the range of 1.8--2.8 $M_{\odot}$ (spanning the full spread of all estimates), with a best-fit value of $2.20^{+0.14}_{-0.13}$ $M_{\odot}$. This potentially places the unseen companion within the mass gap between neutron stars and BLACK HOLEs. Spectral disentangling using high-resolution near-infrared APOGEE spectra shows no absorption features from an additional component, suggesting the presence of a compact object: either a supermassive neutron star or a low-mass BLACK HOLE. The wide, low-eccentricity orbit is difficult to explain through standard binary evolution channels, pointing to the need for improved theoretical models to account for such systems.
[abstract 51 / 62] (score: 2) - Title: Fast Radio Burst Population Constrained by Source-Count Growth and Burst ClusteringAuthors: Shotaro Yamasaki, Tetsuya Hashimoto, Tomoki Wada, Tomotsugu Goto,Comments: 13 pages, 6 figures, submitted to ApJLSubjects: astro-ph.HECreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Whether all fast radio burst (FRB) sources repeat, or whether some produce only a single burst, remains an open question. Using 3,950 bursts from the CHIME/FRB Catalog 2, we measure how the numbers of apparently single and repeating sources change with observing time, correcting for the declination-dependent, beam-weighted exposure and possible variations in the detection rate. Both source counts increase approximately linearly over 300--44,000~hr, as $N_{\rm s}\proptoΔt^{0.98\pm0.02}$ for single sources and $N_{\rm r}\proptoΔt^{1.06\pm0.14}$ for repeaters. Consequently, the observed repeater fraction remains nearly constant at $2.6^{+0.4}_{-0.6}\%$. We interpret these results using population models that account for a distribution of detected burst rates and temporal clustering. The source counts are reproduced by a population spanning a range of rates, including sources expected to produce approximately one detectable burst over the observing time. Its detected burst rates follow a distribution close to $r^{-2}$ over 0.01--1.5~hr$^{-1}$. The burst timing and burst multiplicities provide additional constraints. Among 77 repeaters, only 6 have their first two detected bursts within a single CHIME transit, the median interval between them is 101 days, and 31 of the 52 repeaters with at least three bursts have five or more. These observations support this population and favor moderately clustered emission (Weibull shape $k\simeq0.5$) and active phases lasting months to about a year. Our results are consistent with both a single population of repeaters whose rate distribution steepens below the range probed by CHIME and a mixed population that includes genuinely one-off sources. Thus, the current data do not require a one-off population, but cannot exclude one. Longer observing baselines are needed to distinguish these possibilities.
[abstract 52 / 62] (score: 2) - Title: The SDSS-V Black Hole Mapper Reverberation Mapping Project: Short Lags in the COSMOS FieldAuthors: Zachary Stone, Yue Shen, Scott F. Anderson, Roberto Assef, Franz E. Bauer, W. N. Brandt, Joel R. Brownstein, Megan C. Davis, Jason Dexter, Tom Dwelly, Xiaohui Fan, Catherine J. Grier, Norman A. Grogin, P. B. Hall, Lorena Hernández-García, Keith Horne, Yasaman Homayouni, Anton M. Koekemoer, Dhanesh Krishnarao, Jennifer Li, Diego Mardones-Soto, Mary Loli Martínez-Aldama, Knox Long, Sean Morrison, Leonardo Olivares Latorre, Theodore Pena, B. M. Peterson, Donald P. Schneider, Benny Trakhtenbrot, Matthew J. Temple, Jonathan R. Trump, Qian Yang,Comments: 18 pages, 8 figures, 2 tables. Submitted to ApJSubjects: astro-ph.GACreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
We present the first reverberation mapping (RM) measurements in the COSMOS field included in the SDSS-V Black Hole Mapper Reverberation Mapping Project. Using $\sim$6 months of plate-based spectroscopy (from late 2020 to mid-2021) and accompanying ZTF+DECam \emph{gri}-band photometric light curves, we analyze the variability of over 250 ACTIVE GALACTIC NUCLEi (AGNs) out to $z \sim 3$. We successfully recover reliable $\lesssim$ 200d time lags for 22 AGNs ($z \lesssim 2.5$) in H$α$, H$β$, MgII, or CIV, using a combination of multiple lag detection methods and significance tests. Our measurements are consistent with the radius-luminosity relations from recent large-scale RM programs, providing measured masses of $10^{7-9} M_{\odot}$ for these AGNs. These results and upcoming long-baseline SDSS-V spectroscopy lay the groundwork for large-sample AGN studies in conjunction with other facilities covering the COSMOS field, including the Vera C. Rubin Observatory and Roman Space Telescope.
[abstract 53 / 62] (score: 2) - Title: Non-Gaussian matter fluctuations from primordial MAGNETic fields and galaxy luminosity functionAuthors: Teppei Minoda, Yi Mao, Shohei Saga, Hayato Shimabukuro,Comments: 14 pages, 8 figures, 1 table. Comments welcomeSubjects: astro-ph.CO astro-ph.GA astro-ph.HE gr-qcCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Primordial MAGNETic fields (PMFs) represent a promising candidate for the origin of large-scale MAGNETic fields observed in astrophysical environments. Through the Lorentz force, PMFs generate matter density perturbations, leaving distinct imprints on the formation of cosmic structures. While previous studies have primarily characterized these imprints via the matter power spectrum --- a two-point statistic --- we demonstrate that the one-point statistics of PMF-induced density fluctuations reveal an intrinsically non-Gaussian probability distribution function (PDF), even when the PMFs themselves are statistically Gaussian. In particular, we find that the high-density tail of the PDF is enhanced by over two orders of magnitude relative to the Gaussian case. Adopting the Press-Schechter formalism, we show that this non-Gaussianity significantly boosts the abundance of rare objects, especially massive halos and those at high redshifts. We further compute the ultraviolet luminosity function of galaxies at $z=6$, $12$, and $16$, and compare our predictions with recent James Webb Space Telescope (JWST) observations that have reported an excess of high-redshift galaxies at $z\sim 12$ -- $16$ relative to standard $Λ$CDM expectations. Intriguingly, in the limiting case where the total density field inherits this PDF, our results suggest that the non-Gaussian density fluctuations sourced by PMFs can explain the bright-end ($M_\mathrm{UV}\lesssim -18$) excess at $z\gtrsim 12$, without requiring additional astrophysical enhancements to star-formation efficiency.
[abstract 54 / 62] (score: 2) - Title: Benchmarking Machine-Learning Top Taggers from JetClass to a Full-Simulation $Z'\to t\bar{t}$ Search: Transfer, Extrapolation, Sensitivity and Inference CostAuthors: Manisha Kumari, Amal Sarkar,Comments:Subjects: hep-ex hep-phCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Searches for heavy resonances decaying to \(t\bar{t}\) test physics beyond the Standard Model at the TeV scale, and their reach depends on how well boosted top JETs are identified. Machine-learning top taggers are usually compared on fast-simulation samples without pileup and in a narrow JET-\(p_T\) window, so a benchmark ranking does not directly show how much each tagger adds to a real search. This study trains seven taggers under identical conditions on JetClass. They are a boosted decision tree, two image-based networks, ParticleNet, and three particle transformers (ParT, UParT, and GloParT). The taggers are then applied without retraining to a \(Z'\to t\bar{t}\) search with \(m_{Z'}\) between 1.2 and 2.5~TeV, using 2016 CMS Open Data simulated with Geant4 and realistic pileup. The overall benchmark order of the taggers is preserved. However, taggers with similar area under the ROC curve (AUC) differ by up to a factor of three in JET-level discovery significance. The particle transformers extend the mass reach of the search by \(400~\mathrm{GeV}\), and their lead grows with resonance mass. This gain is seen in fully merged top JETs and is associated with stable performance at JET \(p_T\) above the training range. Pileup has only a minor effect on all taggers. A small convolutional network achieves competitive discrimination at a much lower computational cost. The gaps between tagger groups hold under retraining and within statistical uncertainties. The results show that a tagger must be chosen on its kinematic coverage, the working point of the analysis, its discovery sensitivity and its cost, and not on its benchmark score alone.
[abstract 55 / 62] (score: 2) - Title: Sphere-based test cases for open boundary simulations in electrostatics and MAGNETostaticsAuthors: Marc Boulé,Comments: 18 pages, 9 figuresSubjects: physics.comp-phCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
This paper presents a library of sphere-based test cases for verifying the correctness of open boundary simulations in electrostatics and MAGNETostatics for computational physics and engineering applications. While the energy in the fields of a single sphere is computed for various source configurations, the energy, force and torque (when applicable) are also computed for a pair of spheres. An extension to electroMAGNETic momentum is also given for the single sphere, demonstrating its use as a benchmarking metric. Analytical expressions are provided for each test case, from which the validity of a simulation environment can be assessed. The finite element method is used as the example context, and four different open boundary methods are evaluated. Once verified, the simulation is used to visualize the Poynting vector field associated with an electric charge placed near a permanent MAGNET, a configuration for which no analytical expression is available. Simulation files are made available and all numerical experiments are reproducible with the ONELAB open source software.
[abstract 56 / 62] (score: 2) - Title: SFQED Cascade Saturation and Laser Depletion Dynamics In CP Rotating Laser Standing WavesAuthors: André Beverido, Thomas Grismayer, Marija Vranic,Comments: 16 pages, 12 figuresSubjects: physics.plasm-phCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Multi-petawatt LASER facilities are approaching the regime where colliding LASER pulses can spontaneously ignite self-sustained QED cascades, converting LASER energy into dense electron-positron plasmas. Using 1D PIC-QED simulations of a circularly polarized standing wave, we characterize the complete lifecycle of seeded cascades from exponential growth through RELATIVISTIC opacity and macroscopic LASER depletion. We show that cascade saturation is governed by the competition between pair creation and longitudinal lepton migration out of the MAGNETic nodes. The overdense plasma reflects the driving LASER, disrupting the standing wave and triggering secondary cascades in adjacent nodes, driving an apparent spatial expansion whose velocity scales linearly with the cascade growth rate. Finally, we generalize an analytical LASER absorption model to realistic time-dependent pulse envelopes, accurately reproducing the simulated conversion efficiency of LASER energy into gamma-ray photons and electron-positron pairs.
[abstract 57 / 62] (score: 2) - Title: Relaxation of Quantum Observables in a 4D Black Hole that forms from Collapse of a Null ShellAuthors: Shohreh Gholizadeh Siahmazgi, Anıl Zenginoğlu, Paul R. Anderson, Alessandro Fabbri,Comments: 19 pages, 1 figureSubjects: gr-qcCreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
The vacuum POLARIZATION and luminosity are computed in a four-dimensional spacetime where a spherically symmetric null shell contracts to form a BLACK HOLE. This is done by computing the contribution of the spherically symmetric modes of a massless minimally coupled scalar field to the quantities $\la ϕ^2 \ra_{\rm in} - \la ϕ^2 \ra_U$ and $L_{\rm in} - L_U$. Here the subscript ``in'' denotes the {\it in} vacuum state for the null shell spacetime and the subscript ``U'' denotes the Unruh state in Schwarzschild spacetime. The computation is done outside the null shell and outside the event horizon where the spacetime geometry is the Schwarzschild geometry. It is found that, as expected, these differences approach zero at late times. However, they do so significantly more slowly than in the two-dimensional case where there is no scattering of the mode functions. In both cases, the difference is dominated by a quasinormal mode at intermediate times and a tail term at late times that decays quartically in time. For the luminosity difference, an analytic calculation verifies the late-time result for the tail term.
[abstract 58 / 62] (score: 2) - Title: Euclid Data Release 1 (DR1). NISP spectroscopy of gravitational arcs and multiple imagesAuthors: Euclid Collaboration, P. Bergamini, P. Rosati, M. Meneghetti, M. Melloni, B. R. Granett, L. Tortorelli, A. Acebron, M. Annunziatella, G. Angora, M. Fogliardi, M. Fumana, M. Scodeggio, M. Talia, M. Bolzonella, A. Enia, E. Franceschi, C. Grillo, L. Bazzanini, S. M. Callegaro, G. Di Rosa, M. D'Addona, L. R. Ecker, R. Gavazzi, G. Granata, N. E. P. Lines, M. Lombardi, J. W. Nightingale, S. Schuldt, S. Serjeant, C. J. Storfer, S. H. Vincken, B. Altieri, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, A. Balestra, S. Bardelli, P. Battaglia, A. Biviano, E. Branchini, M. Brescia, J. Brinchmann, S. Camera, V. Capobianco, C. Carbone, J. Carretero, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, A. Costille, F. Courbin, H. M. Courtois, J. -G. Cuby, H. Degaudenzi, S. de la Torre, G. De Lucia, H. Dole, F. Dubath, X. Dupac, S. Dusini, S. Escoffier, M. Farina, R. Farinelli, S. Ferriol, F. Finelli, N. Fourmanoit, M. Frailis, L. Gabarra, S. Galeotta, K. George, B. Gillis, C. Giocoli, J. Gracia-Carpio, A. Grazian, F. Grupp, L. Guzzo, S. Gwyn, W. G. Hartley, S. V. H. Haugan, G. Helou, S. Hemmati, J. Hoar, H. Hoekstra, W. Holmes, F. Hormuth, A. Hornstrup, K. Jahnke, M. Jhabvala, S. Kermiche, A. Kiessling, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, A. M. C. Le Brun, V. Le Brun, D. Le Mignant, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, M. Magliocchetti, G. Mainetti, O. Mansutti, S. Marcin, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. J. Massey, N. Mauri, E. Medinaceli, S. Mei, E. Merlin, G. Meylan, J. J. Mohr, P. Monaco, A. Mora, M. Moresco, C. Moretti, L. Moscardini, E. Munari, C. Neissner, R. C. Nichol, S. -M. Niemi, C. Padilla, S. Paltani, F. Pasian, W. J. Percival, V. Pettorino, A. Pezzotta, S. Pires, G. Polenta, M. Poncet, L. A. Popa, L. Pozzetti, F. Raison, R. Rebolo, A. Renzi, J. Rhodes, G. Riccio, I. Risso, F. Rizzo, E. Romelli, M. Roncarelli, B. Rusholme, R. Saglia, Z. Sakr, D. Sapone, B. Sartoris, P. Schneider, T. Schrabback, A. Secroun, E. Sihvola, P. Simon, C. Sirignano, G. Sirri, L. Stanco, C. Surace, P. Tallada-Crespí, A. N. Taylor, I. Tereno, N. Tessore, S. Toft, R. Toledo-Moreo, F. Torradeflot, A. Tsyganov, I. Tutusaus, J. Valiviita, T. Vassallo, A. Veropalumbo, Y. Wang, J. Weller, A. Zacchei, G. Zamorani, E. Zucca, M. Ballardini, S. Borgani, E. Bozzo, C. Burigana, R. Cabanac, A. Cappi, F. Caro, T. Castro, D. Di Ferdinando, J. A. Escartin Vigo, J. García-Bellido, T. Gasparetto, C. M. Gutierrez, A. Loureiro, J. Macias-Perez, R. Maoli, R. B. Metcalf, A. A. Nucita, M. Pöntinen, E. Sarpa, V. Scottez, M. Sereno, M. Tenti, M. Tucci, M. Viel, M. Wiesmann, J. A. Acevedo Barroso, Y. Akrami, I. T. Andika, S. Anselmi, M. Archidiacono, G. Aricò, F. Atrio-Barandela, M. Baes, D. Bertacca, M. Bethermin, F. Beutler, L. Blot, H. Böhringer, M. L. Brown, S. Bruton, A. Calabro, B. Camacho Quevedo, C. S. Carvalho, Y. Charles, F. Cogato, T. E. Collett, S. Conseil, A. R. Cooray, P. Corcho-Caballero, B. Csizi, O. Cucciati, H. Dannerbauer, T. de Boer, G. Desprez, A. Díaz-Sánchez, S. Di Domizio, J. M. Diego, P. -A. Duc, V. Duret, M. Y. Elkhashab, Y. Fang, A. Farina, A. Finoguenov, A. Franco, Y. Fu, K. Ganga, E. Gaztanaga, Z. Ghaffari, F. Giacomini, F. Gianotti, G. Gozaliasl, A. Gruppuso, M. Guidi, A. Hall, N. A. Hatch, T. Heuberger, H. Hildebrandt, J. Hjorth, M. Jauzac, J. J. E. Kajava, Y. Kang, V. Kansal, D. Karagiannis, J. Kim, C. C. Kirkpatrick, A. Kovács, I. Kova{č}i{ć}, K. Koyama, S. Kruk, M. C. Lam, M. Lattanzi, G. Leroy, G. F. Lesci, J. Lesgourgues, L. Linke, G. Maggio, E. A. Magnier, F. Mannucci, F. R. Marleau, C. J. A. P. Martins, M. Miluzio, G. Morgante, K. Naidoo, P. Natoli, A. Navarro-Alsina, A. Nersesian, S. Nesseris, L. Nicastro, F. Oppizzi, F. Pace, E. Palazzi, D. Paoletti, F. Passalacqua, K. Paterson, C. Pattison, A. Pisani, D. Potter, G. W. Pratt, S. Quai, M. Radovich, F. Ricci, G. Rodighiero, W. Roster, M. Sahlén, D. B. Sanders, A. Schneider, D. Sciotti, E. Sellentin, F. Shankar, L. C. Smith, J. G. Sorce, S. A. Stanford, I. Szapudi, K. Tanidis, C. Tao, G. Testera, R. Teyssier, A. Troja, C. Uhlemann, C. Valieri, A. Venhola, D. Vergani, G. Vernardos, P. Vielzeuf, E. Vilenius, S. Vinciguerra, M. von Wietersheim-Kramsta, N. A. Walton, L. Wang, A. H. Wright, H. W. Yeung, D. Scott,Comments: Paper intended for the A&A Special Issue "Euclid First Data Release". 15 pages, 5 figuresSubjects: astro-ph.CO astro-ph.GACreated: 2026-11-11; Updated: 2026-11-13; Datestamp: 2026-11-13
Applications of strong gravitational lensing in astrophysics and cosmology critically depend on building reliable strong lensing models, which require accurate measurements of on-sky positions of multiple images and of the redshifts of the background sources from which they originate. In this context, Euclid is a unique facility, as it simultaneously provides high-resolution multi-band photometric imaging and slitless spectroscopy for an unprecedentedly large sample of gravitational lenses, most of which are newly discovered. In this work, we exploit Euclid slitless spectroscopic data to determine the redshifts of four spatially extended lensed sources, and to reconstruct emission-line images. Specifically, two of the target sources are lensed into giant arcs by the massive galaxy clusters SPT-CLJ0411$-$4819 ($z_\mathrm{d}=0.424$, where "d" denotes the lensing deflector) and Abell 2280 ($z_\mathrm{d}=0.326$). The third system is a quadruply imaged ACTIVE GALACTIC NUCLEus (AGN) candidate strongly lensed by a massive galaxy at $z_\mathrm{d}=0.68$, while the fourth is a galaxy-scale Einstein ring produced by a lens galaxy at $z_\mathrm{d}=0.235$. This work represents a proof of concept for the exploitation of Euclid slitless spectroscopic data in the study of strong gravitational lensing, providing one of the first determinations of spectroscopic redshifts for strongly lensed features from NISP spectra. These results demonstrate the feasibility of applying the same methodology to the very large sample of gravitational lenses that Euclid has started to discover and is expected to identify over the course of the mission.
[abstract 59 / 62] (score: 2) - Title: Hump around 30 keV in SUZAKU spectra of Aquila X-1 -- Possible evidence of strong rapid-proton capture process --Authors: M. Kubota, A. Dohi, T. Tamagawa, K. Makishima, S. Fujimoto,Comments: Accepted for publication in the Astrophysical Journal; 11 pages with 5 figuresSubjects: astro-ph.HECreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
In a neutron star low-mass X-ray binary, heavy elements (with mass number ~100) are believed to be synthesized through the rapid-proton (rp) capture process, as indirectly indicated by the long tail of X-ray burst light curves. Although direct evidence for the rp-process was lacking so far, we reported in our previous study that an unidentified hump is present at ~30 keV of the SUZAKU spectra of Aquila X-1 in its hard state. The feature was tentatively identified with a recombination quasi-continuum from highly ionized ions of cadmium or indium, which are possibly produced by the rp process during X-ray bursts and lifted up into the neutron-star atmosphere. To reinforce this scenario, we quantitatively evaluated the physical conditions of the assumed emitting region in the atmosphere, and confirmed that the scenario is possible when the putative rp-process ashes in the atmosphere has ~10^7 times higher abundances than their solar values. The results are compared with theoretical model calculations for the nucleosynthesis in X-ray bursts. We suggest that the observed spectral hump is a radiative recombination feature from the stable isotope 106Cd, produced in X-ray bursts via the rp-process. Further issues about the detectability are briefly discussed.
[abstract 60 / 62] (score: 2) - Title: B-fields And Dust in InterstelLar FiLAments Using Dust POLarization (BALLAD-POL): V. Magnetic Fields and Grain Alignment Mechanisms in Serpens Main Using JCMT/POL-2 PolarizationAuthors: Sadhana Singh, Thiem Hoang, Pham Ngoc Diep, Nguyen Bich Ngoc, Woojin Kwon,Comments: Accepted for publication in ApJ. 22 Pages, 17 FiguresSubjects: astro-ph.GACreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
We investigate MAGNETic fields ($B$-field) and grain alignment mechanisms in Serpens Main using 850 $μ$m dust POLARIZATION observations from JCMT/POL-2. We derive a map of $B$-field strength and calculate the mass-to-flux ratio and Alfvénic Mach number, suggesting the subdominance of $B$-fields over gravity but their dominance over turbulence. Fitting the Ricean mean model to the nondebiased POLARIZATION fraction ($P$) as a function of emission intensity ($I$) yields a slope $α= 0.68\pm0.01$, revealing dePOLARIZATION. To understand its origins, we examine the dependence of $P$ on gas column density ($N({\rm H}_{2})$), dust temperature ($T_{\rm d}$), and POLARIZATION angle dispersion function ($S$). We find no correlation between $P$ and $S$, whereas for $P\times S$, an observational proxy for alignment efficiency decreases with increasing $N({\rm H}_{2})$. This suggests that $B$-field tangling is not the primary cause of dePOLARIZATION and instead points to reduced grain alignment in denser regions. To test this interpretation within radiative torque (RAT) alignment theory, we calculate the minimum size of aligned grains ($a_{\rm align}$) and MAGNETic relaxation strength ($δ_{\rm mag,sp}$) using $N({\rm H}_{2})$, $T_{\rm d}$, and our estimated $B$-field map. We find that both $P$ and $P \times S$ decrease with increasing $a_{\rm align}$, supporting reduced grain alignment as the main cause of dePOLARIZATION in Serpens Main. However, neither $P$ nor $P \times S$ shows a correlation with $δ_{\rm mag,sp}$, suggesting that enhanced grain alignment due to MAGNETic relaxation is insufficient to compensate for the reduced alignment associated with increasing $a_{\rm align}$ toward denser regions.
[abstract 61 / 62] (score: 2) - Title: Polarized transport in a Thomson slab: Stokes recursion, asymptotic eigenmodes, and Comptonization applicationsAuthors: Haichao Xu,Comments: 34pages, 16 figures, submitted to MNRASSubjects: astro-ph.HECreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
We develop a scattering-order-resolved Stokes-vector recursion for axisymmetric polarized transport in a finite plane-parallel Thomson slab. The post-scattering radiation field closes exactly within two depth-dependent coefficients, yielding escape probabilities, angular distributions and linear POLARIZATION while conserving photon number. At high scattering orders, the principal eigenmode of the weighted self-adjoint transport operator controls the escape statistics, and the normalized angular distribution and POLARIZATION become independent of the seed source. The subdominant spectrum quantifies convergence, with the characteristic scattering order scaling as the square of the optical depth in thick slabs. We derive logarithmic corrections to the thin-slab complete-POLARIZATION limit away from the slab normal, together with a finite-optical-depth Galerkin approximation. In optically thick slabs, matching bulk diffusion to a polarized Milne surface layer yields finite-thickness corrections to the Chandrasekhar solution. We provide compact formulae for the principal and leading subdominant eigenvalues and the asymptotic angular and POLARIZATION distributions across both regimes. Combining the recursion with an angle-averaged thermal-Compton redistribution kernel gives approximate energy-resolved Stokes spectra. Comparisons with full polarized Compton calculations show that this separable reconstruction is most reliable for cool, optically thick media. Applied to the non-dipping observations of neutron-star low-mass X-ray binary system 4U 1624-49, the model provides acceptable joint fits to the broadband intensity and IXPE Stokes spectra, showing that an extended corona overlying the accretion disc can account for the observed X-ray POLARIZATION.
[abstract 62 / 62] (score: 2) - Title: Residual ellipticity driven by intense MAGNETic stress in the hot neutron star eraAuthors: Yasufumi Kojima, Akira Dohi, Kotaro Fujisawa, Shota Kisaka,Comments: 13 pages, 6 figuresSubjects: astro-ph.HE gr-qcCreated: 2026-11-12; Updated: 2026-11-13; Datestamp: 2026-11-13
A neutron star with a nonaxisymmetric mass distribution continuously radiates gravitational waves. The amplitude depends on the magnitude of the deformation, and is crucial for gravitational-wave astronomy. We studied an evolutionary effect on the MAGNETically induced ellipticity in the neutron star crust. A large deformation at the hot era before solidification is assumed to be produced MAGNETo-hydrodynamically, and the fate at later time follows owing to the decrease in the force associated with the decay and redistribution of the current. Instead of simulating the evolution of deformation with the MAGNETic field over a long timescale, we estimate the ellipticity that remains after the formation of the solid crust by comparing two equilibrium models before and after solidification. The relic ellipticity is $\sim 10^{-8} (B_0/10^{13}{\rm{G}})^2$ in the magnitude for dipole field strength $B_{0}$ at the surface. This value was primarily determined by the MAGNETic field at the later time, with a weak dependence on the initial large deformation. The memory of the presolidification state was retained, but was small because the elastic force contributes little to the equilibrium.
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