Current date: 2026-11-02
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Datestamp limit: 2026-11-02 (0 days ago)
Created/updated limit: 2026-10-26 (7 days ago)
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Scoring abstracts
Number of records retrieved: 628
Keyword score statistics
score 9 -- 1 abstracts
score 7 -- 3 abstracts
score 6 -- 1 abstracts
score 5 -- 3 abstracts
score 4 -- 9 abstracts
score 3 -- 4 abstracts
score 2 -- 21 abstracts
in total -- 42 abstracts
Articles that appeared on 2026-11-02
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[abstract 1 / 42] Wow! (score: 9)
- Title: Gamma-Ray Emission from LS 5039: A 30-500 GeV Excess and Phase-Resolved Broadband Spectral ModelingAuthors: Xiaozhen Zhao, Jiandong Zhang, Pengfei Zhang,Comments: 14 pages, 6 figures, Submitted to ApJSubjects: astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
LS~5039 is a well-studied $γ$-ray binary exhibiting strong orbital modulation from GeV to TeV energies. We present a phase-resolved analysis of 17.3~yr of \textit{FERMI}-LAT observations and identify an additional $γ$-ray excess in the $\sim30$--$500$~GeV at a significance of $\sim7.9σ$. The phase-resolved spectra show pronounced orbital dependence above $\sim10$~GeV, with the inferior-conjunction more complex than the superior-conjunction. To investigate the broadband spectral energy distribution, we combine the \textit{FERMI}-LAT spectra with published H.E.S.S.\ and HAWC measurements and compare purely leptonic and lepto-hadronic models using the Bayesian information criterion. In both intervals, RELATIVISTIC-Maxwellian and MAGNETospheric components dominate below $\sim10$~GeV, while shock-accelerated electrons account for much of the GeV--TeV continuum. The purely leptonic fits leave residuals at $30$--$500$~GeV and underpredict the HAWC measurements above $\sim100$~TeV. In the local one-zone intrabinary shock apex model, SYNCHROTRON cooling and Klein-Nishina suppression make the ultra-high-energy emission difficult to reproduce, although more complex leptonic scenarios remain possible. Adding a phenomenological proton component improves the broadband description, with stronger relative support during superior-conjunction than inferior-conjunction. However, the proton parameters remain weakly constrained and the fast-escape hadronic interpretation is energetically challenging, so a hadronic origin is not uniquely established. Future high-sensitivity, phase-resolved observations at multi-TeV and ultra-high energies will be required to test this interpretation.
[abstract 2 / 42] Wow! (score: 7) - Title: GRB 241113B: the first SVOM and EP GAMMA-RAY BURST A soft GRB likely seen on-axis, from soft X-rays to gamma-raysAuthors: D. Adrien, D. Turpin, T. Maiolino, F. Daigne, F. Piron, Z. -H. Yao, Q. Wu, C. -Y. Dai, A. V. Filippenko, B. Schneider, B. Kumar, B. Cordier, F. Cangemi, A. Coleiro, M. G. Bernardini, N. Dagoneau, Y. -L. Qiu, L. -P. Xin, H. -L. Li, H. Sun, X. -P. Xu, Z. -Y. Liu, M. -Q. Huang, M. -H. Zhang, W. Yuan, W. -K. Zheng, G. Mo, X. Liu, Y. Fang, G. -W. Du, S. Guillot, X. -W. Yu, R. Leticia Becerra, J. -Y. Wei, S. Basa, J. Wang, L. Bouchet, X. -H. Han, M. Brunet, C. Wu, S. Crepaldi, H. -B. Cai, O. Godet, Y. Xu, D. Götz, P. -P. Zhang, A. Saccardi, Y. -J. Xiao, S. Vergani, S. -N. Zhang, S. -L. Xiong, Y. -W. Dong, J. -T. Liu,Comments: 24 pages, 16 Figures, submitted for publication in A&ASubjects: astro-ph.HECreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
In 2024, two new missions were launched to detect high-energy transients. EP and SVOM aim to observe soft transients from X-ray rich GAMMA-RAY BURSTs (XRR), X-ray flashes (XRF), to fast X-ray transients (FXT). GRB 241113B, the first soft GAMMA-RAY BURST (GRB) jointly detected by EP and SVOM from soft X-rays to gamma-rays (0.5--1000~keV). GRB 241113B has an $E^{obs}_{peak} \approx 35$ keV and a redshift (z) likely between 0.5 and 3.5, with $T_{90,γ} \approx 42$~s (4--30~keV). This burst can be classified as either an XRR or XRF, depending on the fluence ratio used. The afterglow is achromatic and featureless with a normal decay ($α\approx -1.40$). The prompt emission does not satisfy the shock-breakout relation, and thus a geometry comprised of a JET is preferred. However, the afterglow fitting favors a JET viewed on-axis dominated by SYNCHROTRON emission due to electrons in a slow cooling regime, interacting with a wind medium. The bulk Lorentz factor ($Γ$) indicates that the motion of the JET is ultraRELATIVISTIC ($Γ_{0}>100$), which discards the dirty fireball model. Hence, the JET baryon loading should be compatible with that of classical GRBs (C-GRBs). The prompt spectral properties of GRB 241113B ($α$, $E^{\mathrm{obs}}_{\mathrm{peak}}$, $E_{γ,iso}$) are comparable to those of XRFs/XRRs and are in the continuity of the C-GRB distributions, setting it apart from the extragalatic FXT population solely detected by EP. Hence, the SVOM mission, with the benefit brought by the instrument ECLAIRs with its high sensitivity and low energy threshold (at 4keV), is able to detect the potential $γ$-ray counterpart of soft transients also observed by EP and help to differentiate them from FXTs. The latter show the interest of the joint operation of both missions to better study the landscape of soft transients.
[abstract 3 / 42] Wow! (score: 7) - Title: Enhanced Detectability of Very-High-Energy Gamma Rays from Off-Axis Short Gamma-Ray Bursts: Impacts of Structured Jets and External Inverse-Compton ScatteringAuthors: Yuri Sato, Bing Theodore Zhang, Kohta Murase,Comments: 9 pages, 4 figuresSubjects: astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
The binary neutron star merger GW170817 established a direct link between gravitational waves and short GAMMA-RAY BURSTs (sGRBs), whose afterglows are commonly interpreted as nonthermal emission from structured RELATIVISTIC JETs viewed off-axis. Some sGRBs exhibit extended or plateau X-ray emission, suggesting prolonged central-engine activity. These X-ray photons can serve as seed photons for external inverse-Compton (EIC) scattering by RELATIVISTIC electrons in the JET, producing very-high-energy (VHE) gamma rays. However, how the angular structure of the JET affects the detectability of EIC emission remains insufficiently explored. Here, we investigate EIC emission from off-axis structured JETs and assess its detectability with the Cherenkov Telescope Array Observatory (CTAO). We find that EIC emission powered by extended and/or plateau X-rays produces detectable VHE signals from nearby sGRBs, particularly during the early afterglow, significantly outshining SYNCHROTRON self-Compton emission. In our adopted models, Gaussian and power-law JETs produce brighter off-axis EIC emission than a top-hat JET, extending the viewing-angle range over which VHE emission may be detectable. These results demonstrate that early VHE observations with CTAO can probe both prolonged central-engine activity and the angular structure of RELATIVISTIC JETs in sGRBs.
[abstract 4 / 42] Wow! (score: 7) - Title: Disk-Corona Energy Balance Evolves with Flux State in the Quasar PDS 456Authors: Fida Fathima S S, Arijit Sar, Tathagata Saha, Ritaban Chatterjee,Comments: Manuscript under review at The Astrophysical JournalSubjects: astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
We investigate the long-term X-ray spectral evolution of the highly luminous, radio-quiet QUASAR PDS 456 using AstroSat observations obtained in 2019 and 2021 together with archival XMM-Newton, NUSTAR and SUZAKU observations spanning 2001-2024. The AstroSat observations provide valuable coverage following the bright flaring state observed in 2018, revealing that the source underwent a relatively quiescent phase in 2019 before re-brightening in 2021. During the AstroSat epochs, PDS 456 exhibits a harder-when-brighter spectral trend, whereas the long-term XMM-Newton, NUSTAR, and SUZAKU observations confirm the overall softer-when-fainter behavior. This behavior is consistent with the presence of a very cool corona (~15 keV), possibly driven by a strong incident photon field for upscattering, as suggested by a prominent big blue bump. Broadband spectral modeling of simultaneous XMM-Newton and NUSTAR observations, complemented by the 2021 AstroSat flaring epoch and interpreted within the self-consistent physical framework reXcor, indicates that the disk-corona energy balance evolves with flux. In low-flux states, the spectrum is reflection-dominated, implying efficient illumination of the inner accretion disk by a compact corona. In contrast, high-flux states show an enhanced contribution from the warm Comptonizing region at larger coronal heights. The Fe Kα emission line displays a positive correlation with the 2-10 keV continuum flux at low to intermediate flux levels, while deviations at the highest flux states suggest a reduced relative reflection contribution as the warm corona becomes energetically dominant.
[abstract 5 / 42] Yes (score: 6) - Title: Spectroscopic observations of periodic bursty ejections during a dome-spire-shaped JETAuthors: Heesu Yang, Maria S. Madjarska, Kyoung-Sun Lee, Klaus Galsgaard,Comments:Subjects: astro-ph.SR physics.plasm-ph physics.space-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Context: The study investigates the complexity of the formation and evolution of a dome-spire-shaped JET (or anemone JET) that originated in an active region and was presumably driven by null-point MAGNETic RECONNECTion. Aims: We aim to provide a quantitative estimation of multi-temperature plasma dynamics and physical parameters of the JET and its blob-like features, together with its temporal evolution in three-dimensional perspective. Methods: For this, we analyze unique sit-and-stare spectral (Si IV, Mg II k, and C II) and slit-jaw imaging 1400 Å and 2796 Å observations obtained with the Interface Region Imaging Spectrograph (IRIS), with a slit uniquely positioned just above the assumed RECONNECTion site. Co-observations taken with the Fast Imaging Solar Spectrograph of the Goode Solar Telescope in the chromospheric H$α$ and Ca II 8542.10 Å lines were also analyzed. These data are complemented by EUV imaging information from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. Results: The IRIS observations reveal that the JET is formed by multiple periodic ($\sim$30 s) plasma ejections with blob-like appearance, each associated with strongly blueshifted Si IV 1402.77 Å transition-region emission reaching about $-300$ km/s. More importantly, the ejections are grouped into well-defined packets, each lasting approximately 3--5 min. In contrast, only a single Doppler component is observed in the chromospheric Ca II line. Multi-Gaussian decomposition of the Si IV line profiles reveals a highly accelerated plasma, with line-of-sight speed toward the observer increasing linearly from $\sim$30 to 112 km/s over 66 s, corresponding to an acceleration of 1.3 km/s$^2$. The kinetic energy release rate is estimated in the range of $\sim$1.0$\times10^{24}$--1.0$\times10^{25}$ erg\,s$^{-1}$.
[abstract 6 / 42] Yes (score: 5) - Title: Ultra-long simulations of collisionless RELATIVISTIC shocks in front-comoving frame: evidence for a steady state and its propertiesAuthors: Mikhail Garasev, Evgeny Derishev,Comments: 18 pages, 13 figures, PRD accepted versionSubjects: astro-ph.HE physics.plasm-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
We present a series of unprecedently long 2D3V PIC simulations of unMAGNETized RELATIVISTIC $e^{-}e^{+}$-pair shocks performed in a front-comoving frame. By implementing a moving-wall boundary condition in the downstream together with continuous injection at the upstream boundary, we maintain a fixed simulation domain size, opening the way to perform substantially longer simulations. Our longest runs extend beyond $100000\,ω_p^{-1}$, exceeding the duration of the previously published simulations by a factor of several. Across a diverse set of simulations --- varying upstream/downstream lengths, transverse sizes, and particle-per-cell counts --- we find strong evidence that the shock, {modelled for a long-time in the front-comoving frame,} approaches an asymptotic, time-independent state. In the downstream region, the steady state depends only on the upstream temperature at the injection boundary and {remains the same if we change the downstream and upstream lengths.} The upstream precursor evolves slower and retains a dependence on the simulation's upstream length, that may be of minor observational consequence, since radiation from astrophysical shocks predominantly originates from the downstream region. {Our simulations also indicate} that FERMI-type acceleration is limited in energy and a true power-law tail never forms. Another important finding is that the downstream MAGNETic field has a soliton-like structure, where individual MAGNETic domains evolve independently, each comprising a compact, highly MAGNETized core embedded within an extended, weakly MAGNETized region. The MAGNETic-field distribution around the centers of these spots has approximately Lorentzian profile.
[abstract 7 / 42] Yes (score: 5) - Title: The Peculiar Astrometric Behaviour and Radio Structure of the Quasar 1524-136 Revealed with Very Long Baseline InterferometryAuthors: Angelina Osetrova, Sándor Frey, Oleg Titov, Alexey Melnikov, Panna Gelle,Comments: 22 pages, 5 figures, accepted for publication in the journal SymmetrySubjects: astro-ph.GACreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
According to astrometric very long baseline interferometry (VLBI) observations accurate to sub-milliarcsecond levels, the radio QUASAR 1524-136 (J1526-1351) exhibited an exceptionally large shift, more than 0.1", between the 1990s and 2010s. This luminous QUASAR is known for its extended (~0.4"), highly asymmetric and non-collinear JET structure. Here we analyse historical VLBI astrometric and imaging data, as well as Gaia optical astrometric information, to find the cause of the sudden apparent change in the position. At the X band (~8.4 GHz frequency), where radio positions are conventionally measured, the core region brightened substantially relative to the hotspot at the end of the northern JET. As a result, the brightness peak shifted from the hotspot to the core, causing the VLBI position to shift accordingly. Similar changes could affect the astrometric positions of other radio sources. A better understanding of the astrophysical reasons behind them is important for maintaining the stability of the VLBI-based celestial reference frame.
[abstract 8 / 42] Yes (score: 5) - Title: Bridging Scales: Multi-Zone GRMHD-Informed Anisotropic AGN Feedback in GalaxiesAuthors: Kung-Yi Su, Hyerin Cho, Priyamvada Natarajan, Claude-André Faucher-Giguère, Ramesh Narayan, Angelo Ricarte, Antonio J. Porras-Valverde, Cora Prather, Philip F. Hopkins,Comments: 19 pages, 8 figures, 3 tablesSubjects: astro-ph.GA astro-ph.HECreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
We present a galaxy-scale BLACK HOLE (BH) accretion and feedback model incorporating results from multi-zone general RELATIVISTIC MAGNETohydrodynamic (GRMHD) simulations spanning the event horizon to the Bondi radius. The model replaces a fixed suppression of the Bondi rate with a nuclear-environment-dependent factor, $κ^{\rm hot}_{\rm cho}$, set by the local ratio of Bondi to gravitational radius, and distributes outflow mass, kinetic energy, and thermal energy according to the angular structure measured in the large-dynamic-range GRMHD calculations. We apply it to idealized isolated simulations of an M87*-like massive elliptical and a Milky Way/Sgr A*-like galaxy, spanning over three orders of magnitude in BH mass without tuning accretion or feedback efficiencies to match observables. In the M87*-like system, the GRMHD-informed angle-dependent feedback model suppresses late-time stellar mass growth more effectively than the isotropic reference model, despite similar long-term BH accretion rates. Varying the uncertain mass loading of the collimated polar component has a modest impact on BH growth and STAR FORMATION, indicating that feedback anisotropy matters more than its detailed mass loading. We find that $κ^{\rm hot}_{\rm cho}$ varies with nuclear environment and time, yielding BH growth histories markedly different from fixed-suppression models. For Sgr A*, this variable factor yields an accretion rate more consistent with Event Horizon Telescope (EHT) constraints than a fixed, suppressed Bondi model. These results show that nuclear-environment-dependent accretion and feedback angular structure affect BH-galaxy evolution, requiring subgrid models to include more than a universal Bondi suppression factor and a scalar feedback efficiency.
[abstract 9 / 42] Yes (score: 4) - Title: The Geometric Crisis in Cygnus~X-3: Limitations of Wind-Fed Accretion and the Case for Roche-Lobe OverflowAuthors: Nicholas E. White,Comments: Accepted for publication in the Astrophysical Journal. 17 Pages, 2 Figures, including 2 Appendices and an erratumSubjects: astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Cygnus~X-3 is a Galactic X-ray binary with a 4.8-hr orbital period operating in the ultraluminous regime. Although the system is viewed at relatively low inclination ($i\approx28^\circ$), it exhibits a deep orbital modulation. Recent IXPE observations show strong linear POLARIZATION orthogonal to the radio JET, indicating that the X-ray emission is dominated by reflection from the inner walls of a supercritical outflow funnel. We propose a Hybrid Roche-lobe overflow (RLOF) scenario in which a massive Wolf-Rayet donor effectively fills its Roche lobe with a focused wind driving a super-Eddington accretion stream. Using a numerical synthesis of the folded light curve, we show that the modulation is reproduced when the central funnel is periodically occulted by a vertically extended, shock-heated Turbulent Wall formed by stream impact on the outer disk rim. This produces a phase lag ($Δϕ\approx0.11$) between X-ray minimum and binary conjunction, with extended attenuation by the WR wind defining a broader Suppression Region. This geometry explains the enhanced iron-line equivalent width during X-ray minimum via a coronagraphic effect. The large radial-velocity amplitude of FeXXVI measured by XRISM ($K_{\rm obs}\approx430$ km s$^{-1}$) and its zero-crossing at $ϕ_X=0.0$ arise naturally in the stream-impact region rather than from orbital motion of the compact object. Finally, we show that the observed secular orbital expansion ($\dot P>0$) follows directly from highly non-conservative mass transfer with inner-disk mass loss, indicating that Cygnus~X-3 is a stable, long-lived system in a supercritical accretion regime.
[abstract 10 / 42] Yes (score: 4) - Title: The pulsar population of Omega Centauri: New TRAPUM searches, timing, and cluster dynamics with MeerKAT and ParkesAuthors: Miquel Colom i Bernadich, Shi Dai, Federico Abbate, Matthew Kerr, Matteo Bachetti, Yash Bhargava, Sarah Buchner, Simon Johnston, Marta Burgay, Andrea Possenti, Rouhin Nag, Alessandro Ridolfi, Amodio Carleo, Alessandro Corongiu, Paulo C. C. Freire, Fernando Camilo, Weiwei Chen, Mario Cadelano, Dhanraj Risbud, Prajwal V. Padmanabh, David J. Champion, Michael Kramer, Benjamin Stappers, Maciej Serylak, Vishnu Balakrishnan, Matthew Bailes, Arunima Dutta, Laila Vleeschower Calas, Vivek Venkatraman Krishnan, Yunpeng Men, Ewan Barr,Comments: Submitted to A&A on March 03, 2026; accepted on October 10, 2026. 26 pages (17 pages main text, 9 pages appendices), 13 figuresSubjects: astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Millisecond pulsars (MSPs) are probes of globular clusters, tracing their stellar evolution, cluster dynamics, and gravitational potential. We searched for and timed MSPs in the Omega Centauri, then investigated their high-energy emission, the cluster potential, and MSP demographics. We performed Fourier-domain acceleration and jerk searches on MeerKAT observations, followed by pulsar timing using MeerKAT and Parkes Murriyang data spanning 2021-2025. We discovered the new isolated MSP PSR J1326-4728S (PSR S, Ps=4.538 ms and DM=96.24 pc/cm3. We updated the timing solutions for PSRs A-E, obtained the first timing solutions for G, H, and K, and updated the orbital parameters for I, L, N, and Q. The latter three, I, N, and Q, have significantly longer orbital periods (Pb=1-7 days) than previously reported. Pulsars B, G, H, K, and L are black widows (Pb=2-4 hours); I is a wide-orbit (Pb=3.50 days) MSP with a light ~0.05 Mo companion; N and Q have ~0.25 Mo companions; and N shows a significant orbital eccentricity (e=0.093). We folded FERMI-LAT and NICER photons to search for high-energy pulsations, but failed to detect them from individual MSPs. Significant spin period derivatives were measured for eight MSPs and interpreted as arising from the cluster gravitational potential. The inferred line-of-sight accelerations are consistent with a King-model gravitational potential, and allow us to set an upper central BLACK HOLE mass limit of Mbh<8e4 Mo at 90% confidence. The high fraction of isolated MSPs (58%) and black widow systems (63% of binaries), and possibly the eccentricity of N, are difficult to reconcile with MSP population predictions based solely on encounter rates. Instead, these properties require alternative formation channels or reflect the complex evolutionary history of Omega Centauri, with part of its MSP population having formed in denser environments than those observed today.
[abstract 11 / 42] Yes (score: 4) - Title: Cosmic merger rates and population evolution of binary BLACK HOLE mergers in AGN disksAuthors: Maria Paola Vaccaro, Alessandro Trinca, Michela Mapelli, Lumen Boco, Raffaella Schneider, Rosa Valiante, Dominika Wylezalek,Comments: 18 pages, 11 figuresSubjects: astro-ph.HE astro-ph.COCreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
Active galactic nuclei (AGN) disks are promising sites for hierarchical binary BLACK HOLE (BBH) mergers, which next-generation gravitational-wave detectors will probe out to high redshift. Predicting their contribution requires linking BBH evolution in AGN disks to the poorly constrained high-redshift evolution of active supermassive BLACK HOLEs (SMBHs). We introduce ARISE (AGN Rates and Intrinsic Stellar-BH Evolution), a framework that embeds semi-analytical models of BBH evolution in AGN disks into a cosmological description of the AGN number density, SMBH mass function, Eddington-ratio distribution, and nuclear metallicity. We consider a conservative AGN-abundance model anchored to observed luminosity functions, as well as Eddington-limited and super-Eddington scenarios based on the CAT cosmological model, compatible with JWST observations of high-redshift AGNs. The merger-rate density is set primarily by the disk viscosity parameter $α$: at $z = 0.2$, we find a rate of $12$--$37$ Gpc$^{-3}$ yr$^{-1}$ for $α= 0.01$ and $0.5$--$6$ Gpc$^{-3}$ yr$^{-1}$ for $α= 0.1$. The redshift evolution depends strongly on how SMBHs grow. The rate density peaks at $z \simeq 1.8$, $3.3$, and $3.9$ ($1.5$, $3.6$, and $3.9$) for $α=0.01$ ($0.1$) in the conservative, Eddington-limited, and super-Eddington models, respectively, and in the super-Eddington model it stays nearly flat out to $z \simeq 10$. For $α= 0.1$, AGN disks account for $\sim 2$--$40\%$ of the LVK-inferred merger rate, consistent with current upper limits from GW--AGN associations. For $α= 0.01$, they match or exceed it. The Einstein Telescope (ET) should detect $\sim 10^{5}$ ($\sim 10^{4}$) AGN-disk mergers per year for $α= 0.01$ ($0.1$). ET will test the AGN channel at redshifts where the AGN population models differ most strongly, providing independent constraints on the growth of early SMBHs.
[abstract 12 / 42] Yes (score: 4) - Title: How to feed your dragon: the role of turbulence in AGN activityAuthors: Olga Borodina, Jake S. Bennett, Yueying Ni, Rainer Weinberger, Michaela Hirschmann, Boon Kiat Oh, Lars Hernquist,Comments: 18 pages, 11 figures, accepted in ApJSubjects: astro-ph.GACreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
Active galactic nuclei (AGN) are thought to be important drivers of galaxy evolution. However, the way AGN JETs couple their energy to the interstellar medium (ISM) remains poorly understood. Recent observations have revealed $\sim$kpc-scale JETs in galaxies of different morphological types. Here, we use idealized turbulent box simulations with accreting BLACK HOLEs to investigate how JET-ISM interactions and feedback shape the evolution of JETs. We show that a turbulent ISM is a key ingredient in both JET launching and JET propagation. Without turbulence, JET feedback initially shuts off the cold gas supply to the BLACK HOLE and the system enters a steady state with JET power $\leq 10^{39}\,\mathrm{erg\,s^{-1}}$ for a $10^{6}\,\mathrm{M}_\odot$ BLACK HOLE. In a turbulent medium, JETs fill voids with hot diffuse material which the turbulence then carries away, replenishing the BLACK HOLE's fuel supply. However, above a critical JET efficiency factor, the JET begins to significantly deplete its fuel supply and enters a self-limiting accretion regime. This critical factor depends on the ISM Mach number, with lower turbulence yielding a lower threshold. Moreover, while the JET power depends on the ambient gas density in the vicinity of the BLACK HOLE, we find that, at fixed turbulent structure, the morphology and extent of JET propagation are largely insensitive to the average background density; turbulence in the ISM dominates over mean density in setting how far JETs propagate, although denser media experience higher total energy injection and stronger heating.
[abstract 13 / 42] Yes (score: 4) - Title: HAWC, FERMI-LAT and Chandra Detections of High Energy Particles in the S106 Star Forming RegionAuthors: Rishi Babu, Stephen DiKerby, Tulun Ergin, Shuo Zhang, Mehr Un Nisa, the HAWC Collaboration,Comments:Subjects: astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Local star-forming regions have recently been the subject of scrutiny as cosmic-ray accelerators and sources of ultra-high-energy gamma-ray emissions. The Cygnus-X region is one of the richest star forming regions in the galaxy and over the last few decades has been extensively studied. Here we report the detection of a star-forming region located in the southern part of Cygnus-X, Sharpless 106 (S106), using the HAWC Observatory. The S106 region is spatially located near the cataloged gamma-ray source 1LHAASO J2027+3657. In this work, we perform a multi-wavelength analysis of S106, by combining HAWC data with re-analysis of FERMI-LAT and archival Chandra data. We construct a fully leptonic model for the multi-wavelength emission from S106 from a single population of high-energy leptons, with the gamma-rays greater than 1 TeV being produced by inverse Compton scattering of the locally-produced IR photon field from S106 itself. Our models show that hadronic mechanisms are not always required to explain the observed flux from gamma-ray star-forming regions and that understanding the specific details of local photon fields is crucial to modeling the multi-wavelength emission from star-forming regions.
[abstract 14 / 42] Yes (score: 4) - Title: Plasmoid Instability in Inhomogeneous Current SheetsAuthors: Kazuma Ikeda, Ryusuke Numata,Comments: 16 pages, 7 figures, submitted to Plasma and Fusion ResearchSubjects: physics.plasm-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Plasmoid instability in inhomogeneous current sheets is investigated using electroMAGNETic gyrokinetic simulations of collisionless MAGNETic RECONNECTion. Simulations with and without small random perturbations are compared to examine the effects of symmetry breaking and spatial inhomogeneity. The current-sheet width immediately before disruption remains close to the electron skin depth, whereas the disruption aspect ratio varies significantly between primary and later current sheets. Random perturbations also produce asymmetric plasmoid topologies in which neighboring X points no longer share a common separatrix. These results suggest that spatial inhomogeneity is an important factor in the disruption of dynamically evolving current sheets.
[abstract 15 / 42] Yes (score: 4) - Title: The Broad-Line Region Size-Luminosity Relation in AGN Constrained by the Viewing Angle with the FRADO ModelAuthors: Junhee Myong, Jong-Hak Woo, Mohammad-Hassan Naddaf, Bożena Czerny, Jimin Kim,Comments: 16 pages, 10 figuresSubjects: astro-ph.GACreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
We investigate the H$β$ broad-line region (BLR) size-luminosity ($R_{\rm BLR}$-$L_{5100}$) relation of ACTIVE GALACTIC NUCLEi (AGN) using a Bayesian viewing angle inference framework based on the Failed Radiatively Accelerated Dusty Outflow (FRADO) model. First, we update the FRADO model by introducing a phase factor to account for the anisotropic visibility of the illuminated cloud surface. Second, we construct a Bayesian framework to constrain the viewing angle by matching the FRADO-based $R_{\rm BLR}$ to the measured H$β$ lags of 151 AGN from Wang & Woo (2024). We successfully reproduce the slope and intrinsic scatter of the observed $R_{\rm BLR}$-$L_{5100}$ relation, finding that the inferred viewing angles are broadly consistent with the estimates from dynamical modeling of velocity-resolved reverberation data, albeit with substantial scatter. As the observed H$β$ time lag and line velocity depend on the viewing angle, the BLACK HOLE mass ($M_{\rm BH}$) calibrated from our work is typically larger than the reverberation-mapping estimates using an average virial factor. Our results provide a physically motivated interpretation of the $R_{\rm BLR}$-$L_{5100}$ relation and the systematic uncertainties in reverberation and single-epoch $M_{\rm BH}$ estimates.
[abstract 16 / 42] Yes (score: 4) - Title: Long-term variability of the 35-day cycle in Her X-1Authors: Vladislav Revnivtsev, Konstantin Postnov, Ruediger Staubert, Sergey Antipin, Sergey Molkov, Nikolai Shakura,Comments: 7 pages, 5 figures, 4 tables, submitted to A&ASubjects: astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Her X-1 is an eclipsing X-ray binary system consisting of an accreting neutron star and an optical component HZ Her. In addition to the 1.24-s X-ray pulsations and the 1.7-d orbital period, the system also shows a 35-day X-ray variability related to the precessional motion of a tilted and twisted accretion disk around the neutron star. The long-term persistence of the 35-day X-ray variability suggests the presence of a stable clock mechanism, most likely free precession of the MAGNETized neutron star. We have studied the long-term behavior of the 35-day cycle of Her X-1 using all available CGRO/BATSE, RXTE/ASM, SWIFT/BAT, FERMI/GBM, MAXI data and archival turn-on moments of the 35-day cycle spanning more than 50 years. We have used a sliding-window averaged X-ray phase light curve and the classical O-C (observed minus calculated) diagram for individual 35-day turn-ons to inspect the long-term trends of the O-C diagram. The O-C diagram demonstrates two similar parabolic trends separated by an anomalous low state (ALS) of the source suggesting a secular decrease in the 35-d precession period with $\dot P_\text{35} =(-1.3\pm0.2)\times10^{-5} \,\mathrm{~s\,s}^{-1}$ and $\dot P_\text{35} =(-4.7\pm0.1)\times10^{-5} \,\mathrm{~s\,s}^{-1}$ before and after the ALS, respectively. We conclude that the decay of the 35-day period as inferred from the O-C analysis can be interpreted in terms of the direct relationship between the change of the precessional period of the accretion disk to the long-term decrease of the period of the free precessional neutron star - due to continued accumulation of accreted matter.
[abstract 17 / 42] Yes (score: 4) - Title: Decay of space plasma turbulence downstream of bow shocks: MMS MAGNETosheath unbiased campaign observationsAuthors: Victor Montagud-Camps, Petr Hellinger, Sergio Toledo-Redondo, Andrea Verdini, Luca Sorriso-Valvo, Francesco Pecora, Julia E. Stawarz, Alexandros Chasapis, Emanuele Papini, Inmaculada F. Albert, Aida Castilla,Comments:Subjects: astro-ph.SR physics.plasm-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Turbulence properties in the solar wind change with increasing heliospheric distance. Observations from different missions have shown how spectral indices converge towards a $f^{-5/3}$ spectrum in the inertial range as the solar wind reaches one astronomical unit, and how the cascade rate decays as the plasma moves away from the Sun. We evaluate whether these properties display similar trends in a smaller astrophysical system, that of a planetary MAGNETosheath. Using data from the 2023 Magnetospheric Multiscale (MMS) unbiased MAGNETosheath campaign, we determine the evolution of the spectral indices and the cascade rate along 15 inbound MAGNETosheath crossings. WIND observations permitted to monitor the state of the solar wind during the campaign and allowed to study the impact of the upstream plasma conditions on the evolution of the cascade rate downstream the bow shock. Our results show an increase of the cascade rate between two to three orders of magnitude after the plasma crosses the bow shock into the MAGNETosheath. Once in the MAGNETosheath, turbulence develops with increasing distance to the bow shock in a way similar to solar wind observations, despite the smaller size of the system. Incompressible Hall-MHD scaling-law estimates of the cascade rate show a clear power-law decay of the cascade rate in the MAGNETosheath, particularly for the cases with upstream slow wind. This suggests that the way energy is injected into the system plays a role in the decay of turbulence as the plasma moves away from the bow shock.
[abstract 18 / 42] (score: 3) - Title: Missing Mergers: On the Unexpected Delay-Time Distribution of Binary Neutron Star MergersAuthors: Ryan J. Foley,Comments: 15 pages, 5 figuresSubjects: astro-ph.HECreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
The LIGO-Virgo-KAGRA (LVK) collaboration has detected two binary neutron star (BNS) mergers, GW170817 and GW190425. While no clear electroMAGNETic counterpart was discovered for GW190425, a coincident counterpart to GW170817 (GRB170817A, AT 2017gfo) was discovered in an early-type galaxy, NGC 4993. Using broad-band photometry and an integrated optical spectrum, we measure a mass-weighted age of $12.4^{+0.5}_{-0.7}$ Gyr (90% credible) for NGC 4993, which is an estimate of the delay time between STAR FORMATION and merger for the GW170817 progenitor. BNS systems are expected to have a power-law delay-time distribution (DTD) with a minimum delay time, $t_{\rm min}$, of ~10 Myr and index $α\approx -1$. This canonical DTD, convolved with the cosmic star-formation history, predicts ~16 BNS mergers at delay times of ~100 Myr for every BNS merger at 10 Gyr; under it, the chance of detecting even one merger as old as GW170817 is ~1.8%. The long delay time of GW170817 therefore implies many "missing" shorter-delay mergers if the canonical DTD holds. A DTD with $t_{\rm min} = 12.6$ Gyr and $α= -1$ is favored over the canonical DTD by a factor of 40-140, and over short GAMMA-RAY BURST and Galactic double-NS DTDs by factors of 80-280. These results are in tension with current population synthesis models, the Milky Way double NS population, and the SGRB population. Explaining the LVK population requires either a dramatically different separation distribution than commonly assumed, an additional channel with a long delay time and comparable rate to an isolated-binary formation scenario, or a large population of BNS mergers missed in the LVK analysis. This result has wide-ranging implications for binary-population synthesis, chemical enrichment models, connections between BNS mergers and SGRBs, and future gravitational wave observations.
[abstract 19 / 42] (score: 3) - Title: As a matter of reconstruction -- varying the MAGNETic Prandtl number in implicit large eddy simulationsAuthors: Vinay Kumar, Philipp Grete,Comments: To be submitted, comments welcome!Subjects: astro-ph.GA astro-ph.HE astro-ph.SR physics.flu-dyn physics.plasm-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
The MAGNETic Prandtl number ($\mathrm{Pm}$), the ratio of viscosity to MAGNETic diffusivity, spans many orders of magnitude in astrophysical plasmas. It shapes how turbulence amplifies and structures MAGNETic fields. In direct numerical simulations (DNS) the viscosity and MAGNETic diffusivity can be controlled explicitly and independently, whereas in implicit large eddy simulations (ILES) they are set by the numerical scheme. We test whether, in a finite-volume code, $\mathrm{Pm}$ can be varied through the reconstruction scheme by applying different methods to the hydro and MAGNETic variables. As a proof of concept, we simulate driven, subsonic, homogeneous MAGNETohydrodynamic turbulence using five pairs of hydrodynamic and MAGNETic reconstruction schemes at varying resolutions. We measure the effective viscosity and resistivity from the energy transfer between scales. Reconstructing the MAGNETic field at higher order than the fluid raises the effective MAGNETic Prandtl number and vice versa. We demonstrate that a mix of second- and third-order reconstruction alone results in a $\gtrsim20\times$ change in $\mathrm{Pm}$. A comparison of DNS with matched explicit dissipation at these values agrees with the ILES. Mixed reconstruction thus offers a simple and efficient way to explore $\mathrm{Pm} \not\simeq 1$ in ILES without adding explicit dissipation.
[abstract 20 / 42] (score: 3) - Title: An approximate separation of the electron and positron degrees of freedom in the Dirac-Heisenberg-Wigner formalismAuthors: Gert Brodin, Sebastian Lundström,Comments:Subjects: physics.plasm-ph hep-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Here we study the quantum RELATIVISTIC phase-space description of the Dirac field referred to as the Dirac--Heisenberg--Wigner (DHW) formalism. By applying a systematic expansion procedure in weak electroMAGNETic fields (compared to the Schwinger critical field) and slow temporal and long spatial scales (compared to the Compton scales), the 16 scalar phase-space functions of the DHW equations can be reduced to 8 scalars. By making a further change of variables, the equations can be interpreted as four evolution equations for the electron degrees of freedom and four for the positron degrees of freedom. We refer to these equations as the weakly coupled electron-positron (WCEP) limit of the DHW equations. Unlike the case after a Foldy--Wouthuysen transformation has been made, the electron and positron degrees of freedom remain weakly coupled. Naturally, further approximations can be made on the 4+4 equations so that only 4 equations for one particle species remain. Importantly, the expansion scheme can be carried out to all orders, in which case the reduced 4+4 model, contrary to other reduced models, will cover most quantum RELATIVISTIC effects. Specifically, this includes vacuum POLARIZATION, a phenomenon that otherwise has been added phenomenologically, but here appears naturally as a feature of the general expansion scheme.
[abstract 21 / 42] (score: 3) - Title: Inferring dominant acceleration mechanisms using the longitudinal spread of solar particle intensities: 28 May 2021 eventAuthors: Jaclyn T. Lang, R. Du Toit Strauss, Jan Gieseler, Stefan Jensen, J. Grant Mitchell, Rami Vainio, Nina Dresing,Comments:Subjects: astro-ph.SR physics.space-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Solar energetic particles (SEPs) are typically accelerated during solar eruptions and propagate along MAGNETic field lines in the inner heliosphere. These eruptions include shock waves driven by coronal mass ejections (CMEs) and MAGNETic RECONNECTion in solar flares. Disentangling these source mechanisms within the measurements has been a long-standing problem for space physics researchers. Since spacecraft rarely reach the acceleration regions close to the Sun, measured SEP intensities reflect a combination of particle acceleration and interplanetary transport. The method used in this study attempts to identify which of the two main acceleration processes is more dominant for specific particle energies and species in a standalone event. Through this approach, we aim to better identify the signatures associated with these two acceleration phenomena and recognize similar behaviors in measurements with transport effects. This study characterizes the longitudinal spread of the SEP event on 28 May 2021 by fitting Gaussian curves at regular time intervals to particle intensities as a function of spacecraft position. This evolution offers unprecedented detail compared to earlier peak-focused studies, which were also limited to only three observers, while we now benefit from a novel fleet. To support the interpretation of the evolving profiles, we use a 2D SEP transport model to test if the evolution of the SEP distribution can also be caused by interplanetary effects. For this event, we find that the particle distribution of 0.1 MeV electrons remains static, while for 14 and 32 MeV protons, the distribution grows and moves to the west. We suggest that the CME-driven shock is the dominant source for protons, and that the flare is the dominant source only for the studied 0.1 MeV electrons. Interplanetary transport processes could also be contributing to the moving particle distributions.
[abstract 22 / 42] (score: 2) - Title: Constraining polymerized BLACK HOLEs with quasi-circular extreme mass-ratio inspiralsAuthors: Sen Yang, Yu-Peng Zhang, Tao Zhu, Li Zhao, Yu-Xiao Liu,Comments: 14 pages, 10 figuresSubjects: gr-qcCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
In this paper, we focus on the gravitational waves emitted by a stellar-mass object in a quasi-circular inspiral orbit around a central supermassive polymerized BLACK HOLE in loop quantum gravity. Treating the stellar-mass object as a massive test particle, we derive its equations of motion and the corresponding radial effective potential. We find that the peak of the radial effective potential decreases with the quantum parameter $\hat{k}$. We also examine the impact of quantum corrections on the properties of stable circular orbits around the polymerized BLACK HOLE. We model the smaller object's trajectory as an adiabatic evolution along stable circular orbits using a semi-RELATIVISTIC approach. In this method, the motion of the object is described by RELATIVISTIC geodesics, and changes in the object's energy and orbital angular momentum due to gravitational radiation are calculated using the mass quadrupole formula. The corresponding gravitational waveforms are generated using the numerical kludge method, revealing that quantum corrections cause phase advances in the gravitational waveforms. We further analyze the potential constraints on the quantum parameter $\hat{k}$ from future space-based gravitational wave observations, concluding that these observations will likely impose stronger constraints on $\hat{k}$ than those obtained from BLACK HOLE shadow measurements.
[abstract 23 / 42] (score: 2) - Title: Reprocessing of X-rays emission in Ultra-Luminous X-ray sourcesAuthors: Manish Kumar, Rahul Sharma, Biswajit Paul,Comments: Accepted for publication in The Astrophysical Journal (ApJ)Subjects: astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Most of the Ultraluminous X-ray Sources (ULXs) harbor either a neutron star or a stellar-mass BLACK HOLE as a compact object accreting at super-Eddington rates. In spite of having such a high accretion rate, the reprocessed emission in ULXs is quite meagre compared to that observed in Galactic X-ray binaries, except for some absorption lines in the winds. In this work, we use archival Chandra and \xmm\ observations to investigate the extent of reprocessed emission in ULXs through three diagnostics: (i) searches for Fe $\rm Kα$ lines in bright well-known ULXs and Ultraluminous X-ray Pulsars (ULXPs), (ii) evolution of hardness ratio around the eclipse transitions in the eclipsing ULXs, and (iii) the flux ratio between eclipse and out-of-eclipse (OOE) phases in eclipsing ULXs. We constrain the equivalent width (EW) of the Fe K$α$ line, with upper limits of $\sim$11-20 eV for a fixed line centroid (6.4 keV) and width (0.1 keV). Allowing the centroid and width to vary yields more conservative upper limits of up to $\sim$50 eV. Furthermore, we have not observed any significant changes in the hardness ratio in eclipsing ULXs during ingress or egress, whereas in Galactic eclipsing X-ray binaries the hardness ratio increases during the transitions. Finally, the reprocessing efficiency (eclipse-to-OOE flux ratio) is found to be larger in ULXs compared to Galactic eclipsing X-ray binaries. Based on these results, we discuss the possibility of a metal-poor or highly ionized environment surrounding the ULXs, which suppresses reprocessed emission features.
[abstract 24 / 42] (score: 2) - Title: Enhanced Cosmic-Ray Cooling in AGN from Dark Matter Deep Inelastic ScatteringAuthors: Linjie Li, Chih-Ting Lu, Arvind Kumar Mishra, Liangliang Su, Lei Wu,Comments: 12 pages, 6 figures. Accepted for publication in Physical Review DSubjects: hep-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
The diffusion of high-energy COSMIC RAYs (CRs) through the DARK MATTER (DM) spikes of ACTIVE GALACTIC NUCLEi entails significant energy loss via interactions with DM. While previous studies of sub-GeV DM have focused on elastic scattering, this process becomes insufficient at higher proton energies and DM masses. In this work, we investigate the CR-DM deep inelastic scattering (DIS) as mediated by a vector portal. We calculate the DIS contribution to the CR energy loss rate and derive stringent exclusion limits on the CR-DM scattering cross-section for DM masses between $10^{-6}$ GeV and $1$ GeV. For higher CR energies and mediator masses, the resulting CR cooling timescales are reduced by orders of magnitude after involving the DIS contribution, producing stringent constraints that surpass most of current experimental limits.
[abstract 25 / 42] (score: 2) - Title: The Multiphase Circumgalactic Medium of DESI Emission-Line Galaxies at z~1.5Authors: Ting-Wen Lan, J. Xavier Prochaska, J. Aguilar, S. Ahlen, A. Anand, D. Bianchi, D. Brooks, F. J. Castander, T. Claybaugh, A. de la Macorra, P. Doel, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, G. Gutierrez, R. Joyce, S. Juneau, R. Kehoe, T. Kisner, A. Kremin, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, J. Moustakas, S. Nadathur, W. J. Percival, F. Prada, I. Pérez-Ràfols, G. Rossi, E. Sanchez, D. Schlegel, M. Schubnell, H. Seo, J. Silber, D. Sprayberry, G. Tarlé, B. A. Weaver, R. Zhou, H. Zou,Comments: 27 pages, 15 figures, accepted by ApJSubjects: astro-ph.GACreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
We study the multiphase circumgalactic medium (CGM) of emission line galaxies (ELGs) at $z\sim1.5$, traced by MgII$\lambda2796$, $\lambda2803$ and CIV$\lambda1548$, $\lambda1550$ absorption lines, using approximately 8,000 ELG-QUASAR pairs from the Dark Energy Spectroscopic Instrument. Our results show that both the mean rest equivalent width ($W_{0}$) profiles and covering fractions of MgII and CIV increase with ELG stellar mass at similar impact parameters, but show similar distributions when normalized by the virial radius. Moreover, warm CIV gas has a more extended distribution than cool MgII gas. The dispersion of MgII and CIV gas velocity offsets relative to the galaxy redshifts rises from $\sim100 \, \rm km \, s^{-1}$ within halos to $\sim 200 \, \rm km \, s^{-1}$ beyond. We explore the relationships between MgII and CIV $W_{0}$ and show that the two are not tightly coupled: at a fixed absorption strength of one species, the other varies by several-fold, indicating distinct kinematics between the gas phases traced by each. We measure the line ratios, FeII/MgII and CIV/MgII, of strong MgII absorbers and find that at $<0.2$ virial radius, the FeII/MgII ratio is elevated, while the CIV/MgII ratio is suppressed compared with the measurements on larger scales, both with $\sim4\, σ$ significance. We argue that multiphase gas that is not co-spatial is required to explain the observational results. Finally, by combining with the measurements in the literature, we show the redshift evolution of CGM properties and estimate the neutral hydrogen, metal, and dust masses in the CGM of DESI ELGs --- found to be comparable to those in the ISM.
[abstract 26 / 42] (score: 2) - Title: From ASTRID to BRAHMA -- The role of overmassive BLACK HOLEs in little red dots in cosmological simulationsAuthors: Patrick LaChance, Aklant Kumar Bhowmick, Rupert A. C. Croft, Tiziana Di Matteo, Yihao Zhou, Fabio Pacucci, Laura Blecha, Paul Torrey, Yueying Ni, Nianyi Chen, Simeon Bird,Comments: Published in the Open Journal of Astrophysics; 18 pages, 9 figures,Subjects: astro-ph.GACreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
We investigate the origin of Little Red Dots (LRDs) using a realization of the BRAHMA cosmological hydrodynamic simulation that produces overmassive BLACK HOLEs at $z \sim 4\text{-}8$. We generate mock JWST observations by modeling galaxy spectral energy distributions (including dust attenuation) together with AGN emission using cloudy-based templates, and test whether such systems reproduce the observed LRD population. We consider both a standard low-redshift AGN emission model and a gas-enshrouded AGN emission model, in which the AGN is embedded within unresolved dense gas that produces a strong Balmer break, and find that LRDs emerge in significantly larger numbers with the latter model. Assuming that all AGN reside in this gas-enshrouded phase, we recover LRD number densities ($Φ\sim 2 \times 10^{-4}~\mathrm{Mpc}^{-3}$), close to the observed abundance. This implies an effective gas-enshrouded duty cycle approaching unity, which is not predicted by current theoretical models. Current JWST constraints on the high-z BLACK HOLE mass function suggest that this tension may arise from a deficit of low-mass ($M_{\rm BH}\lesssim10^7~M_\odot$) LRDs in BRAHMA. Applying the same gas-enshrouded model to the ASTRID simulation, which lacks overmassive BLACK HOLEs, we find that the LRD abundance remains $\gtrsim2~\rm dex$ below observations. Overall, while the overmassive BLACK HOLEs in this BRAHMA realization substantially enhance the production of LRD-like systems, reproducing the observed LRD abundance requires them to reside in dense gas environments with unrealistically high duty cycles. We therefore conclude that overmassive BLACK HOLEs are unlikely to be the sole origin of the observed JWST LRD population, and may instead account for only a subset of these systems.
[abstract 27 / 42] (score: 2) - Title: Measurement of the galaxy-velocity power spectrum of DESI tracers with the kinematic Sunyaev-Zeldovich effect using DESI DR2 and ACT DR6Authors: Edmond Chaussidon, Selim C. Hotinli, Simone Ferraro, Kendrick Smith, Xinyi Chen, J. Aguilar, S. Ahlen, D. Bianchi, D. Brooks, T. Claybaugh, A. Cuceu, A. de la Macorra, B. Dey, P. Doel, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, G. Gutierrez, J. Guy, H. K. Herrera-Alcantar, K. Honscheid, C. Howlett, D. Huterer, M. Ishak, R. Joyce, D. Kirkby, A. Kremin, O. Lahav, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, S. Nadathur, J. A. Newman, N. Palanque-Delabrouille, W. J. Percival, F. Prada, I. Pérez-Ràfols, G. Rossi, L. Samushia, E. Sanchez, D. Schlegel, M. Schubnell, H. Seo, J. Silber, D. Sprayberry, G. Tarlé, B. A. Weaver, C. Yèche, R. Zhou,Comments:Subjects: astro-ph.COCreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
Joint analyses of high-resolution CMB temperature maps with galaxy surveys provide a unique way to reconstruct the radial velocity field of the underlying matter distribution via the kinematic Sunyaev-Zeldovich (kSZ) effect. Using data from the Atacama Cosmology Telescope (ACT) DR6 and the Dark Energy Spectroscopic Instrument (DESI) DR2, we present radial velocity reconstructions for luminous red galaxies (LRGs), emission-line galaxies (ELGs), and QUASARs (QSOs). Leveraging the spectroscopic data, we are able to reliably model the foreground contamination and report a negligible impact on our main observables. We detect the velocity-galaxy cross-correlation at $17.0σ$ for LRGs, and for the first time, at $8.3σ$ for ELGs and $6.8σ$ for QSOs. We further report the first detection of the velocity-velocity correlation using LRGs at $3.1σ$, as well as the highest cumulative detection of the kSZ effect to date at $20.8 σ$. Similarly to previous results, we find a lower amplitude of the kSZ signal compared to our fiducial halo model prediction and electron profile assuming a Battaglia profile. Combining these new observables, we obtain constraints on local-type primordial non-Gaussianity (PNG): $f_{\rm NL}^{\rm loc} = 15.9_{-34.4}^{+34.6}$ at 68\% confidence, which represents the tightest constraint to date derived from the velocity field. The measurements presented here already exhibit lower noise on a per-mode basis than the galaxy auto-correlation on the largest scales, $k<0.004~\rm{Mpc^{-1}}$, highlighting the key role these observables will play in the context of future CMB experiments such as the Simons Observatory.
[abstract 28 / 42] (score: 2) - Title: Curvature-Radiation Geometries Across the Second CHIME/FRB Fast Radio Burst PopulationAuthors: Thonimar V. Alencar, Jéferson A. S. Fortunato, Wiliam S. Hipólito-Ricaldi,Comments: 14 pages and 4 figuresSubjects: astro-ph.HECreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
We present a population-level spectral analysis of fast radio bursts from the second CHIME/FRB catalog using three curvature-radiation-motivated templates: point-source, one-dimensional bunch, and paired-bunch cavity models. Fits are evaluated with reduced chi-squared $χ^2_r$, AIC/BIC, and the Ljung-Box residual autocorrelation test. All three templates yield median $χ^2_r$ values close to unity for both repeating and non-repeating bursts. Repeaters show narrower $χ^2_r$ distributions than non-repeaters, with statistically significant but modest population-level differences. AIC favours the one-dimensional bunch model for the largest fraction of sources, whereas BIC increases the relative preference for the simpler point-source model. However, residual autocorrelation remains widespread across all models: only 15%-21% of sources simultaneously satisfy goodness-of-fit and residual-independence criteria, indicating persistent structured residuals beyond the tested templates. These results suggest that while curvature-radiation-motivated geometries capture the dominant spectral envelope of many FRBs, additional physical ingredients or spectral components are required to describe the fine-scale spectral structure of the data. The inferred coherence scales are $\sim$16-18 cm for the one-dimensional model and $\sim$25-28 cm for the cavity model.
[abstract 29 / 42] (score: 2) - Title: Bayesian inference of the dense matter equation of state built upon extended Skyrme interactions: A generalizationAuthors: Mikhail V. Beznogov, Adriana R. Raduta,Comments: 15 pages, 8 figures, 3 tables. Accepted for publication in PRCSubjects: nucl-th astro-ph.HECreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
The nonRELATIVISTIC theory of nuclear matter (NM) based on Brussels-Skyrme interactions is employed to develop models for dense and neutron-rich matter within a Bayesian framework. We employ the following set of constraints: the four best-known nuclear empirical parameters, the density dependence of the energy per particle in pure neutron matter (PNM), the density dependence of the Landau effective mass ($m_\mathrm{eff}$) of neutrons in PNM and symmetric NM, and a lower limit on the maximum gravitational mass that neutron stars (NSs) can support. In addition, a number of ``sanity checks'' are added: the values of the speed of sound, neutron and proton Landau effective masses, and FERMI velocities are constrained up to the central density of the most massive NS configuration and for isospin asymmetries $δ=(n_n-n_p)/(n_n+n_p)$ ranging from 0 to 1. Our ensemble of models \emph{fully} explores the capacity of nonRELATIVISTIC Brussels-Skyrme effective interactions to describe NM at densities exceeding several times the nuclear saturation density. This is a necessary step toward a better understanding of the properties of dense matter and possible correlations between the parameters of NSs and the parameters of NM. Due to the pronounced U-shaped density dependencies of $m_\mathrm{eff}$, which qualitatively agree with the predictions of ab initio calculations featuring three-body forces, all our models exhibit a non-monotonic ``rise-and-fall'' behavior of the thermal pressure ($p_\mathrm{th}$) as a function of density, which in extreme cases leads to $p_\mathrm{th} < 0$. This work is a generalization of [Beznogov and Raduta, Phys. Rev. C 110, 035805 (2024)].
[abstract 30 / 42] (score: 2) - Title: Surprisingly normal? GW241011 and GW241110 in the context of hierarchical merger classificationAuthors: Cailin Plunkett, Michael Zevin, Salvatore Vitale,Comments: 10 pages, 10 total figuresSubjects: astro-ph.HE gr-qcCreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
Uncovering the origins of merging binary BLACK HOLEs is a key goal in gravitational-wave astrophysics, but identifying the formation channel of a particular binary is complicated by imprecise measurements and uncertain theoretical predictions. While classification often involves computing metrics from an event's inferred properties, measurement precision varies across parameter space. Using the perhaps-surprising low masses of the hierarchical merger candidates GW241011 and GW241110 as a backdrop, we consider the classifiable distribution, which steps beyond detectability to assess what events may be correctly characterized as part of a population. Interpreting classification outcomes, and assessing the falsifiability of theoretical model predictions, are benefit by understanding the regions of parameter space that a priori enable---and do not enable---confident measurement. For hierarchical mergers, we demonstrate that mass ratio is the largest intrinsic driver of identification, while orbital inclination and signal-to-noise ratio are the key extrinsic factors. Further, we show GW241011 and GW241110 achieve classification metrics consistent with similar simulated hierarchical mergers. Model selection and classification require the context of measurement capacity, especially as catalogs offer growing numbers of events with seemingly unusual properties.
[abstract 31 / 42] (score: 2) - Title: Effects of Eddington-inspired Born-Infeld Gravity on Black Hole AccretionAuthors: Merce Guerrero, Razieh Ranjbar,Comments: 10 pages, 5 figuresSubjects: gr-qc astro-ph.HECreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
Black holes offer a unique setting to test gravity in the strong-field regime, where deviations from General Relativity are expected to be most pronounced. We study how modified gravity changes the structure of an advection-dominated accretion flow (ADAF) around a supermassive BLACK HOLE. The gravitational field governing the disc is described by a Paczyński--Wiita-like potential derived in Eddington-inspired Born--Infeld (EiBI) gravity, formulated \textit{à la} Palatini. We solve the ADAF-like equations for this potential and compare the radial profiles of the flow with those obtained for the standard Paczyński--Wiita potential. The largest difference appears in the gas density, which is several orders of magnitude higher in the EiBI case near the inner region and converges to the standard result at large radii. The specific angular momentum and temperature are lower in EiBI gravity, while the radial velocity differs mainly at large radii for both solution branches, $ s=-1$ and $+1$. The angular velocity and the disk aspect ratio $H/r$ change only slightly. These results show that EiBI gravity can modify the density structure of hot accretion flows in the strong-field regime, potentially providing observational discriminators.
[abstract 32 / 42] (score: 2) - Title: From Quantum Field Fluctuations to High-Redshift AGN: Semiclassical Origins of Halo Mass Function Constraints in the JWST EraAuthors: Elan Yogeswaren, Amir-Homayoon Najmi, Robert K Schaefer,Comments:Subjects: astro-ph.CO astro-ph.GACreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
We develop a continuous framework connecting quantum field fluctuations in the early Universe to the abundance and observable properties of galaxies and ACTIVE GALACTIC NUCLEi (AGN) at cosmic dawn. Beginning with quantum fields in curved Friedmann Lemaitre Robertson Walker spacetime, we follow inflationary vacuum fluctuations into the primordial curvature spectrum, linear matter power spectrum, mass variance $σ(MHz)$, mass peak height $ν(MHz)$, and the statistics of nonlinear halo formation. The Press-Schechter and Sheth-Tormen formalisms provide an analytic description of halo abundance and its dependence on peak rarity. A complementary high redshift halo mass function calibrated with the GUREFT simulations of Yung et al. (2024) provides a numerical description specifically constructed for the cosmic dawn regime probed by JWST. The comparison between these analytic and simulation calibrated prescriptions provides a direct measure of the sensitivity of predicted halo populations to the observations. We separate this cosmological supply of halos from the astrophysical and observational mappings that produce stars, ultraviolet luminosities, and ACTIVE GALACTIC NUCLEi. Controlled numerical experiments show that a percent level perturbation in the primordial fluctuation amplitude produces only a modest change in $σ$ and $ν$, but can strongly amplify the exponentially suppressed high $ν$ tail of the Halo Mass Function. This sensitivity increases toward high halo mass and high redshift, identifying rare cosmic dawn populations as potentially powerful probes of primordial statistics while simultaneously exposing the importance of uncertainties in halo abundance. High redshift AGN population statistics and the Ultraviolet Luminosity Function provide additional constraints on the primordial power spectrum and dynamics of primordial inflation theory.
[abstract 33 / 42] (score: 2) - Title: Equipartition between Alfvénic turbulence and energetic ions as the origin of the -5 common spectrum in the heliosphereAuthors: Stanislav Boldyrev, Daniel Humphrey, Vadim Roytershteyn,Comments: 6 pages, 3 figuresSubjects: physics.plasm-ph astro-ph.GA physics.space-phCreated: 2026-10-29; Updated: 2026-11-02; Datestamp: 2026-11-02
Suprathermal ion tails throughout the heliosphere follow a ``common spectrum,'' $f(v)\propto v^{-5}$. We show that scale-by-scale equipartition between strong Alfvénic turbulence and the ions it accelerates predicts both this exponent and the absolute amplitude, $F(v)=B^2/(16π^3 m_i v^5)$, with no free parameters. The prediction agrees within a factor of a few with ACE and Voyager 1 spectra across three decades in MAGNETic energy. We argue that this saturated level is reached where strong turbulence accelerates particles locally; quiet-time tails lie well below it, consistent with nonlocal acceleration.
[abstract 34 / 42] (score: 2) - Title: Kinematic Map of the Galactic Bulge Using HST Proper MotionsAuthors: Zhenhao Wang, Shude Mao, Hongjing Yang, Andrzej Udalski, Weicheng Zang, T. Dex Bhadra,Comments: 14 pages, 9 figures, 1 table; submitted to MNRASSubjects: astro-ph.GACreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Constraining the Galactic bulge's non-axisymmetric dynamics requires proper motions in deep fields across many sightlines, yet crowding and extinction limit such measurements. Using multi-epoch observations of 27 fields in the southern Galactic bulge (-6$^\circ$ < l < 4$^\circ$, -5$^\circ$ < b < -1$^\circ$) from the ultraviolet-visible (UVIS) channel of Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) with time baselines of 3 to 13 years, and combining them with the absolute proper motion reference frame provided by Gaia Data Release 3 (DR3), we measure absolute proper motions for ~ 400,000 stars. Colour-magnitude diagrams are used to separate bulge stars from foreground disc stars, identify red clump stars and correct for interstellar extinction and reddening. Statistical analysis shows that the mean proper motion in Galactic latitude is consistent with that of the central supermassive BLACK HOLE Sgr A*, while the mean proper motion in Galactic longitude is affected by disc stars but agrees with Sgr A* after extrapolation to the Galactic plane. Proper motion dispersions increase towards the Galactic centre and are asymmetric across Galactic longitude, with a steeper gradient for l < 0$^\circ$, revealing the bulge's non-axisymmetric bar structure. The velocity distribution shows clear anisotropy ($σ_l$/$σ_b$ = 1.131 $\pm$ 0.005). The normalised covariance is negative in the l > 0$^\circ$ region (~ -0.085) and close to zero in the l < 0$^\circ$ region. The proper motion distributions are non-Gaussian in both Galactic longitude and latitude, mainly due to contamination by foreground disc stars.
[abstract 35 / 42] (score: 2) - Title: Resolving the Complex Line-Locking Structure in Quasar J004613+010425 with VLT/X-shooter SpectroscopyAuthors: Chen Chen, Wei-Jian Lu, Ying-Ru Lin, Bo Ma,Comments: 15 pages, 10 figures, 2 tables; accepted for publication in Astronomy & AstrophysicsSubjects: astro-ph.GACreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Line-locking (LL) signatures in QUASAR absorption-line systems provide direct observational evidence for radiatively driven outflows. We present a detailed investigation of LL phenomena in the QUASAR SDSS J004613.54+010425.7 ($z_{\rm em} = 2.150$) using medium-resolution VLT/X-shooter spectra, as part of the TOLL project. Compared with previous studies based on Sloan Digital Sky Survey spectroscopy, the X-shooter data resolve the absorption complex into twelve narrow absorption line (NAL) components spanning $\sim$$2700$ km/s in the C IV, N V, Si IV, and Ly$α$ transitions, a factor of $\sim$2.4 more components than identified from lower resolution spectra. We detect fourteen distinct LL pairs across three ionic species, forming one of the largest line-locking webs known to date: three Si IV pairs connecting components (2, 10), (4, 11), and (5, 12); six N V pairs organized into four groups; and five C IV pairs organized into three groups. Monte Carlo simulations show that the probability of this twelve-component LL web arising by chance is $< 10^{-5}$. Photoionization modeling with Cloudy yields ionization parameters of $\log U \approx -2.4$ to $-0.6$ and total hydrogen column densities of $\log N({\rm H}) \approx 18.4$-$20.6$ for the twelve components. A comparison of the properties of shadowed and shadowing clouds shows that ion column densities and ionization parameters typically agree within a factor of $\sim$3, broadly supporting the standard radiative acceleration picture, although several outliers suggest that multi-ion locking and cloud-cloud interactions may also regulate LL stability. These results demonstrate that medium- and high-resolution spectroscopy is essential for resolving the full complexity of line-locked QUASAR outflows.
[abstract 36 / 42] (score: 2) - Title: Accelerating Computation and Resolving Extraneous Roots in the Kinetic Plasma Dispersion Relation Solver BOAuthors: Xizhi Tian, Huasheng Xie, Long Wei,Comments: 21 pages, 7 figures, 2 tables. Code available at https://github.com/FusionAlpha/botianSubjects: physics.plasm-ph physics.space-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Kinetic dispersion relations are widely used to study waves and instabilities in space, astrophysical, and laboratory plasmas. Iterative root searches depend on initial guesses and may fail to converge or miss important branches. The BO/PDRK solvers [Comput. Phys. Commun. 244, 343-371 (2019)] use rational pole expansions to transform the nonlinear dispersion relation into a matrix eigenvalue problem, obtaining all roots of the approximated relation in one calculation. However, high cyclotron harmonics enlarge the matrix and slow computation, while extraneous roots are difficult to separate from physical modes. We develop BO-T (BO-Tian), an improved version of BO combining two methods. First, for matrix reduction, BO-T applies rank factorization to combined residue matrices, preserving the rational dispersion relation and accounting for the removed pole eigenvalues. Second, for root screening, BO-T uses contour comparison between approximate and reference kinetic dispersion matrices along a closed contour enclosing no poles. This provides a sufficient condition for preserving local root counts, with error bounds for isolated roots and criteria for growth rate signs. Benchmarks on representative electrostatic and electroMAGNETic cases show speedups of about 10 to 140 for matrix assembly and eigenvalue calculation, exceeding 30 in most cases with high cyclotron harmonics. Root screening recovers the main unstable branches in agreement with published and archived dispersion curves.
[abstract 37 / 42] (score: 2) - Title: Hydrodynamic regimes of the edge-tone in a simplified recorder mouthpieceAuthors: A. Tassawar, R. Velasco-Segura, P. Rendon, M. Fosas de Pando, R. Ostilla-Mónico,Comments:Subjects: physics.flu-dynCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
The acoustic mechanism of flue instruments originates in the interaction of an air JET with a sharp edge, the labium. Previous studies have examined isolated edge-tones or full instruments in which acoustic resonance obscures the underlying hydrodynamics, and a systematic understanding of how geometric parameters govern JET stability is lacking. We present a large-scale parametric study of the JET-labium interaction in a simplified recorder mouthpiece without a resonator, using more than 200 two-dimensional direct numerical simulations with an immersed boundary method. We vary the mouth distance, the labium angle, the vertical offset of the labium, and the Reynolds number (Re), and characterize the dynamics through spectra of the transverse force on the labium. The baseline configuration oscillates as a predominantly periodic Stage I edge-tone with Strouhal number St ~ 0.07, nearly constant for Re >= 330 and for all labium angles at the baseline mouth distance, so the frequency is set by the geometry rather than by viscosity. The mouth distance has the strongest influence: it is the only parameter that introduces a second oscillation stage, and the Stage I frequency is inversely proportional to it. The second stage is weakly present at five and six windway heights, established from six and a half, and dominant from eight, where it strongly modulates the amplitude. The vertical offset mainly affects the strength of the oscillation, and the labium angle does not change the instability mechanism. A baseline configuration is identified for future aeroacoustic coupling studies.
[abstract 38 / 42] (score: 2) - Title: A Common Type II Origin of Galilean and Carroll SuperstringsAuthors: Mehmet Ozkan, Utku Zorba,Comments: 9 pagesSubjects: hep-th gr-qcCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
We show that the RELATIVISTIC Type-II superalgebras, once the fundamental-string winding charge is retained alongside the momentum, admit a single non-Lorentzian contraction whose two translation ideals carry Galilean and MAGNETic-Carroll supersymmetry, respectively. The complementary vector charge required for this structure is thus intrinsic to string theory. The IIA realization is particle-like and the IIB realization string-like, a distinction fixed by chirality, and spacelike T-duality relates the two while preserving each non-Lorentzian structure. The same contraction is finite on the doubled Green--Schwarz action, including all fermion terms and local kappa symmetry, where the two supersymmetries appear as the two POLARIZATIONs of a single worldsheet theory. These results unify two distinct non-Lorentzian corners of string theory within a common Type-II origin and open a route toward a broader web of non-Lorentzian dualities and possible holographic generalizations.
[abstract 39 / 42] (score: 2) - Title: Co-evolution of AGN and Host Galaxies across Cosmic Time Using JWST dataAuthors: Priyanka Jalan, Tomotsugu Goto, Tetsuya Hashimoto, Angel Rodriguez Barbosa, Chih-Teng Ling, Ece Kilerci, Terry Long Phan, Srivardini Ayyappan,Comments: Published in PASPSubjects: astro-ph.GACreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Understanding the complex co-evolution of ACTIVE GALACTIC NUCLEi (AGN) and their host galaxies across cosmic time remains a fundamental challenge, particularly in identifying how the physical drivers of galaxy diversity evolve from the early Universe to the present day. To understand this, we use a multi-wavelength JWST catalog of 2,709 sources cross-matched from the SMILES and JWST Advanced Deep Extragalactic Survey (JADES) surveys, spanning lookback times from 0.8 to 12.9 Gyr ($0.05
AGN luminosity ($L_{\mathrm{AGN}}$) strongly correlates ($\sim0.8$) with STAR FORMATION rate (SFR) and dust luminosity ($L_{\mathrm{dust}}$), weakly correlates ($\sim0.5$) with stellar mass ($M_\star$) and anti-correlates ($\sim -0.4$) with STAR FORMATION history (SFH) duration and stellar age (Age$_\star$). However, the apparent anti-correlation observed between galaxy age and AGN luminosity is driven by cosmic time rather than by a direct physical connection. Using Principal Component Analysis (PCA), we find that galaxy diversity is fundamentally governed by two principal components: AGN and galaxy activity, and stellar age. At higher redshifts, AGN accretion, STAR FORMATION, and dust emission are tightly synchronized, reflecting gas-rich conditions in the early Universe. In contrast, the present Universe exhibits a clear bimodal structure in host-dominated systems ($f_{\mathrm{AGN}} \leq 0.2$), separating quiescent and star-forming galaxies. Our results demonstrate that AGN luminosity is primarily governed by the host galaxy's current cold-gas supply, of which recent STAR FORMATION is a close observational tracer, with galaxy mass setting the overall potential. This highlights a co-evolution scenario in which BLACK HOLE growth and STAR FORMATION are tightly linked, particularly at early cosmic epochs.
[abstract 40 / 42] (score: 2) - Title: The Evolution of the Circumgalactic Medium after a starburst in DESI Post-Starburst GalaxiesAuthors: Zoe Harvey, Sahyadri Krishna, Rita Tojeiro, Vivienne Wild, Jessica Nicole Aguilar, Steven Ahlen, Eric Armengaud, Florian Beutler, Davide Bianchi, David Brooks, Rebecca Canning, Aurelio Carnero Rosell, Todd Claybaugh, Andrei Cuceu, Axel de la Macorra, Peter Doel, Jaime E. Forero-Romero, Enrique Gaztañaga, Satya Gontcho A Gontcho, Gaston Gutierrez, ChangHoon Hahn, Hiram K. Herrera-Alcantar, Stephanie Juneau, Robert Kehoe, Martin Landriau, Laurent Le Guillou, Marc Manera, Aaron Meisner, Ramon Miquel, John Moustakas, Adam Myers, Seshadri Nadathur, Jeffrey A. Newman, Enrique Paillas, Will Percival, Ignasi Pérez-Ràfols, Francisco Prada, Corentin Ravoux, Graziano Rossi, Rossana Ruggeri, Eusebio Sanchez, Christoph Saulder, David Schlegel, Joseph Harry Silber, Małgorzata Siudek, Gregory Tarlé, Benjamin Alan Weaver, Hu Zou,Comments: 22 pages, 11 figures and 5 tables in the main textSubjects: astro-ph.GACreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
We present a statistical study of the cool circumgalactic medium (CGM) around massive post-starburst galaxies, traced by Mg II $λ\lambda2796,2803$ absorption in background QUASAR spectra from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2. Cross-matching ~1.98 million QUASAR sightlines with luminous red galaxies at $0.4 < z < 0.76$ with stellar masses between $10.6 < \log_{10}(M_*/\mathrm{M}_\odot) < 12$ yields ~143 million galaxy-QUASAR pairs, 50-60 times more per impact-parameter bin than our previous SDSS-based analysis. We stack the Mg II absorption as a function of projected separation and classify the foreground galaxies using mean-field independent component analysis (MFICA), further subdividing the post-starburst population into sub-samples ordered by time since the starburst. The mean Mg II equivalent width declines with impact parameter for every class. Post-starburst galaxies show the strongest absorption of any spectral class, reaching $W_{\rm MgII} = 1.58 \pm 0.32$ Å within 71 kpc, well above star-forming ($0.69 \pm 0.15$ Å) and quiescent ($0.22 \pm 0.05$ Å) galaxies of comparable stellar mass at the same projected separation. Within the post-starburst phase the absorption profile evolves systematically: the youngest systems show the highest, most centrally concentrated absorption and the steepest radial decline, whereas progressively older systems show weaker inner absorption and enhanced absorption at intermediate radii (~300-1000 kpc). Independent Bagpipes star-formation-history fitting confirms that this ordering corresponds to an ageing sequence. We interpret this evolution as the outward redistribution of cool gas expelled by feedback-driven winds, consistent with characteristic outflow velocities of a few hundred km s$^{-1}$, with a residual inner cool-gas reservoir persisting throughout the post-starburst phase.
[abstract 41 / 42] (score: 2) - Title: Stabilization of counter propagating currents by energy conservation in collisionsAuthors: Thomas Kluge, Jannis Schulz, Arthur Hirsch-Passicos, Pawel Ordyna, Ulrich Schramm,Comments:Subjects: physics.plasm-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Current filamentation generates MAGNETic fields and shapes electron transport in dense plasmas, where collisions can either suppress or enhance its growth. Here we show that conserving electron kinetic energy in a collisional model can change both the dominant instability and its characteristic wavelength. We develop a linear kinetic theory for drifting, anisotropic electron populations with a relaxation operator that conserves particle number and laboratory-frame kinetic energy while allowing momentum transfer to a stationary ion background. For counterstreaming currents, energy conservation maintains the stabilizing influence of charge separation over a broader range of collision frequencies than a model conserving particle number alone. At intermediate collision rates, the resulting suppression of transverse filamentation allows a nearly aperiodic oblique mode to dominate, reducing the maximum growth rate and shifting the wavelength of the fastest-growing perturbation. Two-dimensional particle-in-cell simulations support predicted growth rates of up to more than a magnitude lower than expected without energy conserving collision.
[abstract 42 / 42] (score: 2) - Title: Machine learning surrogates for multi-geometry EDGE2D-EIRENE studies of MAST UpgradeAuthors: George K. Holt, Lorenzo Zanisi, Romain Futtersack, James Simpson,Comments: Abstract shortened for arXiv; see manuscript for full abstractSubjects: physics.plasm-phCreated: 2026-10-30; Updated: 2026-11-02; Datestamp: 2026-11-02
Two-dimensional edge plasma transport simulations provide a detailed description of divertor plasma behaviour, but their computational cost limits large parameter scans and iterative modelling. We present a database of 23,379 converged EDGE2D-EIRENE simulations for MAST Upgrade (MAST-U), spanning three divertor MAGNETic configurations, variations in separatrix density and input power, deuterium fuelling locations, and nitrogen seeding rates and locations. Independent multilayer perceptron surrogates are trained for twelve scalar outputs, including divertor front positions, target electron temperature and core-edge boundary quantities. On a held-out test set, the surrogates achieve $0.9462 \leq R^2 \leq 0.9994$, substantially outperforming linear regression baselines. Dense surrogate scans quantify the dependence of carbon radiation front motion on separatrix density, divertor geometry and fuelling location. Nitrogen seeding scans reveal a strong dependence on seeding location, with high-field-side seeding rapidly reducing core-boundary electron temperature, while divertor seeding produces little response. Batch inference for all twelve outputs at 786,432 operating points takes 1.76 s on GPU, compared with a median wall time of 2.61 hours using four CPU cores for separate EDGE2D-EIRENE simulations. These models enable rapid comparison of geometry and source-location effects on divertor and core-boundary conditions within the sampled simulation domain.
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