研究動向

astro-ph.GA2026年9月15日

JWST Observations of Starbursts: A Young Bubble in NGC 253's Central Starburst

Kaitlyn E. Sheriff, Elisabeth A. C. Mills, Xinyu Mai, Utsav Siwakoti, Sara E. Duval, Alberto D. Bolatto, Rebecca C. Levy, Jia Wei Teh et al.

We present a multi-wavelength analysis of a young bubble in the nuclear starburst of NGC 253 using new JWST MIRI-MRS observations together with archival ALMA (100, 350, 690 GHz) and Chandra data. The MIRI maps reveal a prominent bubble-like structure in both ionized and molecular emission lines. The bubble is spatially coincident with one of the least embedded massive young clusters detected with ALMA, suggesting that the cluster is driving the expansion. We measure a radius of $\sim 11.5 \pm 3.…

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astro-ph.GA2026年9月15日

Forged in Quenching: Morphological Transformation across Star-forming and Quiescent Galaxies in EAGLE

Kai Wang, Carlton Baugh, Sownak Bose, Shaun Cole, Carlos S. Frenk, Hao Fu, Cedric Lacey, Shengdong Lu et al.

The connection between morphology and quenching in central galaxies is well established, but its physical origin remains widely debated. We address this by tracing the main progenitor branches of $z=0$ star-forming and quiescent central galaxies in the EAGLE cosmological simulation from $z\gtrsim4$. Their disc-to-total ratio and triaxiality tracks are indistinguishable until $z\approx 1$-$2$, when both diverge concurrently with the onset of quenching, whereas the size and supermassive black hole…

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astro-ph.GA2026年9月15日

The Missing Black Hole in the Large Magellanic Cloud: A Dynamical Prediction for Its Present-Day Location

Robin Chisholm, Elena D'Onghia, Niv Drory, Andrew Fox, Noam Libeskind

There are indications that the Large Magellanic Cloud (LMC) hosts a central supermassive black hole (SMBH), yet no direct detection exists: one reason is that its present-day location need not necessarily coincide with the photometric or kinematic centers. Here we frame a dynamical targeting problem and predict the present-day sky location of the LMC SMBH. We model the recent LMC-Small Magellanic Cloud (SMC) interaction, which induces a bar-disk offset, and integrate SMBH orbits within a realist…

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astro-ph.HEastro-ph.GAastro-ph.SR2026年9月15日

Optical Spectroscopy of a Candidate O-Star X-ray Binary in M33

Margaret Lazzarini, Lara Cullinane, Karoline Gilbert, Puragra GuhaThakurta, Kyros Hinton, Daniel Stern, O. Grace Telford, Tobin M. Wainer et al.

We present new observations of a candidate O-type donor star in a high mass X-ray binary (HMXB) in M33. The candidate donor star is spatially coincident with a hard X-ray point source. The star's optical magnitude and colors are consistent with what is expected for a massive star. The four band optical/UV spectral energy distribution (SED) of the donor star is well fit by an O-giant model with an effective temperature of $\sim$43 kK, mass of 75$_{+9}^{-0.3}$ $M_{\odot}$, and surface gravity of l…

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astro-ph.HEastro-ph.GA2026年9月15日

Jet Feedback and the Self-Regulated Growth of Black Holes Embedded in AGN Disks

Marguerite Epstein-Martin, Kung-Yi Su, Zoltan Haiman, Rosalba Perna

Accretion disks in active galactic nuclei (AGN) are expected to host embedded stellar-mass black holes (BHs) whose gas capture rates can be highly super-Eddington. Without feedback, they would rapidly grow and deplete the disk, but at such high feeding rates, radiation is advected inward with the flow. We test whether the resulting accretion-powered jet and its shocked cocoon can (i) self-regulate the BH's growth rate and (ii) break out of the AGN disk. Using GIZMO, we perform three-dimensional…

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astro-ph.HE2026年9月15日

Dynamic Accretion Disk-Corona Connection and Broad Fe K$α$ Variability in Mrk 766 Revealed by Time-Resolved High Resolution X-Ray Spectroscopic Analysis

Ayon Mondal, Tathagata Saha, Arijit Sar, Ritaban Chatterjee

We present a multi-epoch, primarily X-ray study of the narrow-line Seyfert 1 (NLSy1) galaxy Mrk~766 by combining archival \textit{XMM-Newton} observations spanning nearly two decades together with a \textit{XRISM} observation obtained during its Performance Verification Phase. We analyzed the absorption and emission features in the soft X-ray spectra from RGS and EPIC-pn data, revealing a stratified multi-phase potentially ionised absorber with a column density varying at a timescale of $\sim$1…

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astro-ph.HE2026年9月15日

A pair of unequal jets imparted the kick velocity to the neutron star of Cassiopeia A

Dmitry Shishkin, Muhammad Akashi, Noam Soker

We analyze observations of the Cassiopeia A core-collapse supernova remnant (CCSNR) and identify a pair of opposite rings, attributing their formation to unequal-energy explosion jets that also imparted the neutron star (NS) its kick velocity via the kick-BEAP (kick by early asymmetrical pair of jets) mechanism. We replicate the formation of these ring structures, which we identify as circum-jet rings, with three-dimensional hydrodynamical simulations of two opposite explosion jets in which the…

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hep-phastro-ph.HE2026年9月15日

Multiple-Mediator-Affected Ultra-High-Energy Neutrino Attenuation: Hints for 5D ${U(1)}_{L_μ- L_τ}$ in IceCube

Atri Bhattacharya, Ayushi Kaushik, Kenji Nishiwaki

Recent IceCube observations point to the ultra-high energy neutrino flux exhibiting a very soft spectral nature beyond tens of TeV, which is unexpected from the standard cosmic-ray neutrino connection. As a potential explanation for this behaviour, we investigate neutrino self-interactions in an extra-dimensional $ {U(1)}_{L_μ-L_τ} $ gauge theory, where symmetry breaking leads to a tower of Kaluza-Klein gauge bosons in compactified four dimensions. These multiple gauge bosons may enhance the att…

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astro-ph.GAastro-ph.CO2026年9月15日

Population III Host Candidates at $z\sim2$: Strong He II $\lambda1640$ and Absent UV Metal Lines in HETDEX Ly$α$ Emitters

Mahan Mirza Khanlari, Dustin Davis, Karl Gebhardt, Tiger Yu-Yang Hsiao, Julian B. Muñoz, Alessandra Venditti, Erin Mentuch Cooper, Robin Ciardullo et al.

Population III (Pop III) stars are expected to produce extremely hard ionizing spectra, yet direct evidence for their signature--strong narrow He II $\lambda1640$ emission with weak or absent metal lines--remains elusive. Although Pop III formation peaks at $z\gtrsim10$, models predict that nearly pristine gas pockets can survive to later times, making intermediate-redshift searches a probe of metal mixing across cosmic time. We search 109,545 high-confidence Ly$α$-emitting galaxies at $1.9<z<2.…

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astro-ph.HEgr-qcnucl-th2026年9月15日

On the dynamical accessibility of twin stars

Mahdi Naseri, Vasileios Paschalidis

A sufficiently strong hadron-to-quark first-order phase transition can give rise to a third family of stable compact stars that are commonly referred to as hybrid hadron-quark stars. Stable hybrid stars that have the same gravitational mass as neutron stars are referred to as twin stars. Although equilibrium twin stars may exist, whether they can be dynamically formed remains an open question. We investigate this problem by examining the gravitational binding energy of competing equilibrium conf…

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hep-phastro-ph.HEhep-th2026年9月15日

Testing Higgs-Coupled Minimal Dark Matter with Solar Neutrinos after the LZ High-Recoil Event

Mattia Di Mauro

The LUX-ZEPLIN (LZ) Collaboration has reported a nuclear-recoil candidate at $248$ keV, motivating interpretations in terms of endothermic dark matter (DM). We investigate this signal in Higgs-coupled minimal dark matter (HC-MDM), where the same electroweak interaction responsible for the terrestrial recoil also induces DM capture in the Sun and a potentially observable high-energy neutrino signal. We independently determine the mass splittings required to reproduce the LZ event and perform an i…

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astro-ph.COastro-ph.GAastro-ph.HE2026年9月15日

A Dark-matter Origin of Little Red Dots: Early Seeding and Super-Bondi Accretion

Hua-Peng Gu, Fangzhou Jiang, Xian Chen, Ran Li, Zi-Xiang Jia

The "Little red dots" (LRDs) are a population of accreting supermassive black holes (SMBHs) in the early Universe which often exhibit undermassive or even undetectable stellar hosts. Their early emergence, high space density, and extremely large black-hole-to-stellar mass ratios pose a serious challenge to conventional seeding scenarios that rely on baryon for both the formation and growth of black holes. Here we demonstrate that the above anomalies can be naturally resolved if dark matter is se…

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astro-ph.EP2026年9月15日

Inhomogeneous Cloud Coverage and Altitude-Dependent Heat Transport on the Hot-Jupiter NGTS-10 Ab from its Optical-to-Infrared Phase Curve

Louis-Philippe Coulombe, Vivien Parmentier, Kevin B. Stevenson, Xianyu Tan, Everett Schlawin, Luis Welbanks, Jake Taylor, Yao Tang et al.

Hot-Jupiters, gas giant planets with equilibrium temperatures above 1,000 K, host large temperature gradients between their permanent day- and nightsides, resulting in circulation regimes that have no Solar System analogs. Past Kepler and Spitzer measurements show that the phase curves of these objects typically peak westward of the substellar point at optical wavelengths and eastward in the infrared, indicative of an interaction between circulation and cloud coverage. However, few hot-Jupiters…

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astro-ph.HEastro-ph.COastro-ph.GA2026年9月15日

A Standard Ultraviolet Continuum Can Hide Supercritical Accretion in GN-z11

Samik Mitra, Ramananda Santra

The ultraviolet continuum from a high-redshift accreting black hole is routinely used to infer its mass. GN-z11 offers a sharp test of whether that inference is secure. A thin-disk fit to its continuum gives an Eddington mass of $M_{\rm E}=1.12\times10^{7}\,\Msun$, an order of magnitude above the $\log(\Mbh/\Msun)=6.2\pm0.3$ inferred from broad N~\textsc{iv}. We show that this apparent tension is not imposed by the ultraviolet slope alone. We derive a closed-form criterion comparing the radius w…

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astro-ph.HEastro-ph.COastro-ph.GA2026年9月15日

Can Isotropic Thermal Conduction Heat One of the Hottest Cool Cores?

Samik Mitra, Ramananda Santra, Norbert Werner

Thermal conduction can act as a heating mechanism for cool-core clusters, yet the same transport must erode any temperature discontinuity it crosses. Ophiuchus permits both effects to be tested in the same atmosphere. Its temperature rises from about $1$ keV in the innermost core to $9$ keV at $r\sim30$ kpc, making conductive heating especially favorable, while two sharply resolved cold fronts independently constrain the same transport. \textcolor{black}{We construct a steady radial energy balan…

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astro-ph.HE2026年9月15日

Validating Inverse Fundamental-Plane IMBH Mass Estimates in the SKA/ngVLA Era

Shahram Abbassi, Samik Mitra, Ramananda Santra

The radio/X-ray/black-hole-mass Fundamental Plane (FP) is widely used to estimate masses of accreting intermediate-mass black hole (IMBH) candidates. Its inverse use is justified only when radio luminosity traces a compact jet core and X-rays arise from the same sub-Eddington hard-state accretion flow. We formulate an accretion-state validity criterion for inverse-FP masses using verified BH X-ray binary radio/X-ray tracks as the empirical reference. Using 424 detections from 21 BHXBs and candid…

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astro-ph.IM2026年9月15日

MUSHY: Multimodal Flow-Based Amortized Bayesian Inference for Spectroscopic Data Fusion

Jeff Shen

We are in an era of unprecedented spectroscopic data availability, with surveys such as APOGEE, GALAH, and DESI observing millions of stars. However, data are heterogeneous and to date, efforts to exploit synergies between surveys have been limited. In particular, there is a lack of principled methods that combine spectroscopic data from different surveys to improve inference of physical parameters. In this work we present a new method, MUSHY, for spectroscopic data fusion. MUSHY is an amortized…

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gr-qcastro-ph.HE2026年9月15日

Distinguishing cosmology, astrophysics and systematics: the Bayesian search for a primordial gravitational-wave background in next-generation observatories

Teagan A. Clarke, Sylvia Biscoveanu, Carl-Johan Haster

Next-generation gravitational-wave observatories like Cosmic Explorer will provide an unprecedented opportunity to probe the cosmological stochastic gravitational-wave background, providing insight into the early Universe that is inaccessible with other means. We investigate the prospects for measuring a Gaussian cosmological gravitational-wave background in Cosmic Explorer in the presence of a distinguishable, non-Gaussian foreground of binary black hole mergers, using a Bayesian search that si…

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astro-ph.IMastro-ph.GA2026年9月15日

Disentangling 3D Magnetic Field Geometry from Turbulence: A Polarization-Based Classification Method

Sophia Kressy, Fabian Heitsch

We develop a decision tree classifier that recovers 3D magnetic field geometry from synthetic polarization and position angle maps of a magnetized, turbulent field. We test the classifier for a series of geometries: Uniform, Wavy, Helical, and Hourglass. The classifier is calibrated across a range of Alfvénic Mach numbers and injected Stokes Q,U noise levels for each geometry. Our models show the median and skewness of the polarization fraction, as well as the position angle circular variance, v…

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astro-ph.GA2026年9月15日

Common Excitation Patterns of Star Formation, Active Galactic Nuclei, and Shocks in Seyfert Galaxies

Peixin Zhu, Lisa J. Kewley, Dominika Ł. Król, Giuseppina Fabbiano, Lars Hernquist, Ralph S. Sutherland, Anna Trindade Falcão, Martin Elvis et al.

The growth of galaxies and their central supermassive black holes is closely connected, yet the net effect of active galactic nuclei (AGN) feedback on host-galaxy star formation remains uncertain. AGN may enhance, suppress, or have little measurable impact on star formation, but distinguishing among these outcomes requires separating star-formation and AGN photoionization from shock excitation, which is expected in AGN-driven outflows but has been difficult to isolate. Here we apply a recently d…

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astro-ph.SRastro-ph.GA2026年9月15日

The JWST Proto-PAH Project: Detection of the methyl radical CH$_{3}$ in the highly evolved C-rich object SMP LMC 011

Jialu Li, D. A. García-Hernández, A. Manchado, Debayan Das, J. Cami, Els Peeters, G. C. Sloan, B. Aringer et al.

We report the first detection of the neutral methyl radical CH$_3$ in a highly evolved C-rich object, SMP LMC 011, using JWST MIRI/MRS. CH$_3$ is well fitted by an excitation temperature of $T_{\rm ex} \simeq$~190\,K and a column density of $N_{\rm tot}(\mathrm{CH_3}) \simeq 5.6\times10^{17}$ cm$^{-2}$. We also report the non-detection of ethane (C$_2$H$_6$), consistent with CH$_3$ reacting preferentially with unsaturated radicals rather than self-recombination, which may be inefficient in SMP L…

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astro-ph.HE2026年9月15日

Ce II-IV emission in kilonovae with R-matrix collision strengths and distorted wave recombination rates

Leo Patrick Mulholland, Niamh Ferguson, Luke J. Shingles, Catherine A. Ramsbottom, Connor P. Ballance, Stuart A. Sim

We provide transition probabilities and Maxwellian-averaged collision-strengths for the electron-impact excitation of Ce {\sc ii} - {\sc iv}. These ions are potentially abundant in kilonovae (KNe) and feature both forbidden and allowed transitions in the infrared. These atomic data are obtained using the {\sc grasp}$^0$ atomic structure code, interfaced with the non-perturbative {\sc darc} R-matrix close-coupling codes. We additionally use {\sc autostructure} to produce dielectronic and radiativ…

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astro-ph.HEastro-ph.CO2026年9月15日

Impact of uncertainties on the cosmic optical and infrared backgrounds on the propagation of astroparticles

Lucas Gréaux, Antonio Condorelli, Leonel Morejon, Karl-Heinz Kampert, Jonathan Biteau

When propagating through the universe, gamma rays at very-high energy (VHE, E > 100 GeV) and ultra-high energy cosmic rays (UHECRs, E > 1 EeV) can interact with the optical, infrared and microwave photon fields that permeate the universe. These interactions result in a characteristic absorption imprint in the spectra of extragalactic gamma-ray sources at VHE, and in a change in the mass-composition of UHECRs. The study of both VHE gamma rays and UHECRs therefore requires precise knowledge of the…

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astro-ph.GA2026年9月15日

Rubin Observatory Reveals a Dust-Shrouded Halo Globular Cluster in Ophiuchus

Aashay Pai, William Cerny, Andrew B. Pace, Alex Drlica-Wagner, Peter S. Ferguson, Marla Geha, Chin Yi Tan, Sasha N. Campana et al.

We present the discovery of the Milky Way satellite Rubin-GC1 (Rubin J1628-1735) using data from the NSF-DOE Vera C. Rubin Observatory's Early Data Preview 2. The system was discovered in the direction of the Galactic bulge with $(l, b) \sim (359^{\circ}, 21^{\circ})$ in a region of high stellar density and a foreground reddening of $E(B-V) \approx 0.7$. We simultaneously fit the morphology and isochrone parameters of Rubin-GC1, determining that it is a faint ($M_V = -2.4^{+0.5}_{-0.7}$) and com…

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nucl-thastro-ph.HEhep-phnucl-ex2026年9月15日

Neutron Skin Effects on Particle Emission in Heavy-Ion Collisions: A Topic Review with Astrophysical and Nuclear Structure Connections

Bao-Jun Cai, De-Qing Fang, Yu-Gang Ma

The neutron skin, defined by the difference between neutron and proton root-mean-square radii, is a characteristic manifestation of isospin asymmetry and an important probe of the isovector nuclear interaction. This focused review examines how neutron skins influence particle emission and collective dynamics in heavy-ion collisions, from the Fermi-energy regime to ultra-relativistic energies. By modifying the initial neutron and proton density profiles, the neutron skin affects the isospin compo…

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gr-qcastro-ph.HE2026年9月15日

Analysis of GWTC-3 with multiple quasicircular models

N. Manning, R. O'Shaughnessy

The interpretation of gravitational wave sources depends on the specific choice of model used to interpret signals. Previous analyses of GWTC-3 event candidates using SEOBNRv4PHM, IMRPhenomXPHM, and NRSur7dq4 have sometimes arrived at notably different conclusions about event properties. Subtle analysis settings and code differences can also produce notable differences. We revisit 60 publicly available events from the first three observing runs, released across GWTC-1, GWTC-2, GWTC-2.1, and GWTC…

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astro-ph.SR2026年9月15日

Multi-chromatic observations of classical Cepheids using the CHARA Array interferometer: Surface brightness-colour relation, projection factor, and limb-darkening

M. C. Bailleul, N. Nardetto, D. Mourard, A. Mérand, P. Kervella, A. Gallenne, G. Bras, J. Monnier et al.

The Baade-Wesselink (BW) method compares the linear and angular variations of Cepheids to derive their distance. This method is limited, however, by the projection factor, which relates the observed radial velocity to the true pulsation velocity of the star. Using simultaneous observations from the CHARA Array interferometer in the K, H, and R bands with the MYSTIC, MIRC-X, and SPICA combiners, respectively, we aim to understand the physics of Cepheid atmospheres better. Applying a specific meth…

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astro-ph.HE2026年9月15日

Modeling Gamma-Ray Bursts Using CRISP

Leonel Morejon, Therese Paulsen, Karl-Heinz Kampert

Astrophysical neutrinos are a clear identifier of photohadronic interactions in sources of Ultra-High-Energy Cosmic Rays (UHECRs). As the Pierre Auger Observatory has shown that UHECRs exhibit a composition heavier than protons at Earth, we expect that these heavy primaries undergo nuclear cascades due to photodisintegration in the dense source environments from which they originate. In this contribution, we will derive the neutrino spectra including those originating from nuclei undergoing phot…

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astro-ph.EP2026年9月15日

Thermophysical characterization of the potentially hazardous near-Earth object 2024 YR4

T. G. Müller, E. M. MacLennan, A. Y. Burdanov, B. J. Holler, A. S. Rivkin, J. de Wit, P. Pravec, M. Micheli et al.

The asteroid 2024 YR4 is a potentially hazardous Apollo-type near-Earth object. Its highly eccentric orbit produces close Earth-Moon encounters roughly every 4 years. A collection of light curves, including JWST-NIRCam data, allowed us to constrain the rotation period, spin pole, and convex shape solutions for the object. We analyzed two sets of JWST-MIRI observations obtained in three filters on 26 March 2025. The extracted photometry reveals rotationally driven thermal flux variations. The com…

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astro-ph.COastro-ph.GAhep-ph2026年9月15日

Using the Circumgalactic Medium of Dwarf Galaxies as a Calorimetric Dark Matter Detector

Abby Mintz, Digvijay Wadekar, Romain Teyssier

Many well-motivated dark matter (DM) scenarios, including dark photon DM, axion-like particles, sterile neutrinos, and primordial black holes, can deposit energy into ordinary matter and significantly raise the thermal energy of astrophysical gas. We present a simple, model-independent implementation of DM-induced heating in the RAMSES hydrodynamic simulation code, parameterized by an effective local heat-transfer rate $Γ_{\rm heat}$. Using simulations of an isolated gas-rich dwarf galaxy with p…

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