研究動向

astro-ph.GA2026年9月24日

How Magnetic Fields Regulate Cooling and Mixing in Turbulent Radiative Mixing Layers

Rajsekhar Mohapatra, Lachlan Lancaster, Drummond Fielding, Eliot Quataert, Greg L. Bryan

Turbulent radiative mixing layers (TRMLs) are expected wherever hot and cold gas move past one another, including in the solar corona, galactic winds, and cold filaments in galaxy clusters. These environments are often magnetized, but magnetic effects on mixing and cooling remain less well understood than in the hydrodynamic (HD) case. We present magnetohydrodynamic (MHD) simulations of TRMLs at resolutions up to $1024 \times 2048^2$, spanning fields aligned with and transverse to the shear, and…

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astro-ph.SRnucl-th2026年9月24日

Quantum Phase Transitions in Nuclei and the Origin of Rhodium

P. Agarwal, H. Schatz, A. Francis, F. Montes, B. Pol, L. Roberts

The astrophysical rapid neutron capture process (r-process) is a major nucleosynthesis process responsible for the production of elements heavier than copper. Prominent features in the observationally inferred r-process abundance distributions provide critical clues for astrophysical conditions and possible r-process sites. The lack of clear features for the r-process elements lighter than tellurium has led to a broad range of proposed possible scenarios and alternative processes that may produc…

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gr-qcastro-ph.GA2026年9月24日

Environmental Imprints of Dark Matter and Accretion Disks on Eccentric EMRIs around Kerr Black Holes

Hai-Chao Yuan, Yong Tang

Extreme-mass-ratio inspirals (EMRIs), systems in which a stellar-mass compact object spirals into a supermassive black hole ($M_1$), are prime targets for the space-based gravitational-wave interferometers and are acutely sensitive to their astrophysical environment. We quantify the joint imprint of a dark matter (DM) spike and an accretion disk on the waveforms of eccentric, equatorial Kerr EMRIs, integrating four modular effects---DM dynamical friction, DM self-gravity, Newtonian accretion-dis…

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gr-qcastro-ph.HEhep-phnucl-th2026年9月24日

Multi-messenger and multi-band signal from first-order phase transitions in proto-neutron stars

Christian Ecker, Mauro Giliberti, Luciano Rezzolla

A first-order phase transition (PT) alters a compact star on two scales: globally, via growth of a quark-matter core, and microscopically, via collision of quark bubbles, driving a simultaneous gravitational-wave (GW) emission in the kHz and MHz bands. Using a constrained ensemble of model-agnostic equations of state, we follow the accretion-driven evolution of proto-neutron stars through the PT and compute the resulting multi-band GW signal. The correlations found between the kHz emission and t…

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astro-ph.HEastro-ph.GA2026年9月24日

AGN winds and outflows: from accretion-disc scales to the host galaxy

Delphine Porquet

Ultra-fast outflows (UFOs), launched from the inner accretion disc in active galactic nuclei (AGN), are among the prime candidates for driving AGN feedback in their host galaxies. Determining their physical properties and energetics is therefore essential for assessing their impact on galaxy evolution. This review highlights recent observational progress, with particular emphasis on the groundbreaking insights enabled by high-resolution X-ray spectroscopy. The first X-Ray Imaging and Spectroscop…

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astro-ph.GA2026年9月24日

Galaxy And Mass Assembly (GAMA): The Most Isolated GAMA Galaxies

Steven Phillipps, Roberto De Propris, Malcolm N. Bremer, Phil A. James, Andrew M. Hopkins

While galaxies generally live in clusters and groups, particularly small groups, or other structures such as walls or filaments, some galaxies appear relatively `isolated', i.e. lacking in close neighbours. Here we use the GAMA survey, and an objective measure of isolation, to explore the most isolated galaxies. We then determine whether these have particular physical characteristics. We find that, as expected, while grouped galaxies split between blue, disk-like and star forming and red, sphero…

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astro-ph.GAastro-ph.CO2026年9月24日

Spatial segregation as the origin of anisotropic satellite quenching in haloes and beyond

Zhuoming Zhang, Weiguang Cui, Yun Chen, Romeel Davé

Satellite galaxies in massive halos are seen to be preferentially quenched along the major axes of their central galaxies. In contrast, the AGN jet tends to point along the minor axis, which imposes interesting constraints on the role of AGN feedback in satellite galaxy quenching. Here we use the SIMBA, TNG100, EAGLE, and feedback-free SIMBA cosmological simulations at $z=0$ to show that this satellite anisotropy primarily originates from spatial segregation between quenched and unquenched popul…

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astro-ph.SR2026年9月24日

Estimates of magnetic field strength in the solar corona using observations of thermal radio emission at low frequencies

Shaik Sayuf, Kathiravan C, Ramesh C

Measurements of the magnetic field strength in the solar corona at heliocentric distances $r\,{\gtrsim}\,1.1\,R_{\odot}$, using observations other than transient radio bursts, are rare. Circular polarization observations of thermal bremsstrahlung radio emission at frequencies $ }\,1.1R_{\odot}$ in the solar corona, can be effectively used for this purpose. The thermal bremsstrahlung emission is randomly polarized, but in the presence of a magnetic field it propagates in two oppositely polarized…

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astro-ph.GA2026年9月24日

Potential binary supermassive black holes in Markarian 231 as a scientific case for the spectropolarimeter POLLUX

Biedermann. J, Marin. F, Neiner. C, Bouret. Jean-Claude

It is now widely accepted that a supermassive black hole (SMBH) resides in the core of nearly every galaxy. Within the context of mergers of galaxies, the central SMBHs from each system should form a gravitationally bound binary system. Given the frequency of galaxy mergers throughout cosmic time, the existence of such binary SMBHs is likely to occur within active galactic nuclei. However, identifying them observationally remains highly challenging. The majority of reported candidates rely on in…

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astro-ph.GA2026年9月24日

Probing binary supermassive black hole in quasars tough spectropolarimetry

J. Biedermann, F. Marin

Nearly all galaxies are believed to host a supermassive black hole at their center. In the context of galaxy mergers, the SMBHs from the progenitor galaxies are expected to form a bound binary system. Given the high frequency of such mergers throughout cosmic time, binary SMBHs should be relatively common in active galactic nuclei (AGNs). Yet, their direct detection remains a major observational challenge, with most candidates inferred only through indirect signatures. The quasar Markarian 231 p…

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astro-ph.EPastro-ph.IM2026年9月24日

Exoplanet Detection Techniques: Radial Velocity

Rafael Luque, Matthew R. Standing

The radial velocity (RV) technique enabled the discovery of the first exoplanets orbiting Sun-like stars. Since then, improvements in precision and sensitivity have enabled the detection of smaller planets, bringing us closer to the goal of discovering Earth analogs in the coming years. In this chapter, we provide an overview of the radial velocity method. We begin with a detailed description of the technique, including how precise radial velocities are measured and what limitations must be addr…

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astro-ph.EPastro-ph.IM2026年9月24日

Exoplanet Detection Techniques: Radial Velocity

Rafael Luque, Matthew R. Standing

The radial velocity (RV) technique enabled the discovery of the first exoplanets orbiting Sun-like stars. Since then, improvements in precision and sensitivity have enabled the detection of smaller planets, bringing us closer to the goal of discovering Earth analogs in the coming years. In this chapter, we provide an overview of the radial velocity method. We begin with a detailed description of the technique, including how precise radial velocities are measured and what limitations must be addr…

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astro-ph.SRastro-ph.EPastro-ph.GA2026年9月24日

JWST Observations of the Metal-poor T Dwarf WISEA J155349.96+693355.2: The First Brown Dwarf Associated with the Gaia-Enceladus Milky Way Substructure

Aaron M. Meisner, Adam J. Burgasser, Chih-Chun Hsu, Sherelyn Alejandro Merchan, Jacqueline K. Faherty, Genaro Suárez, ZengHua Zhang, Roman Gerasimov et al.

We present JWST NIRSpec and MIRI observations of the metal-poor T dwarf WISEA J155349.96+693355.2. The combined NIRSpec/prism plus MIRI/LRS spectrum (R ~ 100) provides 0.6-12 $μ$m spectroscopic coverage that reveals the presence of H$_2$O, CH$_4$, and NH$_3$ absorption features, enhanced collision-induced H$_2$ absorption, and weak or absent CO and CO$_2$ absorption, all indicators of a metal-poor low-temperature atmosphere. Comparison of the spectral data to a suite of atmosphere models yields…

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astro-ph.SRastro-ph.EPastro-ph.GA2026年9月24日

JWST Observations of the Metal-poor T Dwarf WISEA J155349.96+693355.2: The First Brown Dwarf Associated with the Gaia-Enceladus Milky Way Substructure

Aaron M. Meisner, Adam J. Burgasser, Chih-Chun Hsu, Sherelyn Alejandro Merchan, Jacqueline K. Faherty, Genaro Suárez, ZengHua Zhang, Roman Gerasimov et al.

We present JWST NIRSpec and MIRI observations of the metal-poor T dwarf WISEA J155349.96+693355.2. The combined NIRSpec/prism plus MIRI/LRS spectrum (R ~ 100) provides 0.6-12 $μ$m spectroscopic coverage that reveals the presence of H$_2$O, CH$_4$, and NH$_3$ absorption features, enhanced collision-induced H$_2$ absorption, and weak or absent CO and CO$_2$ absorption, all indicators of a metal-poor low-temperature atmosphere. Comparison of the spectral data to a suite of atmosphere models yields…

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physics.comp-phastro-ph.HEhep-phphysics.plasm-ph2026年9月24日

Monte Carlo sampling of first-order QED processes in laser and pulsar plasmas

Verneri Sarjomaa, Joonas Nättilä

Monte Carlo sampling of strong-field quantum electrodynamics processes underpins simulations of high-intensity laser experiments and of astrophysical compact-object magnetospheres. Sampling an event requires the total rate of the process together with the cumulative probability that determines how energy is partitioned between the produced particles. Simulations typically tabulate both in advance and invert the tabulated probability numerically. Here we replace this procedure with elementary-fun…

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astro-ph.HE2026年9月24日

Comparative spectro-temporal study between 1A 1246$-$588 and 4U 0614$+$091 using AstroSat

Suchismito Chattopadhyay, Soma Mandal, Ranjeev Misra

We present a comparative broadband spectro-temporal study of the ultra-compact X-ray binary (UCXB) candidates 1A 1246$-$588 and 4U 0614$+$091 using AstroSat observations. Spectral modelling shows that the spectrum of 1A 1246$-$588 is well described by thermal Comptonization and a soft thermal disk component. We identify a candidate narrow quasi-periodic oscillation (QPO) at $993\pm4$ Hz with a single-detector significance of $ ~ 3.7σ$, tentatively consistent with the upper kHz QPO previously rep…

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astro-ph.IM2026年9月24日

GIMLI: a toolkit connecting linear and non-linear magnetohydrodynamic regimes

Jordi De Jonghe, Nicolas Brughmans, Rony Keppens

In this work, we present the General Interface for MPI-AMRVAC / Legolas Interconnection (or GIMLI, for short) as a toolkit for in-depth (magneto)hydrodynamic studies combining linear and non-linear methods. Acting as a bridge between the linear (M)HD spectroscopy code Legolas and the non-linear simulation code MPI-AMRVAC, GIMLI facilitates the initialization of non-linear MPI-AMRVAC simulations with linear solutions. We showcase this functionality on both Cartesian and cylindrical setups, coveri…

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hep-phastro-ph.COastro-ph.HE2026年9月24日

Metastable Neutron Stars as Transient-Rate Detectors of Heavy Dark Matter

Ziwen Yin, Hong-Yi Zhang

Metastable neutron stars can undergo catastrophic conversion to quark-containing stars when a localized energy deposition nucleates a critical bubble. We show that dark-matter-induced conversions can be constrained by the present transient rate of the neutron star population, rather than by the survival of any individual hadronic star as often assumed in previous literature. Population depletion makes the present transition rate nonmonotonic: weak triggering produces few transitions, whereas suf…

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astro-ph.GAastro-ph.HEastro-ph.SR2026年9月24日

A Census of Stellar-mass Black Holes in the Milky Way with POPKIN. I. Isolated Black Holes

Jian-Guo He, Yong Shao, Yu-Dong Nie, Gui-Yu Wang, Xiao-Tian Xu, Chen Wang, Xiao-Jie Xu, Xiang-Dong Li et al.

Gravitational-wave observations have revealed hundreds of stellar-mass black holes, yet only about two dozen are known in the Milky Way, almost all in binaries. We present POPKIN, a Python framework that couples single- and binary-star evolution with Galactic orbital dynamics to trace black-hole progenitors from the zero-age main sequence to the present-day isolated black-hole (IBH) population. Across ten models varying the supernova (SN) prescription, mass-transfer efficiency, and common-envelo…

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astro-ph.SRastro-ph.EPastro-ph.GA2026年9月24日

Metal-Poor Stars as Metal-Rich Impostors via Planet Engulfment

Zongheng Li, Shi Jia, Jie Su, Shang-Fei Liu, Jianheng Guo

Planet engulfment leads to planetary mass accretion and angular momentum deposition into the stellar envelope. This study uses MESA models to investigate the long-term impact of engulfment on stellar metallicity and rotational velocity, as well as the effect of rotational mixing on metal enrichment. Our models show that engulfment occurring during the late main-sequence (MS) stage yields significantly higher surface enrichment than at the ZAMS. Rotational mixing generally suppresses enrichment;…

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astro-ph.SRastro-ph.EPastro-ph.GA2026年9月24日

Metal-Poor Stars as Metal-Rich Impostors via Planet Engulfment

Zongheng Li, Shi Jia, Jie Su, Shang-Fei Liu, Jianheng Guo

Planet engulfment leads to planetary mass accretion and angular momentum deposition into the stellar envelope. This study uses MESA models to investigate the long-term impact of engulfment on stellar metallicity and rotational velocity, as well as the effect of rotational mixing on metal enrichment. Our models show that engulfment occurring during the late main-sequence (MS) stage yields significantly higher surface enrichment than at the ZAMS. Rotational mixing generally suppresses enrichment;…

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astro-ph.GA2026年9月24日

Optical spectropolarimetry of extreme H$α$ line profiles in seven active galactic nuclei

J. Biedermann, F. Marin, D. Hutsemékers, C. M. Gaskell

Some active galactic nuclei (AGNs) are known to show extremely asymmetric broad Balmer lines, with their main peak redshifted or blueshifted by thousands of km s$^{-1}$, severely challenging our understanding of the standard AGN paradigm. We wanted to explore the causes of such asymmetric features by carrying out a spectropolarimetric study of a sample of bright AGNs with known extreme Balmer line profiles. We present optical spectropolarimetry of seven bright (V $<$ 17.5) Seyfert-1 galaxies obt…

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astro-ph.GAastro-ph.EPastro-ph.HE2026年9月24日

Binary-pulsar Timing: A 3D Solar-System Accelerometer and Unknown-Source Probe

Zheng-Long Wang, Zi-Qing Xia, Bo Zhang, Yi-Zhong Fan

The acceleration of the Solar System barycenter (SSB) offers a unique precision probe of the local gravitational environment, enabling searches for otherwise invisible gravitating sources such as Planet Nine and nearby (primordial) black holes. Using the binary-pulsar timing measurements, we develop an analysis framework that combines the line-of-sight differential accelerations of 26 binary pulsars to jointly reconstruct the three-dimensional acceleration of the SSB and place directional upper…

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astro-ph.HEastro-ph.SR2026年9月24日

SN 2025aedz: A typical short-plateau type IIP supernova with rapid post-peak decline

Bo Wang, Luhan Li, Chengyuan Wu, Jujia Zhang, Yongzhi Cai, Yize Dong, Xuefei Chen, Zhanwen Han et al.

Type IIP supernovae (SNe IIP) are the most common subclass of core-collapse SNe in observations. However, SNe IIP with short plateaus of the order of tens of days are rarely observed. The progenitors for this kind of SN can help to address the red supergiant issue in stellar evolution. In this article, we report optical photometry and spectroscopy of SN\,2025aedz, a rapidly post-peak declining SN IIP with a typical short plateau. It exhibits a peak absolute magnitude of $M_r=-17.16\pm0.03$\,mag.…

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astro-ph.GAastro-ph.HE2026年9月24日

Stellar Collisions from Self-consistent Stellar Dynamics Around Growing Supermassive black Holes

Fupeng Zhang, Pau Amaro Seoane

The centers of galaxies harbor the densest stellar environments, where a massive black hole (MBH) accelerates stars to such high velocities that direct collisions can result in high-energetic phenomena, such as gravitational wave sources, kilonovae, and supernova-like transients. These collisions can reshape the cluster's density profile and release gas that can be subsequently accreted by the MBH. However, the evolving rates of such phenomena from self-consistent dynamics around mass-growing MB…

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gr-qcastro-ph.HE2026年9月24日

Learning Inspiral-Merger-Ringdown Waveforms from a Post-Newtonian Baseline

Arghya Chattopadhyay, Shilpa Kastha

Modeling the full inspiral-merger-ringdown signal requires combining analytically controlled inspiral physics with the nonlinear strong-field information supplied by numerical relativity. We represent the numerical relativity contribution beyond an analytic inspiral waveform as residual amplitude and phase corrections. Retaining the leading-order frequency-domain amplitude and the $3.5$ Post-Newtonian TaylorF2 phase, we use a Kolmogorov-Arnold network to learn these residual corrections from SXS…

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astro-ph.GAhep-ph2026年9月24日

Mass-Dependent Dark Matter Deficit from Inelastic Scattering

Daneng Yang, Yi-Zhong Fan

Recent stellar-kinematic and neutral-hydrogen observations indicate a dark matter deficit within the central tens of kiloparsecs of nearby galaxies that grows systematically with stellar mass relative to hydrodynamical simulations. We show that this mass dependence can arise from exothermic inelastic dark matter with strongly velocity-dependent scattering. Two nearly degenerate dark matter states interact through vector and scalar mediators with opposite-sign contributions and unequal ranges. Th…

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astro-ph.SRastro-ph.EP2026年9月24日

On the altitude profile of lower ionospheric D-region response time delay during solar flares

Sayak Chakraborty, Rakhi Paul, Tamal Basak

The D-region ionosphere is sluggish in nature while responding to the incoming solar radiation. We study the altitude (h) profile of mid-latitude D-region response time delay (Delta t) during three chosen solar flares, namely, C5.2, M5.2, and X2.2 classes. We solve "electron continuity equation" numerically at each and every h to obtain Delta t-h profile. We investigate the 1) latitudinal variation (over both Northern and Southern hemispheres) and 2) seasonal variation (throughout the year) of D…

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astro-ph.GA2026年9月24日

High-z galaxies with the JWST and the ELT: Toward Ever-finer Detail

Eros Vanzella

The exploration of the early Universe is being transformed by the James Webb Space Telescope (JWST), which delivers unprecedented angular resolution at infrared wavelengths and opens a unique window redward of the K band (2um). Thanks to NIRCam, NIRISS, NIRSpec, and MIRI instruments, which provide both imaging and spectroscopy with exquisite efficiency, new classes of sources have emerged within the first years of operations. The first half-Gyr of cosmic time is now routinely probed, revealing m…

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astro-ph.IMastro-ph.GAastro-ph.SR2026年9月24日

Uber-calibration-based Two-level Radial-velocity Zero-point Correction for APOGEE

Jinming Zhang, Haibo Yuan, Zhijia Tian

APOGEE delivers high-resolution, near-infrared spectroscopy and highly precise radial velocities (RVs), with extensive repeat observations spanning more than a decade. Long-term RV repeatability is nevertheless limited by instrumental zero-point systematics: exposure-to-exposure drift and fiber-dependent offsets that are only partially tracked by lamp-based wavelength calibration, and that can evolve as fibers are serviced or replaced. We infer and remove these zero points directly from the publ…

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