研究動向

astro-ph.SRastro-ph.HE2026年7月28日

V407 Vul: a triple star system with an AM CVn detectable by gravitational wave observatories

James Munday, Antonio C. Rodriguez, Nicole Reindl, Nina Mackensen, Tin Long Sunny Wong, S. P. Littlefair, Ingrid Pelisoli, Alex Brown et al.

The AM CVn class includes mass transferring, ultra-compact double white dwarf binaries with orbital periods on the timescale of minutes. A long-standing puzzle is that none of the roughly fifty ultra-compact, "verification binaries" which are easily detectable in the millihertz gravitational wave regime reside in a triple star configuration. Much evidence has hinted at V407 Vul being an inspiraling, double white dwarf AM CVn with an orbital period of 569s. Yet, a decisive confirmation has proved…

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astro-ph.EP2026年7月28日

The Influence of Dust Composition on Accretion Outbursts

Nicolas Kaufmann, Anna B. T. Penzlin, Alfie Robinson, Alexandros Ziampras, Tilman Birnstiel, Richard Booth

Context: Episodic accretion outbursts have been shown to occur in protoplanetary discs due to thermal instability at the inner edge of the dead zone. These outbursts periodically heat up the dead zone, significantly altering the composition/chemistry and accretion onto the star. Aims: We investigate how these accretion outbursts affect the inner disc composition and how different dust compositions and properties affect the outbursts' dynamics. Methods: We run vertically integrated axis-symmetric…

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astro-ph.HE2026年7月28日

Timing and Spectral Analysis of the 2024 Outburst of 2S 1553$-$542 with NuSTAR and NICER

Haifan Zhu, Wei Wang, Wen Yang, Mariano Mendez, Chenxu Gao, Ziyi Xu, Pengfu Tian

We report a timing and spectral study of the 2024 outburst of the Be/X-ray binary pulsar 2S~1553$-$542 using \textit{NuSTAR} and \textit{NICER} observations. From the \textit{NuSTAR} light curve we measure a pulse period of $9.285022\pm0.000001$~s. The energy-resolved pulse profiles are dominated by a single peak and show a wing-like structure most clearly in the $12$--$22$~keV band. The pulsed fraction remains above 60\% and increases with energy. The phase-averaged \textit{NuSTAR} spectrum is…

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astro-ph.HE2026年7月28日

Fast optical spectroscopic observations of PSR J1023+0038 over one orbital period

M. M. Messa, M. C. Baglio, P. D'Avanzo, G. Illiano, F. Coti Zelati, K. Alabarta, D. de Martino, Y. D. Hu et al.

Transitional millisecond pulsars (tMSPs) are neutron-star binaries that switch between rotation-powered and accretion-powered states, providing a key link between low-mass X-ray binaries and millisecond radio pulsars. In their sub-luminous disc state, these systems exhibit complex variability whose origin is still debated. We present high-time-resolution optical spectroscopic observations of the tMSP PSR J1023+0038 obtained during its sub-luminous disc state. Our dataset covers for the first tim…

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astro-ph.EP2026年7月28日

Cloud and ammonia vertical profiles in the equatorial atmosphere of Jupiter determined from visible to near-IR observations made by VLT/MUSE, Cassini/VIMS, IRTF/SpeX and Juno/JIRAM

Patrick G. J. Irwin, Asier Anguiano-Arteaga, Michelle Colantoni, Joseph Penn, Santiago Pérez-Hoyos, Davide Grassi, Alessandro Mura, Charlotte L. B. Alexander et al.

We present a combined cloud/ammonia model for Jupiter's equatorial atmosphere from 0.1 to 10 bar, consistent with observations made at a range of observation geometries from 0.35 to 5.15 $μ$m by VLT/MUSE, Cassini/VIMS, IRTF/SpeX and Juno/JIRAM. Our cloud model has three components: 1) an optically-thick lower cloud (radius $r$$\sim$$10$ $μ$m) at 1-2 bar; 2) an optically-thin upper cloud ($r$$\sim$$10$ $μ$m) at $\sim$0.55 bar; and 3) a layer of blue-absorbing chromophore particles ($r$$\sim$$0.2$…

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physics.opticsastro-ph.EPastro-ph.IM2026年7月28日

Geometry resolved atomic oxygen risk assessment for very low earth orbit spacecraft

Gun Hi Won, Hyun Jung Kim, SongYi Park, ChangWon Seo, Eunji Lee, SeongSik Yoon

Atomic oxygen (AO) is a major durability concern for spacecraft in very low Earth orbit (VLEO), yet orbit-averaged fluence does not resolve exposure on individual surfaces and internal components. This study develops a geometry-resolved AO assessment by coupling NRLMSISE-00, HWM07, and SYSTEMA ATOMOX. One-year simulations were performed for a 350 km circular Sun-synchronous orbit at LTAN 06:00 and 12:00 using a baseline spacecraft, a wedge-modified body, and two synthetic aperture radar antenna…

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astro-ph.GAastro-ph.EPastro-ph.SR2026年7月28日

Chemistry of Dark Molecular Clouds

Yuri Aikawa, Izaskun Jimenez-Serra, Paola Caselli

Recent molecular line surveys, particularly toward the starless core TMC-1 CP, have greatly expanded the inventory of interstellar molecules, revealing numerous isomers and even aromatic species. Their diverse formation pathways---from ion-molecule reactions to the possible fragmentation of carbonaceous grains---remain under debate, linking chemistry to the life cycle of the interstellar medium. Simple tracers such as carbon chains and deuterated ions are used to probe the physical conditions an…

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astro-ph.SR2026年7月28日

Decay Length of Slow Magnetoacoustic Waves in the Solar Corona using SDO/AIA and SolO/EUI

R. L. Meadowcroft, N. Narang, D. Berghmans, M. Dominique, V. M. Nakariakov

Slow magnetoacoustic waves have been observed in the solar corona for decades; yet, existing theories do not fully explain the wide range of observed decay lengths, and measurements from different instruments frequently disagree. We present two events with simultaneous SDO/AIA and Solar Orbiter/EUI-HRIEUV observations of slow waves in sunspot-anchored coronal fan feathers. In Event 1, the LoS are separated by 16.2 degrees, while in Event 2, they are almost parallel. Using time-distance analysis,…

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astro-ph.HE2026年7月28日

The afterglow of gamma-ray burst - supernova connections

Marco Muccino, Rahim Moradi, Yu Wang

The X-ray afterglow of several long gamma-ray bursts (LGRBs) associated with broad line type Ib/c supernovae (SNe) exhibits a standard non-thermal afterglow, commonly attributed to synchrotron emission from a relativistic jet, and an evolving thermal component whose physical origin is still debated. We investigate whether these thermal and non-thermal components can be described within a common analytical framework and whether their temporal evolution can provide insight into the physical connec…

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astro-ph.SR2026年7月28日

A Systematic Study of Quiescent and Outburst Properties of X-ray-bright Young Stellar Objects Using XMM-Newton

Koki Sakuta, Ikuyuki Mitsuishi, Seiya Sasamata, Daigo Nonaka, Mai Yamashita, Shin Toriumi, Takato Tokuno, Yohko Tsuboi et al.

Young Stellar Objects (YSOs) exhibit strong X-ray emission, widely attributed to magnetic reconnection and magnetospheric accretion; however, owing primarily to limited photon statistics, observational tests of these mechanisms have often relied on simplified analyses, leaving room for more precise constraints on their emission processes. We aim to derive the X-ray properties of X-ray-bright YSOs selected from multiple star clusters and investigate their emission mechanisms through an approach f…

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astro-ph.GA2026年7月28日

From compact jets to extended lobes: radio morphologies of distant quasars at z > 4

K. É. Gabányi, M. Kunert-Bajraszewska, A. Krauze, S. Frey, M. Krezinger, Z. Paragi, H. Cao, T. An et al.

High-redshift quasars play an essential role in studying the growth and evolution of supermassive black holes and active galactic nuclei (AGN). Radio-loud quasars additionally enable us to investigate the interactions between the jets and their environment. We aimed to reveal the radio morphology of three radio quasars at redshifts z>4 that contain milliarcsecond (mas) scale compact radio features according to previous very long baseline interferometry (VLBI) observations, but show significant f…

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astro-ph.HE2026年7月28日

Residual Galactic binary foreground in LISA stochastic gravitational-wave background inference: source power concentration and spectral degeneracy

Ruo-Yu Guan, Yan Wang

Galactic compact binaries are expected to form a dominant foreground in the millihertz band of the Laser Interferometer Space Antenna (LISA). Residual power from injected sources that do not meet the adopted recovery criteria can bias stochastic gravitational-wave background (SGWB) inference or increase its uncertainty. We use LISA Data Challenge 2A Sangria injections and the Erebor comparison table to construct a catalog residual spectrum between 0.4 and 6.0 mHz with orbit-averaged long-wavelen…

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astro-ph.EPastro-ph.IM2026年7月28日

GRaTer-JAX: An Accelerated Package for Debris Disk Modeling

Mihir Kondapalli, Briley L. Lewis, Jaren N. Ashcraft, Maxwell A. Millar-Blanchaer

GRaTer-JAX is a Python package for modeling debris disks, disks of dust around stars that pro- vide important clues about the formation, structure, and evolution of planetary systems. GRaTer (Generator of Ring-like, axisymmetric, optically Thin dust disks for regularized fitting) is a debris disk modeling framework originally developed for generating and fitting models of optically thin, ax- isymmetric dust disks. JAX is a Python package for high-performance computing that implements just-in-tim…

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astro-ph.HE2026年7月28日

SN 2022xus: bridging the gap between Type IIP and IIL supernovae

Monalisa Dubey, Kuntal Misra, Naveen Dukiya, Kumar Pranshu, Raya Dastidar, K. Azalee Bostroem, Yize Dong, Joseph R. Farah et al.

We present optical photometric and spectroscopic observations of the Type~II supernova SN~2022xus. The SN reached its peak {\em V} band magnitude of $-16.32$ mag within $\sim$7 days of explosion, followed by a plateau phase lasting $\sim$94 days with a declination rate of $\sim$1.2 mag (100 day)$^{-1}$. Early time spectra exhibit broad features that could be caused by the blending of several high-ionisation lines, likely arising from a relatively weak interaction between the SN ejecta and the su…

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gr-qcastro-ph.HEhep-th2026年7月28日

Parametrized beyond-Teukolsky framework in the time domain

Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas, Salvatore Capozziello

Modifications to General Relativity can significantly alter the perturbative response of black holes, leaving imprints on quasinormal-mode spectra, waveform amplitudes and phases, and late-time tails. The parametrized beyond-Teukolsky framework was introduced to capture possible deviations from Kerr dynamics, but the ringdown has so far only been explored as an eigenvalue problem. We present the first time-domain implementation of this framework and perform (2+1)-dimensional scattering experimen…

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astro-ph.GAastro-ph.SR2026年7月28日

Interferometric molecular line observations toward the 21 μm protoplanetary nebula IRAS 06530-0213

Hao-Min Sun, Zhuang Zhang, Jun-Yang Liu, Sheng-Li Qin, Yong Zhang

The identification of the $21\,μ\mathrm{m}$ feature in some protoplanetary nebulae remains a longstanding puzzle, whose interpretation requires characterization of the molecular gas environments of associated sources. Here, we present high-resolution interferometric observations from the Northern Extended Millimeter Array toward the $21\,μ\mathrm{m}$ protoplanetary nebula IRAS 06530-0213. Multiple molecular transitions of $\mathrm{HC_3N}$, $\mathrm{C_4H}$, and $\mathrm{SiC_2}$ are detected and s…

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astro-ph.GA2026年7月28日

From Starburst to Quenching: Physical Properties of Extremely Compact Starbursts at z$\sim$0.1

Can Xu, Mengyuan Xiao, Min Bao, Qiusheng Gu, Longji Bing, Yong Shi, Yifei Jin, Shiying Lu et al.

The compaction phase plays a crucial role in galaxy evolution, as it is strongly linked to star formation activities and structural transformation. We have identified a sample of extremely compact starburst galaxies (eCSBs) at low redshift~(z$\sim$0.1), which represent this critical evolutionary stage. These eCSBs are massive outliers with intense star formation and high infrared luminosities comparable to (U)LIRGs, while their structure already resembles quiescent galaxies. To investigate their…

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astro-ph.IMastro-ph.CO2026年7月28日

LiteBIRD Mission Overview after Mission Reformation

LiteBIRD Collaboration, K. Aizawa, H. Akamatsu, R. Akizawa, E. Allys, A. Anand, D. Audley, J. Aumont et al.

LiteBIRD is a JAXA-led space mission designed to produce all-sky microwave polarization maps. Its primary science goal is to test representative inflationary models by measuring the cosmic microwave background $B$-mode polarization generated by primordial gravitational waves, while also providing new insights into cosmology, particle physics, and astrophysics. The mission concept has been updated following the reformation activities initiated after the Mission Definition Review in 2024. The curr…

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astro-ph.HEastro-ph.COastro-ph.GA2026年7月28日

Tightening Bounds on Warm Dark Matter with High-Redshift Gamma-Ray Bursts

Jun-Jie Wei, Jing-Meng Hao, Ding-Fang Hu, Yang Liu, Bao Wang, Xi Kang, Xue-Feng Wu

The cold dark matter paradigm successfully explains large-scale structure but faces persistent tensions on small scales. Warm dark matter (WDM) with $\mathrm{keV}$-scale particles can alleviate these issues by suppressing small-scale structure formation. The presence of collapsed structures at high redshifts places strong lower limits on the WDM particle mass $m_x$. Gamma-ray bursts (GRBs) are ideal high-redshift probes due to their extreme brightness. Using the most recent \emph{Swift} GRB data…

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astro-ph.EPastro-ph.GA2026年7月28日

KMT-2025-BLG-0975Lb and KMT-2025-BLG-1160Lb: Two Uranus-Mass Planets Beyond the Snow Line Discovered by Microlensing

Cheongho Han, Chung-Uk Lee, Andrzej Udalski, Andrew Gould, Michael D. Albrow, Sun-Ju Chung, Youn Kil Jung, Kyu-Ha Hwang et al.

We present the analysis of two planetary microlensing events, KMT-2025-BLG-0975 and KMT-2025-BLG-1160, discovered during the 2025 Galactic bulge microlensing season through high-cadence survey observations. In both events, short-duration anomalies near the peaks of the lensing light curves reveal the presence of planetary companions. Light-curve modeling yields planet-to-host mass ratios of $q = 8.6 \times 10^{-4}$ for KMT-2025-BLG-0975 and $1.3 \times 10^{-4}$ for KMT-2025-BLG-1160. For KMT-202…

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gr-qcastro-ph.HEastro-ph.IM2026年7月28日

GSpyNetTree-O4: an event validation tool used in the fourth LIGO-Virgo-KAGRA observing run

Sofia Alvarez-Lopez, Man Leong Chan, Franz S. Herbst, Dhatri Raghunathan, Airene Ahuja, Annudesh Liyanage, Julian Ding, Alejandro Garcia-Varela et al.

The frequent presence of non-Gaussian transient noise, or glitches, in gravitational-wave detector data can affect gravitational-wave searches, parameter estimation, and downstream analyses. To identify and mitigate transient noise near gravitational-wave candidates in a timely manner, the LIGO-Virgo-KAGRA Collaboration employs the Data Quality Report. In the fourth observing run, GSpyNetTree-O4 was deployed within this framework as a tool for glitch classification and event validation. We descr…

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physics.plasm-phphysics.space-ph2026年7月28日

Statistical structure of canonical kinetic equilibrium with sheared flow

Daniel W Crews

In isothermal kinetic equilibrium of a plasma with sheared flow, the electrostatic potential is the cumulant generating function of the velocity distribution, encoding all non-Maxwellian statistics. Consequently, of the polynomial-form flux-function equilibrium flows, only the linear one is admissible, and every other equilibrium sheared flow has non-zero cumulants to all orders. The identity is shown for a sheared-flow screw pinch and specialized to the Z pinch, theta pinch, and Harris sheet. A…

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physics.plasm-phastro-ph.SR2026年7月28日

Emergence and Detection of Electron-Scale Current Sheets in Turbulence with MMS Observations and fully kinetic 3D simulations

Zachary Davis, Alexandros Chasepis, Colby Haggerty, Luca Comisso, Derek Sikorski

The solar wind is characterized by turbulence, where a cascade produces intermittent current structures called current sheets (CS) that efficiently dissipate energy into the plasma. These have been studied with in situ spacecraft observations, but single-spacecraft techniques such as the partial variance of increments (PVI) are inherently limited since they lack spatial context. A combined analysis of in situ observations and numerical simulations can provide significant insight into the propert…

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astro-ph.SRastro-ph.HEgr-qc2026年7月28日

Magnetic pressure anisotropy in ultra-dense white dwarfs: Landau quantization and neutronization effects

Edson Otoniel, Juan M. Z. Pretel, Victor B. T. Alves, César O. V. Flores, Clésio E. Mota

Strong magnetic fields modify the thermodynamics of white dwarf (WD) matter by quantizing the transverse motion of degenerate electrons into Landau levels and splitting the pressure into components parallel and perpendicular to the magnetic field. We investigate how this microscopic pressure anisotropy affects ultra-dense WD sequences when Coulomb lattice contributions, electron capture thresholds, neutron drip limits, and nuclear composition are treated consistently in the equation of state (Eo…

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astro-ph.GAastro-ph.SR2026年7月28日

Radiation-Driven Evolution and Gas Kinematics of the Bright-Rimmed Cloud SFO 25

Puja Porel, Archana Soam, William D. Vacca, Janik Karoly

Bright-rimmed clouds (BRCs) are valuable laboratories for investigating how ionizing radiation from massive stars reshapes molecular clouds and influences star formation. We present a kinematic and dynamical study of the BRC SFO 25 using archival JCMT-HARP observations of the $^{12}$CO, $^{13}$CO, and C$^{18}$O ($J = 3-2$) transitions at an angular resolution of about 14-15 arcsec (0.051-0.054 pc). Gaia parallaxes of young stellar objects associated with the cloud yield a revised distance placin…

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astro-ph.SRnucl-th2026年7月28日

Localized magnetic pressure anisotropy in strange dwarfs with crystalline crusts

Mila Leite Garcia Reis, Daniela Eller Uliana, Jaziel G. Coelho, Edson Otoniel

We study equilibrium sequences of magnetized strange dwarfs composed of a self bound MIT bag strange matter core, with \(B_{\rm bag}^{1/4}=145\,{\rm MeV}\), and an ordinary crystalline crust. The aim is to determine how nuclear composition changes and magnetic pressure anisotropy in the crust modify the mass radius relation. The strange core is kept isotropic, while the crust is described either by pure nuclei stopped at the first inverse beta threshold or by electron capture sequences extended…

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astro-ph.GA2026年7月28日

Linking dynamics and chemistry in barred galaxies through action-space mapping

Tetsuro Asano, Victor P. Debattista, Michiko S. Fujii

We aim to extend the action-based framework, proposed by a previous study, for assigning chemical information to collisionless $N$-body simulations of barred galaxies, enabling more realistic comparisons with observations. We developed a new method to map chemistry of star-forming $N$-body+hydrodynamical simulations (donor models) onto pure $N$-body simulations (target models) using a matching algorithm. We applied the method to two barred $N$-body galaxies, one Milky Way (MW)-like with a classi…

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astro-ph.GA2026年7月28日

A Deep Look at the Ultra-Faint Milky Way Satellite Virgo III with Rubin Observatory Data Preview 2

Aashay Pai, Alex Drlica-Wagner, Peter S. Ferguson, William Cerny, Chin Yi Tan, Jeffrey L. Carlin, Yumi Choi, Željko Ivezić et al.

We analyze the ultra-faint Milky Way satellite Virgo III using data from the Vera C. Rubin Observatory Data Preview 2 (DP2). Virgo III was observed in the Rubin "Cosmic Treasure Chest" (M49) First Look field, which contains 924 visits in the u,g,r,i bands comprising ~10.5hrs of exposure time with LSSTCam. These data are considerably deeper than the majority of DP2, with a $5σ$ limiting magnitude that approaches the expected 10-year depth of LSST (~25.2-26.5mag, depending on band). We report the…

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astro-ph.GAastro-ph.HE2026年7月28日

How massive and clumpy must a quasar wind be to create emission line blueshifts?

James H. Matthews

Blue asymmetries (``Blueshifts'') in the C IV 1550A emission line are common in luminous quasars. If they are formed in winds, how much energy, momentum and mass do those winds transport? We address this question by considering how much mass must be supplied through the line-forming region to maintain a given density and ionization state. Using a combination of 1D analytic and 2D numerical models, we find that for blueshifted C IV lines to form in a wind, the wind must have mass outflow rates of…

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astro-ph.GA2026年7月28日

The $σ_s^2-\mathcal{M}$ relation in the multi-phase ISM: Exploring the density PDF with the Cloud Factory simulations

Mairi Nonhebel, Rowan J. Smith, Ralf S. Klessen

The density probability distribution (PDF) of molecular clouds is a crucial component of analytical theories of star formation. In idealised simulations of isothermal turbulence, the width of the density PDF, $σ_s^2$, is dependent on the sonic Mach number of the medium, $\mathcal{M}$. The $σ_s^2-\mathcal{M}$ relation is widely used to connect cloud-scale turbulence to the density PDF, and further to star formation activity, yet its validity within individual phases of the multi-phase interstella…

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