UchUchU

研究動向

宇宙工学・惑星科学・宇宙物理の最新プレプリント。

astro-ph.IM

RAISE: A Low-Frequency Space-Based Payload for Solar Radio and RFI Measurements on the SMiLE Mission

Sangeetha A, Harsha Avinash Tanti, Abhirup Datta, Anshu Kumari, Rajesh Bodade

We present the Radio-wave Apparatus for Investigating Solar & Earth interference (RAISE), a compact low-frequency radio payload proposed for hosting on the SMiLE mission. Operating from Low Earth Orbit, RAISE targets a spectral regime that is largely inaccessible from the ground due to ionospheric effects. The payload is designed to enable space-based observations of low-frequency solar radio emissions while simultaneously characterizing terrestrial and ionospheric radio frequency interference i…

詳細を見る →
astro-ph.GAastro-ph.SR

Low-Metallicity Star Formation Survey in Sh2-284 (LZ-STAR): The Core Mass Function

Yu Cheng, Jonathan C. Tan, Morten Andersen, Alva Kinman, Rubén Fedriani, Kei E. I. Tanaka, Yichen Zhang

We present an ALMA 1.3~mm dust continuum study of the dense core mass function (CMF) in Sh2-284, a low metallicity outer Galaxy star-forming complex with $Z\sim1/3$--$1/2~Z_\odot$. The observations cover six far-infrared bright subregions at $\sim$0.65" (3000~au) resolution. We identify a total of 91 candidate dense cores and define a robust catalog of 68 cores with Gaussian fitting. The high-mass CMF above 2.5 Msun is well described by a Salpeter-like slope, with a fiducial forward-modeled valu…

詳細を見る →
astro-ph.SR

Toward 3D orbits of wide sdO/B binaries I. Six composite systems spatially resolved with VLTI/GRAVITY

K. Deshmukh, S. Geier, H. Sana, H. Dawson, M. Dorsch, A. J. Frost, U. Heber, T. Kupfer et al.

Hot subdwarf stars (sdO/Bs) are widely considered to be products of binary evolution. A significant fraction of them are found in long-period or wide binaries ($P>500$ d) with main sequence (MS) companions, likely resulting from a stable mass transfer episode where the MS companion stripped the hydrogen envelope of the sdO/B progenitor. Consequently, wide sdO/B binaries represent a key population in our pursuit of understanding stable mass transfer. They exhibit a modest range of orbital periods…

詳細を見る →
astro-ph.SR

Herbig AeBe Star AS442A as a UXOR-type system

Nariman Ismailov, Faida Surkhai Huseynova, Volkan Bakış, Namiq Serdar Dzhalilov, Sabahaddin Amanulla Alishov, Shafaq Kamal Ismayilova

Detailed studies of the physical characteristics of young intermediate-mass Herbig Ae/Be (HAeBe) stars require extensive sets of homogeneous observational data collected over long periods. In this paper, we present the results of a multi-year study focusing on the faint Herbig Ae/Be star AS 442A. The goal of this study was to investigate the spectral and photometric variability of the star, utilizing long-term archival photometry alongside our own spectroscopic observations. The long-term photom…

詳細を見る →
astro-ph.COastro-ph.GA

Robust Ly$α$ forest constraints on reionization from semi-analytic galaxy formation models

Yuxiang Qin, J. Stuart B. Wyithe

The high-redshift Ly$α$ forest provides one of the most sensitive probes of the final stages of reionization, but its interpretation can depend on how the ionizing sources are modelled. We test the robustness of Ly$α$ forest-inferred reionization histories using Meraxes, a semi-analytic model of galaxy formation and reionization applied to a cosmological volume of $(210h^{-1}{\rm cMpc})^3$ with merger trees augmented down to the atomic-cooling threshold. We construct a suite of source models in…

詳細を見る →
astro-ph.GAastro-ph.SR

SKAO-ALMA Synergies in Star Formation Science

Jan Forbrich, Gary A. Fuller, Mark A. Thompson, Eleonora Bianchi, Jaime E. Pineda, Marta De Simone, Tomoya Hirota, Katharine Johnston et al.

We highlight the potential for synergies between the SKA telescopes and ALMA, which will begin to be significant already with SKA Early Science. Broadly within star formation science, we focus on 1) (simultaneous) time domain and variability studies (e.g., of (proto-)stars), which is systematically opening a new observing window that will enable us to better constrain the physics of extreme stellar flares and their interplay with mass accretion in young stars, 2) possibilities for complementary…

詳細を見る →
astro-ph.SRastro-ph.GA

Project Hephaistos -- III. Characterizing anomalous infrared sources identified as Dyson-sphere candidates

Andreas J. Korn, Matías Suazo, Erik Zackrisson, Pía Cortés-Zuleta, Adam D. Rains, Armin Nabizadeh

The infrared-flux excess of stars harbouring Dyson spheres represent one potential technosignature of extraterrestrial intelligence. In a previous Project Hephaistos paper, we highlighted seven M dwarfs within 300 pc with unusual infrared properties that seem to resemble those expected for Dyson spheres. In the present study, we present an analysis of photometric and, in some cases, spectroscopic data on these seven objects, plus three additional objects with similar properties, to further const…

詳細を見る →
astro-ph.GA

Tracing Obscured AGN Contribution and Number Fraction Across 0 < z < 6 with JWST

Angel Rodriguez Barbosa, Tomotsugu Goto, Daryl Joe D. Santos, Chih-Teng Ling, Tetsuya Hashimoto, Ece Kilerci, Priyanka Jalan, Terry Long Phan et al.

Active galactic nuclei (AGN) are key drivers of galaxy evolution, yet many remain undetected in ultraviolet and optical surveys due to heavy dust obscuration. In these systems, absorbed emission is re-radiated at infrared (IR) wavelengths, making IR observations essential for identifying the full AGN population. Tracking the AGN IR contribution and number fraction provides insight into both the dominance and prevalence of AGN activity across cosmic time. Using the JWST Systematic Mid-infrared In…

詳細を見る →
astro-ph.IMastro-ph.COcs.CLgr-qc

AI's Capability in Assisting Scientific Research in Physics, Astrophysics, and Cosmology I: Literature Review

Anamaria Hell, Kateryna Vovk, Veena Krishnaraj, Jia Liu, Kosuke Aizawa, Adrian E. Bayer, Linda Blot, Jessica Cowell et al.

We investigate how well large language models (LLMs) can assist with literature reviews for scientific research. We perform a controlled study of eight expert-conceived research projects across the areas of physics, astrophysics, and cosmology. Each project has a defined background and goal, and human experts and AI prompters are asked to perform identical literature review tasks in parallel. We compare the relevant literature selected by humans with that selected by mid-2025 LLMs (ChatGPT-4o, C…

詳細を見る →
astro-ph.SR

From simulations to observations of cool plasma: What we can learn from synthetic spectra

V. Jerčić, T. A. Kucera, A. G. M. Pietrow, P. Antolin, J. M. Jenkins

Cool plasma of coronal rain or prominences and filaments is ubiquitous in the solar corona. We explored the synthetic spectra of MgII h&k lines in detail and analyse how well a non-adiabatic magnetohydrodynamic (MHD) simulation of condensations in the corona matches observations when comparing the synthetic with the observed spectra. We applied, a Python implemented, non-local thermodynamic equilibrium (non-LTE) radiative-transfer framework, Promweaver to create synthetic spectra from a 2.5D MHD…

詳細を見る →
astro-ph.GA

Distribution of the magnetic field relative to the plane of the Galaxy in the region of the Sagittarius spiral arm

R. R. Andreasyan, H. R. Andreasyan, A. M. Mickaelian, A. G. Suqiasyan, G. M. Paronyan

Faraday rotation data for 492 pulsars and more than 2,700 extragalactic radio sources were used to study the magnetic field, in detail, in the direction of Galactic longitude $33^o$ <l< $63^o$, which partially covers the Sagittarius spiral arm region. It was proposed that the Sagittarius spiral arm lies north of the h=-300 pc plane, where h is the distance from the Galactic plane. The (-) sign indicates that this plane is located in the southern hemisphere of the Galaxy. The magnetic field of th…

詳細を見る →
astro-ph.HE

Progenitor and Explosion Mechanism of 3C 397 Indicated from XRISM High-resolution Spectroscopy of Fe-group Elements

Hiroshi Nakajima, Yuken Ohshiro, Shing-Chi Leung, Koji Mori, Yoshiaki Kanemaru, Yoshitomo Maeda, Hiroya Yamaguchi, Masayoshi Nobukawa et al.

We present spatially resolved X-ray spectroscopy of the Type Ia supernova remnant 3C 397, one of the most promising candidates to have originated from a white dwarf with a mass close to the Chandrasekhar limit. The remnant was observed during the performance verification phase of the X-ray Imaging and Spectroscopy Mission (XRISM), with the field of view of the Resolve calorimeter array positioned on the eastern half of the remnant. We divide the Resolve field of view into southeastern and northe…

詳細を見る →
astro-ph.SRastro-ph.HE

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…

詳細を見る →
astro-ph.EP

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…

詳細を見る →
astro-ph.HE

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…

詳細を見る →
astro-ph.HE

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…

詳細を見る →
astro-ph.EP

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$…

詳細を見る →
physics.opticsastro-ph.EPastro-ph.IM

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…

詳細を見る →
astro-ph.GAastro-ph.EPastro-ph.SR

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…

詳細を見る →
astro-ph.SR

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,…

詳細を見る →
astro-ph.HE

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…

詳細を見る →
astro-ph.SR

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…

詳細を見る →
astro-ph.GA

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…

詳細を見る →
astro-ph.HE

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…

詳細を見る →
astro-ph.EPastro-ph.IM

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…

詳細を見る →
astro-ph.HE

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…

詳細を見る →
gr-qcastro-ph.HEhep-th

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…

詳細を見る →
astro-ph.GAastro-ph.SR

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…

詳細を見る →
astro-ph.GA

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…

詳細を見る →
astro-ph.IMastro-ph.CO

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…

詳細を見る →