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宇宙工学・惑星科学・宇宙物理の最新プレプリント。

astro-ph.EP

Information content on Venusian aerosols in VIRTIS-M infrared data

Jaime Reyes-Guerrero, Santiago Pérez-Hoyos, Itziar Garate-Lopez

Venus presents a complex cloud structure with aerosol particles of different sizes located mainly between 48 km and 70 km in altitude. However, the number of free parameters that can describe such a cloud structure is usually overwhelming, and a number of simplified parameterizations are commonly assumed. In this work, we re-analyze the information content on aerosol vertical distribution provided by the nightside infrared data collected by VIRTIS instrument onboard Venus Express. Starting from…

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astro-ph.EPastro-ph.IM

First results of a continuous monitoring campaign of the PLATO Southern field

Thomas Granzer, Jorg Weingrill, Klaus G. Strassmeier, Arto Jarvinen

The BMK10k project started as an ancillary project to the PLATO ESA mission, dedicated to photometrically monitor the PLATO Southern field, to help with source confusion, and to mitigate the problem of false-positive exoplanet detections. Planned as a long-term project, the BMK10k should see an operational time-scale in the order of a decade, well above the proposed PLATO operational phase. Thus, BMK10k may help resolving single- event transit issues detected with PLATO and may be in the unique…

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astro-ph.HE

Observation of Wobbling and Precessing Jet Signatures in Gamma-Ray Emission from Blazar PKS 1424-41

Ajay Sharma, Debanjan Bose

We report a clear observational evidence for jet precession and nutation manifested in the gamma-ray emissions of the blazar PKS 1424$-$41. An analysis of $\sim$16 yr of \emph{Fermi}-LAT observations reveals three distinct and superimposed quasi-periodic oscillations (QPOs), with characteristic timescales of $\sim$5.26 yr, $\sim$0.96 yr and $\sim$1.3 yr. The longer timescale is detected with a local significance of $\sim 4.1σ$ ($99.9958\%$ confidence) and a global significance of $\sim 2.45σ$ ($…

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astro-ph.EP

Dust characterization of the HD 163296 disk with high-resolution multi-wavelength ALMA observations

Kiyoaki Doi, Myriam Benisty, Akimasa Kataoka, Haochang Jiang, Francesco Zagaria, Hauyu Baobab Liu, Carsten Dominik, Ryo Tazaki et al.

Context. Planets form through the growth and accumulation of dust grains in protoplanetary disks. Characterizing dust properties such as size, surface density, and temperature is key to understanding planet formation. Aims. We characterize the dust properties of the protoplanetary disk around HD 163296 by performing spectral energy distribution (SED) fitting of multi-wavelength high-resolution observations. Methods. We present new high-resolution ALMA Band 9 (0.45 mm) observations, which are sen…

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astro-ph.IM

LEO-to-ground low elevation optical communication: optimization of an adaptive optics design robust to scintillation

Timoth{é}e Vene, Aur{é}lie Montmerle-Bonnefois, Laurent Mugnier, Jean-Marc Conan

To maximize the duration of optical downlinks with Low-Earth Orbit satellites, it is crucial to ensure the coupling into the single mode fiber of the ground terminal even at low elevations. Adaptive optics systems are designed to correct the wavefront deformation induced by atmospheric turbulence. However, at low elevations, amplitude fluctuations (or scintillation) challenge this correction. Here we propose a methodology to design a wavefront sensor that is robust to scintillation, taking the S…

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astro-ph.SR

Population synthesis of delta Scuti stars: the instability strip, period-luminosity relation, and large-separation distribution

Simon J. Murphy, Anuj Gautam

Interpreting the observed properties of intermediate-mass stars requires accounting for rotation, binarity, intrinsic population diversity, and measurement uncertainty. We combine these effects in population-synthesis models of 1.4-2.5 M$_{\odot}$ stars that include pulsation properties of $δ$ Sct variables. The synthetic populations successfully reproduce the distributions of stars observed in young associations, validating the mapping between intrinsic and observed stellar properties. Using th…

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astro-ph.HE

Revealing Four Subpopulations of Binary Black-Hole Mergers with the Fifth Gravitational-Wave Transient Catalog

Nir Guttman, Paul D. Lasky, Eric Thrane

Gravitational-wave data are beginning to reveal a structured landscape of black-hole masses and spins, suggesting multiple formation processes are now being resolved observationally. We analyze data from LIGO--Virgo--KAGRA's (LVK's) fifth Gravitational-Wave Transient Catalog and find that the population is naturally described by four distinct subpopulations. The dominant component, contributing $\simeq70\%$ of the astrophysical merger rate, is characterised by a low-mass population centred near…

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astro-ph.GA

Kinematic scaling of thin and thick discs from SAMI to NewHorizon

Sree Oh, J. K. Jang, Giulia Santucci, Sukyoung K. Yi, Matthew Colless, Scott M. Croom, Yohan Dubois, Stefania Barsanti et al.

We revisit the relation between disc stellar mass and disc velocity dispersion (M_*-σ_e) and extend it to thin and thick subcomponents using orbit-based dynamical models of 161 SAMI galaxies and counterpart measurements for 31 disc galaxies in the NewHorizon simulation. On the observational side, we apply Schwarzschild orbit superposition to recover orbital circularity distributions and component kinematics. On the simulation side, we sample thin and thick discs by circularity and, separately, b…

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astro-ph.HE

A post-hypercritical accretion small-scale dynamo in newborn neutron stars

David F. Bambague, Cristian G. Bernal, J. A. Rueda

Hypercritical fallback accretion can advect the surface magnetic field of a newborn neutron star into the newly accreted outer layers. Before this material joins the solid crust and enters the Hall-Ohmic regime, part of it may remain hot, dense, and liquid, allowing turbulent magnetic amplification. We investigate whether a small-scale dynamo (SSD) can operate under these conditions using six local 3D resistive MHD simulations performed with FLASH 4.7 in a periodic domain with externally forced…

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astro-ph.HEastro-ph.GA

Radio Core Size of Low-luminosity Active Galactic Nuclei under the MAD-jet model

Yue Xu, Fu-Guo Xie

After decades of efforts, there are now fruitful high-resolution radio observations of low-luminosity active galactic nuclei (LLAGNs), and the observed frequency has extended from $\sim$10 GHz up to $\sim$200 GHz. In this work, based on a model that combines a magnetically arrested disk (MAD) and a Blandford-Znajek-like jet, we carried out detailed analysis on size and location of the radio core of LLAGNs. The radio core size of nearby LLAGN M104 is re-visited based on this new model. We success…

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astro-ph.HEastro-ph.GA

The Distinctive Evolution and Spectral Energy Distribution of Binary Massive Black Hole Accretion

Yue Xu, Fu-Guo Xie, Ya-Ping Li, Yinhao Wu, Luis C. Ho

Binary (super-)massive black holes (BHs) are expected to reside in the center of some galaxies. In this work, we re-visit accretion onto binary massive BHs, incorporating recent advances in both accretion theory and the mass transfer rate between the two massive BHs. We focus on relatively bright systems with an Eddington ratio of 0.1 for a binary with total BH mass $10^8\,M_\odot$, but consider a wide range of mass ratios $10^{-4} \le q \le 0.5$. The binary system consists of two mini-disks sur…

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astro-ph.EP

A Stable Mineral Fingerprint in the Fading Warm Debris Disk around HD 15407A

Shu Wang, Zhuochao Huang, Xiaodian Chen, Junming He, Haomiao Huang

Extreme debris disks provide time-domain probes of rocky planet assembly after giant impacts. We compare Spitzer and JWST spectra of the warm debris disk around HD 15407A, obtained 14.95 yr apart. Across 6-25$μ$m, the stellar-subtracted mid-infrared excess declined by $14.0\pm1.2$%, while the mineral fingerprint is nearly unchanged. Within the adopted common reduced mineral basis, Mg-rich pyroxene dominates the normalized fitted mineral weights at about 65%, while silica and forsterite contribut…

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astro-ph.GA

The disrupted chemical enrichment history of the Milky Way driven by gas accretion

Jianhui Lian, Qinhao Shao, Min Du, Hanyuan Zhang, Xinxin Duan, Xin Wang, Zheng Zheng

As the only galaxy enabling temporally-resolved observations from an internal vantage point, the Milky Way as a galaxy offers unique insights into galactic chemical enrichment history, establishment of fundamental scaling relations, and the underlying astrophysical processes. However, this insider perspective also introduces strong selection effects, hindering direct measurement of the Milky Way's global properties and comparison with the broader galaxy population, for the vast majority of which…

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astro-ph.GA

Long Tidal Tails of NGC 5024 Hidden in LMS-1 and NGC 5053 Tidal Streams

Xianhao Ye, Yong Yang, Jingkun Zhao, Hao Tian, Yuqin Chen, Gang Zhao

We report the discovery of long tidal tails associated with the globular cluster (GC) NGC 5024. A modified matched filter applied to Gaia DR3 data reveals a broad stellar stream spanning $α\approx 230^{\circ}-175^{\circ}$. The stellar stream overlaps on the sky with the LMS-1 and with the simulated stream of the GC NGC 5053, and all three share similar proper motions and metallicity. Our member candidates may therefore be a mixture of stars from NGC 5024, NGC 5053, and LMS-1. Nevertheless, the t…

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gr-qcastro-ph.HE

From the Early Slope to Curvature: Future Prospects and challenges for Astrophysical Parameter Estimation Using the Core-Collapse Supernova High-Frequency Feature

Alejandro Casallas-Lagos, Marek Szczepańczyk, Michele Zanolin, Anthony Mezzacappa

Gravitational-wave (GW) signals from core-collapse supernovae (CCSNe) contain both stochastic and deterministic components. Among these, the High-Frequency Feature (HFF), associated with PNS oscillations, has emerged as a robust observable for probing dense-matter physics. Previous studies of the HFF have primarily focused on the early-time slope as a diagnostic of PNS contraction and its dependence on the equation of state (EOS). In this work, we extend the analysis beyond the early-time linear…

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gr-qcastro-ph.HEastro-ph.IM

Classifying the nuclear equation of state in LVK interferometric noise through core-collapse supernova gravitational-wave signatures using convolutional neural networks

Alejandro Casallas-Lagos, Marek J. Szczepańczyk, Michele Zanolin, Anthony Mezzacappa, Javier M. Antelis, Daniel Murphy, Claudia Moreno

This paper presents a convolutional neural network (CNN) approach to classifying the nuclear equation of state (EOS). As illustrative examples, we use five two-dimensional core-collapse supernova (CCSN) simulations that differ only in their EOS. We analyze estimates of the initial slope of the high-frequency feature (HFF) reconstructed in real interferometric data from the O3b LIGO-Virgo-KAGRA (LVK) observing run at Galactic source distances of 1, 5, and 10 kpc. The CNN classifier achieves an ov…

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astro-ph.SRastro-ph.HE

Spectral evolution of mildly relativistic electrons in solar flares

Gregory D. Fleishman, Tatyana Kaltman, Sijie Yu, Gelu Nita

Solar flares are a powerful engine capable of accelerating ambient plasma particles to high nonthermal energies. A key characteristic of these particles is their energy spectrum. Numerous studies of nonthermal hard X-ray emission established that a typical spectral evolution of the nonthermal electrons with energies of dozens keV follows a soft-hard-soft pattern in impulsive events and soft-hard-harder pattern in some long-duration events. Here we extend the study of the spectral evolution to th…

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astro-ph.GA

Stacked Reverberation Mapping of High Redshift Quasars in DESI. I. Feasibility Analysis

Rahma Alfarsy, R. E. A. Canning, Eva-Maria Mueller, Jessica Aguilar, Steven Ahlen, David Alexander, Davide Bianchi, David Brooks et al.

The broad line region of quasars has long been probed by reverberation mapping techniques that measure time lags between continuum and broad emission line variations. Stacked reverberation mapping has been proposed as a less observationally expensive alternative to traditional methods. This ensemble approach also reduces biases from small-number statistics. The Dark Energy Spectroscopic Instrument (DESI) is conducting the most extensive spectroscopic survey of quasars to date. We create mock lig…

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astro-ph.HEastro-ph.GA

A GRMHD-Calibrated Semi-Analytical Model for Hot Sub-Keplerian Accretion Flows in Kerr Spacetime

Nabin Bhushal, Manil Khatiwada, Yogesh Maharjan, David Garofalo, Chandra B. Singh

We develop a simple, semi-analytical, kinematic model for hot, thick accretion flows, constructed by interpolating between Keplerian and free-fall geodesic solutions in the Kerr metric. Unlike self-consistent general relativistic magnetohydrodynamics (GRMHD) frameworks, our model contains no explicit magnetic fields or stress terms; instead, it uses a smooth, radially varying transition function T(r) to connect the velocity components from near-Keplerian rotation at large distances to a free-fal…

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astro-ph.SR

Magnetically guided accretion and extremely slow rotation in a metal-enriched white dwarf

S. Bagnulo, M. A. Stroet, C. P. Folsom, M. A. Hollands, J. D. Landstreet, G. Ramsay

White dwarfs that show atmospheric metal enrichment offer a direct window into the bulk composition of exoplanetary material and provide some of the most direct constraints on the building blocks of rocky exoplanetary systems. Recent work has suggested that magnetic fields may influence how this material is accreted, potentially channelling debris along field lines and retaining it near magnetic poles rather than allowing it to be redistributed uniformly across the stellar surface. Here we repor…

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astro-ph.SRastro-ph.EPastro-ph.GA

Rate of caustic crossing microlensing events in stellar binary lenses with significant orbital motion

Arjun Murlidhar, B. Scott Gaudi, Todd. A. Thompson

Binary lens microlensing events in which the source crosses a caustic produce sharp, distinctive magnification peaks and can therefore be readily identified. In this paper, we explore the importance of binary orbital motion for the binary lens caustic crossing cross section. If the orbital timescale of the binary system is smaller than the Einstein ring crossing timescale, the caustics sweep out a larger area in the source plane, generally enhancing the cross section. We find that face-on binari…

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astro-ph.GA

A Multiwavelength Inventory for the Local Group L-band Survey I: Atlas and Radial Profiles of Local Group Galaxies

Cosima Eibensteiner, Adam K. Leroy, Jiayi Sun, Erik Roslowsky, Eric W. Koch, Nickolas Pingel, Chang-Goo Kim, Laura B. Chomiuk et al.

Resolving atomic gas at $\lesssim100$ pc physical resolution is currently feasible only for the very nearest galaxies. We combine 120 pc resolution HI data using the Karl G. Jansky Very Large Array (VLA) from the first data release of the Local Group L-Band Survey (LGLBS) with uniformly processed infrared, ultraviolet, H$α$, and CO maps. We analyze the radial profiles of gas, stars, and recent star formation for six local galaxies: M31, M33, IC 10, IC 1613, NGC 6822, and WLM. Across the sample,…

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astro-ph.COastro-ph.GAastro-ph.HEgr-qc

The diffraction-lensing interpretation of GW231123 with astrophysical priors

Mark Ho-Yeuk Cheung, Digvijay Wadekar, Matias Zaldarriaga, Tejaswi Venumadhav, Javier Roulet, Ajit Kumar Mehta

GW231123, if unlensed, is a rare binary black hole merger with high masses and high spins for both progenitors. We show that the signal is better fitted by a lower-mass, lower-spin merger that is diffraction-lensed by an isolated object of redshifted mass $\sim 1000\,\rm M_\odot$, modeled either as a point mass or as a spherically symmetric compact halo. Because diffraction-lensed events are also rare, hypothesis testing should quote the posterior odds ratio rather than the Bayes factor, which r…

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astro-ph.GA

From relics to stripped systems: the environmental origin of compact galaxies

Guangwen Chen, J. Alfonso L. Aguerri, Carlos del Burgo, Stefano Zarattini

Compact galaxies represent a key population for understanding galaxy evolution, but the relative role of internal structure and environment in shaping their origin remains unclear. We aim to investigate how the abundance and quenching of compact galaxies depend on environment, and to determine whether their formation is governed by a single evolutionary pathway or multiple channels. We analyse a large sample of galaxies in the nearby Universe ($z<0.05$) with stellar masses in the range $8.2<\log…

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astro-ph.GAphysics.atom-ph

Emissivity line ratios for [Mn III] and spectral diagnostics of H II regions

Zher Samak, Sultana N. Nahar, Anil K. Pradhan

We present the first theoretical emission-line study of Mn III as potential determinant of physical conditions and manganese abundance. We compute atomic data for a set of Mn III lines and line emissivity ratios as temperature-density diagnostics. Accurate relativistic Breit-Pauli R-matrix calculations have been carried out for electron impact excitation of Mn III transitions that have not been previously studied. Selected forbidden lines are shown to be sensitive to temperature and density unde…

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astro-ph.IM

Determination of Earth's Orbital Parameters Using Doppler Measurements

Gary Atkins, Marcus Leech, Daniel Marlow, Doug Yuill

Precision determinations of the parameters of Earth's orbit around the Sun using methods based on the Doppler shift of 21-cm emissions from the galaxy and the repetition rate of pulsar J0332+5434 are reported. The observed values and statistical errors for the orbital parameters for the 21-cm observations are semi-major axis $a = 1.00020 \pm 0.00015~{\rm au}$ and eccentricity $e= 0.017077 \pm 0.000077$. For the pulsar observations, the observed values are $a = 1.000034 \pm 0.000034~{\rm au}$ and…

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astro-ph.IM

The FastrSHWFS Development & Test Results

Natasha Popenoe, Benjamin Gerard, Dominic Sanchez

The recent 2020 Decadal Survey of Astronomy and Astrophysics listed habitable exoplanet imaging with future extreme adaptive optics (AO) on 30m-class telescopes as a key priority in the coming decade. However, there is a current 100x contrast gap between the best systems today and what is needed to enable this goal. Astronomical AO is a required approach to enable ground-based diffraction-limited imaging of exoplanets on future extremely large telescopes. Time lag between the end of an exposure…

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astro-ph.GA

Where Do Quasars Live? DESI DR1 Constraints from PAC Measurements

Shanquan Gui, Kun Xu, Donghai Zhao

Quasar environments connect the growth of supermassive black holes, active galactic nucleus feedback, and galaxy evolution. Small-scale quasar clustering probes the one-halo regime and can test whether quasar activity depends on central--satellite status. We seek to obtain precise small-scale measurements of quasar environments at $0.8<z<1.0$ and use them to constrain the quasar--halo connection, particularly the relative probability for satellite subhalos and central halos of the same halo accr…

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astro-ph.HEastro-ph.COastro-ph.GA

On the astrophysical origin of cosmic rays: Constraining the Ultra-High-Energy Cosmic Ray Horizon through Nearby Galaxy Distributions

F. Dávila-Kurbán, F. Duplancic, D. Garcia Lambas

The origin of ultra-high-energy cosmic rays (UHECR) remains a central open problem in astroparticle physics. The observed large-scale anisotropy of UHECR arrival directions above several EeV, together with the spectral suppression at the highest energies, suggests extragalactic sources confined to a limited volume of the nearby Universe, though the effective spatial scale of this contribution remains poorly constrained. We aim to constrain the effective propagation horizon of UHECR with energies…

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astro-ph.EPphysics.geo-ph

Onset of dynamo action in planetesimals

Ludovic Huguet, Jonathan E. Mound, Christopher J. Davies, James F. J. Bryson

Several meteorites have been found to carry primary remanent magnetizations imparted by fields generated within planetesimal cores during the early solar system. Thermal evolution models have shown that thermal convection likely drove the dynamo in the early evolution of these bodies. In such small cores, the magnetic Reynolds number is thought to be close to the threshold for dynamo action. However, the critical value of the magnetic Reynolds number, meaning its value at the onset, is also poor…

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