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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.GA

Velocity-resolved Ionization Mapping of the Broad-line Region. II. Signatures of Eccentric Broad-line Regions from a Quantitative Photoionization-Based Model

Jiancheng Wu, Hai-Cheng Feng, Sha-Sha Li, Qingwen Wu, Xinwu Cao

Velocity-resolved reverberation mapping (RM) is one of the most powerful tools for probing the geometry and kinematics of the broad-line region in active galactic nuclei. However, its interpretation may be non-unique, as similar velocity-delay signatures can arise from different combinations of BLR geometry and kinematics. To address this degeneracy, this series of studies develops velocity-resolved ionization mapping (IM) as a complementary technique. In this second paper of the series, we cons…

astro-ph.IM

Plate-YOLO: An End-to-End Object Detection Framework for Robust Astrometric Registration of Historical Plates

Quanfeng Xu, Zhengjun Shang, Shiyin Shen, Yong Yu, Mingyang Ma, Zhenghong Tang, Meiting Yang, Jing Yang et al.

Historical astronomical plates provide a long temporal baseline for time-domain astrophysics, but degradation and structural artifacts can hinder automated astrometric calibration. We present Plate-YOLO, a framework that combines source detection and stellar classification in one detector and supplies source catalogs to a separate astrometric solver. The detector adapts YOLOv5 with Space-to-Depth feature rearrangement, SimAM attention, a high-resolution P2 head, and a Normalized Wasserstein Dist…

astro-ph.HEastro-ph.SR

Constraints on the Progenitor of SN 2023bee from its Nebular-Phase Spectra

Sophie von Coelln, Qinan Wang, Matthew R. Siebert, Ping Chen, Armin Rest, Luc Dessart, Yossef Zenati, Georgios Dimitriadis et al.

We present late-time photometry (~100-400 days after peak) and nebular-phase optical/NIR spectroscopy (100-360 days) of the Type Ia supernova (SN Ia) SN 2023bee. This SN Ia was observed TESS immediately before and after explosion and showed a relatively weak early excess light-curve feature detected in multiple UV and optical bands. Possible explanations for this early excess feature include interaction between the SN ejecta and a non-degenerate companion, or the decay of radioactive isotopes sy…

math-phastro-ph.GAmath.AGmath.CV

Upper bounds on the number of images produced by point-mass lenses at different distances

J. An

If a light source is sequentially lensed by $n$ intervening point-mass lenses at distinct distances, the number of isolated images for a generic source position cannot be greater than $2\cdot 3^{n-1}$. If lensing shear is present in each lens plane, the image counts could be as large as $4^n$, however. For a general multi-plane point-mass lens system, we also devise the recurrence for the BKK bound on the image counts, which is strictly less than Perry's bound due to the resultant degree for $n\…

astro-ph.SRastro-ph.GAastro-ph.IM

Reading Between the Lines: How Much Information Remains After Fitting a Stellar Spectrum?

Sven Buder, Tomasz Różánski

What if we could model 100% of a stellar spectrum? Modern surveys infer stellar properties by comparing observed spectra with synthetic models, yet even the best fits leave structured residuals. We analyse 7087 GALAH survey spectra and ask what information remains after subtracting each best-fitting model. Across 13927 pixels, 4.5% of residuals exceed $3σ$, far above 0.3% expected from Gaussian noise. We map the amplitude, significance, sign, and recurrence of these residuals and identify 380 si…

astro-ph.IM

Characterization of integrating-sphere systematic effects for photon calibration of the KAGRA gravitational wave detector

Shingo Hido, Misato Onishi, Shinji Miyoki, Takahiro Sawada, Takahiro Yamamoto, Takayuki Tomaru, Yoshiki Moriwaki, Dan Chen et al.

Photon calibration (Pcal) systems are essential for accurately reconstructing gravitational-wave strain in laser interferometric detectors. In the KAGRA Pcal system, the laser power applied to the end test mass is measured using integrating-sphere power sensors. During the first part of the fourth observing run (O4a), repeated calibration measurements showed scatter larger than expected from the uncertainties assigned to individual measurements. Although this excess scatter was empirically refle…

astro-ph.GA

The Next Generation Virgo Cluster Survey (NGVS). XXIX. Demography of Nuclear Star Clusters

Max M. Kurzner, Patrick Côté, Laura Ferrarese, Chelsea Spengler, Eric W. Peng, Rubén Sánchez-Janssen, Joel C. Roediger, Kaixiang Wang et al.

Nuclear star clusters (NSCs) provide insights into processes shaping galaxy cores. We use deep $u^*giz$ CFHT imaging from the Next Generation Virgo Cluster Survey (NGVS) to study NSCs in Virgo cluster galaxies. Our parent sample consists of 3680 certain, likely or possible cluster members spanning more than six orders of magnitude in stellar mass. Using a self-consistent classification framework, we identify 1144 candidate nucleated galaxies: 804 high-confidence NSCs and 340 lower-confidence can…

astro-ph.HEnucl-th

Hyperonic Direct-Urca Neutrino Emission with Lattice-QCD-Informed Form Factors

Andreas Konstantinou

We investigate the sensitivity of direct-Urca neutrino emission in hyperonic neutron-star matter to the structure and momentum dependence of baryonic transition form factors. Using the zero-temperature FSU2H relativistic mean-field equation of state, we derive the relativistic emissivity for general spin-$1/2$ baryon transitions with the complete six form-factor contribution. We compare conventional static flavor-SU(3) couplings with vacuum lattice-QCD-informed form factors, using direct lattice…

astro-ph.GA

Connecting galaxy structure, quenching, and halo environments during cosmic noon

Ziwen Zhang, Cheng Jia, Huiyuan Wang, Enci Wang, Yangyao Chen, Houjun Mo, Xiong Luo, Cheqiu Lyu et al.

The connection between galaxy structure, star formation activity, and large-scale environments provides important insights into the evolution of massive galaxies. However, the relative importance of different galaxy properties in predicting quenching and the environmental dependence of structurally distinct galaxy populations remain poorly constrained at cosmic noon ($1\leq z 10.5$ at $1\leq z<3$ using deep JWST/NIRCam imaging from the COSMOS-Web survey, combining measurements of central stellar…

astro-ph.EPastro-ph.GAastro-ph.SR

Dynamical response of a protoplanetary disk to an FU Ori-type outburst

Roman Zolotarev, Yaroslav Pavlyuchenkov, Vitaly Akimkin

Episodic accretion events onto young stars can significantly change the global structure of their surrounding protoplanetary disks. Using radiation hydrodynamical simulations with the HURAKAN code, we study the response of the outer passive disk to a powerful FU Ori-type outburst. Disk heating initiates a factor-of-two increase in the vertical scale-height, which develops on a local keplerian timescale. This effectively launches an outward travelling wave with a bump whose radial position change…

astro-ph.HEhep-phnucl-th

Statistical Analysis of Neutron Star Cooling: Implications for the Nuclear Equation of State and Nucleon Pairing

Afonso Ávila, Ricardo Z. Ferreira, Violetta Sagun

We perform a statistical analysis of the thermal evolution of isolated neutron stars by confronting theoretical cooling curves with luminosity-age measurements for 24 sources. For each object, we explore five purely nucleonic equations of state (APR4, FSU2R, DD2, IST, and NL3$ωρ$) combined with representative models of neutron superfluidity and proton superconductivity, while varying the gravitational mass and envelope composition. The analysis spans approximately $10^5$ cooling curves. Within t…

astro-ph.SR

Ultraviolet accretion continua reveal a transition in T Tauri magnetic topology

Ana I Gomez de Castro

Magnetic fields regulate accretion in T Tauri stars (TTSs) and evolve as radiative cores emerge during pre-main-sequence contraction. Stars above ~0.35-0.5 Msun transition from fully convective to partially convective interiors, a change associated with increasingly complex magnetic topologies and evolving dynamo behaviour. Because accretion flows are magnetically channelled, this evolution is expected to modify ultraviolet (UV) accretion diagnostics, although observational evidence has remained…

astro-ph.GA

Inferring the shapes of low-mass galaxies at $z>6$ from FIREbox$^{HR}$. Where are the disks?

Haojie Geng, Robert Feldmann, Jorge Moreno, Xuejian Shen, James Bullock

Context. The three-dimensional shapes of galaxies provide clues to their formation and evolution. Inferring intrinsic shapes from projected sizes and axis ratios requires assumptions about the population distribution of shape parameters. Aims. We test commonly adopted assumptions in Bayesian shape inference for high-redshift galaxies. Methods. We analyze FIREboxHR galaxies with $\log(M_\star/M_\odot)=6.5-9.5$ at $z\sim6-15$. We measure intrinsic shapes from stellar particles using the minimum co…

astro-ph.SR

Activity Cycles in Solar-Type Stars

P. D. Colombo, C. A. Peralta, A. P. Buccino, C. G. Oviedo, R. Ibañez Bustos, C. F. Martinez, M. Flores Trivigno, F. Minotti et al.

Systematic observational studies, mainly focused on solar-type stars in the F to early K range, have detected magnetic activity cycles analogous to the solar one. When analyzing the relationship between the length of these cycles and stellar rotation rate, a non-monotonic dependence is observed. Activity periods are discretely distributed into two distinct branches: inactive and active. Intriguingly, some stars with rotation rates faster than the Sun exhibit two coexisting activity cycles, with…

hep-phastro-ph.HEgr-qc

Lorentz-Invariance Violation with neutrinos from gamma-ray bursts using IceCube High-Energy Starting Events 12-year dataset

Mathieu Lamoureux, José Manuel Carmona, José Luis Cortés, Ardit Gkioni, Antoine Kouchner, Maykoll A. Reyes

High-energy astrophysical neutrinos provide a unique probe of Lorentz-invariance violation (LIV), as small energy-dependent deviations from the speed of light can produce measurable time delays over cosmological distances. We search for LIV-induced correlations between neutrinos and gamma-ray bursts using the public 12-year IceCube High-Energy Starting Event dataset and a catalog of 746 bursts with measured redshifts. We develop a likelihood analysis accounting for neutrino directional and energ…

astro-ph.GAastro-ph.SR

IMF-aware N-body forward modelling of membership selection functions for young open clusters

Yue-Yue Shen, Chao Liu, Zepeng Zheng, Long Wang, Xiaoying Pang, Bo Zhang, Hao Tian, Yang Xiang et al.

We present an IMF-aware N-body forward-modelling framework, in which the stellar initial mass function (IMF) is an explicit input, to quantify the membership selection functions of open clusters, namely completeness and contamination as functions of magnitude. Accurate derivation of the IMF requires correcting for these selection effects, which otherwise distort the inferred present-day mass function. Our framework simulates clusters with IMF slopes $α_2 = -2.7, -2.3, -1.9$, converts them into s…

astro-ph.SRastro-ph.HE

On the Nature of the BeWD System Nova FQ Circinus

Shatakshi Chamoli, Philip A. Charles, Judhajeet Basu, G. C. Anupama, Sudhanshu Barway, Przemek Mróz

The classical nova FQ Cir (Schaefer et al. 2026) has recently been shown to have a Be star donor, and has been identified as a High Mass Cataclysmic Variable (HMCV), with an orbital period of $\sim 2.04d$ (twice the 1.02d periodogram peak). Using the extensive OGLE optical archive, together with existing observations from ASAS-SN we instead find significant modulation between $\sim 50-60$~days and propose that the orbital period is likely closer to $\sim 62d$. We interpret the low amplitude 1.02…

gr-qcastro-ph.HE

Moving Beyond Quasinormal Modes and Reinterpreting Direct Waves in Binary Black Hole Merger-Ringdowns

Richard Dyer, Anuj Kankani, Gareth Arturo Marks, Sean T. McWilliams, Christopher J. Moore

Based on black-hole perturbation-theory calculations and an effective-one-body picture of binary black hole mergers, it has been suggested that a direct wave may be present and measurable in the ringdown. Furthermore, it has been suggested that this signal might originate from substantially inside the light ring (or photon sphere) of the remnant black hole, perhaps even from close to the event horizon. In this paper, we present three independent strands of evidence against such claims. In the pr…

physics.comp-phastro-ph.IM

Multigroup Implicit Monte Carlo Radiation Hydrodynamics on Moving Voronoi Meshes with STORM and RICH

Maor Mizrachi, Barak Raveh, Elad Steinberg

We present and validate an Implicit Monte Carlo (IMC) radiation-transport solver in the open-source, mesh-agnostic storm library, coupled to the moving-mesh hydrodynamics code rich in three-dimensional Voronoi tessellations. The solver is multigroup, or continuous in frequency, throughout; it transforms photon packets exactly between the comoving and laboratory frames, books every exchange with the material as a laboratory four-momentum so that the IMC path conserves energy to roundoff, formulat…

astro-ph.SR

Mode power and stability in radial post-AGB pulsations

Jan Zalewski

We examine the relation between mode power and excitation rate for radial pulsations along a sequence of high-luminosity post-AGB envelope models. The net thermodynamic exchange power, including boundary contributions, is compared with the excitation rate and the inertia, compression and horizontal area deformation norms entering the balance relation. We find that positive net exchange power can accompany damping, while negative net exchange power can accompany excitation. Along an individual mo…

astro-ph.EP

Companions of Hot Jupiters: two decades of radial velocity monitoring with CORALIE

Léna Parc, João P. Faria, François Bouchy, Jana Baron, Siddharth Bhatnagar, Nicolas Billot, Yann Carteret, Guillaume Chaverot et al.

Hot Jupiters are thought to form through multiple pathways, some of which can leave observable signatures in the architecture of their planetary systems. Massive outer companions, in particular, can provide important constraints on the dynamical histories of hot Jupiters. We aim to characterize the occurrence rate and orbital properties of additional giant companions in hot Jupiter systems, and to investigate whether these companions provide evidence for the role of dynamical interactions in sha…

astro-ph.IMastro-ph.HE

MACE: Multigroup-Multiangle Integrated Thermal Compton Scattering Kernel

Itamar Giron, Menahem Krief, Elad Steinberg

We present a comprehensive set of accurate Compton-scattering tables for use in multigroup, multiangle radiation-transport calculations. The tables contain the exact thermal Compton kernel integrated over incident-energy groups, scattered-energy groups, and angular bins. To generate them, we develop a deterministic integration method in which the pointwise kernel is evaluated with a robust numerical treatment that remains accurate across challenging regions of parameter space. The multidimension…

gr-qcastro-ph.HE

Destinies of Plasmoids Formed from the Magnetic Reconnection Occurring within the Ergo Region of a Rotating Black Hole

Ho-Yun YuChih, Ye Shen

It is widely accepted that magnetic reconnections occur successively in black hole accretion flows, especially on the equatorial plane, owing to the formation of the equatorial current sheet. When magnetic reconnection takes place within the ergosphere of a rotating black hole, one of the ejected plasmoids (denoted as $p_-$) may acquire negative energy-at-infinity density, while the companion plasmoid (denoted as $p_+$) correspondingly carries the energy extracted from the black hole. This mecha…

math.DSastro-ph.EPmath.SG

Moser Regularization of the CR3BP for Symmetric Orbits: Bifurcation Networks of Lunar Orbits

Cengiz Aydin, Chankyu Joung

We develop a computational framework based on Moser regularization for the analysis of symmetric periodic orbits in the spatial Circular Restricted Three-Body Problem (CR3BP). The formulation enables the numerical continuation of periodic orbit families through collision with either primary, together with the computation of Floquet multipliers and stability indices entirely in regularized coordinates. We further provide a characterization and numerical detection scheme for symmetric periodic col…

astro-ph.EPastro-ph.IMastro-ph.SR

Spectroscopic Studies of Meteors within the Skytinel Network

Ernest Świerczyński, Mateusz Żmija, Paweł Zaręba, Tomasz Żywczak

We present 12 low-resolution meteor spectra recorded at four stations of the Skytinel network in Poland, focusing on consistent reduction and comparison of Fe, Mg, and Na emission features. Spectra spanning approximately 350--850 nm were extracted, background-subtracted, and wavelength-calibrated using IRAF. Corrections accounted for the wavelength-dependent quantum efficiencies of Sony IMX249 and IMX273 detectors and atmospheric attenuation as a function of observing geometry. The corrected spe…

astro-ph.SR

Simulations of Particle Acceleration by an Interplanetary Shock Observed at 0.07 au and 0.7 au

F. -J. Kong, G. Qin, Y. Wang

Parker Solar Probe (PSP) observed a coronal mass ejection (CME)-driven shock at 0.07 au on 2022 September 5, and the same CME-driven interplanetary shock was subsequently observed by Solar Orbiter (SolO) at 0.7 au on 2022 September 6. Such a large difference in heliocentric distance between the two shock events enables our comparative study of particle acceleration in near-Sun and far-Sun regions. Using a backward-in-time test-particle approach in a slab-2D turbulent magnetic field model, we per…

astro-ph.GA

The Star Formation Histories of Different Components of M31's Halo from Photometric Estimates of Fe and $α$ Abundances

Jihye Hong, Evan Kirby, Roman Gerasimov, Masashi Chiba, Yutaka Komiyama, Itsuki Ogami, Tiffany Tang, Timothy Beers et al.

We present the chemical-abundance distributions and star-formation histories of the M31 halo components using photometric Fe and $α$ abundance estimates derived from the PAndAS broad-band $g$ and $i$ filters and the Subaru/HSC $NB515$ narrow-band filter. We selected about 76,400 candidate M31 giant stars and constructed a synthetic photometric training dataset based on model isochrones. We estimated elemental abundances and errors using random forest regression models. We identify various halo c…

astro-ph.HEastro-ph.GA

Supermassive Black Hole Winds in X-rays -- SUBWAYS. VI. Interplay between the soft X-ray excess and ultra-fast outflows

V. E. Gianolli, P-O. Petrucci, S. Bianchi, M. Brusa, G. Lanzuisi, G. A. Matzeu, M. Mehdipour, F. Ursini et al.

We present a broadband, multiwavelength study of the interplay between the soft X-ray excess (SE), ultra-fast outflows (UFOs), and warm absorbers (WAs) in 21 active galactic nuclei (AGN; 0.1 2$, consistent with previous studies. However, 9/21 AGN require the hybrid model, suggesting that the SE has multiple origins whose relative contributions vary. This is especially evident in UFO hosts, where 4/7 observations favor the hybrid model. Compared with sources without UFOs, UFO hosts show lower WC…

astro-ph.EPastro-ph.IM

Single-Transit Parameter Estimation with Calibrated Uncertainties

Helem Salinas, Rafael Brahm, Greg Olmschenk, Melinda Soares-Furtado, Karim Pichara, Joshua E. Schlieder

The growing volume of photometric data from current and upcoming exoplanet surveys demands automated analysis pipelines to detect and characterize exoplanet transit signals. Among these, single-transit events present a challenge, since only one event is observed, and standard transit-fitting techniques for periodic signals do not directly apply because they rely on phase-folding. Beyond detection, characterizing these events is equally critical for follow-up, yet existing approaches are either s…

astro-ph.IMphysics.ins-det

A 4-20 GHz Superconducting 90deg Hybrid Using Capacitively Loaded Coupled Lines for 2SB Heterodyne Receivers

François Joint, Max Behrens, Denis Meledin, Cristian Lopez, Magnus Strandberg, Sven-Erik Ferm, Mathias Fredrixon, Leif Helldner et al.

We report the design and cryogenic characterisation of a broadband superconducting 90deg intermediate-frequency (IF) hybrid covering 4 to 20 GHz for sideband-separating (2SB) heterodyne receivers. The hybrid is implemented in thin-film niobium using capacitively loaded edge coupled transmission lines, avoiding the air-bridge interconnections required in Lange-coupler layouts while retaining a compact superconducting implementation with low loss and good quadrature balance. Cryogenic measurements…