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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

On the current status of tidal tails of Galactic open clusters

Tahereh Ramezani, Nikola Faltova, Prapti Mondal, Katerina Neumannova, Ernst Paunzen, Johana Supikova, Gabriel Szasz

Tidal tails of open clusters provide direct observational evidence of cluster mass loss and dynamical interaction with the Galactic tidal field. The advent of $Gaia$ astrometry has enabled systematic detection of extended stellar structures around nearby clusters, revealing that many systems exhibit complex and extended morphologies beyond their classical tidal radii. In this review, we summarise the current observational and theoretical status of tidal tails in open clusters, focusing on result…

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astro-ph.EPastro-ph.IM

GRACE-DG: A Discontinuous Galerkin method-based code for general non-linear coagulation-fragmentation equations

Jing Yang, Zhuo Chen, Xue-Ning Bai

Dust plays a crucial role in protoplanetary disks (PPDs) evolution and planet formation, influencing disk dynamics through gas-dust coupling, regulating disk temperature by dominating continuum opacity, and altering disk ionization fraction by capturing free electrons. In this work, we develop a high-order discontinuous Galerkin (DG) method-based open-source code GRACE-DG to solve the collision-induced coagulation-fragmentation equations. In particular, we have derived a new conservative formula…

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astro-ph.GA

Adaptive optics imaging of the nuclei of Seyfert 2 galaxies: An unexpectedly high incidence of nuclear stellar rings

Nina Mackensen, Jochen Heidt, Francisco Pozo Nuñez

High-resolution imaging of active galactic nuclei (AGNs) on subkiloparsec scales is essential for investigating their fueling. Observations in the near-infrared (NIR) are especially valuable as they minimize the absorption by dust. However, the inferred nuclear morphology may depend on the method used to analyze the images. We assess whether ground-based adaptive-optics observations of the cores of Seyfert 2 galaxies in the Ks band provide advantages over HST observations at shorter wavelengths…

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astro-ph.GAastro-ph.IMastro-ph.SR

The different methods to calculate cluster membership probabilities

Tahereh Ramezani, Nikola Faltova, Prapti Mondal, Katerina Neumannova, Ernst Paunzen, Johana Supikova, Gabriel Szasz

Reliable membership determination is a fundamental step in the study of star clusters. With the advent of $Gaia$ astrometry, a wide range of statistical and machine-learning techniques has been developed to assign membership probabilities. However, the current situation of membership lists is very unsatisfactory. This review summarises the main methodologies, compares their strengths and limitations, and discusses future directions. The aim is to provide a comprehensive overview and to lead to a…

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astro-ph.SR

Multi-height Diagnosis of MHD Wave Periods and their Propagation in Solar Plages Using IRIS Observations

Gayathri Hegde, Pradeep Kayshap

This work aims to investigate magnetohydrodynamic (MHD) waves in solar plages at five distinct heights, spanning from photosphere to the upper chromosphere, using spectroscopic observations provided by Interface Region Imaging Spectrograph (IRIS). The dominant period is found to not change within the plages, while, in pores, the dominant period decreases linearly from 4.20 to 3.20 minutes from the photosphere to the upper chromosphere. Furthermore, in the solar plages, cross-wavelet analysis rev…

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astro-ph.HEastro-ph.IM

Towards a joint X-ray and gamma-ray analysis of Pulsar Wind Nebulae with Gammapy

Katharina Egg, Alison M. W. Mitchell

For detailed studies of Pulsar Wind Nebulae (PWNe), objects that show photon emission across the entire electromagnetic spectrum, multiwavelength analyses are crucial. The comparison of especially X-ray and gamma-ray emission and their angular sizes can help us to constrain the properties of PWNe, such as their particle transport mechanism or their potential for the acceleration of hadronic particles. In this vein, we are working towards a joint analysis of eROSITA X-ray data and H.E.S.S. gamma-…

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astro-ph.IMphysics.ins-detphysics.optics

Proof of concept of heterodyne interferometry at 10.6 um using photonic correlation

Tituan Allain, Jean-Philippe Berger, Guillaume Bourdarot, Carlo Sirtori, Hugues Guillet De Chatellus

The task of imaging complex dust environments such as the inner astronomical units of a planet-forming disks requires dedicated mid-infrared (MIR) interferometric facilities with kilometric baselines and a large number of telescopes. Extrapolating technologies from current facilities is not straightforward. We aim to demonstrate the feasibility of using MIR heterodyne interferometry with a photonic correlation approach to recombine MIR signals from distant telescopes. We want to determine the cu…

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astro-ph.HEastro-ph.COhep-ph

Assessing the sensitivity to Axion-Like-Particle Dark Matter with very-high-energy gamma-ray observations of selected AGN and galaxy cluster pairs

Cervane Grimaud, Denys Malyshev, Emmanuel Moulin

Axion-Like-Particles (ALPs) are pseudo-scalar particles actively searched as light dark matter candidates. ALPs can couple to photons which give rise to the possibility of oscillations with photons in an external magnetic field. If sufficiently strong, this coupling can imprint distinctive spectral irregularities in the gamma ray spectrum of astrophysical sources. We present a prospective study on the sensitivity of probing ALP-photon interactions using stacked observations of selected active ga…

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astro-ph.EPastro-ph.IMnlin.CD

Advanced Techniques in Stability Analysis of Trans-Neptunian Objects

Tamás Kovács

The trans-Neptunian region (30-50 AU) is a dynamically structured reservoir of icy planetesimals whose orbital architecture reflects resonant dynamics, chaotic transport, and long-term gravitational sculpting by the giant planets. This review synthesizes recent developments in the dynamical investigation of trans-Neptunian objects (TNOs), with an emphasis on mean-motion and secular resonances, as well as chaotic diffusion, in a system whose growing observational census makes it an ideal testbed…

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astro-ph.HEastro-ph.IM

Combined KM3NeT/ARCA and ANTARES search for compact neutrino sources

V. Kulikovskiy, B. Caiffi, S. Alves Garre, J. Aublin, M. de Jong, A. Heijboer, G. Illuminati, R. Muller et al.

High-energy neutrinos from point-like sources are searched in the combined dataset from ANTARES and the available KM3NeT/ARCA data. This analysis demonstrates the potential of combining data from these neutrino detectors using a binned likelihood approach.

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astro-ph.IMastro-ph.SR

Design and Implementation of a Microservice-Architecture Master Control System for AIMS

Li-Yue Tong, Jia-Ben Lin, Jun-Feng Hou, Yuan-Yong Deng, Dong-Guang Wang, Guang-Qian Liu, Song-Bo Xu, Shang-Jie Ren et al.

The mid-infrared solar magnetic field telescope AIMS (An Infrared System for the Accurate Measurement of Solar Magnetic Field) is the first ground-based telescope designed to directly measure solar magnetic fields via Zeeman splitting in the 8-14 um band, overcoming the century-long bottleneck of model-dependent indirect measurements. Its remote high-altitude site, heterogeneous multi-institute components, and complex observation modes comprising Fourier Transform Infrared (FTIR) spectropolarime…

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astro-ph.SRastro-ph.GA

Improving reddening estimates for RR Lyrae stars in the Gaia bands: a machine learning approach to the PAC(Z) relation

A. Garofalo, T. Muraveva, L. Monti, G. Clementini, F. Cusano, L. Valentini

RR Lyrae stars are essential tracers of old stellar populations and distance indicators across the Milky Way and nearby galaxies. However, their use as standard candles is limited by uncertainties in extinction, especially in the Gaia bands. In Gaia DR3, absorption values (AG) for fundamental-mode RR Lyrae (RRab) were based on an empirical period-amplitude-color (PAC) relation calibrated on a small sample and on passband transformations. We aim to recalibrate extinction relations for RRab stars…

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astro-ph.IMastro-ph.SR

JW-ASTClaw: A Generalizable Multi-Agent Framework for Autonomous Solar Telescope and Its Implementation within Chinese Meridian Project

Li-Yue Tong, Jia-Ben Lin, Yuan-Yong Deng, Ying-Zi Sun, Ming-Fu Shao, Hui Wang, Chen Yang

We present the first deployment of an end-to-end autonomous control system driven by a large language model (LLM) on an operational solar telescope-the Solar Full-disk Multi-layer Magnetograph (SFMM), named JW-ASTClaw. This system employs a multi-agent framework adopting a decoupled three-layer architecture (perception-decision-execution) interconnected through the Model Context Protocol (MCP), which addresses real-time adaptive scheduling under complex environmental conditions while achieving h…

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astro-ph.EP

SaNDi-SHoP: Searching for Satellites'N'Disks with a Star-Hopping Program II. Spectrophotometric analysis and orbital monitoring of directly imaged companions

Andrea Bernardi, Alice Zurlo, Cecilia Lazzoni, Silvano Desidera, Dino Mesa, Sebastian Pérez, Pedro Henrique Nogueira, Domenico Barbato et al.

Over the past decade, advances in high-contrast imaging instrumentation, coupled with extreme adaptive optics systems, have enabled the discovery of tens of planets and brown dwarfs orbiting at wide separations from their host stars (a larger than 10 au). The existence of companions at these separations challenges current planet-formation paradigms, highlighting the importance of high-contrast imaging as the only technique capable of directly probing this region of planetary systems. In this pap…

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astro-ph.SRphysics.plasm-phphysics.space-ph

Ion-Scale Current Sheets Embedded in Reconnection Jet Shear Layer of the Near-Sun Heliospheric Current Sheet

Dae-Young Lee, Dooyoung Choi, Kyung-Eun Choi, Sung Jun Noh

Context. Magnetic reconnection in the heliospheric current sheet (HCS) plays an important role in restructuring the solar wind magnetic topology and generating plasma jets and magnetic islands. While large-scale signatures of HCS reconnection have been reported in many observational studies, the kinetic-scale structure embedded within reconnection regions remains less well understood. Aims. We investigate the ion-scale currents sheets (CSs) embedded within an HCS reconnection region and their re…

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astro-ph.IMastro-ph.SR

Scientific-Intention Driven Embodied Intelligent Solar Telescope: Conceptual Design

Lin Jiaben, Tong Liyue, Wang Hui, Shao Mingfu, Yang Chen

Artificial Intelligence (AI) is profoundly transforming the paradigms of scientific research. Cutting-edge technologies such as Large Language Models (LLMs) and embodied intelligence are continuously pushing the boundaries of scientific instrumentation. Against this backdrop, this paper proposes a novel conceptual system: the Scientific-Intention Driven Embodied Intelligent Solar Telescope (SIDEST). The system is designed with three core layers to achieve three types of intelligent scientific re…

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physics.space-ph

Influence of Magnetospheric Plasma Environment on Surface Charging of the Lunar South Pole

Yaqi Xiao, Xiaoman Wang, Ronghui Quan

The lunar south pole is a key candidate region for future lunar exploration and base construction, but its charging characteristics under real topographic conditions and dynamic plasma environments remain insufficiently understood. A high-fidelity terrain model of the lunar south pole spanning 86°S-90°S was constructed from optimized LRO/LOLA elevation data. Surface charging evolution over half a lunar orbital cycle was then simulated with a finite element-BP neural network scheme, using lunar-p…

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astro-ph.HE

Inverse Transfer in Non-helical 2D Collisionless Magnetic Turbulence: Island-Merger Picture with Kinetic Effects

Yangyang Cai, Hongzhe Zhou, Yosuke Mizuno

Magnetic inverse transfer is often invoked to connect small-scale magnetic-field generation to larger coherence scales in high-energy and cosmological plasmas. The underlying magnetohydrodynamic (MHD) arguments combine two logically distinct ingredients: a bulk quantity that is asymptotically conserved in the limit of small resistivity, and a time scale determined by the decay dynamics. In this work, we explore whether this scenario still holds in decaying nonhelical turbulence formed by collisi…

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astro-ph.HEastro-ph.SR

Distinct Velocity Components in the Absorption Lines of the Neutron Star X-ray Binary AX J1745.6-2901

Kai Matsunaga, Maxime Parra, Yutaro Nagai, Teruaki Enoto, Yoshitomo Maeda, Takayuki Hayashi, Shifra Mandel, Kaya Mori et al.

Accretion disks in X-ray binaries regulate mass transfer onto compact objects and drive radiative and kinetic feedback to their surroundings. Here we report X-ray spectroscopy of the eclipsing neutron star low-mass X-ray binary AX J1745.6-2901 with XRISM/Resolve. The phase-averaged Fe XXVI Lyα absorption profile exhibits two absorption minima with relative depths that are inconsistent with the theoretical Lyα1/Lyα2 doublet ratio expected from a single velocity component. We demonstrate that this…

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astro-ph.GA

Probing the Orientation Distribution of Nearby Double White Dwarfs through Gravitational Waves with LISA

N. Seto, G. C. Liu

We present a framework to study the orientation distribution of nearby double white dwarf binaries with LISA, explicitly accounting for the fourfold degeneracy in the polarization angle. Exploiting the belt-like sky distribution of the nearby sample along the Galactic plane, we show that the low-multipole extraction can be recast as an effectively one-dimensional Fourier analysis along Galactic longitude, within a spherical-harmonic expansion based on the Wigner-\(D\) formalism. The symmetry wit…

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astro-ph.IM

Linear motion (R-FLEX) for minature 6.2 mm pitch optical fiber position robots with polar (R-theta) kinematics

Nicholas R. Wenner, Joseph H. Silber, Michael S. Schubnell, David J. Schlegel, Robert W. Besuner, William V. Shourt, Andrew P. Hope

R-FLEX is a compact, low-part-count flexure-based radial positioning mechanism designed for the next generation of massively parallel fiber-fed spectroscopic telescope instruments. Current instruments such as the Dark Energy Spectroscopic Instrument (DESI) employ 5,000 robotic fiber positioners at 10.4 mm pitch, whereas future surveys require 2.5-3x higher packing density, necessitating new positioning technologies. The R-FLEX mechanism converts small rotations at the flexure base into large, ne…

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astro-ph.EP

Revisiting TOI-4438 and TOI-442 planetary systems with new observations from SPIRou and TESS

J. Serrano Bell, G. Hébrard, E. Martioli, R. F. Díaz, L. de Almeida, D. Lorenzo-Oliveira, A. Salmi, C. Dorn et al.

We present a comprehensive re-analysis of two star-planet systems: TOI-4438, an M3.5V star hosting a mini-Neptune in a 7.4-day orbit, and TOI-442, an M1V star with a 4-day period planet located within the hot Neptune desert. Both systems were originally identified as transiting planet candidates by TESS and subsequently validated through the radial velocity (RV) method. Our work incorporates new TESS transit data and high-resolution spectroscopy from the SPIRou near-infrared spectropolarimeter.…

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astro-ph.GA

COSMOS2025: A Machine Learning Census of Massive Quiescent Galaxies at $2.5 < \text{z} < 5$

Vahid Asadi, Hosein Haghi, Akram Hasani Zonoozi

The existence of massive quiescent galaxies at high redshifts ($ \text{z} \gtrsim 2$) strongly constrains the rapid quenching mechanisms in galaxy evolution models. We present a machine learning framework to identify massive ($\log(\text{M}_*/\text{M}_\odot) > 9.5$) quiescent galaxies at $2.5 < \text{z} < 5$ in the COSMOS2025 catalog. We train a \texttt{CatBoostClassifier} on mock photometry from the Santa Cruz semi-analytic models (SAMs), incorporating key JWST NIRCam bands and realistic noise…

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nucl-thastro-ph.HEgr-qc

Neural-Accelerated Bayesian Calibration of Chiral Mean-Field Models to Nuclear Saturation and Vacuum Properties

Isaac Legred, Mateus Reinke Pelicer, Veronica Dexheimer, Jacquelyn Noronha-Hostler, Nicolás Yunes

Chiral models of nuclear interactions provide approximate, phenomenological descriptions of dense matter that respect the symmetries of quantum chromodynamics. Their Lagrangian parameters, however, are difficult to calibrate because these models are not controlled effective theories. Furthermore, repeated model evaluations are computationally expensive, and most parameter choices fail to reproduce acceptable saturation properties or hadron masses in vacuum. To address this, we develop a Bayesian…

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astro-ph.IM

MORFEO: Advancing Towards Final Design

Lorenzo Busoni, Guido Agapito, Marco Bonaglia, Alfio Puglisi, Marco Xompero, Matteo Aliverti, Francesca Annibali, Carmelo Arcidiacono et al.

The Multiconjugate adaptive Optics Relay For ELT Observations (MORFEO) is a first-generation adaptive optics module for the Extremely Large Telescope (ELT), designed to deliver a diffraction-limited, highly uniform 53x53 arcsec field of view to the MICADO near-infrared camera. As the project advances toward its Final Design Review (FDR), significant consolidations have been achieved across all subsystems. This paper presents an updated overview of the MORFEO system, highlighting its dual operati…

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astro-ph.EP

Piercing through the Haze: Characterizing Titan-like terrestrial exoplanets with JWST

L. C. Mayorga, Jacob Lustig-Yaeger, Andrew P. Lincowski, Kathleen E. Mandt, Ryan C. Felton, Adrienn Luspay-Kuti, Kristin S. Sotzen, Cameron A. Gutsgell et al.

As we enter a new era of using JWST to characterize exoplanet atmospheres, a top priority is defining observational needs and parameters in the search for life on an exoplanet. Although some studies have begun to consider Titan-like exoplanet atmospheres, more work is needed to prepare for the potential discovery and characterization of Titan analogues with JWST and future missions. We explore the effectiveness of exoplanet atmospheric retrieval methodologies on the Cassini/VIMS-IR spectrum of T…

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astro-ph.HE

Time-resolved leptonic modeling of the prompt emission of GRB 211211A

Maria Petropoulou, Maria Gkoni, Konstantinos Xyloportas, Stamatios I. Stathopoulos, Georgios Vasilopoulos, Apostolos Mastichiadis

GRB 211211A is a long duration gamma-ray burst with a compact object merger origin. In this work, we model the time-resolved prompt-emission spectra of GRB 211211A within a leptonic radiation framework. Our goal is to infer the physical properties of the emitting region, study the temporal evolution of the radiating particle distribution, and make predictions for prompt emission at TeV energies. We perform Markov Chain Monte Carlo fitting of the time-resolved numerical spectral energy distributi…

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

Rigidity spectra and onset geometry of the two largest Forbush decreases of solar cycle 25 from visibility-graph curvature

D. Sierra-Porta

We apply a geometric network diagnostic -- the nodal Forman-Ricci (FR) curvature of natural visibility graphs (NVG) -- to the two largest Forbush decreases (FDs) of solar cycle 25: the Gannon storm of 2024 May 10-11 and the 2025 June 1 event. Using 30-min NMDB records from six NM64 stations spanning cutoff rigidities $R_c \simeq 0$-$7\,$GV, we show that nodal FR curvature exhibits a sharp, coherent minimum at FD onset in both events, with onset-to-quiet median curvature ratios of 2.5-5.2 (Gannon…

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astro-ph.GAastro-ph.IM

When X-ray Features Hurt: Label Noise and Luminosity Overlap in Machine Learning Classification of AGN and Star-forming Galaxies

Jaymin Ding

In a previous paper, we found that adding an X-ray flux feature to a Random Forest Classifier of active galactic nuclei (AGN) and star-forming galaxies (SFGs) decreased classification accuracy from 97.51% to 89.26%, a counterintuitive result given the prevailing theory that X-rays are a reliable AGN diagnostic. This paper investigates the source of that discrepancy through both astrophysical and machine learning lenses. On the astrophysical side, we show that the X-ray luminosities of AGN and SF…

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astro-ph.EP

Growing Planets Produce Extreme Dust Signatures

Philip J. Carter, Zoë M. Leinhardt

Collisions between planetary bodies are essential to the assembly of rocky planets like the Earth, but they are extremely difficult to observe. We therefore rely on indirect signatures of planetary impacts such as extreme debris disks - bright infrared excesses around other stars. Extreme debris disks are thought to be the result of energetic collisions that ejected large amounts of vaporized rock which rapidly condensed into mm- or cm-sized dust. However, previously there has been no clear way…

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