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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.SRastro-ph.HEphysics.space-ph

Long-Baseline VLF Observations of Solar Flares from Antarctica

Kamen Kozarev, Peter Petkov, Ivaylo Nachev, Veselka Radeva, Momchil Dechev, Galin Borisov, Anton Atanasov

We present long-baseline Very Low Frequency (VLF) observations of solar flare-induced ionospheric disturbances obtained at the Bulgarian Polar Astronomical Observatory (St. Kliment Ohridski Base) on Livingston island, Antarctica. Using continuous VLF transmissions at 21.4 kHz (NPM, Hawaii) and 24.0 kHz (NAA, Maine), propagating over trans-hemispheric paths exceeding 11000 km, we analyze observations of solar flares during the period 24 January--8 February 2025. After removing the strong diurnal…

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astro-ph.SR

A Homogeneous Spectroscopic and Evolutionary Study of cool HgMn and hot Metallic A Stars

F. Kahraman Aliçavuş, E. Çelik, E. Niemczura

We present a homogeneous spectroscopic and evolutionary analysis of chemically peculiar stars, focusing on HgMn and metallic A (Am) subclasses. Particular emphasis was placed on the coolest HgMn stars and the hottest Am stars, motivated by the long-standing hypothesis that these objects may represent consecutive evolutionary stages of a similar stellar population. High-resolution spectra of 13 HgMn and 14 Am targets were analyzed to derive atmospheric parameters and detailed chemical abundances.…

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astro-ph.GA

Mapping Dust Attenuation at Kiloparsec Scales. IV. A Dust-model Interpretation of Attenuation Curves in Nearby Galaxies

Ruonan Guo, Cheng Li, Tao Jing, Shuang Zhou, Niu Li, Zhuo Cheng

In this fourth paper on kiloparsec-scale dust attenuation, we ask whether the empirical trends found in Papers I--III can be translated into effective dust properties. Using attenuation curves for 2487 high-continuum-S/N spaxels in 91 SwiM v4.2 galaxies, we construct a grid of uniform-screen dust models composed of astronomical silicate and graphite grains with MRN-like size distributions. We fit the normalized attenuation-curve shape to constrain model parameters and then use the attenuation am…

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

Cradle of Life: From the Formation of Stars to Habitable Worlds with the SKAO

Eleonora Bianchi, Joseph R. Callingham, the Cradle of Life working group

This chapter provides an overview of the different science cases covered by the "Cradle of Life" working group, which aims to leverage the capabilities of the Square Kilometre Array Observatory (SKAO) to trace the physical and chemical pathways toward stars and planets formation, how such stars impact their planets, and whether life could exist in such conditions. At its highest frequencies, the SKAO will probe the earliest stages of the raw material fuelling planet formation, while enabling dee…

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astro-ph.IM

Fabrication of focusing optics for TA-MOONS: Micro-MOONS

Ceiwynn Longworth, Megan Delamer, Suvrath Mahadevan, Joe P. Ninan, Kathleen Gehoski, Krushna Jadhav

Understanding star and planet formation requires optical to near-infrared spectroscopic observations of a large number of young stellar objects. The TIFR-ARIES Multi-Object Optical to Near-infrared Spectrometer's (TA-MOONS) primary objective is to preform a large spectroscopic survey of young stellar objects across wavelengths of 360 nm to 2.5 microns, with the multiplexed capability of observing up to eight sources simultaneously. Multiplexity is achieved by moving pickup mirrors on robotic arm…

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astro-ph.SRastro-ph.IM

The SKA as a Probe of Heliospheric Turbulence and Radio-wave Propagation Effects

Nicolina Chrysaphi, Eduard P. Kontar, Hamish A. S. Reid, Sophie Musset, Shilpi Bhunia, Kamen Kozarev

Density turbulence in the heliosphere can impact traversing radio photons originating from anywhere in the universe, leading to distortions of both the spectroscopic and imaging properties of the radio sources. Extra-solar radio sources exhibit scintillation and angular broadening, while monochromatic signals from spacecraft are spectrally broadened. It was recently demonstrated that such impacts, referred to as radio-wave propagation effects, are particularly significant in observations of sola…

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astro-ph.EP

Reflation: redox-driven atmospheric inflation as tracer of super-Earth geochemistry

Lorenzo Cesario, Tim Lichtenberg, Mara Attia, Harrison Nicholls, Imre Kisvardai, Quentin Changeat

We demonstrate that the redox-sensitivity of mantle outgassing can trigger transient episodes of atmospheric re-inflation in highly irradiated and geochemically-reduced super-Earths, a mechanism we term reflation. Mantle redox governs the outgassing and speciation of CHONS volatiles, setting the background secondary atmospheric composition during extended photoevaporation at highly irradiated conditions. Using simulations of the coupled atmosphere-interior evolution of irradiated super-Earths, w…

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astro-ph.GA

RABBITS IV: Stellar feedback and SMBH merging time-scales in the sub-Milky Way mass regime

Ruby J. Wright, Roosa Heiskanen, Shihong Liao, Alexander Rawlings, Peter H. Johansson, Max Mattero, Fiona H. Panther, Atte Keitaanranta et al.

Merging supermassive black holes (SMBHs) in low- and intermediate-mass galaxies are important sources for future millihertz gravitational-wave observatories such as LISA. Predicting the delay between galaxy coalescence and SMBH merger is therefore critical for modelling the observable SMBH merger population. Using the KETJU code, we perform 16 equal-mass galaxy merger simulations as part of the Resolving supermAssive Black hole Binaries In galacTic hydrodynamical Simulations (RABBITS) series to…

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astro-ph.SR

Unveiling the nature of G6096: a likely hierarchical triple system

Yinghao Xu, Xinlin Zhao, Song Wang, Guang-Yao Xiao, Zikun Lin, Xue Li, Hao-Bin Liu, Henggeng Han et al.

G6096 (Gaia DR3 609651611028044544) was recently reported as a wide ($P\sim 450$ days) and eccentric ($e\sim0.18$) binary possibly hosting a massive white dwarf or neutron star. In this work, through analyses of the projected rotational velocity between the blue and red bands, spectral disentangling, joint radial velocity and astrometric fitting, and X-ray emission, we suggest that the system contains additional visible component(s) rather than a compact object. We develop a new approach to reve…

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hep-phastro-ph.HEgr-qc

High-Energy Neutrinos from Black Hole Evaporation in Neutron Stars

Ioannis Dalianis

We investigate the production of high-energy neutrinos from microscopic black holes formed through the gravitational collapse of asymmetric dark matter accumulated inside neutron stars. When Hawking evaporation dominates over accretion, long-lived, feebly interacting particles beyond the Standard Model escape the neutron star and subsequently decay into high-energy neutrinos. We analyze the repeated cycle of dark matter capture, black hole formation, and evaporation, identifying two distinct reg…

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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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