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.SRastro-ph.GA

The potential broader complex linked to the key Cepheid SV Vul

Daniel Majaess, Ignacio Negueruela, Leonid N. Berdnikov, Charles J. Bonatto, David G. Turner, Dante Minniti, Vittorio F. Braga, Giovanni Carraro et al.

A new distance was established to the Cepheid SV Vul ($P\simeq45^{d}$) and its host cluster Alicante 13, and is tied in part to deeper UKIDSS-DR6 photometry and Gaia DR3 observations ($d=2.30\pm0.13$ kpc). SV Vul and Alicante 13 possibly belong to a broader coeval stellar complex, which could include Liu-Pang 1738. The clusters and Cepheid share comparable astrometry (e.g., $σ_π\simeq0.02$ mas, $σ_{μ_δ}\simeq0.06$ mas yr$^{-1}$), and similar cluster turnoffs (ages) exist as indicated by ultravio…

詳細を見る →
gr-qcastro-ph.HE

DARK-HIDE: Dark matter versus hidden dimensions in black hole images

Mohsen Fathi

Dark matter near a black hole and effective extra-dimensional corrections can change the same horizon-scale observables. This creates a simple but important question: if an image differs from Kerr, what caused the difference? We study this problem with DARK-HIDE. The dark-matter branch is described by rotating metrics with radial mass functions, while the hidden-dimensional branch is a rotating braneworld metric with a non-electromagnetic tidal charge. We compare photon regions, critical curves,…

詳細を見る →
astro-ph.HEhep-phhep-th

The Origin of Multi-TeV Gamma-rays in LHAASO J0341+5258 via Cosmic Ray Illumination of Molecular Clouds

Abhijit Roy, Alan Sunny, Martina Cardillo, Jagdish C. Joshi, Ritabrata Sarkar

We investigate the origin of the ultra-high-energy $γ$-ray emission detected by the Large High Altitude Air Shower Observatory (LHAASO) from the source LHAASO J0341+5258, which has not yet been associated with any known astrophysical object within the detector's field of view. The observed UHE emission is modelled within two independent frameworks: initially with a time-dependent, source-independent hadronic scenario implemented with the numerical package GAMERA, where particles propagate throug…

詳細を見る →
astro-ph.COastro-ph.GA

A Universal Relation Between Primordial Density-Potential Cross-correlation Coefficient and Spin Factor Distribution

Jun-Sung Moon, Jounghun Lee, Juhan Kim

Recent studies have revealed that the key properties of visible galaxies like their optical sizes, stellar ages, star formation rates and morphologies are closely linked with the angular momenta of their host dark matter halos. According to the linear tidal torque theory, the halo angular momentum, as a conserved quantity, is directly proportional to the primordial spin factor, $τ$, defined as the degree of misalignment between the principal axes of the initial density and potential Hessian matr…

詳細を見る →
astro-ph.GA

Even central galaxies feel their environment: cosmic siphoning of cool gas accretion

Ke Xu, Tao Wang

Identifying the key processes regulating cool gas accretion in galaxies is essential for understanding the baryon cycle within galactic ecosystems. Recent studies indicate that the most fundamental internal process is likely the competition between halos and central black holes. This is revealed through a universal relation between increasing black hole masses and decreasing cool gas fraction ($μ_{\rm HI} \equiv M_{\rm HI}/M_{\star} \propto M_{\rm BH}^{-0.6}$). Here we further explore the primar…

詳細を見る →
cs.CVastro-ph.IM

PlumeQuant: Uncertainty-aware consistency assessment of methane plume masks and emission-rate estimates

Parisa Masnadi Khiabani, Wolfgang Jentner, Alireza Rangrazjeddi, Michael C. Wimberly, Binbin Weng, David Ebert, Charles Nicholson

Imaging spectrometers increasingly distribute source-resolved methane plume products in which the plume mask, integrated mass enhancement (IME), plume length, emission rate, and uncertainty are physically and algorithmically linked. Using 63 EMIT-derived Carbon Mapper plume records from 27 scenes, we show that these published scalar quantities do not uniquely constrain the plume boundary: substantially different yet plausible masks reproduce the same IME, plume length, and emission rate. Genetic…

詳細を見る →
astro-ph.GA

The dynamical environment of the high-mass star-forming region G28.288$-$0.364

Jyotirmoy Dey, Devendra K. Ojha, Jagadheep D. Pandian

Massive stars form within deeply embedded dust cores, and the development of hypercompact and ultracompact H II regions characterizes their early evolution. Identifying and analyzing such regions is essential for understanding the physical processes that govern massive star formation and the transitions between early evolutionary stages. In this article, we investigate the physical and kinematic properties of the massive star-forming region G28.288$-$0.364 to constrain the evolutionary stages of…

詳細を見る →
nucl-thastro-ph.HEphysics.comp-ph

NNStar: An end-to-end AI agent for nuclear matter and neutron star physics

Yao Ma, Yong-Liang Ma, Jia-Ying Xiong

Constraining the equation of state of dense matter requires confronting effective models with massive data that spans many orders of magnitude in scale, from sub-saturation nuclear matter properties to the masses, radii, and tidal deformabilities of neutron stars. Exploring the high-dimensional coupling space of such a model and fine tuning it against all of these constraints is a labor- and time-intensive task. We present \textsc{NNStar}, an end-to-end artificial-intelligence agent that automat…

詳細を見る →
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…

詳細を見る →
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.…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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-…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →
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.

詳細を見る →
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…

詳細を見る →
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…

詳細を見る →