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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.IMcs.SE

A ready-to-deploy MLOps software platform for satellite and NEO detection at meter-class ground-based observatories

Rafael Carrillo Navarro, Pablo García-Martín, René Duffard, Juan Luis Orellana Montes de Oca, Oscar Ortega Ríos

Ground-based astronomical observations frequently contain streaks produced by artificial satellites, space debris, and potentially Near-Earth Objects (NEOs). While machine-learning models can reliably detect these features, their practical adoption in observatory operations is often limited by the lack of integrated tools for visual inspection, validation, workflow management, and structured data storage. This paper presents the StreakMind Workbench, a framework that applies MLOps practices to b…

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astro-ph.HEastro-ph.IM

Energy estimation of direct and reflected cosmic-ray events aboard balloon-borne radio detectors

Sergio Cabana-Freire, Jaime Alvarez-Muñiz, Matias Tueros

Balloon-borne radio detectors offer a highly effective approach to monitoring immense volumes of the Earth's atmosphere and ice for ultra-high-energy cosmic rays and neutrinos. Because these payloads measure radio emission from a single, highly elevated vantage point, reconstructing the air-shower energy using traditional methods is not possible. In this work, we present a comprehensive, simulation-based energy reconstruction framework tailored to the unique cosmic-ray event geometries observed…

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astro-ph.HE

A magnetar-powered jet-wind outflow in gamma-ray burst-associated supernovae: Application to the thermal components of GRB 060218-SN 2006aj

Yun-Peng Li, Da-Bin Lin

A rapidly rotating magnetar formed in the collapse of a massive star may release its spin-down power through both a collimated polar jet and a quasi-isotropic magnetar wind. With its long-lasting soft X-ray blackbody component and the double-peaked UV/optical light curves of SN 2006aj, GRB 060218-SN 2006aj provides a useful test case for such a two-component energy-injection scenario. We developed a magnetar-powered jet-wind model in which the two outflows interact with homologously expanding SN…

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astro-ph.HEastro-ph.GA

Multi-Band Optical Variability Characteristics of the $γ$-ray emitting blazar 1ES 0647+250 during its 2020 flare

K. Subbu Ulaganatha Pandian, C. S. Stalin, S. Muneer, S. Umayal, Aditi Agarwal, Amit Kumar Mandal, B. Natarajan

We present a multi-band optical variability study of the $γ$-ray emitting high-synchrotron-peaked blazar 1ES~0647+250 during its enhanced optical activity in 2020. The analysis utilizes 107 epochs of high-precision $B$, $V$, and $R$-band photometry obtained with the 75 cm telescope at the Vainu Bappu Observatory, combined with high-cadence $z_g$ and $z_r$ survey data from the Zwicky Transient Facility. The combined light curves reveal coherent variability across all optical filters, with the sou…

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astro-ph.EPastro-ph.IM

Probing Exoplanetary Chemistry with Ariel: Scientific Priorities and Observational Strategies

Olivia Venot, Yamila Miguel, Robin Baeyens, Stefano Bellotti, Giuseppe Cassone, Quentin Changeat, Ryan Cloutier, Athena Coustenis et al.

Over the past two decades, increasingly precise observations have revealed that exoplanet atmospheres are chemically diverse and often far from equilibrium, with processes such as vertical mixing, photochemistry, and atmospheric circulation producing significant departures from thermochemical expectations. As large surveys across a wide range of planets begin to uncover population-level chemical trends, a coherent interpretation of these patterns remains elusive, particularly for gas giants and…

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astro-ph.HE

Broad-band spectral-timing: simultaneous NICER and HXMT observations reveal an anticorrelation between the softest and hardest X-ray fluxes in MAXI J1820+070

Niek Bollemeijer, Phil Uttley, Bei You

Black hole X-ray binaries (BHXRBs) in the hard state show variable X-ray emission across a wide range of energies. Hard X-rays are thought to be produced through Compton-upscattering of seed photons from the accretion disc by the hot X-ray corona, leading to a spectral component roughly shaped like a power-law with a high-energy cut-off. A complete study of the coronal variability requires a full view of the spectrum, from the low-energy cut-off at the seed photon energy to the high energy cut-o…

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astro-ph.EPastro-ph.IM

Juice-SWI during the Lunar-Earth-Gravity-Assist (LEGA) - Part 2: Instrument operations

T. Cavalié, R. Moreno, L. Rezac, F. Herpin, C. Jarchow, P. Hartogh, A. Carrasco-Gallardo, S. Goodyear et al.

The Jupiter Icy Moons Explorer (Juice) embarked in 2023 on a 8-year interplanetary journey to Jupiter and its icy moons. The Submillimetre Wave Instrument (SWI) is one of the ten science instruments aboard the spacecraft. SWI is a sophisticated and first-of-its-kind payload visiting the outer solar system, featuring dual-band tunable receivers, two independent pointing mechanisms, and spectrometers capable of high resolution (up to a resolving power of 10^{7}). It is designed to support the dive…

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astro-ph.EP

Europa smooth plains formation: a SPH cryovolcanic model

Bastien Bodin, Daniel Cordier, Ashley Gerard Davies

Cryovolcanism is a fundamental geodynamical process that has been observed on several icy moons. Europa stands out as a primary target for investigating potential cryovolcanic activity and its role in shaping icy moon surfaces. This work characterizes the physical state of ascending cryomagma and evaluates the relevance of terrestrial analogues to explain Europa's surface features. After investigating cryomagma depressurization, we developed CryoPy, a numerical model based on Smoothed-Particle H…

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astro-ph.HE

Relativistic accretion-disc models of Cyg X-1 in the soft state: a case study

Luciano Ye, Luigi Foschini

The thermal continuum of Cygnus X-1 in the soft state is often modelled with a multicolour disc in a Newtonian spacetime approximation. That choice is convenient for estimating the inner radius, but it neglects relativistic effects near the black hole; these are usually restored through colour-correction and boundary-condition factors. Using Suzaku data from one exemplary observation, we compare this Newtonian description with some fully relativistic disc models, keeping the same treatment of ab…

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astro-ph.SRastro-ph.HE

White Dwarf Pulsars: an emerging class of compact binaries

David A. H. Buckley

I summarise the expanding class of white dwarf pulsars for which the prototype, AR Scorpii, was only discovered in 2016. At the time of this meeting, two further systems had been found (eRASSU J191213.9-441044 and SDSS J230641.47+244055.8). These are thought to be detached (or nearly detached) white-dwarf--red-dwarf binaries, where the white dwarf's magnetic field interacts with the M-star's corona, resulting in the capture and acceleration of electrons to relativistic velocities in the magnetos…

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astro-ph.SR

Tracing magnetic flux rope footpoints in AR 12975 with coronal dimmings and data-driven magnetofrictional simulations

Andreas Wagner, Amaia Razquin, Astrid M. Veronig, Emilia K. J. Kilpua, Karin Dissauer, Jens Pomoell

Coronal mass ejections (CMEs) are driven by the eruption of magnetic flux ropes (MFRs) whose footpoints are often observed indirectly as coronal dimming regions. However, the relationship between observed dimmings and true MFR footpoint locations remains uncertain due to limitations in both detection methods and coronal magnetic field modelling caused by the complexity of eruptive events. We aim to investigate the M4 flare and CME event on 28 March 2022 in AR 12975 to determine how well observed…

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astro-ph.HEgr-qc

PANGU I: A Parthenon-Based Framework for Fixed-Spacetime GRMHD

Yuehang Li, Fan Zhou, Mingyang Luan, Minyong Guo, Bin Chen

Existing general-relativistic magnetohydrodynamics (GRMHD) codes offer complementary capabilities, but these capabilities remain distributed across different frameworks. To unify them, we introduce PANGU--Parthenon-Based Astrophysics for Numerical Relativity and GRMHD in a Unified Framework--a modular computational framework that integrates a shared solver across physical regimes, flexible spacetime geometry, and extensible computational infrastructure within a single architecture. In the first…

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hep-phastro-ph.HEastro-ph.SRnucl-th

Finite-Temperature Axion-Admixed Neutron Stars in a Quarkyonic Crossover Framework

S. K. Patra, D. Dey, Jeet Amrit Pattnaik, R. N. Panda

We analyze the effect of axion contribution on the mass, radius and dimensionless deformability of a neutron star (NS) at finite temperature. Although the cooling of an NS is mainly due to the emission of neutrinos, additional cooling cannot be ruled out due to the emission of axions. The existence of an axion is needed for addressing the strong CP problem within the standard model. The Peccei-Quinn (PQ) symmetry breaking mechanism generates axions. They are pseudo-Nambu-Goldstone bosons. Their…

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astro-ph.SRastro-ph.HE

H_alpha observations of the Be/X-ray binary MWC 656

R. Zamanov, V. Marchev, K. A. Stoyanov, M. D. Christova, M. Minev, M. Moyseev, D. Marchev, J. Marti et al.

Context. MWC 656 is a Be/X-ray binary identified as an emission-line object, X-ray and radio source and might be a weak gamma-ray source, harbouring an enigmatic secondary component. Aims. Our aim here is to study the orbital modulation of the H-alpha emission line, disc truncation and to evaluate the binary parameters. Methods. During the period 2021-2026, we obtained high resolution (30000) optical spectra of MWC 656 and analysed them together with the published data. Results. We find an orbit…

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astro-ph.HE

Origin of the high-energy spectral cutoff in gamma-ray pulsar halos

Qi-Ling Chen, Ming-Ming Kang, Kun Fang, Hong-Bo Hu, Yi-Qing Guo, Chao-Wen Yang

The spectra of gamma-ray pulsar halos exhibit a clear cutoff feature at tens of TeV. This work investigates the origin of the spectral cutoff by interpreting the HAWC data of the Geminga halo. The most straightforward interpretation is that the cutoff reflects the maximum electron acceleration capability of the central PWN. We model this scenario using spherically symmetric diffusive shock acceleration, where the upstream scale of the PWN termination shock limits the maximum energy. We also prop…

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astro-ph.HEastro-ph.GA

On the rates of binary star collisions around hypermassive black holes

Megha Sharma, Alexander Heger, Evgeni Grishin, Daniel J. Price

Observations of the Milky Way show that galaxies have binary stars in their centres. Using Monte Carlo simulations, we model the population statistics of encounters of such binaries with galactic central black holes (BHs) of mass 10^5-10^{10} Msun (hypermassive BHs >= 10^8 Msun HMBHs). Whereas main-sequence single stars cannot undergo tidal disruption events around HMBHs, stellar collisions of main-sequence binary stars may produce observable transients. We use the post-Newtonian Einstein-Infeld…

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astro-ph.EPphysics.space-ph

Kelvin-Helmholtz vortices in the Martian +E hemisphere downstream of crustal magnetic anomalies

Junxi Niu, Tong Dang, Jiuhou Lei, Binzheng Zhang, Wenya Li, Binbin Tang, Junjie Chen, Sudong Xiao et al.

At unmagnetized planetary bodies, the Kelvin-Helmholtz (KH) instability at the solar-wind boundary is a key driver of atmospheric escape, fundamentally shaping long-term climate evolution. This shear-driven plasma mixing is theoretically predicted to be asymmetric, strongly favoring the hemisphere where the solar-wind electric field points toward the planet (-E hemisphere). Here we report the observation of a coherent train of fully developed KH vortices in the traditionally unfavorable +E hemis…

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astro-ph.GA

Ubiquitous nuclear disks and bars embedded in massive galaxies in the cosmic morning

Jianyuan Luo, Fangzhou Jiang, Jinning Liang, Boris S. Kalita, Pinsong Zhao, Jinyi Shangguan, Bingcheng Jin, Zeyu Gao et al.

The morphology of the central regions of high-redshift galaxies remains relatively unexplored, while recent case studies suggest that giant disks can emerge without first developing a prominent central spheroid. Here, we investigate the inner structures of a mass-complete sample of 45 massive galaxies at $z=3$ in the TNG50 simulation. Through double-Sérsic profile decomposition, isodensity ellipse fitting, intrinsic three-dimensional shape measurements, and stellar kinematics, we find that these…

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astro-ph.EP

Dynamical Behavior and Surface Features of Large Super-Fast Rotator Near-Earth Asteroid (436724) 2011 UW158

Caio Gomes, Andre Amarante, Filipe Monteiro, Alessandra Ferreira, Leonardo Braga, Allan Kardec de Almeida, Duncan Lyster, Nicoli Rocha et al.

The sub-kilometer Super-Fast Rotator and Potentially Hazardous Asteroid (436724) 2011 UW158 exhibits an extreme dynamical environment driven by its rotational period of 0.61072 h. Using a 3-D polyhedral shape model, we investigate the surface dynamic stability under both cohesionless and cohesion-modified conditions, while also addressing families of periodic orbits, station-keeping maneuvers, and energy states in this rapidly rotating, irregular-body regime. Our results show that, with the incl…

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astro-ph.GA

Distance Estimation using Globular Clusters and Ultra-Compact Dwarfs

Bas van Heumen, Jonah S. Gannon, Duncan A. Forbes, Jean P. Brodie, Aaron J. Romanowsky

The tight scaling relation between absolute magnitude and internal velocity dispersion ($σ$) for globular clusters (GCs), referred to as the GC velocity dispersion (GCVD) relation, has shown great potential as a distance estimator. However, at the high-luminosity end of the GC luminosity function, GCs mix with ultra-compact dwarfs (UCDs). As GCs appear to smoothly transition into UCDs with dynamical mass, we investigate the possibility of a unified distance estimation relation applicable to both…

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astro-ph.EP

The Dynamical Environment of Kepler-223 Planetary System

Carlos E. Chavez, Adrián Fierro, Ándres Avilés

The Kepler space telescope was a successful mission that used the transit method. Multi-planetary systems are interesting because they are dynamically rich due to the planets' interactions. Kepler's mission was the first to find a system with four planets all in resonance, that is Kepler-223. The Kepler-223 system is of unique dynamical interest as the first exoplanetary system confirmed to host four sub-Neptune planets in a precise 3:4:6:8 resonant chain. Previous dynamical studies have struggl…

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nucl-thastro-ph.SRnucl-ex

Multi-Model Analysis of the Astrophysical $S(E)$ Factor for the $^{9}\mathrm{Be}(p,α)^{6}\mathrm{Li}$ Reaction and Its Impact on Astrophysical Reaction Rates

Xue-Jian Wang, Wei-Ke Nan, Qing Wang, Tian-Yu Tao, Qun-Gang Wen, Jian-You Guo, Cheng-Bo Li, Hui-Ming Jia et al.

The $^{9}\mathrm{Be}(p,α)^{6}\mathrm{Li}$ reaction is a destruction process for $^{9}\text{Be}$ in stars and the Big Bang. The Trojan Horse Method (THM) is a well-established indirect technique that enables the determination of reaction cross sections within the Gamow energy region while avoiding the uncertainties associated with low-energy extrapolations of the $S(E)$ factor and electron-screening effects. In this work, the bare-nucleus THM data reported by Wen \textit{et al.} are systematicall…

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astro-ph.HEastro-ph.IM

Estimating redshift distributions of Fermi blazars with multiple machine-learning models

Kerui Zhu, Jiaming Chen, Yonggang Zheng, Ruixin Zhou, Shan Chang, Li Zhang, Niansheng Tang

Approximately half of the Fermi-LAT-detected blazars lack spectroscopic redshift measurements, which limits population studies and investigations of the cosmological evolution of the gamma-ray blazar population. We aim to develop a multi-model ensemble framework to systematically evaluate the performance of machine-learning models for blazar redshift estimation and to provide predictive redshift probability distributions with quantified uncertainties for all blazars without measured redshifts. W…

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gr-qcastro-ph.COastro-ph.GAastro-ph.HE

Quasinormal-mode redshifts of black holes in galactic halos with radial pressures

Che-Yu Chen, Hassan Hassanabadi, Soroush Zare

We investigate the black-hole quasinormal mode redshifts induced by a galactic dark-matter halo with nonvanishing radial pressure. The halo is described by an anisotropic fluid with a generalized density profile and a constant radial equation-of-state parameter $w$. We construct the corresponding static, spherically symmetric spacetime and study the resulting corrections to the unstable light ring and quasinormal-mode spectrum. For dilute halos and $w\neq -1$, the light-ring angular frequency an…

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astro-ph.SRastro-ph.HE

Orbital and spin periods of the intermediate polar 2PBC J0800.5-4306

Yabing Zhao, Chunhua Zhu, Sufen Guo, Guoliang Lü, Xizhen Lu, Xinyu Liu

2PBC J0800.5$-$4306 (Swift J0800.7$-$4309; optical counterpart Gaia DR3 5533020382479508736) is a hard-X-ray-selected cataclysmic variable whose magnetic subtype had remained uncertain. We analyse \textit{TESS} photometry from Sectors 88 and 89 and archival \textit{XMM-Newton} timing data. The \textit{TESS} data show signals at the orbital frequency $Ω$, its first harmonic $2Ω$, the white-dwarf spin frequency $ω$, and the spin--orbit beat frequency $ω-Ω$. We measure $P_{\rm orb}=5.38540^{+0.0002…

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astro-ph.IMastro-ph.CO

FPCA-Enhanced Simulation-Based Inference for Robust Type Ia Supernova Cosmology

Moonzarin Reza, Lifan Wang

Precision cosmology is a cornerstone of modern astronomy, and upcoming wide-field photometric surveys make it crucial to develop robust, data-driven inference methods that can handle complex survey systematics without relying on closed-form likelihoods. Simulation-Based Inference (SBI) meets this need by enabling forward simulations that encode complex survey characteristics. Previous SBI analyses in supernova cosmology have used SALT2 light-curve parameters as summary statistics; however, SALT2…

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astro-ph.HE

Is accretion flow magnetically arrested in M87?

Yuao Ma, Xinwu Cao, Jia-Wen Li, Jianchao Feng, Qingwen Wu

It is still debating on whether the disc is magnetically arrested in M87. We assume that a weak external magnetic field is dragged inwards by the accretion disc, which is substantially enhanced to drive strong jets near the black hole horizon via Blandford-Znajek mechanism. The jet power of M87 has been well constrained with the observational data, while the accretion rate in the inner region of the accretion flow in M87 is estimated by fitting the multi-waveband continuum spectrum and the data…

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astro-ph.HEastro-ph.CO

A multi-telescope fit to the FRB population, allowing for FRB repetition

Jordan L. Hoffmann, Clancy W. James, Jason X. Prochaska, Ines Pastor-Marazuela, Kritti Sharma, Liam Connor

Fast radio bursts (FRBs) are millisecond-duration radio pulses with extragalactic origins. A majority of FRBs have only had a single pulse detected from them; however, an increasing number have been identified as repeaters. Here we present a full redshift -- dispersion measure ($z$-DM) analysis including a simple power-law model of repetition rates. We assume all FRBs are drawn from the same intrinsic population and fit these FRB population parameters using data from ASKAP, Murriyang (Parkes), D…

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hep-phastro-ph.COastro-ph.GAastro-ph.SR

Axions and the RR Lyrae Period-Luminosity Relation

Jeremy Sakstein, Djuna Croon

We investigate the impact of axions on the period-luminosity relation (PLR) of RR Lyrae stars. During the red giant branch phase, emission through the electron coupling cools the core, increasing its mass at ignition. The larger core produces more luminous horizontal-branch stars, systematically shifting the zero point of the RR Lyrae PLR toward brighter magnitudes. We model the RR Lyrae population of the globular cluster M3 using stellar evolution and pulsation calculations tailored to its age…

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astro-ph.IMastro-ph.EP

Increasing Sensitivity to Trailed Solar System Objects in Archival JWST NIRCam Imaging with Group Differencing

Anthony Girmenia, Stanimir Metchev

The JWST archive contains thousands of NIRCam exposures distributed across the sky. Small solar system bodies (SSSBs) are present in many of these fields, but are often trailed and more difficult to detect. The standard pipeline produces a single image by fitting a slope to a sequence of $N$ cumulative ``up-the-ramp" groups of the detector. Thus, each JWST image comprises a time series of cumulative reads. We demonstrate that transforming the ramp into a series of group difference images reduces…

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