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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。

gr-qcastro-ph.HE

Testing Extra-Dimensional Gravitational-Wave Polarizations with Compact-Binary Observations

Hai-Tian Wang, Dicong Liang, Lijing Shao, Yu-Xiao Liu

Extra spatial dimensions arise naturally in theories beyond four-dimensional general relativity (GR), but direct observational evidence remains elusive. Gravitational waves offer a distinctive probe: geometric projection onto the observable three-dimensional spatial subspace can produce apparent tensor, vector, and scalar polarizations. We consider one additional spatial dimension and a two-mode tensor-wave ansatz for which the projected polarization components are fixed linear combinations of t…

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astro-ph.HE

Investigating the nature of magnetic turbulence in Tycho's SNR using X-ray observation

Ashwin Aravindaraj, Hui Zhu, Adrien Picquenot, Hsiang-Kuang Chang

Supernova remnants (SNRs) are widely regarded as the primary sources of Galactic cosmic ray acceleration and the particles are energized at the shock front of SNRs through the diffusive shock acceleration (DSA) mechanism, gaining energy by repeatedly crossing the shock. Magnetic turbulence plays a crucial role in scattering these particles back and forth, making the investigation of turbulence essential to understanding the acceleration process. In this study, we apply the two-point correlation…

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astro-ph.HE

Investigating the nature of magnetic turbulence in Tycho's SNR using X-ray observation

Ashwin Aravindaraj, Hui Zhu, Adrien Picquenot, Hsiang-Kuang Chang

Supernova remnants (SNRs) are widely regarded as the primary sources of Galactic cosmic ray acceleration and the particles are energized at the shock front of SNRs through the diffusive shock acceleration (DSA) mechanism, gaining energy by repeatedly crossing the shock. Magnetic turbulence plays a crucial role in scattering these particles back and forth, making the investigation of turbulence essential to understanding the acceleration process. In this study, we apply the two-point correlation…

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astro-ph.HE

The Hand of God Revisited: Revealing the Shell Structure and Jet-Supernova Remnant Interaction in MSH 15-52

Lingxiao Dang, Isabel Sander, Samar Safi-Harb, Christopher Fryer

We present an X-ray analysis of the supernova remnant (SNR) MSH 15-52 associated with the young rotation-powered pulsar PSR B1509-58, using Chandra, XMM-Newton, and eROSITA, complemented by MeerKAT radio data. We report the discovery of the missing southern counterpart to the bright northern RCW 89 region and identify a foreground X-ray source that may be a previously unidentified SNR candidate. Imaging and spectroscopy with XMM-Newton and eROSITA reveal the shell properties of MSH 15-52 and sug…

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astro-ph.SR

What powers the most energetic flares in the Kepler field? Revisiting the superflaring star KIC 2852961

Zs. Kővári, B. Seli, L. Kriskovics, K. Oláh, P. Odert, M. Leitzinger, B. Schmercz, K. Vida et al.

Flare activity in red giants is quite common when continuously monitored with high-precision space photometry. In fact, the most powerful flares, also known as "superflares" have been observed on red giant stars. KIC 2852961 is a red giant star producing the highest-energy flares in the Kepler field, and is also known for its large-amplitude starspot-induced light variations. Our goal is to find out what causes the extreme flare activity and flare energies in this star. For our investigations, w…

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astro-ph.SRastro-ph.EP

Metallicity does not reorder line-to-line sensitivity to granulation in solar-like stars

Dušan Vukadinović, Sowmya Krishnamurthy, Valeriy Vasilyev, Veronika Witzke, Andrew Collier Cameron

Stellar granulation imprints line-dependent wavelength shifts and profile variations that limit the precision of radial velocity (RV) measurements used for exoplanet detection and characterization. Understanding how the sensitivity of individual spectral lines to granulation depends on stellar parameters is therefore essential for mitigating granulation-induced RV signals. Here, we investigate the effect of metallicity using MURaM 3D magnetohydrodynamic simulations of stellar granulation includi…

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astro-ph.SRastro-ph.GA

Probing Massive Star Formation with Intrinsic Multiplicity Constraints from TESS Eclipsing Binaries

Jasmine Vrancken, Alex Kemp, Andrew Tkachenko, Conny Aerts, Hugues Sana

Massive stars play a central role in stellar and galactic evolution as progenitors of supernovae, neutron stars, black holes, and gravitational wave sources. Despite their importance, the dominant formation mechanisms of massive binaries remain poorly constrained observationally. We aim to use a large, homogeneous sample of eclipsing binaries to observationally constrain binary formation across a wide range of primary masses and test predictions from various formation scenarios. We combine photo…

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astro-ph.IMastro-ph.HE

A Coherent Harmonic Summing Pulsar Search Code

Scott M. Ransom

Pulsars have narrow pulses, so their signals spread over many harmonics in a Fourier transform. Standard pulsar searches add the powers of those harmonics and discard their phases, which throws away the pulse shape and some of the signal. Folding the time series at each trial period keeps both, but is expensive even with the Fast Folding Algorithm (FFA). We describe CoherentSearch.jl, an open-source Julia code that reconstructs the pulse profile at every trial spin frequency directly from the Fo…

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gr-qcastro-ph.HEhep-th

Nonreciprocal black holes with primary hair in beyond Horndeski gravity: Exact solutions and stability

Sebastian Bahamonde, Theodoros Nakas, Simon Iteanu

We develop a novel systematic method for constructing exact, static, and asymptotically flat black-hole solutions in shift-symmetric and $Z_2$-symmetric beyond Horndeski theories. In contrast to previous studies, our approach does not rely on the restrictive reciprocal condition $g_{tt}g_{rr}=-1$, allowing for more general geometries characterized by two independent metric functions. The resulting solution space contains two qualitatively distinct types of hair originating from different branche…

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

Gravitational Microlensing

Aikaterini Vandorou, Stela Ishitani Silva

Gravitational microlensing is a unique planet-detection method that does not rely on detecting light from the host star or planet. Instead, planets are discovered when their gravitational field perturbs the light coming from a distant source. The mechanics of this method offer several advantages. It has the ability to detect wide-orbit planets of various masses around host stars of different types, at and beyond the system's snow line. Thus, microlensing complements the other detecting technique…

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astro-ph.HE

Radio Continuum Study of One of the Brightest Large Magellanic Cloud Supernova Remnants N 132D

Rami Z. E. Alsaberi, Zachary J. Smeaton, Miroslav D. Filipovic, Roland Kothes, Hidetoshi Sano, Ahmed H. Abdullah, Dejan Urovsevic, Sanja Lazarevic et al.

We present a new radio continuum study of the Large Magellanic Cloud supernova remnant N 132D using observations from the Australia Telescope Compact Array (ATCA) and MeerKAT. The radio morphology shows a clear spatial correlation with the X-ray emission in the central and left regions of the remnant, as well as in the right portion of the shell, indicating a close connection between the thermal and non-thermal plasma components. Polarisation measurements reveal predominantly radial magnetic fie…

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astro-ph.HE

Radio Continuum Study of One of the Brightest Large Magellanic Cloud Supernova Remnants N 132D

Rami Z. E. Alsaberi, Zachary J. Smeaton, Miroslav D. Filipovic, Roland Kothes, Hidetoshi Sano, Ahmed H. Abdullah, Dejan Urovsevic, Sanja Lazarevic et al.

We present a new radio continuum study of the Large Magellanic Cloud supernova remnant N 132D using observations from the Australia Telescope Compact Array (ATCA) and MeerKAT. The radio morphology shows a clear spatial correlation with the X-ray emission in the central and left regions of the remnant, as well as in the right portion of the shell, indicating a close connection between the thermal and non-thermal plasma components. Polarisation measurements reveal predominantly radial magnetic fie…

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astro-ph.GA

Measuring radial flows in disc galaxies

Yi He, Filippo Fraternali, Pavel E. Mancera Piña, Enrico M. Di Teodoro

Numerous theoretical studies suggest that gas accretion from the intergalactic medium is essential to feed star formation in galaxies throughout cosmic time. However, the mechanism of gas accretion remains poorly understood, as direct evidence is lacking. In some models, gas accretion is expected to take place in the outer discs of galaxies, from where it should be transferred to the inner star-forming discs through radial flows. Finding such flows and quantifying them, therefore, opens the poss…

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astro-ph.GAastro-ph.SR

Isotopic ratios as probes of star formation and the origin of molecular gas in the Central Molecular Zone

Laura Colzi

The Central Molecular Zone (CMZ) contains most of the dense molecular gas in the Milky Way but forms stars at a surprisingly low rate. Isotopic ratios provide a unique tool to investigate both the local physical conditions and the nucleosynthetic history of this gas. I summarize recent isotopic studies toward the molecular cloud G$+$0.693$-$0.027. Deuterium fractionation (D/H ratios) reveals a cold ($T_{\rm kin}\lesssim30$ K), relatively quiescent gas component embedded within the otherwise warm…

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astro-ph.SRastro-ph.EP

Gaseous SiO and Silicate Clouds in Three Benchmark Early-L Dwarfs

Zhijun Tu, Shu Wang, Xiaodian Chen, Haomiao Huang, Jifeng Liu

Tracing silicon from gaseous SiO into silicate condensates provides a direct view of the condensation process that forms silicate clouds in L-dwarf atmospheres. Here we present evidence for gaseous SiO in three benchmark early-L dwarfs, HD 89744B, GJ 1048B, and LSPM J0632+5053B, using JWST/NIRSpec and MIRI spectroscopy. Atmospheric retrievals with and without SiO under multiple cloud prescriptions identify the strongest SiO signatures at 4.0--4.2 and 7.7--8.2 $μ$m, with the local likelihood diag…

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astro-ph.IM

Pseudo Closed-Loop Bootstrapping for Reinforcement Learning Based AO Control

Eemil Halonen, Jalo Nousiainen, Markus Kasper, Nuutti Hyvönen

High contrast imaging with ground-based telescopes requires extremely precise wavefront control. The performance of the controller ultimately depends on the quality and efficiency of the wavefront sensing technique, which has led to the development of ever more sensitive wavefront sensors (WFS). However, the increase in sensitivity comes at the cost of greater nonlinearity, which poses challenges for conventional linear reconstructors and controllers. Reinforcement Learning (RL) is a branch of m…

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astro-ph.HEhep-ph

Neutron star cooling with $Δ$ dUrca processes

Yogeesh N, Monika Sinha, Vishal Parmar

The cooling of neutron stars (NSs) provides insight into their composition and equation of state. However, a complete understanding of this phenomenon is still an open question. The early stage of NS cooling is dominated by neutrino emission from the core, which rapidly cools the star. Urca processes are one such mechanism where neutrinos escape from the core, carrying away most of the heat. Nucleonic and hyperonic direct Urca processes are known rapid cooling mechanisms. The possible appearance…

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astro-ph.IM

radio-astro-tools: linking radio astronomical data to the astronomical Python ecosystem

Eric W. Koch, Adam Ginsburg, Thomas P. Robitaille, Erik W. Rosolowsky, Alyssa Bulatek, Savannah Gramze, Jonathan D. Henshaw, Derek Homeier et al.

We present the radio-astro-tools code suite, which consists of several Python packages that enable analysis of radio data, especially interferometric spectral cubes, in the context of the Astropy software ecosystem. While these tools were designed with radio data in mind, they are built to be general and have applications on data sets at other wavelengths. The core package, spectral-cube, handles reading, writing and analysis of cube data, and it enables straightforward parallelization via dask…

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astro-ph.SR

Oxygen isotopic ratio in open cluster RGB stars: A new method for accurate mass and age estimations

O. Straniero, C. Abia, I. Domínguez, P. de Laverny

Determining precise and homogeneous absolute ages of open clusters (OCs) remains a challenge in stellar astrophysics, mainly due to parameter degeneracies in photometric methods and line-of-sight extinctions. We present a novel method for estimating the ages of intermediate-age and old OCs, based on the strong initial-mass dependence of the surface oxygen isotopic ratio, 16O/17O, measured in RGB stars following the first dredge-up. Using updated theoretical stellar models computed with the FuNS…

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eess.SYastro-ph.IMeess.SP

Reference-Filter-Driven Transition Probabilities for IMM-Based Satellite Maneuver Detection

Euiseok Han, Sangheon Choi, Seung-Hyun Kong

Maneuver detection of non-cooperative satellites is an essential task of space situational awareness. The interacting multiple model (IMM) filter has been applied to detect unannounced maneuvers, but the standard IMM assumes a fixed Markov transition probability matrix (TPM) that must be tuned without knowledge of the maneuver rate of the target. To avoid this tuning, adaptive-TPM approaches update the TPM online from statistics computed inside the IMM. However, these statistics already depend o…

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astro-ph.SRphysics.plasm-ph

Direct Numerical Comparison of Data Driving Strategies for Solar Flux Emergence in Magnetohydrodynamics: B-driving vs E-driving

Kyriakos Christos Tapinou, Axel Raboonik, David I. Pontin, Michael S. Wheatland, Mark C. M. Cheung, Hannah Schunker

Data driving is an important technique for modelling realistic magnetic field and plasma evolution in regions of the solar atmosphere where direct observations are either absent or insufficient. This technique uses observational data to drive the evolution of the simulation, while the modelled solar atmosphere evolves self-consistently. A common approach for data-driven simulations is B-driving, which uses the observed magnetic field at the surface of the Sun as a boundary condition. However, on…

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hep-phastro-ph.HEhep-th

Analysis of p-Wave Sommerfeld Resonance Behavior in Finite-Size Dark Matter

Wu-Long Xu, Jin Min Yang, Rui Zhu

Different stages of cosmic evolution impose different requirements on the dark matter annihilation cross section. Sommerfeld enhancement provides a possible way to accommodate them. However, in the point-like dark matter scenario, satisfying these requirements with either $s$-wave or $p$-wave Sommerfeld enhancement can strongly constrain the dark matter and mediator masses and their coupling. A finite dark matter size introduces an additional parameter and may relax these constraints. Motivated…

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astro-ph.HE

Improved analysis of time delays between radio wavelengths and X-ray of Sgr A* flares in the shock oscillation model

Ramiz Aktar, Toru Okuda, Chandra B. Singh

We present an improved analysis of the time delays between radio and X-ray flares from the supermassive black hole Sagittarius A* (Sgr A*), extending our previous shock oscillation model by incorporating Compton scattering. Our simulations predict delay times of 1-4 h between X-ray and radio flares, 20-40 min and 0.5-1 h between 334 GHz and 4.5 $μ$m and 2-8 keV flares, and 7-20 min and 0.5-1 h between 22-43 GHz and 350 GHz radio flares, respectively, in good agreement with recent observations. T…

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astro-ph.GAastro-ph.SR

The Binary Fraction of Milky Way Field Stars in DESI: Dependence on Chemical Abundance

Tian Qiu, Wenting Wang, Sergey E. Koposov, Songting Li, Nathan Sandford, Ting S. Li, Joan Najita, Jessica Nicole Aguilar et al.

Binary populations encode information about the physical conditions of star formation and the subsequent evolution of stellar populations. Adopting a statistical method based on multi-epoch line-of-sight velocity variations, we constrain the binary fraction, $f_b$, of field main-sequence turn-off stars in the Milky Way using data from the second data release of the DESI Milky Way Survey. $f_b$ is found to primarily increase with lower [Fe/H]. At $[\mathrm{Fe}/\mathrm{H}]\gtrsim -1.3$, $f_b$ show…

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nucl-thastro-ph.HE

Production Memory of the $^{225}\mathrm{Ra}$-$^{225}\mathrm{Ac}$ Clock in Neutron-Star Merger Ejecta

Hisham Anwer

Radioactive nuclei in neutron-star merger ejecta carry information about both their abundance and their production history. Using the $^{225}\mathrm{Ra}$-$^{225}\mathrm{Ac}$ sequence, we establish exact conditions linking a surviving isotope partition to the time available for parent decay. An Ac fraction of 0.1 produced solely through Ra decay requires at least 2.456 days, providing a direct consistency test for proposed source states. We show that subsequent activity retains additional product…

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hep-phastro-ph.HE

Systematic Uncertainties in Ultralight Boson Constraints from Superradiance

P. S. Aswathi, Ling Sun

Ultralight bosons are well-motivated candidates for physics beyond the Standard Model and may constitute part or all of the dark matter. Black-hole superradiance provides a powerful means of probing these particles through their gravitational interaction with rotating black holes. This mechanism has motivated a growing body of constraints from electromagnetic measurements of black-hole spins and, more recently, gravitational-wave observations. Gravitational-wave probes draw on several distinct s…

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gr-qcastro-ph.IM

Accounting for detector calibration uncertainty in black-hole ringdown analysis

Rowina S. Nathan, Shingo Hido, Neil Lu, Mallika R. Sinha, Sizheng Ma, Ling Sun

Detector calibration systematics can bias measurements of a remnant black hole's mass and spin, producing spurious evidence against general relativity if unaccounted for. The ringdown phase in the gravitational-wave signal produced by a binary black-hole merger encodes the remnant properties: at sufficiently late times, the signal is well described by a superposition of quasinormal modes, each with a frequency and damping time set only by the remnant mass and spin. Here we present two complement…

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astro-ph.COastro-ph.GAgr-qc

Galaxy Clustering Can Reveal Host-Galaxy Properties of Binary Black Hole Mergers

Daiki Watarai, Hayato Imafuku, Fumihiro Chuman

Galaxy clustering encodes information about the host galaxies of binary black hole (BBH) mergers even when individual hosts remain unidentified, because the distribution of neighboring galaxies depends statistically on the host-galaxy population. We construct event-level host-type likelihoods from host-conditioned galaxy-count distributions within gravitational-wave localization regions and combine them to infer the fractions of BBH mergers hosted by different galaxy populations. The framework a…

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astro-ph.GAastro-ph.SR

NGC 6426: Colour-Magnitude diagram and variable star population as indicators of metallicity, distance, and age

A. Arellano Ferro, R. Michel, D. Deras, M. Vaca Montejano, S. Muneer, I. Bustos Fierro

We present new VI CCD photometry of the globular cluster NGC 6426. The membership status of all point sources and, in particular, of all the variables in the field of view is discussed, including four recently detected variables. The double mode nature of variables V3 and V9 is confirmed and their periods are calculated. The presence of a cluster member anomalous Cepheid (V17) is reported. Employing only likely members we produce a decontaminated colour-magnitude diagram (CMD) differentially der…

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astro-ph.IM

DeepDISC on LSST Data Preview 1: Scene-Level Detection, Deblending, and Star/Galaxy Classification in the ECDFS and EDFS Fields

Prince Yadav, Yaswant Sai Ejjagiri, Xin Liu, Grant Merz, the LSST Dark Energy Science Collaboration

We present the first application of DeepDISC, a scene-level deep-learning framework, to real LSST data, using the Data Preview 1 (DP1) coadded images of the Extended Chandra Deep Field-South and the Euclid Deep Field-South fields. In a single pass, DeepDISC jointly detects, segments, and classifies sources as stars or galaxies, rather than treating these tasks as separate steps as in traditional pipelines. We warm-start from a model pretrained on LSST simulations and fine-tune it on DP1 six-band…

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