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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.HEhep-thphysics.plasm-ph

Resistive alignment of a black-hole magnetosphere

Ruben Lier, Oliver Porth

Recent numerical simulations have shown that black-hole magnetospheres evolve rapidly toward alignment between the magnetic axis and spin axis but the physical origin of this process has remained unclear. We develop an analytic theory of this alignment within resistive relativistic magnetohydrodynamics. Taking the slow-spin Blandford-Znajek monopole solution as the exterior magnetic field, we reduce the induction equation to a relaxation equation for the current-sheet inclination angle. Our anal…

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astro-ph.EP

Towards a coupled activity-fallback model for comets I) 67P/Churyumov-Gerasimenko's water activity from a microphysics model with dynamic dust-depth

Nicholas Attree, Yuri Skorov, Pedro Gutiérrez, Olivier Groussin, Abhinav Jindal, Raphael Marschall, Samuel P. D. Birch

We apply a two-layer thermophysical model, with water sublimating from below a dust-crust with dynamically varying depth, to simulate the water outgassing rate, dust-ejections, and non-gravitational forces and torques of comet 67P/Churyumov-Gerasimenko. The dust-depth is determined at each time-step by the balance of dehydration and subsurface pressure, leading to alternating ejections and crust build-up. This model is the first stage of implementing a fully coupled activity-fallback model that…

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astro-ph.EPastro-ph.IM

Combination of multi-observatory photometry to determine asteroid rotation periods

Kristers Nagainis, Ilgmars Eglitis

This study aims to determine asteroid rotation periods from sparse, unevenly sampled, multi-observatory photometry using the Lomb-Scargle (L-S) method. The photometric measurements of the asteroids are taken from the circulars of the Minor Planet Center (MPC). Twelve asteroids, four of them with known rotation periods, were analyzed with two complementary methods. In the separate dataset analysis (S-method), each observatory dataset was analyzed separately, and the final period was obtained as a…

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astro-ph.GA

The Population of Type~1 Active Galactic Nuclei in Dark Energy Spectroscopic Instrument. I. Profile-dependent Measurements of the Low-redshift Sample

Zhu-Heng Yao, Wei-Jian Guo, Shuo Zhai, Yu-Chang Li, Cheng Cheng, Jun-Rong Liu, Shuang Jin, Antonios Katsianis et al.

We present a spectral analysis of a large sample of low-redshift type 1 active galactic nuclei (AGNs) selected from the first data release of the Dark Energy Spectroscopic Instrument (DESI DR1). For objects at $z\le0.9$, we perform spectral fitting and ML-assisted refinement, yielding 114,754 type 1 AGNs. We use two fitting schemes that differ only in the broad-line model: the broad Balmer components are fitted with either a Lorentzian function or a sum of Gaussians. The continuum and [O III] lu…

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gr-qcastro-ph.HE

Binary Ellis-Bronnikov wormholes in 3+1 numerical relativity: mergers, fly-bys and gravitational waves

Nikita M. Shirokov, Ilya Nachevsky

We present what are, to our knowledge, the first 3D numerical-relativity evolutions of wormhole binaries: pairs of massive Ellis-Bronnikov drainholes held open by a ghost scalar field. Each throat is an unstable fixed point whose e-fold time matches the González-Guzmán-Sarbach linear rate to within 1.9%. Two throats obey a charge-sign rule: like scalar charges repel and opposite charges attract, with a measured attraction-to-repulsion ratio of $1.462\pm0.022$ against the predicted 3/2, so only o…

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astro-ph.EPastro-ph.SR

Detailed study of HD 219134: a benchmark K-dwarf with a compact planetary system

Jérôme Bétrisey, Camilla Pezzotti, Gaël Buldgen, Aline A. Vidotto, Colin P. Folsom, Michaël De Becker, Michaël Gillon

Space missions such as CoRoT, Kepler, and TESS have transformed asteroseismology and its synergies with exoplanet science. We revisit the nearby K-dwarf HD 219134 to investigate the tension between asteroseismic and interferometric radii, update its fundamental parameters, and reconstruct the rotational, magnetic, and atmospheric evolution of the system. We combine forward asteroseismic modeling with seismic inversions to assess systematics from non-seismic constraints, radius measurements, and…

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astro-ph.HEastro-ph.IMhep-ex

Simulation Study of Reconstruction of Cosmic Ray Extensive Air Shower with Thermal Neutron Detected by ENDA

Fan-Ping Li, Xin-Hua Ma, Hu Liu, Tian-Lu Chen, Shu-Wang Cui, Danzengluobu, Xin-Rui Gao, Wei Gao et al.

In the investigation of the "knee" region within the cosmic ray energy spectrum, extensive air shower (EAS) reconstruction by using different EAS secondary particles are of paramount importance for energy determination and composition separation and finally measurement of energy spectrum of different cosmic ray composition. The Electron-Neutron Detector Array (ENDA) is designed to detect thermal neutrons generated in the ground by high energy hadrons which constitute the "backbone" of EAS and ca…

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astro-ph.HE

Flux Evolution of PSR B0540--69 and the Spectral Energy Distribution of its Pulsar Wind Nebula

Juan Zhang, Xuezhi Liu, Junyang Zhang, Hanlong Peng, Mingyu Ge, Songzhan Chen, Shanshan Weng, Shijie Zheng et al.

The young Crab-like pulsar PSR B0540--69, located in the Large Magellanic Cloud, underwent a spin-down rate transition (SRT) in 2011 December, after which its pulsar wind nebula (PWN) was reported to brighten up to 2018. In this work, we extend the study of its X-ray and $γ$-ray flux evolution through 2026 by combining observations from multiple X-ray instruments with data from the Fermi Large Area Telescope, thereby constructing a flux history of the PSR$+$PWN system spanning more than two deca…

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astro-ph.SR

Formation Dynamics of a Rotating Solar Spicule-like Event and Associated Energy-Mass Transport

Liufan Gong, Lei Ni, Guanchong Cheng, Jiajia Liu, Quan Xie, Robert Erdélyi

We performed three-dimensional radiative magnetohydrodynamic(3D RMHD) simulations in an upward-directed (positive-polarity) open magnetic field with an initial background strength of 10 G. We identified vortex-associated spicule-like events and carried out a detailed analysis of one representative event. Prior to the formation of this spicule-like event, a photospheric vortex appears and twists the magnetic field lines, then develops upward into higher atmospheric layers, forming a magnetic torn…

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astro-ph.EP

Star Cluster Ecology VIII. -- Dynamically Forming S-Type and $α$Centauri-like Systems

Erwan Hochart, Simon Portegies Zwart

Aims: To analyse the impact of dynamically formed binaries emerging naturally from various star cluster environments on already established planetary systems. Methods: Numerical simulations replicating the star-forming region NGC 1333 are conducted. We consider three models, each using identical cluster realisations and simulation parameters. The cluster itself is initially sub-virial and fractally distributed. Model~A assumes planetary systems are initially in mean motion resonance. In Model~B,…

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astro-ph.GAastro-ph.CO

A Relationship Between Fast Radio Burst Dispersion Measure and Host Galaxy Inclination

Lachlan Marnoch, Stuart D. Ryder, Sunil Simha, Alexa C. Gordon, R. M. Shannon, Nicolas Tejos, Marcin Glowacki, Ziteng Wang et al.

It is commonly thought that fast radio bursts (FRBs) trace star formation, and that they are produced by magnetars. Both hypotheses imply that their sources are hosted primarily (but not exclusively) in galactic disks. Although there is evidence in that direction, it has yet to be shown conclusively. In addition, a tension exists with the fact that at least one FRB source is found in a globular cluster far from the disk of the host. If FRBs originate primarily in disks, the galaxy orientation co…

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astro-ph.GA

Redshifted Cool Gas in the Disturbed HI Disk of the Starburst Dwarf NGC 4214

Shulan Yan, Taotao Fang, Xiaochuan Jiang, Junfeng Wang, Qingzheng Yu, Chuanpeng Zhang, Ming Zhu

We report redshifted cool gas toward the central star-forming region of the nearby starburst dwarf galaxy NGC 4214. HST/COS spectra show low-ionization absorbers redshifted relative to the systemic velocity, most clearly in SII ($Δv=19.8\pm2.6\ {\rm km\,s^{-1}}$) and supported by MgII ($Δv=30.3\pm3.0\ {\rm km\,s^{-1}}$), while PII remains tentative ($Δv=7.5\pm3.4\ {\rm km\,s^{-1}}$). The Keck/HIRES spectra also reveal a redshifted CaII absorption component ($Δv=25.6\pm1.5\ {\rm km\,s^{-1}}$). Be…

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astro-ph.HEastro-ph.IM

ASKAP Monitoring of the Rubin Deep Drilling Fields

Dougal Dobie, James Freeburn, Iris de Ruiter, Katie Auchettl, James Coulson, Brent Miszalski, Anais Möller, Nikhil Sarin et al.

In the past decade, time domain astronomy surveys across the multi-messenger spectrum have developed "alert streams" which circulate observational information in real-time to the wider astronomical community. Despite this being standard practice for optical, gamma-ray and gravitational wave time domain astronomy for several years now, this kind of infrastructure has not yet been deployed at-scale for radio telescopes. We are conducting a long-term monitoring program that targets the Rubin Deep D…

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

An Ultraviolet Instrument on the Habitable Worlds Observatory: Considerations and Capability Trades on the Multi-Object, Integral-field, and High-resolution modes of a potential UVI

Brian Fleming, Kevin France, Dmitry Vorobiev, Jeanette Donber, Eric Frater, Thomas Delker, Vicki Herde

The Habitable Worlds Observatory (HWO) is NASA's next-generation astrophysics platform, delivering transformative capability in the search for life and study of the origins of the universe. Amongst the instruments under consideration for HWO is a multi-purpose ultraviolet spectrograph and imager that provides a deep toolbox for some of the most pressing science investigations of the next several decades. In this paper, we present a basic draft model of a potential UVI, including a multi-object s…

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astro-ph.EP

The Neptunian Final Parsec Problem: How Inertial Waves Enable Neptunes and Gas Giants to Survive Tidal Migration

Tim Hallatt, Adrian J. Barker, Sarah C. Millholland

Observations indicate that some hot Neptunes and Jupiters underwent high eccentricity migration (HEM). A longstanding issue facing HEM theory remains, however: in order to shrink their orbits by ${\sim}1{-}2$ orders of magnitude, planets must dissipate ${\gtrsim}10{\times}$ more orbital energy than is contained in their structural binding energy. Previous work suggests that excitation of planets' fundamental modes (''$f$-modes'') at very high eccentricities, $e{\sim}$0.99, can shrink semi-major…

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astro-ph.IMastro-ph.HE

In-flight Timing Calibration of the Follow-up X-Ray Telescope on Board the Einstein Probe

Juan Zhang, Xiaofan Zhao, Dawei Han, Hao Wang, Yong Chen, Mingyu Ge, Shijie Zheng, Shumei Jia et al.

After the launch of Einstein Probe (EP), pulsars are observed to calibrate the timing system of the onboard Follow-up X-ray Telescope (FXT) by measuring the times of arrival (TOAs). FXT has two independently operating modules, namely FXTA and FXTB, each equipped with the Wolter-I optics and the pnCCD camera. For scientific observations, each pnCCD has three distinct readout modes that differ in frame cycles, the full frame mode (FF, 50 ms per frame), the partial windowed mode (PW, 2.2 ms per fra…

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astro-ph.GA

Decomposing the Kinematics of SNR G180.0-01.7 with Medium-Resolution Spectra

Juan-Juan Ren, Wei Zhang, Chao-Jian Wu, Chao Liu, Jian-Jun Chen, Hong Wu

The exceptionally large angular diameter and intrinsic optical faintness of the Galactic supernova remnant (SNR) G180.0-01.7 (S147) have historically hindered a comprehensive spectroscopic census of its filamentary structure. We present the first dedicated medium-resolution (R ~ 7500) spectroscopic study of S147 using the LAMOST Medium-Resolution Spectroscopic survey of Galactic Nebulae (MRS-N). By implementing multi-Gaussian decomposition on the H$α$, [NII], and [SII] emission complexes and app…

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physics.opticsastro-ph.IM

Phantom Zernike Wavefront Sensor: Phase Contrast with Engineered Focal Plane Reference Speckles

Benjamin Courtney-Barrer

We introduce the Phantom Zernike Wavefront Sensor (phantom ZWFS), an engineered reference extension of phase-contrast wavefront sensing in which controlled pupil plane modulation generates off-axis coherent speckle structures that undergo localized focal plane phase shifts. These references may replace the central ZWFS reference when the on-axis PSF core is required for another optical function, such as photonic science coupling, or may augment a conventional central ZWFS response to provide add…

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astro-ph.GAphysics.chem-ph

Predicted state-to-state collisional rate coefficients from neural networks

Lisán David Cabrera-González, Carlos Cárdenas, Otoniel Denis-Alpizar

Molecular spectra observed in the interstellar medium are commonly analyzed using non-local thermodynamic equilibrium models, which requires accurate state-to-state collisional rate coefficients. Close-coupling calculations become prohibitively expensive for transitions from highly excited rotational states, therefore available datasets are often truncated at low initial states and temperatures; and since each new system also requires an accurate ab initio potential energy surface, many detected…

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astro-ph.GAastro-ph.SR

Bridging Theory and Observation: Synthetic Far-infrared Insights into Star Formation Efficiency

Alexander Escamilla, Michael Y. Grudić, Anna L. Rosen

The star formation efficiency per free-fall time ($ε_{\rm ff}$) quantifies how efficiently giant molecular clouds (GMCs) convert gas into stars and is often observed to be orders of magnitude lower than expected for free-fall collapse. Observers typically estimate $ε_{\rm ff}$ by mapping far-infrared (FIR) dust emission to infer gas surface densities ($Σ_{\rm gas}$) and counting embedded protostars, assuming simplified lifetimes and masses. Using the fiducial STARFORGE radiation-magnetohydrodyna…

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astro-ph.GA

Exploring Case B I: The Footprints of Hidden Radiation Fields in H I Balmer Decrements

Maryam Dehghanian, Fransisco Guzman, Peter van Hoof, Chamani Gunasekera, Gary Ferland

Theory predicts that H I emission from photoionized clouds should lie close to the Case B limit established by Menzel and Baker, and observations of nearby nebulae have largely confirmed this expectation. However, recent observations of more distant high-redshift systems have revealed a small fraction with striking departures from Case B. What additional physics might be at work in these objects? This paper is part of a series exploring the physical processes that can produce such departures. In…

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astro-ph.EP

The GAPS programme at TNG LXXXII. The first atmospheric investigation of the gas giant WASP-13b at high resolution with GIARPS

D. Sicilia, M. Basilicata, G. Guilluy, G. Scandariato, F. Borsa, C. Di Maio, M. Brogi, A. Chiavassa et al.

Low-density transiting gas giant exoplanets are key benchmarks for atmospheric studies. Despite their large-scale heights, many of them remain poorly characterised. We present the first atmospheric investigation at high-resolution of the inflated (R$_\mathrm{p}$$\sim$1.4 R$_{\mathrm{J}}$), hot Jupiter (T$\sim$1500$ \mathrm{K}$) WASP-13 b aiming at constraining its atmospheric composition and refine its orbital geometry. We analysed four transits observed with GIARPS at the TNG. Updated stellar a…

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astro-ph.EP

Dust-driven vertical shear instability in an isothermal shearing box: I. Turbulence and gas dynamics without dust feedback

Jip Matthijsse, Hossam Aly, Sijme-Jan Paardekooper, Richard P. Nelson

The classical vertical shear instability (VSI) is a baroclinic instability that arises from height-dependent azimuthal velocities and is a leading candidate for driving anisotropic turbulence in discs with extended vertical modes. The classical VSI requires fast cooling times and radial temperature gradients, which are absent in an isothermal stratified (barotropic) setup. We investigate the dust-driven vertical shear instability in an isothermal, stratified shearing box, where the VSI is genera…

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

The Fast & Fourier: Using neural operators to speed up radiative modeling of protoplanetary disks

Lukas Welzel, Melissa K. McClure

Edge-on protoplanetary disks provide a spatially resolved view of the vertical distribution of icy planetary building blocks, but inferring their relative abundances requires radiative-transfer (RT) modeling with multiple anisotropic scattering. Each model costs $10^{1}$-$10^{3}$ CPU hours, which precludes principled Bayesian inference and homogeneous, population-scale analyses. We develop and validate a fast and reusable surrogate for Bayesian inference with ice-bearing edge-on disk models. We…

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

"Mega-Earths" are likely an artifact of stellar activity

Casey L. Brinkman, Nicolas Cowan

Empirical relations and planet formation simulations suggest an upper mass limit for rocky planets of $\sim$10M$_{\oplus}$, as cores above this will almost certainly undergo runaway gas accretion. Nevertheless, a small number of planets appear to have densities consistent with rocky Earth-like compositions above this threshold, indicating that unusual formation and evolutionary scenarios are capable of producing extremely massive rocky planets called "Mega-Earths." However, all of these planets…

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astro-ph.GA

When dust growth takes over: the origin of dust in post-reionization galaxies

Omima Osman, Gabriella De Lucia, Andreas. L. Faisst, Lizhi Xie, Fabio Fontanot, Michaela Hirschmann

The post-reionization epoch ($z\sim4$-6) marks a critical phase in galaxy evolution, during which galaxies rapidly assemble their stellar mass, enrich their interstellar medium, and build up substantial dust reservoirs. The physical processes responsible for such rapid dust enrichment remain uncertain. We investigate the dust enrichment history of the ALPINE-CRISTAL-JWST (ACJ) sample using the semi-analytic galaxy formation model GAlaxy Evolution and Assembly (GAEA), which follows galaxy assembl…

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astro-ph.EPastro-ph.SR

The accretionally heated atmospheres of protoplanets and brown dwarfs

Nick Choksi, Peter Gao, Jerry Xuan, William Balmer, James Mang

The ranks of accreting planets and brown dwarfs are growing. To help interpret their spectra, we study how accretion affects a planet's atmosphere. The atmosphere is irradiated from above by whatever nonthermal radiation from the accretion shock does not directly escape into space. This accretional heating drives a temperature inversion. Even relatively slow accretion, corresponding to mass doubling times longer than system ages, can raise temperatures by many hundreds of Kelvin at ambient press…

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astro-ph.GA

A Single Line-Emitter Identified in an Unbiased Search with JWST/NIRSpec: Multi-Object Coronagraphy for Slitless Spectroscopy

Mason S. Huberty, Claudia Scarlata, Matthew J. Hayes, Alaina Henry, Danielle A. Berg, Vieri Cammelli, Richard Ellis, Anne E. Jaskot et al.

We report the detection of a previously unknown object with a single emission line within the Hubble Ultra Deep Field, using a new JWST NIRSpec technique called Multi-Object Coronagraphy for Slitless Spectroscopy (MOCSS) with the G140M/F100LP observing mode. The MOCSS technique involves opening almost all the shutters on the NIRSpec microshutter array, while simultaneously closing the shutters that lie on top of known low redshift objects, facilitating a wide field slitless spectroscopic search…

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astro-ph.HEastro-ph.GA

Disk Structure May Determine AGN Variability and Explain the Accretion Disk Size Problem: No Broad Line Region Required

Amy Secunda, Yan-Fei Jiang, Jenny E. Greene

Variability is a crucial probe of active galactic nuclei (AGN) disks, but the impact of the structure and internal physics of the disk on this variability is poorly understood. We perform 3D multi-frequency radiation magnetohydrodynamic simulations of the $1300-5940~\rmÅ$ emitting region of an AGN disk. This turbulent disk simulation happens to stochastically have different disk thickness above and below the midplane. Light curves emitted from the thin top of the disk are broadly consistent with…

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astro-ph.HE

Discovery of Hidden Extragalactic Pulsars in the Parkes Archival Data

Rahul Sengar, Laila Vleeschower, Matthew Bailes, Fronefield Crawford, Duncan R. Lorimer, Joshua P. Ridley

Just over 1% of the known radio pulsar population resides in the Large and Small Magellanic Clouds (MCs), the satellite galaxies that are 50-62 kpc distant from the Milky Way. These pulsars are important for constraining the peak of the pulsar luminosity function, and may give insights into neutron star populations formed from stars of different metallicities than the Milky Way. Using search techniques that have proven highly effective at discovering a large number of pulsars in archival data by…

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