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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.HEgr-qc

An improved self-gravity treatment in general relativistic smoothed particle hydrodynamics

Pritam Banerjee, Kowsona Chakraborty, Niles Mondal, Tapobrata Sarkar

General relativistic smoothed particle hydrodynamics (GRSPH) on a fixed black hole (BH) spacetime is suitable for fluid bodies that are much less massive than the BH, but the self-gravity of the fluid is added as an extra term in the equation of motion. Standard GRSPH implementations add this as a Newtonian source term to the momentum equation, which is no longer valid when the fluid moves at a sizeable fraction of the speed of light, close to the BH. We develop an improved prescription by deriv…

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astro-ph.IM

Estimator Precision and Selection for Up-the-Ramp Sampling with a High-Read-Noise InGaAs Camera

Wei-Jie Meng, Fang-Yu Xu, Zhen-Yu Jin, Guang-Qian Liu

The noise properties of an InGaAs camera vary with gain, requiring a trade-off between implementation complexity and precision. Using generalized least squares (GLS) with known covariance as the precision benchmark, we examine the applicability and precision penalties of ordinary least squares (OLS) and correlated double sampling (CDS) at different noise operating points. We define $η=fT/σ_\mathrm{R}^2$, where $f$ is the total pixel count rate, $T$ the fitting span, and $σ_\mathrm{R}$ the single…

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astro-ph.IM

Gaussian process-based Bayesian imaging of bolometric (sub-)millimetre data

Richard Fuchs, Jonas Würzinger, Joshiwa van Marrewijk, Thomas W. Morris, Tony Mroczkowski, Luca Di Mascolo, Aileen Chen, Adriaan J. Duivenvoorden et al.

Widefield single-dish telescopes operating at (sub-)mm wavelengths ($λ\sim 4$~mm to 350~$μ$m) tend to feature much faster mapping speeds than radio interferometers at the same wavelengths, and are more suitable for measuring signals on larger spatial scales. However, the data are dominated by atmospheric fluctuations on large scales and by photon and instrumental noise on smaller scales, making it difficult to recover the true astronomical sky. We build on maria-nifty, a Gaussian process-based B…

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astro-ph.HE

Short-timescale X-ray variability of the blazar 1ES 1959+650 observed with AstroSat/SXT

Sikandar Akbar, Zahir Shah

We analyse the AstroSat Soft X-ray Telescope (SXT) observation of the high-synchrotron-peaked blazar 1ES 1959+650 taken on 2023 September 2, which covers 362 ks with about 95 ks of good exposure. We build 0.6-7 keV light curves in six sub-bands, binned at 5830 s (the orbital period) and 1000 s. All sub-bands show excess variance, with fractional variability of 3.7 to 6.5 per cent that increases with energy ($\propto E^{0.32\pm0.07}$). The power spectrum of the total band, fitted with a model tha…

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gr-qcastro-ph.IM

Untangling Extreme Mass Ratio Inspirals and Massive Black Hole Binaries in LISA Data

Rishav Agrawal, Clémence Allietta, Ollie Burke, Alvin J. K. Chua

The Laser Interferometer Space Antenna (LISA) will observe sources in the millihertz regime, such as Galactic Binaries (GBs), Massive Black Hole Binaries (MBHBs), and Extreme Mass Ratio Inspirals (EMRIs), so its data stream will be a superposition of an unknown number of gravitational-wave sources. We consider the joint inference of various representative combinations of MBHB and EMRI signals in LISA data (with assumed instrumental noise and stochastic GB foreground). Our Bayesian analyses confi…

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astro-ph.HE

Probing Nearby Electron Sources and Local Diffusion with the TeV All-Electron Spectrum

Zhen Xie, Ruizhi Yang

Radiative losses restrict multi-TeV cosmic-ray electrons to young nearby accelerators, allowing the all-electron spectrum (electrons plus positrons) to retain information about particle release and local transport. We investigate how a nearby source can shape this spectrum using Vela as a representative example. We compare a birth-time burst with continuous release for the same total injected electron energy and examine the dependence on the diffusion coefficient, injection index, and source ene…

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astro-ph.IMcs.LGhep-exnucl-exphysics.ins-det

A Radiation-Hardened, Fault-Aware Quantized Neural Network That Self-Heals

Peter Xiangyuan Ma, Joshua S. Bloom

Deep learning (DL) models are increasingly being deployed into radiation-challenging environments in spacecraft, particle accelerators, and, soon, space-based data centers. Instantiated as a learned orchestration of numbers stored in persistent memory, models are susceptible to continual degradation as high-energy particles corrupt data. At inference time, new data passed through the network fundamentally break the off-line assumptions and guarantees of a static model determined during training.…

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astro-ph.IMastro-ph.EPcs.LG

Solar System Surface Technosignatures: Searching for Signs of Artificial Design on Extraterrestrial Terrain

Ana Henrique, Sofia Sheikh, Benjamin Fields

Artificial radio emissions have historically been a major focus of technosignature searches. Here, we apply an anthropological lens to expand this scope to surface technosignatures: non-random, intentional patterning on planetary terrain, similar to long-lasting human-made landscapes and monuments on Earth. On geologically inactive bodies such as the Moon and Mars, artificial traces and patterns could potentially remain visible for hundreds of millions of years. We discuss two recent development…

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astro-ph.GA

A $\wedge$-like metallicity profile in the disk of the Sagittarius dwarf galaxy

Zixi Guo, Xiang-Xiang Xue, Jiang Chang, Chao Liu, Zehao Zhong, Bingqing Zhang, Ruizhi Zhang, Shi Shao et al.

Unveiling the properties of the progenitors that formed the tidal structures of the Milky Way (MW) is essential for exploring the MW's assembly history. Such studies further afford a unique opportunity to dissect the formation and evolution of dwarf galaxies by contrasting surviving and disrupted systems. However, reconstructing the intrinsic structure of progenitors solely from the positions and velocities of their tidal debris remains a formidable challenge. Here, we decode the chemo-kinematic…

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astro-ph.HE

Constraining the FRB Central Engine from Flux Variations of Persistent Radio Sources: FRB 20240114A as the First Attempt

Hirotaka Matsumiya, Kazumi Kashiyama, Tomonori Totani

Some repeating fast radio bursts (FRBs) are associated with persistent radio sources (PRSs), likely driven by the long-term activity of a central engine. We investigate FRB 20240114A-currently the most active repeating FRB-to explore the link between its burst activity and the flux variability of its associated PRS. We model electrons responsible for FRB emission being continuously injected from a central magnetar into its magnetar wind nebula (MWN), where synchrotron radiation produces the PRS.…

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astro-ph.EPastro-ph.SR

Exomoonlight Sonata: On the Fate of Exomoons Around Migrating White Dwarf Planets

Ritvik Sai Narayan, Joseph R. Livesey, Juliette Becker

The survival of exomoons around close-in white dwarf planets offers a potential constraint on their migration histories and an alternative pathway to post-main-sequence habitability. We investigate whether moons can survive the tidal circularization of planets via high-eccentricity migration, and consider a hierarchical three-body system (white dwarf-planet-moon) after an initial eccentricity excitation of the planetary orbit. Using an analytic equilibrium tidal model, we compare the evolution o…

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astro-ph.EP

Size, Albedo, and Taxonomy of Asteroid (1201) Strenua from Stellar Occultation and ATLAS Photometry

A. T. P. Jatmiko, M. Yusuf, B. Dermawan, T. Perhati, D. G. Ramadhan, M. Z. Aprianizar, S. Fatkhusalma, D. Mandey et al.

Context. A multi-chord stellar occultation by (1201) Strenua observed on 26 April 2026 is combined with ATLAS $c$- and $o$-band photometry. Aims. We aim to determine the size and geometric albedo of Strenua and reassess its taxonomic classification. Methods. Four positive chords from a 47-station campaign across Indonesia were fitted within a Bayesian forward-modeling framework to derive an ellipse cross-section and equivalent diameter. ATLAS photometry was modeled using the $H, G_1, G_2$ phase-…

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physics.ins-detastro-ph.IM

P-ONE-1: the first detector line of the Pacific Ocean Neutrino Experiment

O. Aghaei, M. Agostini, A. Alexander Wight, K. Baş, N. Baily, P. S. Barbeau, A. J. Baron, S. Bash et al.

Neutrino telescopes instrument optically transparent media with three-dimensional arrays of photosensors to detect Cherenkov radiation induced by neutrino interactions within or near the instrumented volume. The small cross-sections of the weak interaction and the low neutrino fluxes above TeV energies require vast detector volumes, which only natural media on Earth can realistically provide. Spurred by the detection of the first neutrino sources by the IceCube Neutrino Observatory, a new genera…

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astro-ph.HEastro-ph.GA

Core-Collapse Supernova Rates in the Dark Energy Survey

K. Boyne, O. Graur, M. Vincenzi, P. Wiseman, M. Grayling, M. Smith, C. Frohmaier, C. Lidman et al.

Over its five-year campaign (2013-2017), the Dark Energy Survey (DES) supernova (SN) survey recorded 31,636 light curves. Using a custom-built, two-stage random forest classifier, we identified 2,445 likely core-collapse SNe (CC SNe) within the survey rate analysis footprint. With this sample, we measure the volumetric CC SN rate from redshift z = 0 to 1.3 in 11 redshift bins, representing the most detailed single-survey coverage to date across nine billion years of lookback time. Over this inte…

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astro-ph.HEastro-ph.SR

SN 2023iop: An Extreme 1987A-like Supernova and the Death of Very Massive Stars

Steve Schulze, Avinash Singh, Nikhil Sarin, Ofer Yaron, Jesper Sollerman, Takashi J. Moriya, Avishay Gal-Yam, Bart van Baal et al.

Supernova (SN) 1987A showed that some hydrogen-rich core-collapse supernovae (SNe) rise slowly to peak, defining a distinct subclass. Wide-field surveys have uncovered more extreme members, such as OGLE-2014-SN-73, SN 2020faa, and SN 2023vbw, that challenge neutrino-driven explosion models. We present ultraviolet-to-infrared, radio, X-ray, and spectropolarimetric observations of SN 2023iop at $z = 0.1020$, the most extreme 87A-like event to date. It rose for $\gtrsim88$ rest-frame days to $M_r \…

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astro-ph.HE

Source velocities of fast radio bursts constrained by their dispersion measure variations

S. K. Ocker, A. L. Piro

Growing evidence suggests that many fast radio bursts (FRBs) originate from extragalactic magnetars. Like all neutron stars, magnetars may be kicked at birth to large velocities, the values of which directly inform the physics governing stellar explosions and compact object formation. A subset of repeating FRBs show significant variability in their dispersion measures (i.e., electron column densities) over time, often exhibiting apparently secular trends. Here we show that all repeating FRBs wit…

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astro-ph.HEastro-ph.IM

Globular Clusters GMRT Pulsar Survey (GCGPS) III: ORION - a multi-beam acceleration search pipeline

Nishant Deo, Jyotirmoy Das, Jayanta Roy, Saurabh Raj, Karel Adamek, Wesley Armour, Bhaswati Bhattacharyya, Jayaram Chengalur et al.

Globular clusters host rich millisecond pulsar populations, but the known population remains incomplete. We present the observing strategy for Phase II of the Globular Clusters GMRT Pulsar Survey (GCGPS), which uses the SPOTLIGHT system to form 160 synthesised beams simultaneously, substantially expanding the instantaneous field of view compared with the two phased-array beams of Phase I. The configuration is tunable through the beam overlap and the number of contributing antennas, allowing spat…

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astro-ph.HEgr-qc

The presence and order of QCD phase transitions from gravitational-wave observations of neutron star mergers

Paul D. Lasky, Alexander Clevinger, Andre G. da Silva, Ricardo L. S. Farias, Veronica Dexheimer

Gravitational-wave observations of neutron star mergers allows us to probe the dense portion of the nuclear equation of state. We develop a formalism for testing the existence and order of phase transitions in the cores of neutron stars using only gravitational-wave observations of their inspiral. We test our formalism on data from the first binary neutron star mergers GW170817 and GW190425, and use synthetic injections assuming the next and uber-next upgrades of the LIGO observatories, A+ and A…

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

J-PLUS: Identifying Outlier Spectral Energy Distributions in the Fourth Data Release Using Unsupervised Machine Learning

F. Quispe-Huaynasi, F. Roig, V. Loaiza-Tacuri, V. M. Placco, V. Marra, F. Jiménez-Esteban, A. del Pino, B. Anguiano et al.

The selection of candidates belonging to rare or underrepresented stellar populations, as well as novel objects, is essential for spectroscopic follow-up. In this work, we demonstrate how combining broad- and narrow-band photometric information with machine-learning techniques enables this selection. Using photometric data in twelve filters from the Javalambre Photometric Local Universe Survey (J-PLUS) as input, we applied an anomaly detection technique based on autoencoders to identify spectral…

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astro-ph.IMcs.CY

AI and The Enclosure of the Scientific Commons

P. K. G. Williams

The scientific literature can be viewed as an "information commons:" an intangible resource that "no one owns and is shared by everyone." There are well-established economic and political frameworks for understanding such commons, emerging from the history of agricultural common lands found in places like preindustrial England. This article provides a primer on the history and these frameworks, and considers a key difference between the information commons and the fields of yore: while informati…

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astro-ph.COastro-ph.GAhep-ph

Searching for Dense Perturbers in Cold Dark Matter Simulations

Xingyu Zhang, Hai-Bo Yu, Demao Kong, Ethan O. Nadler

Recently, several low-mass, dense perturbers have been inferred from astrophysical observations of gravitational lensing, stellar streams, and satellite galaxies. If interpreted as dark matter subhalos, their inner densities exceed the predictions of the standard cold dark matter (CDM) model. We systematically investigate this tension using a CDM-only zoom-in simulation of a Milky Way analog. We analyze more than 5000 subhalos with masses down to $10^6\,M_\odot$ and reconstruct their inner densi…

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astro-ph.SR

Large-scale Vortices in the Solar Photosphere: Statistical Properties and the Reliability of Local Correlation Tracking

Mashael Aldhafeeri, Suzana S. A. Silva, Istvan Ballai, Gary Verth, Haruhisa Iijima, Hideyuki Hotta, Viktor Fedun

Vortices are observed throughout the solar atmosphere, spanning a wide range of spatial scales. Although small-scale vortices have been studied extensively, mesoscale vortices remain less explored, and it is still unclear whether they can be reliably recovered from observations. Mesogranular-scale motions are recovered from the R2D2 simulations by applying Gaussian spatial smoothing to the horizontal velocity field with full width at half maximum (FWHM) values of 2.5-4.0 Mm. To evaluate the accu…

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gr-qcastro-ph.IM

High-cadence GW astrometry in the $μ$Hz gap

Giorgio Mentasti, Carlo Contaldi

We forecast the sensitivity of a dedicated, fast-spinning astrometric survey to a stochastic gravitational-wave background (SGWB) in the microhertz gap between pulsar timing arrays (PTAs) and LISA. Spinning the satellite faster samples each star more often, raising the Nyquist frequency and opening higher frequencies at no cost in noise: the shorter, noisier exposures are exactly compensated by their number, so the white-noise floor of each position stream is independent of cadence. High frequen…

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astro-ph.GA

Ionized Gas Kinematics and Star-forming Clumps in Extremely Metal-poor Galaxies

Jyoti Yadav, Casiana Muñoz Tuñón, Cecilia Farina, Alejandro Lumbreras-Calle, Jorge Sánchez Almeida, Bruce G. Elmegreen

Extremely Metal Poor (XMP) galaxies are the least chemically evolved objects in the local Universe and provide important constraints on galaxy formation in low-metallicity environments. This work investigates the ionised gas kinematics and star formation properties of XMP galaxies to identify disturbed or multi-component gas motions and explore their connection with star formation. We analyse long-slit spectroscopic observations of nine XMP galaxies obtained with the Intermediate Dispersion Spec…

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astro-ph.EPastro-ph.IMphysics.ins-det

Analytical Chemistry at the Planetary Frontier

Mavia Anjum

Planetary science depends on chemical measurements made under conditions very different from those in a terrestrial laboratory. This review treats the analytical methods of planetary science as one connected chain, from orbital remote sensing through in-situ measurements by landers and rovers and sample collection and curation, to the micro-analysis of returned material on Earth. Orbital methods, including visible and near-infrared reflectance, thermal emission and gamma-ray and neutron spectros…

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astro-ph.SRastro-ph.HE

Evolution of Massive Main-Sequence Stars in Binary Population Synthesis. II. Consequences for Black Hole High-Mass X-ray Binaries and Binary Black Holes

Adam Brček, Ryosuke Hirai, Ilya Mandel, Jack Yutong Chen

Interactions and mass loss during the main-sequence (MS) phase of massive binary stars can significantly alter their subsequent evolution and the properties of the black holes (BHs) they ultimately produce. We use the rapid binary population synthesis code \textsc{COMPAS}, incorporating a new treatment of MS evolution that self-consistently tracks the convective core under arbitrary mass-loss or mass-gain histories. We explore the properties of black hole high-mass X-ray binaries (BH-HMXBs) and…

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astro-ph.HEastro-ph.SR

The Imprint of Core-collapse Asymmetries on Supernova Shock Breakout

David K. Khatami, David Vartanyan, Hai P. Le, Daniel N. Kasen, Adam Burrows

Shock breakout is the first electromagnetic signal of a supernova, generating a highly luminous and fast-timescale burst of thermal radiation. Motivated by recent theoretical progress in producing successful three-dimensional supernova explosions of massive stars, we undertake a detailed numerical study on the impact that the core-collapse asymmetries might have on the breakout signal. We perform the first fully 3D multi-group radiation hydrodynamics simulations of shock breakout for the case of…

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astro-ph.GA

The GLEAM 4-Jy (G4Jy) Sample: V. Broadband spectral analysis

Sarah V. White, Siegfried A. Gawenda, Giulia Macario, Samuel P. Hansen, Ross J. Turner, Thomas M. O. Franzen, Joseph R. Callingham, Randall Wayth et al.

The G4Jy Sample consists of 1,863 of the brightest sources in the southern sky, as selected at 151 MHz using the GaLactic and Extragalactic All-sky MWA (GLEAM) survey. We supplement existing, low-frequency radio data by completing visual inspection of radio images from the Rapid ASKAP Continuum Survey (RACS) at 887.5, 1367.5 and 1655.5 MHz. Doing so on a source-by-source basis allows us to assess the quality of the association of the radio emission, which we indicate via a flag system. Having mu…

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astro-ph.GA

A MUSE Study of Stellar and Ionized-Gas Kinematics in Central Group Galaxies

V. Olivares, E. O'Sullivan, P. Temi, S. Suárez, K. Kolokythas, M. Gaspari, F. Ubertosi, M. Aravena et al.

Understanding gas accretion and feedback in low-mass galaxy groups bridges the gap between isolated ellipticals and cluster-dominant galaxies. We present new Multi Unit Spectroscopic Explorer (MUSE) observations of 17 nearby brightest group galaxies (BGGs), revealing diverse origins for their gas reservoirs. Warm ionized gas, traced by Halpha and [N II], is detected in 77% (13/17) of the sample, with morphologies including rotating disks with or without tails and diffuse emission, rings, and fil…

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astro-ph.HE

Numerical shock broadening and supernova neutrino conversion: implications for DUNE

Rafael C. R. de Lima, Pedro Martins Bailer

Hydrodynamical simulations spread the supernova shock front over a few grid zones, a width set by the numerical scheme rather than by the physics of the shock. Where the front crosses the H resonance, that width can make the computed MSW evolution artificially adiabatic. We quantify the effect on six three-dimensional blue-supergiant explosion models from the Garching archive by propagating individual rays twice: through the stored profile, and with the front replaced by a narrow reconstruction,…

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