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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.DCphysics.comp-ph

STORM: RDMA-based Monte Carlo Transport Scheme for Distributed-Memory Particle Simulations

Maor Mizrachi, Barak Raveh, Elad Steinberg

Monte Carlo particle transport enables high-fidelity astrophysical radiation and neutrino simulations - from core-collapse supernovae and neutron-star mergers to accretion flows - by handling multidimensional geometries, frequency dependence, and moving media without angular discretization. However, inter-rank communication limits scalability on unstructured meshes: standard two-sided MPI requires receivers to post receives and poll completions, creating per-iteration progress overhead that grow…

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astro-ph.GA

A Naked Dwarf: Molecular Gas in the Completely Stripped HI Tail of VCC 1249

Bumhyun Lee, Aeree Chung, Paolo Serra, Nikki Zabel, Sungsoon Lim, Hyein Yoon, A. Boselli, Matteo Fossati et al.

We present the first observational hints of the severe removal of both molecular and HI gas from the dwarf galaxy VCC 1249. This extreme stripping event is thought to be driven by the combined effects of tidal interaction and ram pressure. Using deep CO (2$-$1) observations from the James Clerk Maxwell Telescope (JCMT), we obtained marginal CO detections in three regions within the stripped HI tail, with molecular masses of $\sim$10$^{5}$ to 10$^{6}$$M_{\odot}$, comparable to typical masses of g…

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astro-ph.HEastro-ph.GA

Time-evolving Diagnostic of the Ionized Absorbers in NGC 4051. II. High-throughput Time-resolved Spectroscopy

Alfredo Luminari, Fabrizio Nicastro, Roberto Serafinelli, Riccardo Middei, Yair Krongold, Elias Kammoun, Luigi Piro, Francesca Diaferia et al.

Active Galactic Nuclei (AGNs) are one of the most powerful sources in the Universe. The accretion-liberated energy can strongly impact the surrounding environment, up to the host galaxy and beyond. Notwithstanding their ubiquitous presence, nuclear outflows are poorly characterised, mainly due to the degeneracy between their number density $n_e$ and radial location $r$, intrinsic in the photoionisation equilibrium models which are usually employed to fit the observations. This degeneracy prevent…

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hep-phastro-ph.HEhep-ex

Dark Matter Weather: Probing Sub-GeV Interactions with Earth-Shielding Modulation

Tetiana Kozynets, Rebecca Leane, Juri Smirnov

Daily modulation from Earth shielding provides a powerful search handle for sub-GeV dark matter (DM) in low-threshold experiments. We use this effect as a probe of interaction structure in scenarios where DM couples to both electrons and nuclei. Nuclear scattering in the Earth alters the incident DM flux, while electron scattering produces the observable ionization signal, so the total rate and modulation pattern encode different aspects of the underlying interactions. We develop this two-intera…

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astro-ph.HE

Polarization of impulsive relativistic jets propagating in a stratified medium

Gal Birenbaum, Paz Beniamini, Jonathan Granot

Gamma-ray bursts (GRBs) and at least some tidal disruption events (TDEs) are highly energetic transients involving impulsive relativistic jets. As these jets propagate into their surrounding media, they drive a relativistic forward shock into it, which radiates multi-wavelength polarized synchrotron emission, known as an afterglow. Analyzing the afterglow light curve along with its polarization curve can shed light on the geometrical properties of the GRB or TDE system such as the magnetic field…

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astro-ph.SRastro-ph.GAastro-ph.HE

A dust-free hierarchically nested supermassive-star model for James Webb Space Telescope Little Red Dots

Pau Amaro Seoane

Observations by the James Webb Space Telescope reveal a population of high-redshift objects, the little red dots. These sources exhibit optical reddening alongside blue ultraviolet continua, host broad Balmer lines indicative of active black holes, and lack detectable x-ray emission. Their cosmic abundance at early epochs exceeds standard Eddington-limited growth timescales. Prevailing models invoke specific dust geometries to reconcile these traits. We propose a dust-free physical framework. We…

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astro-ph.GAastro-ph.SR

Two stellar clocks, one history: a Gaia colour-magnitude-diagram reconstruction of the solar-neighbourhood star-formation history tested against white dwarfs

Michele Cignoni, Pier Giorgio Prada Moroni, Martina Gabbanini, Scilla Degl'Innocenti, Antonio Tinarelli

The solar-neighbourhood star-formation history (SFH) can be constrained from the colour-magnitude diagram (CMD) of non-degenerate stars and tested independently with the white-dwarf luminosity function (WDLF). These two tracers sample complementary evolutionary phases and provide a consistency check on both the recovered SFH and the adopted WD cooling models. We reconstruct the local SFH from the Gaia DR3 CMD and test whether the resulting history reproduces the observed 40 pc WDLF. We fit non-d…

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astro-ph.SRastro-ph.HE

A Framework for Linking Pre- and Post-Common Envelope Binary Properties with Star Clusters: The First Demonstration with a Massive White Dwarf+M Dwarf Binary in Alessi 12

Steffani M. Grondin, Maria R. Drout, Jason Nordhaus, Philip S. Muirhead, Bailey Filer, Alexander Laroche, Jeremy J. Webb, Floor S. Broekgaarden et al.

Common envelope (CE) evolution is a critical phase in the lives of binary stars, producing close binaries that are progenitors of type Ia supernovae and gravitational wave sources. Despite its importance, CE evolution remains poorly understood, largely due to the scarcity of systems with constrained pre- and post-CE properties. Here, we present a star cluster-based framework for reconstructing the evolutionary histories of white dwarf+main-sequence (WD+MS) post-CE binaries, where cluster members…

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astro-ph.HE

The Origin of the Magnetic Flux Driving TDE Jets

Nimrod Tripto, Julian Krolik, Tsvi Piran

Tidal Disruption Events (TDEs) occur when a star approaches a black hole closely enough to be torn apart by tidal forces, after which the stellar debris begins to orbit the black hole. Over the past decade, hundreds of TDEs have been identified, with many more expected from upcoming surveys. A small subset of these events launch transient, highly luminous relativistic jets (10^47-10^48 erg/s isotropic-equivalent). These are generally interpreted in terms of the Blandford--Znajek mechanism, imply…

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hep-phastro-ph.HE

Earth rotation turns event timing into a geometric probe of UHE neutrino origin

Andrew Cheek, João Paulo Pinheiro, Jordi Salvado

It has been proposed that the ultra-high-energy (UHE) event $\rm KM3-230213A$ detected by KM3NeT could be explained by dark matter (DM) decay. Prima facie this seems unlikely because the arrival direction of the event is opposite to the Galactic Centre. We develop a per-event test statistic to quantitively assess this possibility and forecast the required future events to exclude the DM hypothesis in favour of an isotropic signal. For the single event observed, the DM decay hypothesis is disfavo…

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astro-ph.HE

Revealing the Structure and Magnetization of GRB Jets with ALMA Polarization Observations

Tanmoy Laskar, Collin T. Christy, Noah Franz, Gavin Farley, Kate D. Alexander, Jonathan Granot, Ramandeep Gill, Tarraneh Eftekhari et al.

We present a systematic study of the currently available ALMA millimeter polarimetric sample of gamma-ray burst (GRB) afterglows. Our sample comprises 24 observations (20 new) of 11 long-duration GRBs spanning $\approx0.1$-87 days after the burst. We detect significant linear polarization in 8 observations across 6 events, with polarization degrees ranging from $Π_L\approx0.6\%$ to $2.4\%$. For the remaining observations, we place deep upper limits (median $Π_L\lesssim1\%$). Multi-epoch observat…

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astro-ph.GA

A New Model for the Milky Way Halo Dispersion Measure with the ENGAWA Simulations: Low DMs and Large Anisotropy

Scott Lucchini, Liam Connor, Samuel McCarty, Ralf M. Konietzka

Fast radio burst (FRB) dispersion measures (DMs) are powerful tracers of the low density universe, but interpretation is made difficult by the integrated nature of DM. In this paper, we analyze the new ENGAWA cosmological zoom-in simulation suite to constrain the DM contribution from the Milky Way (MW) halo. The ENGAWA simulations consist of four Milky Way-like galaxies with enhanced resolution in the circumgalactic medium, making them an excellent tool to probe the properties of the gaseous hal…

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gr-qcastro-ph.HE

Black hole-neutron star binaries with high spins and large mass asymmetries: III. Properties of the ejected material and its electromagnetic signatures

Konrad Topolski, Samuel D. Tootle, Paramvir Singh, Mattia Bulla, Luciano Rezzolla

Compact binary systems consisting of a black hole (BH) and a neutron star (NS) are expected to provide detectable signals both in the gravitational wave and in the electromagnetic channels, thus representing excellent sources for multi-messenger astronomy. In this third paper in a series, we report on the geometric and thermodynamic properties of the purely dynamical ejecta component modeled in our general-relativistic magnetohydrodynamical simulations of BHNS systems over a comprehensive binary…

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astro-ph.IM

Structural, thermal and optical tolerance analysis of SHARP, a near infrared spectrograph for next generation telescope

H. Mahmoodzadeh, P. Saracco, I. DI Antonio, P. Conconi, D. Scaccabarozzi, B. Saggin, E. Molinari, C. Arcidiacono et al.

The design and verification of cryogenic near-infrared spectrographs require rigorous multidisciplinary analyses to ensure optical performance under realistic operational conditions. In this work, we present a structural-thermal-optical performance (STOP) analysis of the SHARP instrument, a multi-mode spectrograph designed for use with upcoming multi-conjugate adaptive optics (MCAO) systems on Extremely Large Telescopes (ELTs). Transient and steady-state thermal simulations were performed using…

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astro-ph.GA

Outflows in the Early Universe: Neutral gas Absorption in Galaxies at z > 3 from low-resolution JWST Spectroscopy

Matteo Sapori, Sirio Belli, Letizia Bugiani, Amir H. Khoram, Caterina Liboni, Gabriel Maheson, Gabriel Brammer, Rebecca Davies et al.

Recent JWST/NIRSpec observations have shown that Na I D absorption tracing neutral gas outflows is widespread in massive galaxies at Cosmic Noon ($z\sim2$-$3$), but their prevalence at higher redshift remains largely unexplored. Here we investigate whether similar outflows are already in place during the first 2 Gyr of cosmic history ($z>3$), using a sample of 811 galaxies at $3 5$ in their JWST/NIRSpec PRISM low-resolution spectra ($R\sim100$). We derived physical properties and star formation…

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astro-ph.HEastro-ph.SR

Semi-analytical Light Curve Model for Transients Preceding Binary Mergers. I: Supernova Precursor Emission from Compact Object Companions

Daichi Tsuna, Morgan Macleod, V. Ashley Villar

A binary undergoing dynamically unstable mass transfer could rapidly shrink its orbit and lead to a merger, with the whole process often observable in human timescales. We construct a semi-analytical light curve model of binary systems composed of a star and a compact object accretor, that would display long-rising accretion-powered emission prior to a final merger-driven explosion. We apply the model to the precursors of interacting supernovae (SNe) that display long-rising light curves of year…

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astro-ph.GA

Estimating Cluster Galaxy Infall Time from Phase Space in TNG

Cameron Lawlor-Forsyth

Using the TNG300 and TNG-Cluster simulations, phase space-based estimates for galaxy infall time onto clusters with $M_{\mathrm{h}} \geqslant 10^{14}~M_{\odot}$ are determined for all simulation snapshots with $z \leqslant 1$. These infall time estimates are consistent with previous work in the literature, and can be readily applied to observations of cluster galaxies, where no other estimate is feasible, based only on the galaxy's position in projected phase space. The analysis pipeline used to…

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astro-ph.GAastro-ph.IM

Spectral Data-cube Cleaning for CCAT Deep Spectroscopic Survey. I. Effect of correlated noise and filtering on the power spectrum

A. Dev, C. Karoumpis, Y. Okada, K. Basu, F. Bertoldi, D. Chung, J. Clarke, R. Freundt et al.

The Epoch of Reionization Spectrometer (EoR-Spec) on the Fred Young Submillimeter Telescope (FYST) will conduct the CCAT Deep Spectroscopic Survey (DSS) to perform line-intensity mapping of redshifted [C II] emission. Atmospheric $1/f$ noise and instrumental systematics affect power-spectrum recovery. We present realistic end-to-end simulations to quantify these effects and evaluate a Filter-and-Bin (F&B) pipeline. The simulated observations include instrument response, astrophysical emission, a…

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astro-ph.HE

Pulsar glitches in the presence of vortex traps

Anantharaman Sekharipuram Viswanathan, Dipankar Bhattacharya, M. Ali Alpar, Erbil Gügercinoğlu

Pulsar glitches are thought to originate when angular momentum is transferred to the crust of the neutron star from the superfluid enclosed within, mediated by vortex avalanches. This idea has been qualitatively validated in the existing literature by simulating a star with a small number ($\sim 10^{3}$) of superfluid vortices, subject to deceleration and uniform pinning. Here, we employ the Barnes-Hut approximation to simulate up to $10^{5}$ vortices in a reasonable time. Using the new setup, w…

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astro-ph.GAastro-ph.HE

Gas accretion onto the Milky Way: high-velocity cloud survival and the revival of the terminal-velocity paradigm

Michael M. Schulreich, Dieter Breitschwerdt, Jürgen Kerp

The terminal-velocity paradigm has long been used to interpret the motion and infer the distances of HVCs accreting onto the Milky Way, yet its validity under realistic Galactic conditions remains uncertain. We investigate its dynamical limits by combining analytical modelling with three-dimensional hydrodynamical simulations of clouds moving through a stratified Milky Way halo. We derive a generalized equation of motion including gravity, ram-pressure drag, a phenomenological mass-exchange mode…

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physics.ins-detastro-ph.IM

Overview and design optimization of a custom hybrid X-ray telescope for the International Axion Observatory (IAXO)

Yue Yu, Jooyun Woo, Ipek Altunyurt, Stefano Basso, Vadim Burwitz, Francisco R. Candón, Juan Francisco Castel Pablo, Marta M. Civitani et al.

We present the design optimization for maximizing the effective area of a custom X-ray optic for the International Axion Observatory (IAXO) and BabyIAXO, including its novel hybrid configuration that enables full coverage of the 700-mm-diameter magnetic bore with minimal stress imposed on the mirrors; shell layout optimized for axion spectra and spatial distribution; and the coating recipes that enhance reflectivity in the energy range of interest. We evaluate how these design choices improve th…

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astro-ph.IM

The High-Speed FPGA Readout System for the Advanced X-ray Imaging Satellite (AXIS)

Declan O'Neill, Jill Juneau, Peter Orel, Sven Herrmann, Gregory Prigozhin, Eric D. Miller, Steven W. Allen, Marshall W. Bautz et al.

The Advanced X-ray Imaging Satellite (AXIS) is a Probe-class mission concept designed to deliver arcsecond spatial resolution, high-sensitivity spectral imaging across the 0.3-10 keV band. The X-ray Astronomy and Observational Cosmology (XOC) Group at Stanford, in collaboration with the MIT Kavli Institute (MKI) and MIT Lincoln Laboratory (MIT-LL), is developing the AXIS X-ray camera, including both the detector and the front-end readout electronics required to meet the mission's demanding perfo…

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astro-ph.HE

Probing the High-Energy Emission of the VHE-emitting Changing-Look Blazar B2 1420+32

Anjum Peer, Zahir Shah, Sikandar Akbar, Bari Maqbool, Ranjeev Misra

We present a multi-wavelength temporal and spectral study of the changing-look blazar B2~1420+32 using \emph{Fermi}-LAT, \emph{Swift}-XRT, and \emph{Swift}-UVOT data from MJD~58818--60721. The source reached a peak 0.1--300~GeV photon flux of $(4.62 \pm 0.29) \times 10^{-6}\,\mathrm{ph\,cm^{-2}\,s^{-1}}$ around MJD~60488, about 60 times the 4FGL-DR4 average, during which the photon index hardened to $2.19 \pm 0.14$; the flux--index evolution shows only weak evidence for global harder-when-bright…

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astro-ph.COastro-ph.GA

The burgeoning rise of the 21-cm forest I: constraints on the optical depth of the intergalactic medium at $5.38 < z < 5.84$

Chanasorn Kongprachaya, Gianni Bernardi, Emilio Ceccotti, Andrei Mesinger, Benedetta Ciardi, Oleg M. Smirnov

The redshifted 21-cm line is a promising probe of the Epoch of Reionization, during which the first generation of stars ionized the InterGalactic Medium (IGM). We aimed to constrain the IGM neutral Hydrogen fraction and spin temperature via redshifted 21-cm absorption against high-redshift radio sources. We analysed an 18-hour observation of the radio-loud quasar PSO J352.4034-15.3373 ($z = 5.84$) in the 203-222.5 MHz band. We obtained a continuum image with a $0.66$ mJy/beam rms noise and a spe…

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astro-ph.IM

Fast, low-noise CCD systems for future strategic X-ray missions

Haley R. Stueber, Tanmoy Chattopadhyay, Tonya L. Peshel, Abigail Y. Pan, Steven W. Allen, Marshall W. Bautz, Kevan Donlon, Catherine E. Grant et al.

Future strategic X-ray missions, such as those targeted by the Great Observatories Maturation Program (GOMaP), require fast, low-noise X-ray imaging spectrometers. To achieve the speed and noise capabilities required by such programs, our Stanford team, in collaboration with the MIT Kavli Institute (MKI) and MIT Lincoln Laboratory (MIT-LL), is developing enhanced X-ray charge-coupled devices (CCDs) and readout systems that leverage tailored application-specific integrated circuits (ASICs). Here,…

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astro-ph.IM

HARMONI at ELT: Reoptimization of the NGSS natural guide star sensors system for MCAO compatibility

Kjetil Dohlen, David Le Mignant, Anne Bonnefoi, Marc Dubbeldam, Johan Floriot, Iago Funes Vecino, Laurent Jocou, Yoann Richaud et al.

HARMONI is the first-light, adaptive optics assisted, near-IR integral field spectrograph for the ELT. It covers a spectral range from below 800nm to 2400nm with resolving powers from 3000 to 7000 and spatial sampling of 25mas and 6mas. It can operate in three adaptive optics (AO) modes: single conjugate AO (SCAO), high-contrast AO (HCAO), and multi-conjugate AO (MCAO). The project is resuming its final design phase after a rescope design phase that has lasted two years. This paper describes the…

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astro-ph.HE

Long-lived intermittent accretion disks in the jittering jets explosion mechanism (JJEM) of core-collapse supernovae

Noam Soker

Motivated by observations of core-collapse supernova (CCSN) remnants that suggest cases where one to three energetic pairs of jets dominate the CCSN remnant morphology and, hence, the CCSN explosion energy, I examine the formation of long-lived intermittent accretion disks that launch such pairs of energetic jets in the framework of the jittering-jets explosion mechanism (JJEM). In the JJEM, pairs of jets explode all CCSNe. In most CCSNe, stochastic angular momentum fluctuations in the convectiv…

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physics.ins-detastro-ph.HEastro-ph.IMhep-exhep-ph

Fabrication status and expected performance of the inner-core X-ray optic for BabyIAXO

Jooyun Woo, Yue Yu, Ipek Altunyurt, Todd Decker, Desiree Della Monica Ferreira, Peter Lindquist Henriksen, Eftychia Kotsiou, Sonny Massahi et al.

BabyIAXO, a pathfinder for the International Axion Observatory (IAXO), is designed to demonstrate all key technologies at scale while achieving an improvement in sensitivity over the recent CERN Axion Solar Telescope (CAST) experiment by approximately a factor of five. Such improvement is enabled by the X-ray optics, which allow for maintaining a high signal-to-noise ratio at the detector despite a cross-sectional area of the magnetic bore being over 250 times larger than that of CAST. The optic…

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astro-ph.EPastro-ph.SR

Planetesimal Formation Across the Stellar Mass Spectrum and its Influence on Exoplanet-Inherited Volatile Budgets

Joe Williams, Sebastiaan Krijt, Joanna Drążkowska, Tim Lichtenberg

Protoplanetary discs emerging from collapsing molecular clouds are capable of forming planetesimals at the water snowline during both the cloud collapse and Class II disc phases; such a scenario could be responsible for creating the carbonaceous/non-carbonaceous (CC/NC) heterogeneity observed in the Solar System, and bears important implications for emergent planetary compositions. We use 1D simulations of a viscously evolving disc coupled with cloud collapse and planetesimal formation to explor…

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astro-ph.GA

Testing dark matter density profiles based on Padé approximants of different orders

Talgar Konysbayev, Orlando Luongo, Marco Muccino, Yergali Kurmanov, Kuantay Boshkayev, Gulnara Suliyeva, Ainur Urazalina, Guldana Rabigulova et al.

We investigate whether low-order Padé rational functions can be used as empirical density profiles for modeling dark matter halos from galaxy RCs. We introduce three parameterizations determined from Padé series, denoted Padé 02, Padé 12 and Padé 03, and compare them with pseudo-isothermal, Burkert, Beta, Brownstein, exponential-sphere and Persic models. The analysis is performed for eight galaxies under the assumption that RCs are dark matter dominated. The parameters are inferred from RC data…

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