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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.SRastro-ph.EP

Coronal Mass Ejections from the Young Sun: Deceleration-Powered Solar Energetic Particles as a Self-Extinguishing Forcing of the Early Earth

Olga A. Panasenco

At $\sim$3.9~Ga (stellar age $\sim$0.6~Gyr), the young Sun was far more magnetically active than today. It launched $\sim$$10^2$ large, fast coronal mass ejections (CMEs) per year into a denser, more magnetized wind. We follow these eruptions to Earth's atmosphere with a semi-analytic model chain. We find that a CME launched at $v_0\sim3\text{--}4\e{3}\unit{km\,s^{-1}}$ dissipates $ΔE_k\sim6\e{25}\unit{J}$ as it decelerates, an amount set only by its launch and final speeds. Diffusive shock acce…

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astro-ph.GA

Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) -- IV. Methyl cyanide isotopologues toward BHR71-IRS1

P. Nazari, A. Coutens, J. K. Jørgensen, A. Belloche, A. L. Plunkett, S. Maret, D. Harsono, M. N. Drozdovskaya et al.

Methyl cyanide is one of the most abundant nitrogen-bearing complex organic molecules observed in the gas phase around low- and high-mass protostars. However, very few observations exist with a broad enough frequency coverage and sufficiently high sensitivity to systematically characterize its minor isotopologues toward such regions. We add to this number by analyzing data toward BHR71-IRS1 taken as part of the Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) Large Pr…

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astro-ph.IM

Space-based Cosmic Neutrino Measurements

John F. Krizmanic

Space-based neutrino detection employs celestial bodies, the Earth, moon, and the sun, as neutrino targets and particle cascade generators. These cascades, or showers, have an immense content of charged particles, mainly electrons and positrons, that can form signals that can be detected by orbiting or balloon-borne (for the Earth) experiments. Here the focus will be on the using the Earth as the neutrino target and using the atmosphere to generate optical and radio signals from extensive air sh…

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astro-ph.COastro-ph.GA

Halo Mass Function Constraints on Early Galaxy and AGN Populations in the JWST Era

Elan Yogeswaren, Robert Schaefer

The discovery by the James Webb Space Telescope (JWST) of massive galaxies and luminous active galactic nuclei (AGN) at high redshift provides an increasingly sensitive test of the connection between cosmological structure formation and the astrophysical processes that make dark matter halos observable. We develop a framework connecting the linear matter power spectrum to the mass variance, peak height, halo mass function (HMF), cumulative halo abundance, and observable galaxy and AGN population…

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astro-ph.GA

Galaxy merger-driven signatures in massive black hole pair hosts across cosmic time

Pranav Satheesh, Aklant K. Bhowmick, Laura Blecha

Galaxy mergers can drive gas toward galactic nuclei, enhancing both star formation and black hole accretion in post-merger galaxies. Here we use the IllustrisTNG-50 simulation and two boxes from the BRAHMA simulation suite, all of which adopt different black hole formation models, to characterize merger-associated signatures in candidate massive black hole (MBH)-pair hosts. In all three simulations, we select post-merger galaxies whose progenitors both host MBHs and quantify their enhancements i…

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astro-ph.IM

Nancy Grace Roman Space Telescope Wide Field Instrument: Grism Saturation Response to Bright Sources during Thermal-Vacuum Testing

Lipika Chatur, Dana R. Louie, Joshua E. Schlieder, Robert F. Wilson, Evan Bray, Scott Rohrbach

The Nancy Grace Roman Space Telescope launched on August 30th, 2026 and is expected to begin its science mission in 2027. Although Roman's core science will focus primarily on faint and distant sources, as a survey telescope, it will also observe many bright sources that can saturate the detector pixels. Our goal is to study the behavior caused by bright sources dispersed through the grism and to assess how detector properties may impact scientific analysis. We analyze detector saturation behavi…

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astro-ph.HE

Unveiling the Accretion Architecture of GS 1354--64: A Broadband X-ray and Polarimetric Study of its 2025--2026 Outburst

Kaushik Chatterjee

A comprehensive multi-satellite analysis of the dynamically confirmed black hole candidate GS 1354-64 during its highly active 2025-2026 outburst is presented. Leveraging simultaneous broadband spectroscopy, fast timing, and X-ray polarimetry, I map the evolution and geometry of the accretion flow. During the initial Compton-dominated hard state rise, strong, narrow Type-C quasi-periodic oscillations (QPOs) evolving from 0.08 Hz to 1.73 Hz with high fractional RMS (~8-10%) are detected, showing…

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astro-ph.HE

It Takes Two: nucleosynthesis in core-collapse supernova simulations of binary-star progenitors

Gaétan Jalin, Almudena Arcones, Evan P. O'Connor, Andrea Ercolino, Norbert Langer

Binary interaction is common amongst massive stars and can significantly alter their pre-supernova structure and composition. This has important consequences for the nucleosynthetic yields and observable properties of the resulting supernovae. However, binary-evolved progenitors remain largely unexplored in modern neutrino-driven core-collapse supernova simulations. In this work, we present one- and two-dimensional core-collapse supernova simulations of single- and binary-star progenitors. We in…

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gr-qcastro-ph.HE

Constraining the gravitational-wave breathing mode with LVK antenna patterns and GWTC data

Hong-Bo Jin, Yanyan Zheng

Metric theories of gravity admit a massless breathing scalar $b$ besides the tensor modes $+$ and $\times$. Many scalar--tensor models predict a much smaller breathing amplitude; gravitational quantum field theory (GQFT) instead allows $h_b$ comparable to the tensor amplitudes. We evaluate the LIGO--Virgo--KAGRA (LVK) antenna patterns with PyCBC, including Michelson suppression of $b$. Here $F_b$ is the breathing antenna pattern and $\mathcal{S}_b=\sum_d F_b^{d2}$ is the network breathing power.…

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astro-ph.EP

SOPHIE and TESS characterization of fourteen TESS Objects of Interest: nine planetary systems and five low-mass stellar companions

N. Heidari, G. Hébrard, S. Sousa, T. Forveille, F. Destriez, J. D. Eastman, J. M. Almenara, D. W. Latham et al.

We present fourteen TESS Objects of Interest (TOIs) from the SOPHIE-TESS follow-up program. Combining TESS photometry, SOPHIE radial velocities (RVs), ground-based photometry, and high-resolution imaging, we establish the nature of all targets. Nine systems (TOI-6457, TOI-6883A, TOI-6649, TOI-6842A, TOI-5217A, TOI-6893A, TOI-7025, TOI-7176, and TOI-5893) host planets. TOI-6649 b, TOI-6842A b, and TOI-5217A b are transiting hot Jupiters with periods of 4.4-6.0 d, radii of 1.3-1.6 RJ, masses of 0.…

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astro-ph.HE

Assessing transitional pulsar candidates through a quantitative estimation of their light-curve similarity

D. F. Torres, C. R. García, F. Coti Zelati, D. de Martino, G. Illiano, A. Papitto, A. Patruno, M. C. Baglio et al.

Transitional millisecond pulsars are often identified through X-ray light-curve morphology, especially by visual comparison with the prototype PSR J1023+0038. Such classifications remain qualitative and lack a calibrated notion of how much variability is already present within the prototype itself. We introduce a Dynamic Time Warping (DTW) framework that compares light curves through moving-window similarity distributions and calibrates candidate-prototype distances against the internal heteroge…

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gr-qcastro-ph.HE

Line-of-Sight Acceleration-driven waveform corrections for unequal-mass compact binary coalescences

Mohd Asim Ansari, Avinash Tiwari, Sajad A. Bhat, Aditya Vijaykumar, Shasvath J. Kapadia

A constant line-of-sight acceleration (LOSA) of the centre-of-mass of a quasi-circular compact binary coalescence (CBC) leads to modulations in the gravitational-wave (GW) waveform at $-4$ post-Newtonian (PN) order. In our previous work, we calculated the phase and amplitude corrections only for the $(\ell,m) = (2,2)$ mode. The gravitational wave event GW190814 has recently attracted considerable attention because it has been suggested to provide evidence for a nonzero LOSA. However, several LOS…

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astro-ph.SR

Mapping of interstellar ices with JWST in protostellar envelopes: Spatial variations of $^{13}$CO$_2$, $^{12}$CO$_2$, CO, OCN$^-$ and H$_2$O ice

N. G. C. Brunken, E. F. van Dishoeck, A. C. A. Boogert, P. Nazari, Y. Chen, J. Santos, H. Beuther, A. Caratti o Garatti et al.

The composition of planets and their atmospheres is largely determined by the formation environment of the planet. This environment is pre-determined during early stages when the protostar is still forming. Charting the structure of protostellar envelopes is therefore crucial for understanding how the chemistry is linked to the physical processes occurring in stellar nurseries. We use JWST NIRSpec IFU observations to extract spectra at every pixel in the IFU and map the distribution of $^{13}$CO…

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astro-ph.HE

The Potential Contribution of Radiative Supernova Remnants to the Local Cosmic Ray Spectrum

P. Cristofari, V. H. M. Phan, S. Recchia, S. Gabici

Recent observations of very-high-energy gamma rays from massive stellar clusters and microquasars have demonstrated that these systems can efficiently accelerate particles to very high energies, renewing the debate on the dominant sources of Galactic cosmic rays (CRs) and casting further doubt on the role of supernova remnants (SNRs), long considered the prime candidates. In these astrophysical environments, particle acceleration is generally thought to be driven by diffusive shock acceleration…

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astro-ph.EPastro-ph.GAastro-ph.HEastro-ph.IMphysics.flu-dyn

Reflex instabilities II: The reflex motion of the central object drives at least seven instabilities in accretion discs

Nathan Magnan, Michel Tagger, Clément Baruteau, Aurélien Crida, Jean-François Gonzalez, Héloïse Méheut

This series of papers studies the stability of accretion discs to the reflex motion of the central object under the gravitational pull of the disc itself. In this second paper, we use linear analysis to reproduce or discover seven distinct instabilities. We outline their defining characteristics and propose a classification. Of the four instabilities that had already been discovered, three are artificial: one does not survive the transition to modern surface density profiles such as power-laws,…

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astro-ph.EPastro-ph.GAastro-ph.HEastro-ph.IMphysics.flu-dyn

Reflex instabilities I: Boundaries makes grid-based disc simulations frame-dependent

Nathan Magnan, Michel Tagger, Clément Baruteau, Aurélien Crida, Jean-François Gonzalez, Héloïse Méheut

If the mass distribution within an accretion disc is asymmetric, it will exert a gravitational pull on its central object. The central object must then move away from the origin of the reference frame, resulting in atypical gravitational pulls on the disc. The goal of the present series of papers is to investigate the stability of this feedback loop. In this first paper, we report a surprising finding: the choice of reference frame affects the number and nature of the waves and instabilities con…

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astro-ph.HE

Predicting High-Energy neutrino emission from X-ray absorption in CSM-interacting SNe

Silvia Gagliardini, Simone Dall'Osso, Dafne Guetta

Core-collapse supernovae (CCSNe) interacting with a dense circumstellar medium (CSM) are promising sources of high-energy neutrinos. Most neutrino predictions rely on specific assumptions about the CSM density profile and progenitor mass-loss history. We develop a data-driven framework that connects X-ray observations directly to the expected neutrino signal. Using the temporal evolution of the hydrogen-equivalent absorbing column density, N_H(t), together with the shock velocity inferred from t…

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gr-qcastro-ph.HE

Line-of-sight Acceleration Driven Effects in Eccentric Compact Binary Coalescences

Mohd Asim Ansari, Avinash Tiwari, Sajad A. Bhat, Sreejith Nair, Shasvath J. Kapadia

The line-of-sight acceleration (LOSA) effect, imprinted in the gravitational wave (GW) signal of an inspiralling compact binary by an external gravitational potential, is one of the most promising means of probing the environment of compact binaries on a single-event basis. However, this effect is potentially degenerate with other low-frequency effects, particularly the binary's orbital eccentricity. LOSA effects and orbital eccentricity can mimic each other if only one or the other (but not bot…

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astro-ph.IM

Rapid Sequence Cost Evaluation for Multi-Spacecraft Rendezvous: A Permutation-Invariant Set Transformer

An-yi Huang

Multi-spacecraft multi-rendezvous mission design requires repeated evaluations of the total cost of visiting a target set within a given time window, and the efficiency of this evaluation is the primary barrier to global search. Existing methods either optimize the order and epochs of each candidate sequence, which is expensive, or estimate the cost leg by leg, in which case the error accumulates with the sequence length. This paper proposes a deep model that regresses the total cost of an unord…

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astro-ph.COastro-ph.GA

The impact of feedback and cosmology on Cosmic Infrared Background cross-correlations

Sara Maleubre, David Alonso, Reggie Dunsdon, Adrien La Posta, Amy Wayland, Joop Schaye

We study the evolution and clustering properties of the star formation rate density (SFR) $ρ_{\rm SFR}$ in the FLAMINGO suite of hydrodynamical simulations, with the aim of exploring the possibility of constraining AGN and stellar feedback prescription, as well as the effect of cosmology, using cross-correlations between the Cosmic Infrared Background (CIB) and other tracers of the large-scale structure. Specifically, we consider tomographic measurements of the bias-weighted SFR-density $\langle…

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astro-ph.GA

The $\mathrm{[O\ III]}\lambda5007$ Equivalent Width as an Ionization-Parameter Diagnostic Across Cosmic Time

Dian P. Triani, Lisa J. Kewley

Nebular emission lines and stellar continua probe the conditions of $\mathrm{H\ II}$ regions. The optical emission line $\mathrm{[O\ III]}λ5007$ is important because it is observable across a wide redshift range, enabling studies of interstellar medium (ISM) conditions across cosmic time. We investigate the equivalent width of $\mathrm{[O\ III]}λ5007$ (EWO3) as an ionization-parameter diagnostic, providing an alternative to the $\mathrm{[O\ III]} λ5007 / \mathrm{[O\ II]} λ3727$ (O32) ratio, whic…

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cs.CVastro-ph.EPcs.CRmath.AG

Decoy and disclosure radii of invariant shape descriptors

Tanush Shaska, Lubjana Beshaj

A recognizer that compares rotation-invariant descriptors sees a surface only up to the fiber of the descriptor. We measure this fiber by its radius in the orbit distance from the enrolled surface. A large radius admits decoys, that is, distant shapes that pass the matcher. A small radius discloses the enrolled shape to anyone who captures the stored value. For star-shaped surfaces truncated to spherical harmonics of degree at most $L$, with $n$ coefficients, a descriptor of generic rank $r$ has…

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astro-ph.COastro-ph.GA

ApPolLO: Apertif counterparts of Polarised LOFAR sources

A. Berger, B. Adebahr, H. Dénes, R. -J. Dettmar

Knowledge of the structure and evolution of cosmic magnetic fields is indispensable to understand how primordial magnetic fields were generated and amplified during the lifetime of the Universe. Polarisation studies over significant redshift ranges are an important tool in understanding cosmic magnetic fields. We aim to understand the structure and evolution of cosmic magnetic fields, utilising the polarised spectra and depolarisation characteristics of (background) radio sources. Using radio po…

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astro-ph.HE

Probing turbulence in the ionized interstellar medium using young pulsars. I. Dispersion measure variations

S. J. I. Melfor, A. Parthasarathy, S. Johnston, A. Chalumeau, S. Dai, M. Kerr, M. E. Lower, R. N. Manchester et al.

Temporal variations in the dispersion measure (DM) of pulsars probe fluctuations in the free-electron density of the ionized interstellar medium (IISM). While DM variations have been studied extensively in millisecond pulsars, young pulsars provide a complementary probe due to their lines of sight (LoSs) intersecting supernova remnants, pulsar wind nebulae, and other turbulent environments. However, systematic studies of DM variability in young pulsars remain limited. In this paper, We character…

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astro-ph.HEastro-ph.GA

X-ray spectral scaling of black hole mass in quasi-periodic eruptive source RX J1301.9+2747

Lev Titarchuk, Elena Seifina, Vadim Arefiev, Diana Makhinya, Alexei Le

We present a spectral and timing analysis of X-ray emission from the actively accreting supermassive black hole (SMBH) in RX~J1301.9+2747 with prominent quasi-periodic eruptions (QPEs) using {\it ASCA, ROSAT, XMM-Newton}, and {\it NICER} observations. {\it NICER} detected renewed QPE activity from this source in 2024. We examined in detail the X-ray spectrum formation in this source during QPE outbursts applying the first-principal model, Bulk Motion Comptonization. We find an increase of the ph…

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astro-ph.EPastro-ph.IM

Blinding Lights: Simulation-Based Evidence for Terrestrial Giant Impacts as Astronomically Observable Events

Lucy Taylor, Simon J. Lock, Philip J. Carter, Zoë M. Leinhardt

Giant impacts (collisions between planet-sized bodies) are violent events that fundamentally alter the properties of planets and the structure of planetary systems. Observations of these events provide important constraints on the role of giant impacts in the formation of planetary systems. However, relating such observations to the specifics of the impact responsible is challenging, since numerical simulations struggle to resolve the expected extreme low densities of observable material at the…

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astro-ph.SRastro-ph.GAastro-ph.IM

Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) II. Approach to data reduction and products for line-rich broadband (sub)millimeter spectra

Adele L. Plunkett, Sébastien Maret, Daniel Harsono, Jes K. Jørgensen, Audrey Coutens, Maria N. Drozdovskaya, Jeong-Eun Lee, Arnaud Belloche et al.

Studying the chemical composition of the warm gas surrounding embedded solar-type protostars is one of the areas for which the Atacama Large Millimeter/submillimeter Array (ALMA) is particularly well suited. Recently, the ALMA Large Program ``Complex Organic Molecules in Protostars with ALMA Spectral Surveys'' (COMPASS) carried out an observing campaign of a sample of 11 protostellar regions to investigate the chemical impact of their environments and evolutionary stages. The aim of this paper i…

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astro-ph.SR

Starspots on weak-lined T Tauri stars in the sigma Orionis cluster

Andrew J. Wilson, Darryl J. Sergison, Tim Naylor, Robin D. Jeffries

The light curves and spectra of T Tauri stars indicate the presence of cool starspots covering large areas of their photospheres. Heavily spotted stars should have a larger mid-infrared flux than the equivalent single-temperature photospheres. To test this prediction we first fit single and two-temperature models to optical spectra of young stars in the 4 Myr-old sigma Orionis cluster and a control set of older field stars. The fits to the young stars favour two temperatures while the field star…

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astro-ph.COastro-ph.HEhep-ph

Evolution of neutrino distributions under repeated electron scattering

Jens Chluba, Bryce Cyr, Michiru Uwabo-Niibo, Masahide Yamaguchi

We study the energy redistribution of neutrinos by repeated elastic scattering with an isotropic thermal bath of free electrons. Starting from the relevant Boltzmann collision integral, we formulate the evolution equations in terms of the neutrino--electron redistribution kernel derived in our companion work. The scattering kernel formulation retains recoil, relativistic kinematics and Pauli blocking, while reducing the calculation to a one-dimensional integral in the outgoing neutrino energy. T…

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astro-ph.GA

Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) VI. Discovery of a class I methanol maser transition and its association with acetaldehyde

Jae-Hong Jeong, Jeong-Eun Lee, Jes K. Jørgensen, Audrey Coutens, Maria N. Drozdovskaya, Adele L. Plunkett, Arnaud Belloche, Sébastien Maret et al.

CH3OH masers that are collisionally pumped, referred to as `class I', commonly trace shock interfaces in star-forming regions, but their incidence in low-mass protostars remains poorly quantified. We use data from the COMPASS ALMA Large Program to establish the occurrence, spatial origin, and excitation of a newly detected class I CH3OH maser at 302.9 GHz towards low-mass protostars and to test whether its pumping environments exhibit signatures of shock-driven complex chemistry. COMPASS provide…

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