研究動向

astro-ph.HE2026年10月6日

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-dyn2026年10月6日

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-dyn2026年10月6日

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.HE2026年10月6日

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.HE2026年10月6日

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.IM2026年10月6日

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.GA2026年10月6日

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.GA2026年10月6日

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.AG2026年10月6日

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.GA2026年10月6日

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.HE2026年10月6日

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.GA2026年10月6日

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.IM2026年10月6日

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.IM2026年10月6日

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.SR2026年10月6日

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-ph2026年10月6日

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.GA2026年10月6日

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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hep-phastro-ph.HEastro-ph.SR2026年10月6日

The neutrino magnetic moment and supernovae with strong magnetic fields

Clément Ehrhardt, Maria Cristina Volpe, Miguel Ángel Aloy, Martin Obergaulinger

Despite several decades of searches, the neutrino magnetic moment remains unknown. If it is large, the neutrino evolution can be affected by its coupling to strong magnetic fields like the ones present in at least some core-collapse supernovae. We explore these effects for Majorana neutrinos. We first discuss a schematic model often employed and show the impact of resonant spin-flavor precession on the neutrino signal for a future galactic supernova. Then, we consider detailed simulations of a n…

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astro-ph.EPastro-ph.IMastro-ph.SR2026年10月6日

Ariel Tier 3 Observations: An Opportunity to Explore both Stellar and Planetary Variability through Broad Wavelength Time-domain Spectroscopy

Alexandra H. Thompson, Quentin Changeat, Theresa Luftinger, Giovanna Tinetti

Ariel's Tier 3 observing strategy offers a unique opportunity to explore planetary and stellar variability in the spectral and time domain. However, without the correct toolkit, temporal variability of the host star may complicate combined analysesof observations obtained at different epochs. We investigate the impact of stellar variability on Ariel Tier 3 observations and establish three different mitigation approaches of increasing physical complexity. Using simulated repeated observations of…

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astro-ph.SR2026年10月6日

Exploring an X1.8 flare and associated quasi-periodic pulsations using SDO and Aditya-L1 observations, alongside NFFF extrapolation

Pawan Kumar, Sanjay Kumar, Sadashiv, Sachin Rajkapoor Kanaujiya, Yogesh Kumar Maurya

The paper seeks to explore the initiation of an X1.8 class solar flare (SOL2024-10-09T0124) and the related quasi-periodic pulsations (QPPs), which are situated within NOAA active region 13848. To achieve this, we perform a multi-wavelength analysis of the event utilizing data from the Solar Dynamic Observatory (SDO) and Aditya-L1. Importantly, the observations indicate the emergence of a sigmoidal brightening at the onset of the flare, alongside the evolution of a complex morphology of flare br…

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astro-ph.GAnucl-th2026年10月6日

Early galactic heavy element production - a phenomenological approach

B. Wehmeyer, D. Blaschke, F. K. Röpke, G. Röpke

The high abundances of heavy elements in early, extremely metal-poor stars is still an unsolved issue in Galactic Chemical Evolution (GCE). Standard approaches, such as mergers of neutron stars, have several difficulties, and several non-merger production channels are under discussion. Here, we suggest that pre-enriched inflow might explain the heavy elements seen in low metallicity stars in the Galaxy. To characterize the conditions of the origin of such a pre-enriched infall, we apply a heavy-…

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astro-ph.EP2026年10月6日

HD 715 b, a Warm Jupiter Orbiting a Massive Subgiant Discovered from a Single TESS Transit

Alexander Venner, Robert A. Wittenmyer, Andrew Vanderburg, Karen A. Collins, David W. Latham, Allyson Bieryla, Tyler R. Fairnington, Chelsea X. Huang et al.

Transiting Warm Jupiters orbiting bright stars are scarcely known, but a substantial number of these planets have been uncovered by the TESS mission. In this work we report the discovery and confirmation of a transiting Warm Jupiter orbiting the bright ($V$ = 8.70) subgiant star HD 715 (TOI-6893). HD 715 b was originally identified from a single transit event in TESS Sector 70. We acquired two seasons of radial velocity follow-up using the PFS, TRES, and MINERVA-Australis spectrographs, which cl…

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astro-ph.SRastro-ph.HEphysics.plasm-phphysics.space-ph2026年10月6日

Does Diffusive Shock Acceleration Reach Steady State? Insights from a Near-Sun Shock Observed by Parker Solar Probe

Immanuel Christopher Jebaraj, Mikhail Malkov, Nicolas Wijsen, Oleksiy Agapitov, Athanasios Kouloumvakos, Alexandr Afanasiev, Federico Fraschetti, Edin Husidic et al.

Collisionless shocks accelerate particles at a rate set by the diffusion coefficient of those particles in waves they themselves generate. Theory fixes that coefficient only in steady state, and no measurement has tested whether an evolving shock ever reaches that state. We report Parker Solar Probe observations of a fast, near-parallel interplanetary shock at 0.24 au, encountered four hours after eruption, with the upstream waves and the protons they scatter recorded on the same magnetic field…

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gr-qcastro-ph.IM2026年10月6日

Time-Frequency Analysis for LISA: Galactic Foreground Modulation

Sudhi Mathur, Neil J. Cornish

Observations by the Laser Interferometer Space Antenna (LISA) will contain time-varying, cyclostationary confusion noise from the Galaxy, which is naturally handled using time-frequency analysis methods. We present a fast, forward model that maps the parameterized Galactic gravitational-wave luminosity density onto the annually modulated, unresolved confusion foreground in the complete set of time-delay interferometry channels. The line-of-sight luminosity integral is evaluated on a HEALPix grid…

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astro-ph.HEgr-qc2026年10月6日

Scalable and sequential inference of the neutron star equation of state with the Einstein Telescope

Thibeau Wouters, Thomas C. K. Ng, Hauke Koehn, Fabian Gittins, Peter T. H. Pang, Tim Dietrich, Chris Van Den Broeck

Future gravitational-wave observatories such as the Einstein Telescope will detect tens of thousands of binary neutron star mergers per year, making gravitational waves a dominant probe of the neutron-star equation of state in the coming decades. However, extracting this information requires hierarchical inference across a rapidly growing catalog of events, and existing methods must restart from scratch whenever a new event arrives, making them impractical at this scale. In this Letter, we intro…

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astro-ph.IMphysics.optics2026年10月6日

Optimizing Laguerre-Gaussian Mode Interferometry in Gravitational-Wave Detectors through Modal Degeneracy Breaking

Liu Tao, Eleonora Capocasa, Matteo Barsuglia

Higher-order Laguerre-Gaussian modes can reduce test-mass thermal noise in gravitational-wave interferometers, but their implementation is limited by degeneracy-induced coupling losses in realistic high-finesse cavities. We mitigate these losses by optimizing the mirror curvature to break modal degeneracy. We develop a general framework for designing an axisymmetric corrective test-mass surface profile that lifts the degeneracy of the sixth-order Laguerre-Gaussian subspace while preserving an in…

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astro-ph.GAastro-ph.CO2026年10月6日

Chaotic accretion can (still) explain early supermassive black hole growth

Kastytis Zubovas, Matas Tartėnas

The origin of supermassive black holes (SMBHs) is still debated, with hypotheses ranging from massive seeds to super-Eddington growth to chaotic accretion. Recent discoveries of very high redshift SMBHs constrain their possible origin and growth scenarios. We investigate whether the chaotic accretion scenario can explain the most extreme high-redshift SMBH masses. We predicted the exponential growth timescale of black holes accreting chaotically in a slowly-spinning dark matter halo, in which un…

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gr-qcphysics.space-phquant-ph2026年10月6日

Horizon-Scale Corrections to Black Hole Geometry from a Conserved Quantum Atmosphere

Kashif Ammar Yasir

Black holes are usually described either as classical geometries on which quantum fields propagate or as objects whose complete quantum description lies beyond semiclassical gravity. Hawking radiation already shows, however, that a black hole is not an exactly isolated system: the horizon carries a thermal scale and, after coarse graining, may be associated with fluctuations, dissipation and environmental correlations. Whether this horizon-scale openness can be encoded directly in the gravitatio…

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astro-ph.GA2026年10月6日

Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS): I. Overview of the ALMA Large Program

J. K. Jørgensen, A. Coutens, M. N. Drozdovskaya, J. -E. Lee, A. L. Plunkett, S. Maret, A. Belloche, D. Harsono et al.

It remains a fundamental research question in astrochemistry to characterize the inventory of complex organic molecules formed during the early stages of star formation, which may affect the eventual chemical composition of protoplanetary disks and potentially planets. The Atacama Large Millimeter/submillimeter Array (ALMA) provides the angular resolution and sensitivity to zoom in on the hot (T > 100 K) gas surrounding embedded solar-type protostars and chart their molecular inventories with hi…

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astro-ph.GAastro-ph.EPastro-ph.SR2026年10月6日

COSMOS-3D: Spectro-photometric Confirmation of Shabgard, a Cool, Metal-poor Brown Dwarf in the COSMOS Field

Bahareh S. Salmasi, Priyanka Jalan, Tomotsugu Goto, Tetsuya Hashimoto, Feige Wang, Tayyaba Zafar, Koki Kakiichi, Ece Kilerci et al.

Brown dwarfs are unique laboratories for studying cool atmospheres, the low-mass end of star formation, and the transition between stars and giant planets. Identifying and characterizing the coldest brown dwarfs remains challenging, particularly at faint magnitudes in deep extragalactic surveys. We investigate COSMOS2025 ID639188, hereafter Shabgard, a compact source previously selected as a brown-dwarf candidate from COSMOS-Web photometry. We use serendipitous JWST/NIRCam F444W wide-field slitl…

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