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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.SR

Searching for Stellar Activity Cycles using Flares II: The TESS CVZ

Tobin M. Wainer, Holland M. Stuart, Guadalupe Tovar Mendoza, Andrew R. Casey, Tom Wagg, James R. A. Davenport

Magnetic activity cycles provide a fundamental constraint on stellar dynamos, but remain difficult to identify beyond the Sun. However, recent studies have shown that flares offer a unique tracer of activity cycle behavior. In this study, we use seven years of short-cadence observations from the Transiting Exoplanet Survey Satellite (TESS) for over 14,000 stars in the Continuous Viewing Zone to search for long-term changes in flare activity. For each star, we perform injection and recovery tests…

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astro-ph.IM

The MICADO first light imager for the ELT: the SCAO module AIT in France, from the beta flat configuration towards the flat and final configurations

Yann Clénet, Vincent Lapeyrère, Eric Gendron, Fabrice Vidal, Frédéric Chapron, Mathieu Cohen, Sylvain Guieu, Roderick Dembet et al.

MICADO is the designated ELT first light instrument, a near-infrared imager working at the diffraction limit of the telescope thanks to a SCAO and an MCAO mode. Since summer 2024, MICADO is in its AIT phase and all MICADO partners are currently integrating their subsystems. The MICADO SCAO module will follow three successive AIT phases in France: the beta flat configuration, the flat configuration and the final configuration. In this contribution I will first present the progress made in the AIT…

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astro-ph.SR

K 1-6 is a photoionised ISM nebula shaped by a fast-moving hot white dwarf in a triple system

Jaroslav Merc, David Jones, Ana Escorza, Henri M. J. Boffin, Nicole Reindl, Michael Abdul-Masih, Thomas Masseron, Paulina Sowicka et al.

K 1-6 has long been classified as a planetary nebula (PN) hosting a binary central star, yet it has remained poorly studied due to its faintness. The central star exhibits pronounced photometric variability whose origin has so far been unclear. We aim to present a comprehensive characterisation of the K 1-6 system, including the physical properties of its stellar components and the nature of the surrounding nebulosity. We conducted a multi-wavelength analysis combining optical and UV spectroscop…

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astro-ph.SR

Inferring 3D Coronal Magnetic Fields Through Seismology Assisted Inversions of $IQU$-only Spectropolarimetric Observations

Alin Răzvan Paraschiv

The routine measurements of the Stokes $IQUV$ signals of emission lines in the solar corona is still a challenging endeavor, particularly for observations using small-aperture instruments. Therefore, recent studies have explored the use of coronal seismology and propagating Alfvénic waves as alternative diagnostics of the coronal magnetic field. In particular, Yang et al. (2024) showed that plane-of-sky (POS) phase-speed measurements provide a direct and consistent diagnostic of the POS magnetic…

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astro-ph.SR

Southern massive stars at high angular resolution: WR 25 is a massive hierarchical triple system

K. Deshmukh, L. Mahy, H. Sana, A. J. Frost, E. Gosset, C. Lanthermann, J. -B. LeBouquin, D. Pauli et al.

WR 25 is a massive colliding-wind binary in the Carina nebula comprising a WN6ha primary with an O5 companion in an eccentric 208-d orbit. Recent spectroscopic analysis estimates the total binary mass to approach $100\,M_\odot$, and a primary-to-secondary mass ratio of $q= M_1/M_2\approx2$. The presence of additional spectroscopic signatures from a third, intruder star was also noted, making it a candidate hierarchical triple system. In this study, we present a VLTI/PIONIER interferometric obser…

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astro-ph.IM

The MICADO first light imager for the ELT: an overview of the RAM analysis and consequent design and maintenance strategy

Federico Biondi, Yann Clénet, Patrick Caillier, Veronika Wimmer, Tristan Buey, Luis Neumeier, Florian Lang, Sebastian Rabien et al.

MICADO is a cryogenic near infrared Multi-AO Imaging Camera and Spectrometer developed for the first light operations at the ELT. It will operate in a "Standalone" configuration with a Single Conjugate Adaptive Optics module for a nominal period of two years. After this time, the system will be re-arranged in the "MICADO-MORFEO" configuration, being able to switch between the SCAO and a Multi Conjugate Adaptive Optics module in the later phase of the project. The lifetime requirement of minimum…

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astro-ph.HEastro-ph.GA

EP-FXT Observations of Abell 1795: X-ray Properties and Structure out to $R_{200}$

Y. Tang, S. M. Jia, H. H. Zhao, C. K. Li, H. Yu, Y. Chen, S. S. Weng, X. Y. Zheng et al.

We present deep X-ray observations of the nearby, X-ray luminous galaxy cluster Abell 1795 obtained with the Einstein Probe Follow-up X-ray Telescope (EP-FXT), with a total exposure time of 480 ks. Exploiting the large field of view and low particle background of EP-FXT, we directly measure the radial temperature profile of A1795 out to $R_{200}$ with full azimuthal coverage, which increases with radius within 6 arcmin and then gradually declines toward larger radii. The surface-brightness resid…

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astro-ph.IM

The MICADO first-light imager for the ELT: first steps of the SCAO system MAIT

Yann Clénet, Eric Gendron, Fabrice Vidal, Mathieu Cohen, Frédéric Chapron, Arnaud Sevin, Tristan Buey, Sylvain Guieu et al.

MICADO is the ELT first light instrument, an imager working at the diffraction limit of the telescope thanks to two adaptive optics (AO) modes: a single conjugate one (SCAO), available at the instrument first light and developed by the MICADO consortium, and a multi conjugate one (MCAO), developed by the MORFEO consortium. Although the project final design review process is about to be completed, the review board and ESO acknowledged that "the review of the final design can be considered complet…

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astro-ph.HEcond-mat.stat-mechhep-phphysics.bio-ph

Supernova Neutrinos and the Origin of Biomolecular Homochirality

Amirmasoud Jannat, Soroush Shakeri, Farhad Shahbazi

We investigate the role of parity-violating interactions between supernova neutrinos and chiral molecules in nearby interstellar molecular clouds as a potential source of biomolecular homochirality. We introduce neutrino interactions into the autocatalytic chemical reactions in a far-from-equilibrium noise-induced system. These interactions create a directional bias between L and D enantiomers in the racemization reactions, which is amplified by autocatalysis and stochastic fluctuations. We solv…

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astro-ph.IM

Enhanced wavefront sensing for the Roman Coronagraph Instrument: Gaussian probes and compact model validation

Lukas Delaye, Iva Laginja, Pierre Baudoz, Axel Potier, Johan Mazoyer, Raphaël Galicher, Susan F. Redmond, Alexis Lau et al.

The Coronagraph Instrument on the Roman Space Telescope will be the first space-based system to demonstrate closed-loop focal-plane wavefront sensing and control, a key step towards the Habitable Worlds Observatory. Beyond the baseline Hybrid Lyot Coronagraph, "enhanced modes" are being developed to improve efficiency and science yield. One such mode uses Gaussian probes for electric field estimation, extending the linear regime and allowing higher probe amplitudes. This may increase signal-to-n…

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astro-ph.EPastro-ph.SR

Plasma chemistry and electron-moderated pathways in substellar atmospheres: a new perspective on the L/T transition

Matthew I. Swayne, Declan A. Diver, Craig R. Stark

The long-standing puzzle of the CO/CH$_{4}$ transition in brown dwarfs endures. Although the bulk spectral evolution across an atmosphere can be accounted for through thermal equilibrium cloud models, the behaviour in the NIR remains unaccounted for, indicating that additional, non-thermal processes may influence atmospheric chemistry alongside conventional pathways. We explore cloud-driven electrical activation, where low-energy sparks to full lightning discharges, unlocks non-equilibrium react…

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astro-ph.HE

Identifying potentially missed extended sources in the Fermi-LAT 4FGL Catalog using clustering analysis

Giovanni Cozzolongo, Alison M. W. Mitchell, Samuel T. Spencer, Dmitry V. Malyshev, Tim Unbehaun

Context. Since its launch in 2008, the Fermi Large Area Telescope (LAT) has detected thousands of sources, many of which remain unassociated. Some may be extended sources represented in the catalog by multiple point-like entries. The reinterpretation of HESS J1813-178 as a single extended source motivates a systematic search for further missed extended sources. Aims. We search for clusters of unassociated Fermi-LAT sources and test whether single extended-source models describe them better than…

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gr-qcastro-ph.HEastro-ph.IMphysics.ins-det

Evaluating KAGRA upgrade scenarios for multimessenger observations of binary neutron stars

Yuta Michimura, Soichiro Morisaki, Kenta Hotokezaka, Masaomi Tanaka

Binary neutron star mergers are key targets for multimessenger astronomy, motivating future upgrades of gravitational-wave detectors. For KAGRA, both broadband sensitivity improvements that increase the binary neutron star detection range, and high-frequency optimizations targeting neutron-star physics are under consideration. We present a computationally efficient framework to evaluate the multimessenger performance of detector upgrades by combining Fisher-matrix estimates of localization area…

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astro-ph.IMphysics.hist-ph

A genetic algorithm for peer-review panel composition

Ferdinando Patat

The composition of scientific review panels is a constrained optimization problem in which a finite pool of experts must be distributed among multiple panels while balancing scientific expertise and demographic diversity. As the number of possible panel configurations grows very rapidly with the number of reviewers, exhaustive searches rapidly become computationally impractical. In this paper I present a genetic algorithm designed to optimize panel composition for the European Southern Observato…

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astro-ph.HE

An internal shock model calibrated with real gamma-ray burst light curves using a genetic algorithm

Manuele Maistrello, Cristiano Guidorzi, Shiho Kobayashi, Romain Maccary

The origin of gamma-ray burst (GRB) prompt emission remains an open question. The internal shock (IS) model is a leading scenario for converting relativistic ejecta kinetic energy into gamma rays, but its parameters have not yet been fully calibrated against observed GRB light curves (LCs) to reproduce their diversity. We adopt a machine-learning framework to optimise the IS model by comparing simulated and observed LC properties from three GRB catalogues (Swift/BAT, Fermi/GBM, CGRO/BATSE). Assu…

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astro-ph.HE

Constraining the High-Density Equation of State with Present and Future NICER Observations Using Physics-Informed Regularized Machine Learning

Utkarsh Atul Deshmukh, Asim Kumar Saha, Ritam Mallick

The precise mass and radius measurements of neutron stars by NICER have significantly advanced our ability to constrain the properties of matter at supranuclear densities. In this work, we develop a physics-informed regularized conditional Invertible Neural Network (cINN) that bijectively maps mass--radius posterior distributions directly onto the corresponding central energy density and pressure, eliminating the need for explicit high-dimensional parameter sampling. The physics-informed regular…

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astro-ph.GAastro-ph.HE

Perturber-Driven Dynamics of Supermassive Black Hole Binaries in Galaxy Merger

Julian Chan, Alessia Gualandris, Walter Dehnen, Justin I. Read

The orbital eccentricity of massive black hole binaries (MBHBs) at binary formation shapes the stochastic gravitational-wave background (GWB) detectable by pulsar timing arrays (PTAs). Previous $N$-body simulations show large run-to-run scatter in this quantity, dominated by Poisson noise, raising the question of whether physical substructure adds genuine astrophysical stochasticity. We test this with high-resolution re-simulations of a major merger from IllustrisTNG100-1, evolved with the Griff…

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astro-ph.GAastro-ph.CO

Radar-Chart Analysis of Star-Formation Quenching Stages Across Circular Velocity Curve Classes in Nearby CALIFA Galaxies

Veselina Kalinova, Dario Colombo

We analyze the circular velocity curves of 215 non-active galaxies from the Calar Alto Legacy Integral Field spectroscopy Area survey. Using radar-chart analysis, we compare two classification schemes: the circular velocity curve classification and the quenching classification. We find a systematic progression from slow-rising to flat, round-peaked, and sharp-peaked curves that mirrors the transition from star-forming to fully retired systems. Star-forming galaxies are mainly slow-rising and fla…

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astro-ph.HE

Coupled Shock Cooling and Radioactive Heating in the Type IIb Supernova SN 2024aecx: An Extended Envelope and Rapid Optical Decline

Na Wei, Yu-Hao Zhang, Liang-Duan Liu, Guang-Lei Wu, Jing-Yao Li, Yun-Wei Yu, Ning-Chen Sun

SN~2024aecx is a nearby, rapidly evolving stripped-envelope supernova with a prominent double-peaked ultraviolet--optical light curve. We model its multiband evolution with an extended version of \texttt{TransFit}, in which the early shock-cooling emission and the subsequent radioactive heating are treated within a single time-dependent radiative diffusion calculation. To describe the stratified ejecta expected for a Type~IIb progenitor, we adopt a compact inner ejecta connected to a dilute exte…

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astro-ph.SRastro-ph.GA

Symbiotic binaries in the Gaia data. II. Symbiotic candidates from general variability classification in DR3

Jaroslav Merc, Lionel Mulato, Joanna Mikołajewska, Paul G. Beck, Ana Escorza, Michael Abdul-Masih, Stéphane Charbonnel, Olivier Garde et al.

We investigate the reliability of the symbiotic star class in the general variability classification of Gaia DR3 and search for new genuine symbiotic systems among the objects assigned to this category. The sample contains 649 sources, including 246 previously known symbiotic stars, 61 literature candidates, and 339 new candidates proposed by the Gaia variability pipeline. Diagnostics based on the Gaia colour-magnitude diagram, near-infrared photometry, and the pseudo-equivalent width of H$α$ in…

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astro-ph.IMastro-ph.CO

Status and future development of the COSMOCal Project for absolute CMB polarization calibration

Silvia Micheli, Alessia Ritacco, Alessandro Carones, Jonathan Aumont, Stefano Berta, Ludovico Bizzarri, François Boulanger, Andrea Catalano et al.

Cosmic Microwave Background (CMB) polarization measurements are pushing instrumental sensitivities to levels where calibration systematics become a dominant limitation. The large dynamic range between cosmological and Galactic emission prevents future experiments from relying only on diffuse sky measurements or standard celestial calibrators. To address this challenge, the COSmological Microwave Observations Calibrator (COSMOCal) project proposes an artificial calibration source deployed as a gu…

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astro-ph.GA

Tidal Grinding of Dwarf Galaxies in Cluster Environments

Sanjaya Paudel, Suk-Jin Yoon, Tek Prasad Adhikari, Eun-Taek Gim, Myung-Hun Kim, Inhyuk Park, Nau Raj Pokhrel

Dwarf elliptical galaxies (dEs) dominate galaxy clusters and provide key constraints on environmentally driven galaxy evolution. Here we examine whether the projected shapes of dEs retain information about their accretion and transformation histories using a homogeneous sample of 1,108 bright (m_g 0.74) subsamples and compare their spatial and kinematic properties. We find that flat dEs are distributed more uniformly across the cluster, whereas round dEs preferentially occupy regions of stronger…

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astro-ph.IM

ngVLTI: Cost and Feasibility of a Four-Telescope VLTI Expansion for Milliarcsecond-Scale Imaging

Sylvestre Lacour, Johan Kosmalski, Michael Mueller, Célia Desgrange, Oscar Carrión-González, Mathias Nowak, Elsa Huby, Julien Woillez et al.

We assess the cost and technical feasibility of extending the Very Large Telescope Interferometer (VLTI) through the addition of four 8 m-class Unit Telescopes (UTs), an upgrade we refer to as the new generation VLTI (ngVLTI). Such an upgrade would provide a dense and homogeneous uv coverage with baselines up to 220 m, enabling true imaging at milliarcsecond angular resolution across science cases ranging from Solar System bodies to distant active galactic nuclei. Because each image is reconstru…

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astro-ph.SRastro-ph.GA

Symbiotic binaries in the Gaia data. I. Known symbiotics in DR3 and FPR

Jaroslav Merc

Symbiotic stars are long-period interacting binaries composed of an evolved giant and a hot compact companion. Their complex spectra and variability make them both astrophysically valuable and observationally challenging. We investigate how known symbiotic stars are represented in Gaia DR3 and the Focused Product Release (FPR), assess the reliability of these data, and evaluate their usefulness for candidate analysis and searches for new systems. We crossmatched Gaia DR3 and the FPR with confirm…

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nucl-thastro-ph.HEhep-ph

Thermal conductivity of dense $npΛ$ matter in neutron star cores

Tanay Choudhary, Athira S., Monika Sinha

The possible presence of hyperons in the cores of massive neutron stars has important implications for their microscopic transport properties and thermal evolution. Despite recent progress in modelling core transport, a dedicated analysis regarding the thermal conductivity of a specific \(npΛ\) mixture remains absent from the existing literature. In this work, we investigate the thermal conductivity of dense, \(β\)-equilibrated \(npΛ\) matter within the framework of the variational linearized Bo…

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astro-ph.GAgr-qc

Discovery of a star sensitive to the spin of Sgr A*

K. Abd El Dayem, R. Abuter, N. Aimar, P. Amaro-Seoane, A. Berdeu, J. -P. Berger, G. Bourdarot, W. Brandner et al.

Residing in the center of the Milky Way, Sgr A* is the closest massive black hole (MBH). Its vicinity has allowed measuring individual stellar orbits around it. The stars act as test particles and probe the gravitational potential around the $4.3 \times 10^6 M_\odot$ MBH. These observations have determined the central mass to sub-percent precision, and the mildly relativistic motions of stars have given access to the dominant relativistic corrections, the gravitational redshift, the transverse D…

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astro-ph.EPastro-ph.IM

Direct Retrieval of Protoplanetary Disk Dust Properties using Auto-differentiable Gaussian Processes and Its Application to the HD 169142 Disk

Tomohiro C. Yoshida, Enrique Macías, Giovanni Rosotti, Stefano Facchini, Elena Viscardi, Kiyoaki Doi

Retrieving dust properties in protoplanetary disks, including the surface density distribution, temperature, and grain size distribution, is a fundamental task in observational studies of planet formation. While multi-wavelength analysis of the spectral energy distribution (SED) using interferometers such as the Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful diagnostic tool, traditional methods are often hindered by strong biases arising from a limited imaging beamsize. In thi…

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astro-ph.IMastro-ph.HE

PSRDISP: A novel approach to modeling dispersive processes in single-pulsar noise analysis using epoch-wise dispersion measures

Churchil Dwivedi, Abhimanyu Susobhanan

We present PSRDISP, a novel approach to modeling deterministic and stochastic dispersive processes in pulsar timing datasets using high-precision epoch-wise dispersion measure (DM) estimates, with a Gaussian Process based approach. Unlike the conventional single-pulsar noise analysis methodology, which is applied to frequency-resolved times of arrival (ToAs) of pulses, this technique is applied to epoch-wise DMs which are derived from these ToAs. It can also be applied to wideband DMs measured s…

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astro-ph.SR

Mean-field interpretation of star-in-a-box simulations of red giants

Carolina A. Ortiz-Rodríguez, Axel Brandenburg, Petri J. Käpylä

Context: The origin of magnetic fields and the dynamo mechanism in red giants are still not fully understood. Aims: We aim to interpret the dynamo behaviour of global 3D simulations of red giants using mean-field dynamo models. Methods: We use mean-field models constrained by the differential rotation profile extracted from 3D simulations. We perform $α^2$, $αΩ$, and $α^2Ω$ mean-field dynamo simulations, varying the strength of the $α$ effect and the differential rotation. Results: The mean-fiel…

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astro-ph.GAastro-ph.CO

The Three Hundred project: Low Gas Fraction Galaxy Clusters properties and their environment

Francesco Guidi, Marco De Petris, Sara Santoni, Raphael Wicker, Antonio Ferragamo, Hippolyte Froget, Stefano Andreon, Weiguang Cui et al.

Galaxy cluster samples based on X-ray and Sunyaev-Zel'dovich (SZ) observations are affected by selection biases. These catalogs preferentially include systems with high gas content and surface brightness. Excluding objects with depleted gas content, low-gas-fraction clusters (LGFCs), could lead to an incomplete sampling. We aim to investigate the abundance and the properties of the LGFCs population using The Three Hundred hydrodynamical simulations, focusing on the Gadget-X code. In particular,…

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