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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.EPastro-ph.IM

The EMA Justitia Probe: Terminator Frame-Based Deployment Orbit Selection and Surface Coverage Analysis

Shamil Biktimirov, Fatima Alnaqbi, Anton Ivanov

The Emirates Mission to the Asteroid Belt (EMA) probe is designed to perform asteroid imaging during an uncontrolled ballistic descent to (269) Justitia. The mission design is constrained by main spacecraft proximity operations, uncertain asteroid gravity, limited knowledge of the final deployment trajectory, and requirements for illumination and safe operations. These constraints necessitate a mission design that ensures suitable illumination, attitude determination and control, and payload poi…

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astro-ph.GA

Extending the M33 Extinction Map with Radio and Far-Infrared Gas Observations

Yuxi Wang

As the third-largest galaxy in the Local Group, M33 requires high-precision, wide-area extinction maps to recover the intrinsic luminosity and enable accurate studies, yet the available maps remain limited in coverage. In this work, we extend the stellar-based extinction map within the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER) footprint to the outer disk by calibrating empirical $A_V$-H\,\textsc{i} and $A_V$-total hydrogen relations in the PHATTER overlap regio…

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astro-ph.GA

Probing the Assembly of Triangulum: Precision Metallicities and $α$ Abundances of M33's Star Clusters from APOGEE Integrated-Light Spectroscopy

Benjamin J. Gibson, Borja Anguiano, Sten Hasselquist, Gail Zasowski, Anil Seth, Rachael L. Beaton, Christian R. Hayes, Geraint F. Lewis et al.

The star cluster system of M33 provides an excellent opportunity to investigate whether galaxy formation physics is dependent on a galaxy's mass. Older globular clusters (GCs) trace hierarchical assembly and chemical enrichment, while younger clusters trace the recent star formation. By studying the M33 star cluster system as a whole, we can probe the formation physics of galaxies at a lower mass than the Milky Way, and look for signals of accretion. To that end, we present analysis of 37 M33 st…

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astro-ph.GA

PRISMS/U13151. A Glimpse into the Earliest Phases of Galaxy Formation through an Ultra-Faint System $\approx$ 500 Myr after the Big Bang

Pierluigi Rinaldi, Javier Álvarez-Márquez, Alejandro Crespo Gómez, Luis Colina, Stefano Carniani, Sarah Kendrew, Edoardo Iani, Angela Adamo et al.

Detailed UV-to-optical studies of galaxies at z >= 10 have largely focused on bright systems (MUV <= -20 mag), leaving intrinsically faint galaxies virtually unexplored to date. Combining NIRCam, NIRSpec, and MIRI imaging and spectroscopy, we investigate UNCOVER-ABELL2744-13151 (U13151), an ultra-faint galaxy at z = 9.7995 (MUV = -17.44 mag), magnified by Abell 2744 ($μ$ = 12.8). U13151 is very blue ($β$ ~ -2.64), ultra-low mass (log10(M*/Msun) ~ 6.68), young (~ 5.5 Myr), metal-poor (Z ~ 3-6% Zs…

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astro-ph.HEastro-ph.GA

The accretion flow and jet of M87: broadband modelling across spatial scales

Eduardo M. Gutiérrez, Santiago del Palacio, Tomás Tobías Mazzei

The nearby radio galaxy M87 is an ideal laboratory for studying accretion flows and relativistic jet emission. The EHT collaboration conducted the most comprehensive multi-wavelength observational campaign of M87, in which radio instruments with resolutions ranging from tens of microarcseconds to about an arcsecond sampled different portions of the outflow. We model these data using a radiatively inefficient accretion flow (RIAF) with winds and a new multi-zone jet model, initially magnetically…

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astro-ph.GA

Star formation history of Draco revealed by DESI DR1: suppressed early star formation efficiency for Milky Way dwarf galaxies

Yujiao Yang, Maosheng Xiang, Yang Huang, Meng Zhang, Lanya Mou, Chao Liu, Jifeng Liu

Dwarf galaxies serve as fossils for understanding the early star formation history of the local Universe. In this work, we use stellar abundances for individual stars derived from the first data release of the Dark Energy Spectroscopic Instrument (DESI DR1) to investigate the star formation history of the dwarf spheroidal galaxy Draco. We simultaneously fit the stellar metallicity distribution function (MDF) and the [Mg/Fe]-[Fe/H] trend using the galactic chemical evolution (GCE) model flexCE. O…

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astro-ph.GAastro-ph.SR

The Milky Way's Early Disk Was Built in Bursts. I. Evidence from Low-angular-momentum, High-$α$ Stars Scattered Out of the Protodisk by Merger Events

Tiancheng Sun, Maosheng Xiang, Shaolan Bi, Jifeng Liu, Meng Zhang, Yaqian Wu

Stars born in the high-$α$ disk can later acquire low angular momentum through dynamical scattering during early merger events. Their age--metallicity distribution thus provides a fossil record of the history of both star formation and dynamical perturbations in the early Milky Way disk. Here we identify a sample of 2,078 such stars from more than two million Gaia DR3 subgiants with robust determinations of ages, kinematics, and abundances. From this sample we reconstruct their intrinsic age--me…

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physics.opticsphysics.space-ph

Self-Oscillating Photonic Frequency Comb for Sub-THz Local Oscillator Generation in Earth Observation Systems

Dimitrios Kastritsis, Ioannis Stratakis, Stavros Iezekiel

Earth observation missions rely on microwave and sub-terahertz radiometry for retrieving atmospheric parameters such as temperature, humidity, and cloud properties, with the 183- and 229-GHz spectral regions being particularly relevant. Local-oscillator (LO) generation at these frequencies requires low phase noise and high frequency stability while meeting stringent size, weight, and power (SWaP) constraints. Conventional architectures employ dielectric resonator oscillators followed by cascaded…

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astro-ph.GA

The Central Molecular Zone of our Galaxy, a chemical complexity factory: first interstellar detections of molecules towards G+0.693

Víctor M. Rivilla

The Central Molecular Zone (CMZ) of our Galaxy is a prime laboratory for interstellar chemistry because of its extreme conditions, such as shocks and high cosmic-ray ionisation rates. It is an efficient factory of molecules, with many species first discovered in CMZ sources. This document reviews key results from the study of the CMZ G+0.693-0.027 molecular cloud. Using ultra-sensitive broadband spectral surveys together with laboratory spectroscopy, more than 140 molecules have been identified,…

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astro-ph.GA

The Central Molecular Zone of our Galaxy, a chemical complexity factory: first interstellar detections of molecules towards G+0.693

Víctor M. Rivilla

The Central Molecular Zone (CMZ) of our Galaxy is a prime laboratory for interstellar chemistry because of its extreme conditions, such as shocks and high cosmic-ray ionisation rates. It is an efficient factory of molecules, with many species first discovered in CMZ sources. This document reviews key results from the study of the CMZ G+0.693-0.027 molecular cloud. Using ultra-sensitive broadband spectral surveys together with laboratory spectroscopy, more than 140 molecules have been identified,…

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astro-ph.SRastro-ph.IM

Linear Polarimetry of the Solar Corona during the Total Solar Eclipse of 8 April 2024: Multi-Band Observations and HDR Imaging

Suprit Singh, Paras Sharma, Bharti Arora, Shivam Burman, Chaitanya Gandhi

High-Dynamic-Range (HDR) multi-band linear polarimetry of the solar corona during total solar eclipses provides a vital ground-based diagnostic tool for mapping plasma morphology and magnetic topology in the inner and middle corona. Extracting reliable polarimetric signals requires rigorous observational calibration, spatial co-alignment, and noise reduction via stacking. We report optical linear polarimetric observations acquired during the 8 April 2024 total solar eclipse from Dallas, Texas, U…

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astro-ph.SR

Kinematics and Thermodynamics of Coronal Mass Ejections

Soumyaranjan Khuntia

Coronal mass ejections (CMEs) are major drivers of space weather, yet their thermodynamic evolution remains insufficiently constrained. This thesis develops a comprehensive framework linking CME kinematics, thermodynamics, internal force balance, and geoeffectiveness through analytical modelling and multi-viewpoint observations. The developed FRIS model uses observed kinematics to infer otherwise inaccessible internal plasma properties, including the polytropic index. A systematic investigation…

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physics.space-ph

Proton acceleration at interplanetary shocks: A numerical study for the HENON mission

Luisa Scarivaglione, Giuseppe Prete, Silvia Perri, Gaetano Zimbardo

The ESA-ASI HENON CubeSat mission will operate in a distant retrograde orbit about 0.08 au upstream of Earth to provide advance space-weather monitoring. Its instruments include an energetic particle detector measuring protons from 2 MeV to hundreds of MeV. Early detection of energetic particles is crucial for protecting technological infrastructure. To investigate proton acceleration at interplanetary shocks, we developed a test-particle numerical simulation in which protons move in the drift a…

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astro-ph.SRastro-ph.HE

Disc breaking and parametric instability in warped accretion discs driven by differential precession

Loren E. Held, Gordon I. Ogilvie

We present the first local simulations of accretion disc breaking (or disc tearing) with differential precession. Precession can occur due to a non-spherical potential (e.g. tilted circumbinary discs), or relativistic effects (e.g. tilted discs around spinning black holes). This tends to induce a twist in the disc, potentially causing it to break into rings. We extend earlier work on free (unforced) warps in Held+2026 [arXiv:2511.18655v1] to include differential precession in the shearing box, a…

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astro-ph.COastro-ph.HEgr-qc

Gamma-ray Bursts as Cosmological Probes Calibrated with Strongly Lensed Quasars and Neural Networks

Wei Hong, Luca Izzo, Massimo Della Valle, Orlando Luongo, Marco Muccino, Tong-Jie Zhang

Gamma-ray bursts (GRBs) extend distance measurements to redshifts beyond those routinely probed by Type Ia supernovae, but their use in cosmology is limited by calibration circularity and possible redshift-dependent effects. We investigate strongly lensed quasars as external calibrators of the Amati and Combo GRB relations. We reconstruct the luminosity-distance relation using an artificial neural network trained on TDCOSMO strong-lensing distances, with the absolute scale inherited from the len…

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astro-ph.SRastro-ph.EPastro-ph.GA

Competitive roles of turbulence and magnetic field on the formation of unipolar outflows in isolated molecular cloud cores

Daisuke Takaishi, Yusuke Tsukamoto, Miyu Kido, Shigehisa Takakuwa, Yoshiaki Misugi, Yuki Kudoh, Yasushi Suto

We investigate the impact of turbulence and magnetic field on the formation of unipolar outflows in the gravitational collapse of isolated low-mass cloud cores using three-dimensional non-ideal magnetohydrodynamics simulations. In the models explored in this study, we find that unipolar outflows are formed in cloud cores with the super-Alfvénic turbulence of $M_{\rm{A}}>1$, where $M_{\rm{A}}$ is the Alfvén Mach number of the initial cloud core. In contrast, bipolar outflows are formed in cloud c…

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astro-ph.GA

Effect of galaxy mergers on dust masses

W. J. Pearson, M. Romano, K. Małek, D. Donevski, K. Lisiecki, A. P. Cotter, S. Dey, T. Goto et al.

Dust mass (M$_{Dust}$) is one of the key physical properties of galaxies that track the cold interstellar medium. However, the M$_{Dust}$ in merging galaxies is poorly understood. We aim to derive how the cold dust mass of galaxies is affected by major mergers at low redshifts. M$_{Dust}$ was estimated for approximately 500 major mergers in the North Ecliptic Pole extragalactic field using spectral energy distribution fitting runs with CIGALE, with different dust attenuation and emission models.…

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astro-ph.HE

Probing the Interstellar Medium towards the Double Pulsar and the Gum Nebula using Low-Frequency Pulse Broadening Measurements

C. P. Lee, N. D. R. Bhat, B. W. Meyers, W. van Straten

Long-term timing of the double pulsar system (PSR J0737-3039A/B) has enabled some of the most stringent constraints on strong-field gravity. Yet, despite the system's high profile, there have been very few observations at frequencies below 300 MHz, where pulse broadening due to interstellar scattering becomes significant. Measurements of the pulse broadening timescale and its frequency scaling, $τ_\mathrm{s}\proptoν^α$ (where $α$ is the scattering spectral index), provide valuable constraints on…

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astro-ph.HE

Pulse Morphology and Spectral Study of LPT J1634+44 Using GMRT

Ashish Kumar, Yogesh Maan, Ayushi Shrivastava, Banshi Lal

Long-period radio transients (LPTs) are a recently discovered class of Galactic coherent radio emitters characterized by rotation periods of minutes to hours and highly polarized radio pulses. Their nature remains uncertain, with proposed scenarios invoking isolated or binary systems containing neutron stars (NSs) or white dwarfs (WDs). We investigate the nature of CHIME/ILT J1634+44 through multi-band observations with the Giant Metrewave Radio Telescope (GMRT), examining its pulse morphology,…

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astro-ph.GAastro-ph.HE

PSR~B0355+54: An Unexpected Compendium of Nearly All Scintillation Arc Morphologies

Zhen-Long Liao, Zhen Yan, Zhi-Qiang Shen, Rui Wang, Xun Shi, Ke-Jia Lee, Ju-Mei Yao, Xiao-Wei Wang et al.

Scintillation arcs are sensitive probes of multipath propagation, offering a window into the distribution of scattering material in the interstellar medium. Contrary to the common observational finding that individual pulsars exhibit only a limited range of scintillation arc morphologies, we report that PSR~B0355+54, observed simultaneously at 2.25/8.60~GHz with the Shanghai Tianma Radio Telescope, displays nearly the full range of known arc patterns, many of which evolve rapidly. Across 54 obse…

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gr-qcastro-ph.COastro-ph.GAastro-ph.IM

Searching for lensed gravitational waves with unlensed templates

Digvijay Wadekar, Barak Zackay, Mark Ho-Yeuk Cheung, Tousif Islam, Javier Roulet, Ajit Kumar Mehta, Tejaswi Venumadhav, Jonathan Mushkin et al.

Gravitational lensing can split the signal of a binary merger into two images, which either overlap and interfere or arrive as separate events. We show that the matched-filter output of every two-image template can be straightforwardly constructed from the signal-to-noise ratio (SNR) time series that searches already compute with unlensed templates. This enables a marginalized detection statistic that increases search sensitivity without additional matched filtering and is more than 150 times fa…

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astro-ph.GA

The Solar System through dust maps. Encounter statistics with interstellar gas

E. Maconi, J. Alves, S. Hutschenreuter, S. Ratzenböck, M. Pantaleoni, C. Zucker, C. Levy, G. Edenhofer et al.

During its orbit around the Milky Way, the Solar System crosses different environments, including dense ISM regions. These encounters increase dust influx, leave geological signatures, and affect the heliosphere. For the local ISM, we estimate crossing frequencies and durations, the fraction of time spent above gas density thresholds, and how Solar vertical motion and ISM stratification influence these statistics. We quantify gas influx and dust exposure. We use Gaia-based 3D dust maps of the So…

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astro-ph.EP

A 36.34-day Sub-Neptune Candidate Transiting the Nearby K Dwarf TIC 402710280

Rishit Vora

We report a transiting sub-Neptune candidate with a period of 36.34 days around TIC 402710280 (TYC 9041-03677-1), a K dwarf of TESS magnitude 9.24 at 66.8 pc that the Transiting Exoplanet Survey Satellite (TESS) has observed only in full-frame images. Four transits, recorded between 2021 and 2026 in Sectors 39, 93, 100 and 102 and reduced by three independent pipelines, share a depth of $2092 \pm 47$ ppm and a duration of $5.27 \pm 0.05$ h. Two of them fall on consecutive cycles, and every short…

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astro-ph.EP

A 36.34-day Sub-Neptune Candidate Transiting the Nearby K Dwarf TIC 402710280

Rishit Vora

Transiting sub-Neptunes on orbits longer than a month are rare around bright stars. We report a candidate with a 36.34-day period around TIC 402710280, a $V = 10.0$ K dwarf at 66.8 pc that the Transiting Exoplanet Survey Satellite (TESS) has observed only in full-frame images. Four transits from 2021 to 2026, reduced by three independent pipelines, have consistent depths (mean $2092 \pm 47$ ppm) and a duration of $5.27 \pm 0.05$ h. Two are 36.36 days apart. The light curves exclude every shorter…

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quant-phastro-ph.IM

HyQ-LC: Improving Light-Curve Classification with Hybrid Quantum--Classical Learning

Xinghang Yu, Bin Yang

Light curves reveal stellar variability and support studies of stellar evolution and cosmic distances. Reliable classification is therefore important for large time-domain surveys. We present HyQ-LC for ten-class stellar light-curve classification using 359 handcrafted features and 633,034 training objects. The main model combines a window multilayer perceptron (MLP) backbone with a nine-qubit readout using amplitude encoding and angle re-uploading. Both this hybrid and its pure-MLP control have…

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astro-ph.SRastro-ph.EPastro-ph.GA

Kinematic structure and age of a Scorpius--Centaurus subcomponent: implications for PDS 70 planetary system

Arunima Arunima, Mike Ireland, Mark Krumholz

PDS~70, the only system with two directly imaged protoplanets embedded in their natal disk, is a benchmark for giant-planet formation theory. Interpreting the planetary luminosities requires a precise age for the host star, but the widely adopted isochronal age of $5.4\pm1.0$~Myr is substantially younger than ages inferred for the Upper Centaurus--Lupus (UCL) population with which it is associated. We address this discrepancy by determining a new kinematic age for PDS~70 using radial velocities…

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astro-ph.SR

Gravity-mode main-sequence asteroseismology of 16 open clusters and associations

Gang Li, Haotian Wang, Anuj Gautam, J. S. G. Mombarg, Simon J. Murphy, Mara Bernizzoni, Mingjie Jian, Saakshi Wadhwa et al.

Coeval stellar populations offer a unique advantage for studying stellar physics because their members share a common age and broadly similar initial chemical composition, allowing the free parameters in stellar models to be constrained more efficiently. Meanwhile, asteroseismology, through the study of pulsation modes that propagate through stellar interiors, provides powerful constraints on internal structure and the physical processes operating beneath stellar atmospheres. The combination of…

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astro-ph.GA

A high-Galactic-altitude scattering screen: scintillation from Globular Cluster pulsar M53A

Qiuyi He, Xun Shi, Dejiang Yin, Di Li

While known interstellar scattering screens are largely confined to the Galactic disk, the scattering properties of the circumgalactic medium (CGM) in the deep Galactic halo have remained unexplored. Using observations from the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we report the first detection of scintillation arcs in the secondary spectra of the high-latitude pulsar J1312+1810A (M53A). Under the 1D anisotropic and 2D isotropic thin-screen models considered here, the inf…

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astro-ph.GA

The DARWIN Project: Cosmological Simulations of Galaxy Formation down to Dwarf Scales in Diverse Environments

Jaehyun Lee, Kyungwon Chun, Taysun Kimm, Yonghwi Kim, Jihye Shin, Ena Choi, Sungwook E. Hong, Myoungwon Jeon et al.

We present the DARWIN project, a suite of cosmological simulations with RAMSES to study dwarf-galaxy formation and evolution across diverse environments. DARWIN-1 is a full-box simulation in a cubic volume of $(65.5\,{\rm cMpc})^3$ with a minimum cell size of 500pc, while DARWIN-2 comprises zoom-in simulations of 24 field regions and a Milky Way analog connected to a filament, reaching 62.5pc resolution. The simulations employ baryonic physics tailored to their aims. For DARWIN-2, we include rad…

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astro-ph.GA

The DARWIN Project: Cosmological Simulations of Galaxy Formation down to Dwarf Scales in Diverse Environments

Jaehyun Lee, Kyungwon Chun, Taysun Kimm, Yonghwi Kim, Jihye Shin, Ena Choi, Sungwook E. Hong, Myoungwon Jeon et al.

We present the DARWIN project, a suite of cosmological simulations with RAMSES to study dwarf-galaxy formation and evolution across diverse environments. DARWIN-1 is a full-box simulation in a cubic volume of $(65.5\,{\rm cMpc})^3$ with a minimum cell size of 500pc, while DARWIN-2 comprises zoom-in simulations of 24 field regions and a Milky Way analog connected to a filament, reaching 62.5pc resolution. The simulations employ baryonic physics tailored to their aims. For DARWIN-2, we include rad…

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