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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.EPastro-ph.SR

How eccentric is the debris disk of epsilon Eridani? ALMA reveals a near-circular belt

Oto Ulrich, Joshua B. Lovell, David J. Wilner, Antranik A. Sefilian, Mark Booth

The nearby (3.2 pc) K2V star $ε$ Eridani hosts the closest detected debris disk and an exo-Jupiter analog ($ε$ Eridani b). In this work, we reanalyse ALMA Band 6 (1.29 mm) observations of $ε$ Eridani to assess whether its outer debris belt exhibits a non-zero eccentricity, potentially induced by planet-disk interactions. Considering two models, one that accounts for the disk's forced eccentricity ($e_\mathrm{f}$) and another that accounts for a proper eccentricity ($e_\mathrm{p}$), we place stri…

astro-ph.HEastro-ph.GAastro-ph.IM

XClass: An Automated Multiwavelength Machine-Learning Pipeline for Classification of Extragalactic X-ray Sources. I. Pipeline Description

Blagoy Rangelov, Nicholas Moore, Haley Dutton, Erika Marentes

Most X-ray sources detected in nearby galaxies by the Chandra X-ray Observatory lack astrophysical classifications. We present XClass (X-ray Classifier for extragalactic sources), an end-to-end machine-learning pipeline that classifies extragalactic X-ray point sources into seven classes: AGN, LMXBs, HMXBs, CVs, low-mass and high-mass foreground stars, and supernova remnants. The key challenge is photometric heterogeneity: training sources are predominantly Galactic with photometry from wide-fie…

astro-ph.GA

Which Milky Way Streams Make the Best Dark Matter Detectors?

Vedant Chandra, Charlie Conroy, Risa Wechsler, Ana Bonaca, Andrew Benson, Jacob Nibauer, Tara Dacunha, Philip Mansfield et al.

The abundance and properties of low-mass dark matter subhalos can be inferred by measuring the density and velocity structure of stellar streams, testing physical models of dark matter. Which streams make the most promising dark matter detectors, and which subhalos would they encounter? We use the semi-analytic model galacticus to simulate the Milky Way's dark subhalos, including tidal stripping under the influence of the galactic disk. Deriving stream initial conditions that best match present-…

astro-ph.HE

Three New Likely Spider Millisecond Pulsar Binaries and Optical Kinematic Tracers of Intrabinary Shocks

Jay Strader, Rebecca Kyer, Laura Chomiuk, Elias Aydi, Peter Craig, Thomas M. Do, Isabella Molina, Teresa Panurach et al.

We report the discovery of three candidate spider millisecond pulsars via multi-wavelength follow-up of unassociated Fermi Large Area Telescope gamma-ray sources. All have optical spectroscopy from the SOAR 4.1-m telescope and X-ray data from Swift. Two optical/X-ray sources are exceptionally strong redback candidates, sitting close to the centres of the localization ellipses of the gamma-ray sources 4FGL J1020.4-5314 and 4FGL J1408.7-3747. We show that both optical sources are spectroscopic bin…

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

Gaia neutron stars: demographics, birth rates, and connections to other neutron star populations

Cheyanne Shariat, Natsuko Yamaguchi, Kareem El-Badry, Thomas J. Maccarone

Gaia DR3 revealed a new class of neutron stars (NSs) in au-scale orbits with solar-type companions. How these 'Gaia NSs' form remains unclear, and constraining their intrinsic population properties is a necessary step toward understanding their origin. However, the current sample of 27 Gaia NS candidates is strongly biased by Gaia's astrometric sensitivity. In this work, we carefully model the Gaia selection function and incorporate it into a hierarchical Bayesian framework to infer the \textit{…

astro-ph.GAastro-ph.CO

Probing the Reionization History and Bubble Sizes with JWST Lyman-$α$ Fraction Measurements

Aritra Kundu, Adam Lidz, Guochao Sun

Recent James Webb Space Telescope (JWST) measurements quantify the fraction of ultraviolet-selected galaxies showing detectable Lyman-alpha (Ly-$α$) lines at $z \sim 6-14$. These Ly-$α$ fractions are partly shaped by Ly-$α$ scattering from neutral hydrogen in the surrounding intergalactic medium (IGM), and so the observed Ly-$α$ fraction evolution can inform our understanding of the reionization history and the size distribution of ionized bubbles during reionization. We compare the JWST measure…

astro-ph.GAastro-ph.EPastro-ph.IM

Water enhances the formation of refractory sulfur in interstellar ices

Carlos del Burgo Olivares, Hector Carrascosa, Guillermo M. Muñoz Caro, Rafael Lebron-Aguilar, Jose E. Quintanilla-Lopez, Yao-Jen Chen

Sulfur is the tenth most abundant element in space, yet it is strongly depleted in the gas phase of dense interstellar regions, suggesting sequestration in dust grain components that are difficult to detect. We study whether UV irradiation and thermal processing of H2S-containing interstellar-ice analogues can produce refractory sulfur species, and whether water-dominated ice enhances their formation. We performed UV irradiation and warm-up experiments on H2S-containing ice analogues with and wi…

astro-ph.IM

Two bits about lossy compression: On the limits of compression in cosmology

Hurum Maksora Tohfa, Matthew McQuinn

Astronomy is in an era of enormous sky surveys and of the large simulation suites needed to interpret them, both costly to store and slow to share. Simulation outputs are stored as 32-bit floats, yet numerical noise and astrophysical uncertainties make better than percent-level pixel accuracy unnecessary. Because cosmological fields are statistically homogeneous with nearly Gaussian mode amplitudes, classic rate-distortion results apply directly, and non-Gaussian structure permits further compre…

astro-ph.GA

Sub-kiloparsec Test of the Kennicutt-Schmidt Relation in a Strongly Lensed Dusty Star-Forming Galaxy at z~2.78

C. Cornil-Baïotto, J. Molina, G. Mahler, G. Rihtaršič, M. Boquien, M. Bradač, E. Ibar, A. H. Gonzalez et al.

[abridged] Star formation is a key process driving galaxy evolution, but understanding how it proceeds within the interstellar medium (ISM) requires resolving cold molecular gas and dust on sub-kpc scales. At z~2-3, near the peak of cosmic star formation, such resolution can generally only be achieved through strong gravitational lensing. We present an ALMA study of SMMJ0658, a 20x-magnified main-sequence star-forming galaxy at z=2.7768 +/- 0.0002, lensed by the Bullet Cluster (z=0.296) into thr…

astro-ph.HE

A new method for inspiral-to-ringdown waveforms of compact binaries: Helmholtz orbits and spherical-Bessel flux

Hong-Bo Jin

The waveform is obtained from one balance of energy and radiation on Helmholtz orbits of the retarded mass kernel, with a spherical-Bessel flux. That balance follows from the Dirac--Maxwell equation with a modified vertex, the single $U(1)$ coupling being replaced by the eight operators of the source interaction. After contact that balance is the energy loss of one packet: a bounded well for a black-hole remnant and the Coulomb ladder of one star for a neutron-star remnant. Ringdown starts from…

astro-ph.GA

The assembly history of NGC 1365 through chemical archaeology

Lisa J. Kewley, Kathryn Grasha, Alex Garcia, Paul Torrey, Jeff Rich, Z. S. Hemler, Qian-hui Chen, Peixin Zhu et al.

Galaxies build through infalling gas and galaxy mergers. Tracking the dynamical history of a galaxy from a single snapshot in time is notoriously difficult. We show that the dynamical history of a galaxy can be tracked using oxygen abundances as archeological tracers. We derive the gas-phase oxygen abundances for 4546 spaxels across the face-on spiral galaxy NGC~1365 at a spatial resolution of 175 pc, providing one of the most detailed chemical fossil records of a spiral galaxy outside our Milky…

astro-ph.EPphysics.flu-dyn

Flow dynamics of cryolava or impact melt on Titan's surface

Daniel Cordier, Bastien Bodin, Stephane Le Mouelic, Ashley G. Davies

Titan, a unique body in the solar system, resembles a life-size Miller-Urey experiment where pockets of liquid water might interact with abundant organic matter. Its young surface (less than a billion years) shows signs of material exchange with the interior, and an isotopic signature is detected in the atmosphere. Cryovolcanism and meteor impacts represent potential high energy mechanism for these exchanges. Although cryolava or impact melt properties are largely unknown, Titan's internal struc…

astro-ph.GAastro-ph.CO

When Streams Curve Away: a Test of Dark Matter from Extragalactic Stellar Stream Populations

Nathaniel Starkman, Jacob Nibauer, Sarah Pearson, Sirui Wu, Lina Necib

The nature of dark matter sets the shape of galactic halos: collisionless cold dark matter (CDM) predicts triaxial halos, while scattering in self-interacting dark matter (SIDM) rounds them toward sphericity. We show that a large catalog of projected stellar stream tracks can statistically constrain halo shapes, and therefore the particle nature of dark matter, without detailed modeling of any individual stream or gravitational potential. We develop a new geometric diagnostic for stellar streams…

astro-ph.SRastro-ph.IMcs.CV

MAGiDiff: Sampling the Photospheric Vector Field from UV/EUV Filtergrams

Ruoyu Wang, David Fouhey

Photospheric vector magnetic fields are foundational to modeling, understanding, and forecasting solar activity. These data are usually produced by inverting and disambiguating the full Stokes vector at multiple passbands, which is demanding. Here, we investigate how well we can estimate photospheric vector magnetograms from UV/EUV filtergrams. This problem is challenging and intrinsically ambiguous without polarization information, as the mapping from UV/EUV intensity to the magnetic field is i…

astro-ph.SRastro-ph.GA

Tracing star formation across the Rosette nebula using deep Spitzer imaging

Daniel Capela, Aleks Scholz, Koraljka Muzic, Herve Bouy, Belinda Damian, Victor Almendros-Abad, Amelia Bayo

We present a deep large-scale infrared survey of young stellar objects in the Rosette Nebula. Our analysis is based on stacked archival Spitzer/IRAC images. The images have been treated with the software DeNeb to remove nebulous emission. Our catalogue contains ~20000 sources with photometry in all 4 IRAC bands from 3.6 to 8.0 microns, complemented with near-infrared and optical data. From this database, we identify YSOs using multi-filter colour-colour criteria. We select 1528 YSOs, from which…

astro-ph.EPastro-ph.IM

Project CERES: Nuclear Thermal Transportation and In-Situ Propellant Production A Foundational Architecture for Solar System Logistics

S. P. Worden, F. G. Kennedy

Project CERES proposes a reusable deep-space transportation architecture centered on the dwarf planet Ceres, combining nuclear thermal propulsion (NTP) with in-situ production of water, hydrogen, oxygen and ammonia. Its first flight, a Pathfinder that surveys Ceres and returns samples, also bears on the question of life: Dawn found the ingredients of prebiotic chemistry there, and returned material would show just how far that chemistry went. We survey every direct Earth-Ceres opportunity from 2…

astro-ph.IM

Toward the Italian Astronomical Community's Contribution to HWO: Science, Technology, and Instrument Concepts

A. Fontana, F. Annibali, N. Antonietti, S. Bianchi, L. Biasiotti, K. Biazzo, E. Bisesi, A. S. Bonomo et al.

This paper summarizes the interest of the Italian astronomical community in the possible participation in the development of the Habitable Worlds Observatory (HWO). It is largely based on the outcome of a dedicated meeting held in Rome in July 2025, and it includes further revisions and new suggestions that have arisen in the following months. It includes a succinct description of the main scientific interests and of the key technologies that the Italian community can contribute to the developme…

astro-ph.GA

A New Sample of Closely Separated Dual and Binary AGN Candidates Revealed with the Radio Fundamental Catalog

Emma Schwartzman, Ryan Pfeifle, Tracy Clarke, Nathan Secrest, Henrique Schmitt, Barry Rothberg

The Big Multi-AGN Catalog (BigMAC) provides the first literature-complete compilation of confirmed and candidate dual, binary, and recoiling active galactic nuclei (AGN). The BigMAC provides a basis for the first population-wide radio study of multiple AGN (multi-AGN). The Radio Fundamental Catalog (RFC) is composed of four decades of Very Long Baseline Interferometry (VLBI) observations capable of resolving parsec-scale structure. All BigMAC candidate and confirmed multi-AGN were cross-matched…

astro-ph.GA

The role of velocity dispersion in the Kennicutt-Schmidt relation

Chryssi Koukouraki, Konstantinos Tassis

The resolved Kennicutt-Schmidt (KS) relation is a power-law relation between the surface densities of the star formation rate ($Σ_\mathrm{SFR}$) and molecular gas ($Σ_\mathrm{mol}$) in star-forming galaxies on kiloparsec scales. Despite its apparent simplicity, it exhibits substantial scatter, suggesting the influence of additional physical parameters beyond gas surface density. We investigate whether molecular gas velocity dispersion ($Δv$) acts as a hidden parameter in the resolved KS relation…

astro-ph.GA

High-Priority Compact-Object Candidates in Young Clusters from the \textit{Gaia} DR3 Non-Single-Star Catalog

Dejian Liu, Kangteng Chang, Yao Huang, Yingjie Li, Xianjin Shen, Zehao Lin, Jingjing Li, Zhenyu Wu et al.

The search for massive compact objects such as black holes (BHs) or neutron stars (NSs) in star clusters is longstanding challenge in astrophysics, yet no definitive identification of such compact objects in young clusters has been reported. In this Letter, we construct a sample of high-priority candidates for follow-up investigation. By cross-matching the cluster catalog with the Gaia Non-Single-Star database and estimating companion masses, we identify 13 systems with companion masses exceedin…

astro-ph.SRastro-ph.GA

Towards breaking the degeneracy between stellar ages and unresolved multiplicity

Friedrich Anders, Anna B. A. Queiroz, Sagar Malhotra, Cristina Chiappini, Arman Khalatyan

Stellar age is the central desirable parameter we need to disentangle different Galactic formation scenarios. Nevertheless, no stellar age dating method is completely model-independent. Even in the best-case scenarios, present-day stellar age estimates are only precise to $\sim7\%$ and accurate to $\sim10-15\%$. A main drawback of state-of-the-art stellar parameter inference codes like {\tt StarHorse} is that they do not take into account unresolved stellar multiplicity. Especially in the case o…

astro-ph.HE

XRISM Resolve Spectroscopy of GX 5-1: Constraints on Iron Spectral Features in a Luminous Neutron-Star Binary

Tasuku Hayashi, Shinya Yamada, Shun Inoue, Teruaki Enoto, Noriko Yamasaki, Shunji Kitamoto, Shogo Kobayashi, Yusuke Sakai et al.

GX 5-1 is one of the brightest persistent neutron-star low-mass X-ray binaries in the Galaxy and one of the classical Z sources accreting at luminosities close to or above the Eddington limit. We present the first high-resolution X-ray spectroscopic study of GX 5-1 with the Resolve micro-calorimeter onboard the X-Ray Imaging and Spectroscopy Mission (XRISM), based on a 50 ks AO1 observation. With an energy resolution of approximately 5 eV at 6 keV, Resolve enables a sensitive non-dispersive sear…

astro-ph.GA

High velocity dust grains produced by a supernova explosion

Evgenii O. Vasiliev

Motivated by the discovery of a meteor with velocity more than 300~km/s (Afanasiev et al. 2007) we study how dust grains formed in the supernova (SN) ejecta at its free-expansion phase can keep their high velocity obtained from the gas, where these grains were born. Using a one-dimensional spherically symmetric Lagrangian approach we follow the dynamics of grains during the interaction of a SN ejecta with the ambient interstellar gas. We found that grains larger $\sim 0.3~μ$m can cross the SN fo…

astro-ph.GAastro-ph.HE

Deep radio characterization of the supernova remnant G343.1-00.7

S. Loru, A. Ingallinera, C. Trigilio, G. Umana, D. Urošević B. Arbutina, D. Leahy, C. Bordiu, F. Bufano et al.

Supernova remnants (SNRs) are extended radio sources whose morphology and evolution are shaped by the interaction of strong shocks with the surrounding medium. We combined the 0.944 GHz Australian Square Kilometre Array Pathfinder (ASKAP) image from the Evolutionary Map of the Universe (EMU) survey with 0.088-0.200 GHz MWA-GLEAM data to characterize the integrated radio spectrum of G343.1$-$00.7 and perform its first sensitive spatially resolved spectral analysis. We derived an integrated spectr…

astro-ph.GA

Internal Structure, Not Environment, Shapes Metallicity Gradients in Low-Mass Galaxies from MaNGA

Anuroop Dasgupta, Namrata Roy, Saumyadip Samui, Ritaban Chatterjee, Fuyan Bian

Dwarf and low-mass galaxies are highly sensitive to stellar feedback and gas flows, yet their spatially resolved gas-phase metallicity remains poorly characterised. We measure radial gas-phase metallicity gradients for 382 star-forming low-mass galaxies from MaNGA DR17, spanning $7.2 \leq \log(M_{\star}/M_{\odot}) \leq 9.1$ and $z \leq 0.05$. Spectra are stacked in elliptical radial bins and metallicity is derived from the N2 index. After removing the primary dependence on local stellar mass sur…

gr-qcastro-ph.IMcs.LG

MADGRAV: a multilevel anomaly-detection pipeline for gravitational-wave searches applied to LIGO data

Gianluca Inguglia, Huw Haigh, Ulyana Dupletsa, Alessandro Longo

We present the results of \textbf{MADGRAV}, a deep-learning-based search for high-mass compact binary coalescences, applied to the data collected by the LIGO interferometers during the third observing run and during the first and second part of the fourth observing run. The \textbf{MADGRAV} pipeline consists of a series of sequential convolutional neural networks that perform anomaly detection, glitch classification, coherence testing, and signal ranking. Data from the Hanford and Livingston LIG…

astro-ph.IMastro-ph.GA

ArxSP: A Python-Based Modular Application for the Reduction of Digitized Archival Spectra

Ildana Izmailovaa, Adel Umirbayeva, Manas Khassanova, Laura Aktay, Saule Shomshekova

We present a methodology for the reduction of archival spectral data together with the description of a newly developed Python-based software package featuring an interactive graphical interface. The work is primarily aimed at processing spectra obtained with electron-optical converters (EOCs), which are characterized by geometric distortions induced by the magnetic field of the registration system. Such data are preserved, in particular, in the archive of the Fesenkov Astrophysical Institute (F…

astro-ph.IMastro-ph.GA

ArxSP: A Python-Based Modular Application for the Reduction of Digitized Archival Spectra

Ildana Izmailova, Adel Umirbayeva, Manas Khassanov, Laura Aktay, Saule Shomshekova

We present a methodology for the reduction of archival spectral data together with the description of a newly developed Python-based software package featuring an interactive graphical interface. The work is primarily aimed at processing spectra obtained with electron-optical converters (EOCs), which are characterized by geometric distortions induced by the magnetic field of the registration system. Such data are preserved, in particular, in the archive of the Fesenkov Astrophysical Institute (F…

astro-ph.IM

FAIR-Compliant Architecture for Heterogeneous Astronomical Data: KazVO Framework

Ildana Izmailova, Denis Yurin, Yerlan Aimuratov, Maxim Makukov, Aleksander Serebryanskiy, Saule Shomshekova, Vitaliy Kim, Chingis Omarov et al.

This paper presents the architecture of the Kazakhstani National Virtual Observatory (KazVO) - an International Virtual Observatory Alliance (IVOA) compliant node that unifies the heterogeneous observational datasets of the Fesenkov Astrophysical Institute (FAI). The architectural foundation of the system is built upon a partitioned Data Lake, a German Astrophysical Virtual Observatory (GAVO) Data Center Helper Suite (DaCHS) publishing backend, and a PostgreSQL database that maps heterogeneous m…

astro-ph.EPastro-ph.SR

Early Planet Formation in Embedded Disks (eDisk). XXV. Inclination-Induced Minor-Axis Brightness Asymmetries Reveal Limited Dust Settling in Embedded Protostellar Disks

Sidhant Kumar Suar, Zhe-Yu Daniel Lin, Zhi-Yun Li, Nagayoshi Ohashi, Shigehisa Takakuwa, John Tobin, Leslie Looney, Mayank Narang et al.

How and when dust settles in young protostellar disks is a key open question for the dust concentration needed to form planetesimals and, ultimately, planets. However, directly measuring the vertical dust distribution in embedded (Class 0/I) systems remains challenging. We show that brightness asymmetry along the minor axis of highly inclined disks provides a simple, powerful geometric diagnostic of vertical dust structure. Using radiative transfer modeling with RADMC-3D, we generate synthetic c…