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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.SR

A precise TESS ephemeris for the short-period binary TIC-259864042

Rana Khan

This paper presents a precise eclipse-timing analysis of TIC 259864042 (= EC 02406--6408, Gaia DR3 4647004122914240640) using eleven sectors of TESS photometry spanning 2018--2025 (7.1 yr). The system exhibits a single deep eclipse with a V-shaped profile at phase 0 and no detectable counterpart at phase 0.5. Four independent period-search methods converge to a common period agreeing to within 7 parts per million. An independent reduction with the SHERLOCK pipeline, using its own 120-second TESS…

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gr-qcastro-ph.HE

Parameter Constraints on $f(R^{1+ε},T_{μν}T^{μν})$ Gravity from Exotic Compact Objects

S. Wilhelmina, B. N. Jayawiguna, A. Sulaksono

According to General Relativity (GR), gravity is described as the curvature of spacetime caused by mass and energy. Although GR has been highly successful in describing gravitational phenomena, exotic compact objects with high mass and strong gravitational fields, as well as low-mass objects, have motivated the study of modified theories of gravity. One of the modified gravity frameworks is $f(R,T^2) = R^{1 + ε} + ακ^2 T_{μν} T^{μν}$, which provides an extension of GR by introducing modification…

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astro-ph.EPastro-ph.IMastro-ph.SR

Searching for substellar companion candidates with Gaia. V. M dwarfs within 15 pc studied with absolute astrometry, radial velocities, and direct imaging

F. Destriez, A. -M. Lagrange, G. Hébrard, F. Kiefer, P. Rubini, E. Lefevre-Forjan, F. Arenou, N. T. Lam et al.

In this work, we survey M-type stars within 15 pc observed by Gaia based on their colour, magnitude, and quality of astrometric data. We aim to detect new substellar companions using primarily Gaia astrometry and, when available, proper-motion anomaly (PMa) along with radial velocity (RV) and direct imaging (DI) data. We used the GaiaPMEX tool to search for bound companions around 582 M dwarfs. We identified all previously known stellar and planetary companions that were consistent with the Gaia…

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astro-ph.HE

Weak Radio and Bright Early Optical Emission in EP260321a: A Comparative Study with XRO 080109 Reveals the Role of Circumstellar Material Mass

Cui-Yuan Dai, Xiang-Yu Wang, Jian-He Zheng

Shock breakout (SBO) occurs when a radiation-mediated shock wave, formed during a core-collapse supernova (SN) explosion, breaks out from the stellar surface of the progenitor or from the circumstellar material (CSM), if the CSM is optically thick. The X-ray outburst XRO 080109, associated with a Type Ib/c SN 2008D, has been suggested to be an SBO event from a regular supernova. The recent detection of EP260321a, associated with a broad-lined Type Ic SN 2026gzf, by the Einstein Probe adds a new…

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astro-ph.HE

Search for Ultra-Relativistic Magnetic Monopoles with LHAASO-KM2A

Zhen Cao, F. Aharonian, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, W. Bian et al.

Ultra-relativistic magnetic monopoles traversing the atmosphere are expected to initiate extensive air showers characterized by a muon deficit and a compact lateral profile. Using 1438.81 live days of data from the LHAASO-KM2A array, we present a search for these cosmic particles within the Lorentz factor range of $10^5$ to $10^7$. A machine-learning classifier utilizing lateral shower shape observables from the electromagnetic detectors is deployed to separate the signal from the hadronic backg…

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astro-ph.GAastro-ph.HE

EP J062132.0+623837: A Multi-wavelength Study of a Changing-look Active Galactic Nucleus Discovered by Einstein Probe

Lin-Na Xu, Ning Jiang, Tinggui Wang, Shifeng Huang, Yibo Wang, Zhenfeng Sheng, Mingxin Wu, Jiazheng Zhu et al.

EP J062132.0+623837 is a new X-ray source identified in 14-day binned survey data from the Wide-field X-ray Telescope aboard the Einstein Probe (EP). Subsequent X-ray observations with the Follow-up X-ray Telescope (FXT) on board EP localized the source to the central region of the galaxy 2MASX J06213207+6238390 at $z=0.084$. Here, we present a comprehensive analysis of the multi-wavelength data for this object. During the FXT and Swift/XRT follow-up, the source remained X-ray active, with obser…

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astro-ph.EPastro-ph.IM

Cross-Validation of Infrasound Detections and Fireball Observations from the Global Fireball Observatory

Iona Clemente, Eleanor K. Sansom, Hadrien A. R. Devillepoix, Elizabeth A. Silber, Svetlana B. Nikolova, Spiro Spiliopoulos, Peter Jenniskens, Jim Albers et al.

How do infrasound signals from fireballs relate to atmospheric entry conditions and the physical properties of their parents meteoroids? In this study, we investigate the detectability of infrasound generated by local-to-regional fireballs and use the associated signals to constrain meteoroid physical properties. Across Western Australia and California, the Global Fireball Observatory (GFO) recorded nearly 300 fireball events with well-constrained trajectories within 500 km of an infrasound arra…

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astro-ph.GA

Stability of rotation axis of galactic disks in HESTIA suite

Naira R. Arakelyan, Sergey V. Pilipenko, Stefan Gottlöber, Noam I. Libeskind, Gustavo Yepes, Yehuda Hoffman

We have found that in approximately 1/4 of Milky Way or M31 analogues in the HESTIA suite of simulations there is a significant, $>45^\circ$, change in the axis of rotation orientation of the gaseous disk during the last 6 Gyr. In 6 out of 7 such cases the change is likely caused by the accretion of individual satellites, while in one case such a connection is not obvious. All galaxies that underwent a significant change in rotation axis direction also had angular momentum amplitudes below the s…

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hep-exastro-ph.IM

CURTAIN: Towards a Foundation Model for Neutrino Telescopes

Severin Magel, Felix J. Yu, Carlos A. Argüelles

Neutrino telescopes record more than a trillion photon detections per year, yet there does not exist a self-supervised learning (SSL) task which fully satisfies all three conditions: improving as the pretraining set grows, transferring to a different detector, and outperforming the best model trained without pretraining at all. We introduce CURTAIN, a temporal masking scheme and the first SSL task for neutrino telescopes that achieves all of these goals. Downstream performance monotonically impr…

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astro-ph.HEhep-ph

Relativistic Dynamical Evolution of Kilonova Spectral Emission

Sara Karimi, Soroush Shakeri

We develop a relativistic dynamical model for the thermal evolution of expanding kilonova ejecta, in which the effective temperature is determined by the ejecta mass, opacity, velocity, and radioactive heating rate. The resulting thermal evolution follows a broken power law as the ejecta transition from the optically thick to the optically thin regime. We incorporate this thermal history into a relativistic spectral calculation that accounts for the equal-arrival-time surface geometry and Dopple…

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astro-ph.EPastro-ph.IM

Uncertainty estimation of incoming comet trajectories with a thermophysical non-gravitational force model for Comet Interceptor encounter planning

Nicholas Attree, Pieter de Boer, Pedro Gutiérrez, Pedro Lacerda, Michael Küppers, Dominic Dirkx

The European Space Agency Comet Interceptor mission is designed to fly-by an as-yet undetermined incoming long-period or dynamically-new comet, which will require an accurate prediction of its trajectory. Cometary orbits are perturbed from purely gravitational trajectories by non-gravitational accelerations (NGAs) stemming from their outgassing, however, and these must be taken into account in the navigation. We here test the ability of ground-based astrometry and standard NGA-fitting techniques…

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astro-ph.GA

A neural-network model to find correlations in astrochemical space

Daniel Giovanni Vargas, Darío Barreiro-Lage, Carlos Cabezas, José Cernicharo, Germán Molpeceres

The detection of new interstellar molecules is central to astrochemistry, and arguably the most transformative development in the field in past decade has been the increase in both number and diversity of detected species. Using natural language processing models, we develop a machine-learning pipeline, similar to other approaches reported in the literature, to connect molecular structures, encoded as chemical strings, and molecular column densities in TMC-1. The workflow generates astrochemical…

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astro-ph.GA

Discovering supernovae in the Virgo Cluster during the LSST era

Jozsef Vinko, Eniko Regos, Krisztian Sarneczky

In the era of unprecedentedly wide, deep and high-cadence sky surveys the chance for discovering new explosive transients in nearby, rich galaxy clusters within hours after explosion is expected to increase dramatically. In this paper we focus on the Virgo cluster ($D \simeq 16.5$ Mpc), and estimate the expected numbers of new, very young supernovae in different sub-structures and galaxy types of the cluster during the proposed lifetime (~10 years) of the Legacy Survey of Space and Time (LSST) b…

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astro-ph.GA

A recurring changing state AGN discovered in the SAMI Galaxy Survey and SDSS

Scott M. Croom, Rebecca McElroy, Dougal Dobie, Thomas Dunn, Yasmeen Janschek, Tyler Klinger, Shaun Parasher, Mitchell Spanner et al.

We present a detailed analysis of the AGN in galaxy J085337.26+014303.6 at z=0.0582. A combination of SDSS and SAMI Galaxy Survey data shows that this object has gone through at least one full changing-look AGN cycle, from type 1.9 in 2001 to type 1 in 2015 and 2021, and then type 1.9 again in 2022. While the broad lines in this object show evidence of dust obscuration, detailed spectral analysis plus WISE photometry demonstrate that the changes in this object are related to a physical state cha…

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astro-ph.SRastro-ph.GA

The ALMA-QUARKS survey: A Keplerian Circumbinary Disk Candidate in the High-mass Star-forming Region IRAS 08303-4303

Gyuho Lee, Kee-Tae Kim, Tie Liu, Xunchuan Liu, Sheng-Yuan Liu, Lei Zhu, Guido Garay, Jihyun Kang et al.

We present the ALMA Band 6 continuum and molecular line observations of IRAS 08303-4303, a high-mass star-forming region, with an angular resolution of $\sim 0.3''$ ($\sim 700$ au at the distance of 2.35 kpc). Six dense condensations are identified in the 1.3 mm continuum, and at least four of them are associated with molecular outflows. The estimated outflow parameters, particularly mass outflow rates $\geq 10^{-4}$ $M_{\odot}$ yr$^{-1}$, suggest that the driving sources are high-mass young ste…

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astro-ph.IMastro-ph.EP

Astrometric detection of rocky exoplanets from inexpensive space platforms

Peter G. Tuthill, George Ayad, Donald G. Dansereau, Thomas Holland, Connor J. Langford, Milo Langker, Kieran Larkin, Grace Piroscia et al.

The detection of orbiting exoplanets by way of astrometric monitoring of the host star to reveal gravitationally induced reflex motion requires extreme precision and measurement stability when targeting Earth-mass objects. Despite this, astrometry is widely regarded as the most promising avenue for the most desired of all targets: true Earth analogue systems in the solar neighbourhood. Formerly thought to require flagship class investment, recently several smaller concepts such as the TOLIMAN an…

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astro-ph.SR

Distinct stellar-parameter dependencies of granulation and mesogranulation in red giants

Anohita Mallick, Jharnesh Verma, Shatanik Bhattacharya, Shravan M Hanasoge

Granulation and mesogranulation represent different spatial and temporal scales of convection, but are commonly assumed to follow the same stellar atmospheric scaling relations in red giants. We test this assumption using the largest sample assembled for this purpose to date -- 9,328 Kepler red giants spanning the red giant branch and red clump phase, cross-matched with APOGEE stellar parameters. We model each star's power spectrum background to obtain the radius-corrected amplitude and characte…

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

Lomb-Scargle Recovery of Periodic Binary Signals across Black Hole Mass and Cadence

Karan Akbari, Sayantan Bhattacharya

Searches for periodic supermassive black hole binaries in quasar light curves rely on recovery fractions, the share of injected signals detected, which forecasts use as detection efficiencies. Lin, Charisi, & Haiman (2026) measured them for the Lomb-Scargle periodogram on damped-random-walk light curves matched to 12,400 bright, high-mass Palomar Transient Factory (PTF) quasars with Sloan Digital Sky Survey Data Release 7 (DR7) masses. To test them over four decades of mass, we inject their sinu…

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gr-qcastro-ph.HE

Axial Perturbations of Extended Tolman III in the New $f(R,T)$ Theory

B. N. Jayawiguna, G. A. Sabian, H. S. Ramadhan, A. Sulaksono

We investigate compact objects using the extended Tolman III equation of state in the framework of $f(R,T)=R+2χT$ gravity. In the matter sector of the Lagrangian density, we employ a new formalism based on the evaluation of the second-order derivative of the matter Lagrangian with respect to the metric \cite{Jayawiguna:2026das}. We analyze the corresponding observational signatures through axial gravitational perturbations including stellar stability and gravitational echo. We find that the effe…

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hep-exastro-ph.IM

Natural Chlorine Enhances Antineutrino Detection in the Deep Ocean

Ruike Cao, Iwan Morton-Blake, Donglian Xu, Qichao Chang, Shuhua Hao, Jingtao Huang, Weilun Huang, Yifan Jiang et al.

Large-volume neutrino telescopes such as IceCube and KM3NeT exploit natural ice or water as detection media, but their sparse instrumentation makes MeV neutrino interactions difficult to identify individually. We show that chlorine naturally abundant in seawater provides an intrinsic neutron-capture target that enables efficient tagging of electron antineutrinos through inverse beta decay. In contrast to the 2.2 MeV $γ$-ray from neutron capture on hydrogen, capture on chlorine produces an $\sim$…

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astro-ph.HE

Search for high-energy neutrinos from Einstein Probe detected Fast X-ray Transients using 14 years of IceCube muon track data

Sri Devaki Meduri, Shantanu Desai

We perform a time-integrated search for high energy neutrinos from 27 fast X-ray transients (FXTs) detected by Einstein Probe, using 14 years of publicly available IceCube muon-track data. We employ the unbinned maximum likelihood method which is used for IceCube point source searches. We do not find any statistically significant excess from any of the FXTs. The largest TS value is obtained for EP240801a (TS=4.77), corresponding to a local $p$-value of 0.04, which is not significant. We therefor…

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astro-ph.HEastro-ph.SR

Early panchromatic spectra reveal helium in the thermonuclear supernova 2024kce

Abigail Polin, Dillon Hasenour, Sahana Kumar, Willem Hoogendam, Jing Lu, Daniel Polin, Danielle Dickinson, Braden Garretson et al.

Faint Type I supernovae blur the boundaries between spectroscopic classes, obscuring their progenitors and explosion mechanisms. One proposed origin is a double detonation, in which ignition of an accreted helium shell triggers the explosion of a carbon oxygen white dwarf. Surviving helium is a direct prediction of this mechanism, but its strongest near-infrared feature overlaps with carbon and is ambiguous in isolation. Here we present SN 2024kce, observed with simultaneous optical and near-inf…

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astro-ph.GAastro-ph.SR

A 13 Year Black Hole Microlensing Survey in Omega Centauri

Zack Freeman, Maximilian Häberle, Anil Seth, John Zaris, Matthew Whitaker, Carl L. Rodriguez, Elena González Prieto, Andrea Bellini et al.

Star clusters are born with massive stars that leave behind a large population of stellar mass black holes. These black holes may account for a large fraction of binary black hole mergers seen in gravitational waves as the dense environment enables retention of black holes and the formation of binaries. However, direct measurements of stellar mass black holes in globular clusters are limited, with just a few found in binary systems thus far. In this paper, we examine the possibility of detecting…

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physics.ed-phastro-ph.IM

From Venus to the Parking Lot: A Flexible Stellar Interferometry Experiment

Eric J. Friedman, Michelle Goman

We describe a simple extension of our earlier Venus interferometry demonstration that can be performed indoors or outdoors, independent of planetary visibility or atmospheric seeing. A small flashlight is placed 15-50 meters away from a telescope and covered with a circular aperture mask (hole diameter 2-6~mm). A small telescope fitted with an opaque mask bearing two 2~mm holes, spaced between 5 and 20~mm apart, is then used to observe interference fringes from this artificial extended source. B…

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astro-ph.GAastro-ph.SR

The Milky Way's Early Disk Was Built in Bursts. II. The Multi-component Age-Metallicity Structure of the High-$α$ Disk

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

Whether the high-$α$ disk experienced a continuous or episodic star-formation history remains an open question. Here we investigate the age--metallicity distribution of the high-$α$ disk using approximately 145,000 Gaia DR3 subgiants with $[\mathrm{Fe/H}]>-1$, 6.5~kpc $\lesssim R\lesssim9.5$~kpc, and $|Z|\lesssim1.5$~kpc. We adopt a forward-modelling framework that accounts for individual age and metallicity uncertainties and corrects for sample selection effects. The reconstructed distribution…

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astro-ph.IMastro-ph.HE

Photometric classification and out-of-taxonomy detection of ZTF transients with FLARE

Argyro Sasli, Felipe Fontinele Nunes, Xuanrui Zhang, Dimitrios Kourtesis, Saina Nikmehr, Alexandra Junell, Jesper Sollerman, Antoine Le Calloch et al.

Photometric classifiers decide which of the million nightly alerts of time-domain surveys receive one of the few thousand spectra taken each year, and they are the first place where a transient outside the trained classes can be noticed. We present flare, the photometric classification and anomaly-detection module of AppleCiDEr, evaluated on 10 497 spectroscopically confirmed ZTF transients in six classes and 53 objects from families outside the taxonomy. Catalogue context raises the macro F1 sc…

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astro-ph.HEastro-ph.GA

Multiwavelength Classification of Chandra Sources in Omega Centauri

Steven Chen, Oleg Kargaltsev, Jeremy Hare, Hui Yang, Oleg Smirnov, Ian Heywood, Talon Myburgh

We present a comprehensive study of X-ray sources in the globular cluster NGC 5139 to date. Over 200 Chandra sources are cross-matched to multiwavelength catalogs from HST, JWST, and MeerKAT. We employ a machine-learning classification pipeline (MUWCLASS) for the first time in such a crowded stellar environment and introduce the globular-cluster-specific training dataset, which compiles previously classified sources from 25 Galactic globular clusters. Given the challenges presented by the high-d…

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astro-ph.SRastro-ph.EP

Detection of Solar-like Oscillations and Granulation at Infrared Wavelengths using JWST

Angharad Weeks, Daniel Huber, Timothy R. Bedding, Jared Splinter, Hans Kjeldsen, Yaguang Li, Courtney Crawford, Daniel Hey et al.

Stellar oscillations and granulation are key probes of stellar convection, one of the most poorly understood processes in stars. Stellar models predict strong wavelength dependence of the amplitudes of oscillations and granulation, but hitherto both processes have only been measured at optical wavelengths. Here we present the first detection of oscillations and granulation at infrared wavelengths, using JWST time-series observations of the F6V main-sequence star WASP-121 that were obtained to st…

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gr-qcastro-ph.GA

Multi-orbit S-star probes of Lorentz violation at the Galactic Center

Jia-Yuan Fang, Jian-Ming Yan, Zong-Kuan Guo

We investigate the potential of Galactic-center S-star observations to probe Lorentz violation in the minimal pure-gravity Standard-Model Extension (SME), focusing on parameter degeneracies associated with anisotropic orbital signatures. We construct simulated astrometric and spectroscopic observations of S2 and S55 using fiducial orbital and Galactic-center parameters based on the multi-star solution from the GRAVITY Collaboration and evolve the stellar trajectories using the leading Lorentz-vi…

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physics.space-phastro-ph.EP

Deep-Learning Identification and Global Characterization of Energetic O2+ Beams at Mars

Chi Zhang, Chuanfei Dong, Kathleen G. Hanley, Yaxue Dong, Hans Nilsson, Eduard Dubinin, Jasper Halekas, Janet Luhmann et al.

Martian ionospheric ions can be accelerated away from Mars by the solar wind, contributing substantially to atmospheric ion escape. Here, we develop a U-Net-based image segmentation model to identify a distinct population of escaping planetary ions, energetic O2+ beams, from a decade of Mars Atmosphere and Volatile EvolutioN (MAVEN) observations and perform an event-based statistical analysis of their global properties and dependence on external conditions. We find that O2+ beams are widely dist…

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