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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.GA

Corona Australis 151: an extremely young protostar

E. Redaelli, S. Spezzano, P. Caselli, J. Harju, D. Arzoumanian, O. Sipilä, A. Belloche, F. Wyrowski et al.

Context. Prestellar cores are the birthplace of stars and planetary systems, but they are short-lived objects, since the initial stages of dense core evolution, collapse, and the formation of a protostellar seed are fast. In an effort to build a catalogue of bona-fide prestellar cores in the Solar neighbourhood, we used APEX observations to identify dynamically evolved cores among dense cores observed with Herschel. One of them, Corona Australis 151, stood out because of its centrally peaked str…

astro-ph.HE

The October 2022 flare in OJ 287 and the mass of its primary black hole

Mauri J. Valtonen, Staszek Zola, Manpreet Singh, Andrei V. Berdyugin, Kari Nilsson, A. Gopakumar, Alok C. Gupta, Tapio Pursimo et al.

The bright blazar OJ~287 has demonstrated a sequence of flares, which are well explained by a quasi-Keplerian orbit model. The flares are associated with the impact of the secondary on the accretion disk of the primary. The orbit must precess in order to produce the correct sequence of flares, and from the precession rate we calculate the mass of the primary. This precession rate gives the mass of the primary $M_{BH} = (18.35\pm0.05) \times 10^9 M_{\odot}$. Two kinds of flares have been identifi…

astro-ph.EPastro-ph.IM

Updated in-flight calibration of the Hayabusa2/NIRS3 spectrometer: new global near-infrared photometric properties of asteroid (162173) Ryugu

Antonin Wargnier, Eri Tatsumi, Koki Yumoto, Mayumi Ichikawa, Shin-ya Murakami, Yuichiro Nagai, Kazuhiro Honda, Yasuhiro Yokota et al.

The Near InfraRed Spectrometer (NIRS3) onboard Hayabusa2 observed asteroid (162173) Ryugu, searching especially for signatures of water-bearing minerals. However, during the mission, absolute reflectance measured by the Telescopic Optical Navigation Camera (ONC-T) and NIRS3 showed a systematic offset. Additionally, touchdown operations have modified the instrumental response, which has made post-second-touchdown data less reliable. Correction of these issues is crucial to interpret the subtle sp…

astro-ph.GA

Rubin J122659.4+090236: An Extremely Low Surface Brightness Galaxy Candidate Discovered in the Rubin LSST Early Data Preview 2

Dipanjan Mitra, Kanak Saha, Sugata Kaviraj, Alister W. Graham, Sandro Tacchella, Ricardo Demarco, Dieu D. Nguyen, Elham Saremi et al.

We report the serendipitous discovery of an exceptionally low surface brightness galaxy (LSBG) candidate, Rubin J122659.4+090236, in Rubin Observatory imaging of the interacting NGC 4410 system, identified in the Cosmic Treasure Chest public release. 2D Sérsic modelling of the Rubin g, r, and i images reveals a nearly round system with a shallow profile (n ~ 0.4), an effective radius of R_e ~ 6'', and central surface brightnesses of $μ_{0,g}=27.52\pm0.04$, $μ_{0,r}=27.62\pm0.07$, and $μ_{0,i}=27…

astro-ph.EP

Mapping the WISPIT2 Planet-Hosting Cavity at Sub-Hill-Radius scales

Myriam Benisty, Stefano Facchini, Richard Teague, Francesco Zagaria, Pietro Curone, Viviana Pezzotta, Jaehan Bae, Gabriele Cugno et al.

We present new deep, very high angular resolution observations of the sub-mm continuum (19x13 mas) and 12CO (67x52 mas) emission from the disk surrounding the planet host WISPIT2. Our analysis reveals a clear gas gap carved by WISPIT 2b and an empty cavity within the orbit of WISPIT 2c. We also find a gaseous and optically thin dusty ring located between the orbits of the two planets. Channel maps show a pronounced change in the emission surface height of the disk, which transitions from flat wi…

astro-ph.EP

The metallicity of giant exoplanets around low-mass stars and how Ariel can help

Ravit Helled, Sho Shibata, Shubham Kanodia, Billy Edwards

Giant planets orbiting low-mass stars represent a unique population of giant planets that can be studied to constrain planet formation theory. Surveys of transiting giant exoplanets around M-dwarfs (GEMS) allow for measurement of their masses and radii, which in turn can be used to estimate their bulk densities. Coupling these observations to interior structure and evolution models can yield the bulk metallicity of these planets, however there are degeneracies to this that are improved by measur…

astro-ph.EPastro-ph.GA

Multi-Wavelength Post-Perihelion Polarimetry of Interstellar Comet 3I/ATLAS

Zuri Gray, Galin Borisov, Ludmilla Kolokolova, Johannes Markkanen, Yuna G. Kwon, Stefano Bagnulo, Alberto Cellino, Rosemary C. Dorsey et al.

We present new post-perihelion polarimetric observations of the third discovered interstellar object, 3I/ATLAS (C/2025 N1; hereafter 3I), obtained using FORS2 at the Very Large Telescope, ALFOSC at the Nordic Optical Telescope, and FoReRo2 at the 2 m Ritchey-Chrétien-Coudé telescope. The observations span phase angles 1-30$^{\circ}$, providing the most extensive polarimetric phase angle coverage obtained for an interstellar object to date. The post-perihelion measurements reveal that the unusual…

astro-ph.EP

Disk dispersal freezes overstable resonant librations

Linghong Lin, Beibei Liu

Context. Convergent migration in a gaseous protoplanetary disk can capture a planet pair into mean-motion resonance. Eccentricity damping can subsequently make the resonant libration overstable and drive the pair out of resonance. Most studies of this process, however, assume a static disk. Aims. We examine how the decay of disk torques during dispersal changes this outcome and whether it can freeze an overstable libration before the pair escapes. Methods. We describe disk dispersal by allowing…

astro-ph.GA

Quantifying collision-driven mass loss in supermassive star formation: the role of stellar structure and accretion

P. A. Solar, B. Reinoso, D. R. G. Schleicher, R. Banerjee

Observations of high-redshift galaxies with JWST have renewed interest in scenarios where supermassive stars form via runaway stellar collisions in dense clusters, yet the impact of collision-driven mass loss on their growth remains uncertain. In this work, we perform a post-processing analysis of 3D hydrodynamical simulations of the formation of a supermassive star, applying an analytic mass-loss prescription to stellar collisions while exploring different assumptions for the internal stellar s…

astro-ph.EPastro-ph.IM

Habitable-zone Earths at the detection frontier: Measured completeness and false-alarm rate of a transit pipeline for the PLATO M-dwarf sample

Yohann Tschudi

The PLATO mission will observe its first long-pointing field, LOPS2 (Long-duration Observation Phase, South field), for at least two years, bringing the habitable zones (HZ) of its M-dwarf sample within reach of a transit search. The completeness and false-alarm rate of a pipeline validated on TESS M dwarfs are measured on simulated PLATO photometry and converted into a candidate-level forecast for the LOPS2 M dwarfs. Simulated PLATO light curves (717 d baseline; three stellar cells of the faint…

astro-ph.GAastro-ph.SR

Membership Determination of 45 Open Clusters Beyond 3 kpc

Qian Cui, Zhihong He, Yangping Luo, Yan Jiang

Context. Open clusters (OCs) are fundamental tracers for studying the structure and chemical evolution of the Galactic disc. Reliable identification of cluster members, particularly at the faint end of the main sequence, remains challenging owing to severe field-star contamination and the declining photometric completeness for distant, obscured systems. Aims. We aim to identify and characterise distant OC candidates at heliocentric distances $d \gtrsim 3$ kpc using Gaia DR3 astrometry, with emph…

astro-ph.COastro-ph.IM

A guide to choosing data compression methods for cosmological inference

Susan Pyne, Benjamin Joachimi, Calum Gordon, Kiyam Lin

We provide a pedagogical guide to help researchers choose an appropriate compression method for cosmological inference and numerical covariance estimation, trading off the balance between information loss and complexity. We describe methods used in the literature, categorising them by the form of the loss function -- Fisher information, mutual information, or mean squared error -- and by whether they are linear or non-linear. We consider in detail the linear compression methods: massively optimi…

astro-ph.EPastro-ph.SR

Signatures of rocky debris accretion in AF-Type planet hosts

J. Maldonado, I. Mendigutía, S. Barceló Forteza, G. M. Mirouh, B. Montesinos, E. Villaver

The gas-giant planet-metallicity correlation plays a fundamental role in our understanding of planet formation. We determine in a homogeneous way the metallicity and individual abundances of a sample of A and early-F stars, with and without known planetary companions, and discuss their abundance distribution and trends. We find that stars with planets generally exhibit higher abundances of both iron-peak and volatile elements compared to stars without known planets although in most cases this te…

astro-ph.HE

The angular structure of the GW170817 jet from prompt emission alone

R. Moradi, R. Ruffini

We determine the angular structure of the GW170817 jet by the prompt emission alone, without afterglow fitting, circumburst density or microphysical parameters. We assume that GRB 090510 and GW170817 have outflows of the same kind, observed respectively on-axis and at the interferometric viewing angle of $20^\circ$. We support this assumption with independent gravitational-wave data showing compatible binary masses and radiated energies. We show that for an observer whose beaming cone is filled…

astro-ph.HE

Through a glass, darkly: a combined framework for estimating fast radio burst host galaxy and population properties in an era of uncertain host identification

C. W. James, B. C. Andersen, L. Marnoch, J. L. Hoffmann, N. Loudas, J. X. Prochaska, S. D. Ryder, M. Woodland et al.

The identification of fast radio burst (FRB) host galaxies, and subsequently their redshifts ($z$), has allowed the FRB dispersion measure (DM) to be used to probe the cosmological distribution of ionised gas, and study the properties of the FRB population itself. However, current methods cannot account for FRBs with uncertain host galaxy associations, leading to underutilisation of data, and potential biases towards nearby, bright hosts. In this work, we develop a methodology which can. We do s…

astro-ph.HE

Evidence of Orbital Evolution of Gigahertz-Peaked Spectra in Binary Millisecond Pulsar

Rahul Sharan, Bhaswati Bhattacharyya

We present the first systematic investigation of the continuous orbital evolution of the Gigahertz-Peaked Spectum turnover frequency ($ν_{peak}$) in the binary millisecond pulsar, PSR J2144$-$5237. Using approximately 50 hours of densely sampled observations spanning the $\sim10$-day orbit with the Parkes Ultra-Wideband Low frequency receiver, we obtained continuous frequency coverage from 704 MHz to 4 GHz, enabling robust measurements of the spectral evolution throughout the binary orbit. We de…

astro-ph.IM

Validating the SCALES DRP: A Performance Study of the Medium-Resolution IFS Mode

Athira Unni, Steph Sallum, Max Brodheim, Rosalie McGurk, Andy Skemer, Matthew Brown, Peyton Benac, Michael P. Fitzgerald et al.

We present a performance verification of the medium-resolution integral field spectrograph (IFS) mode of the SCALES Data Reduction Pipeline (SCALES-DRP) using data obtained during recent cryogenic cooldown testing. SCALES (Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy), scheduled for deployment on the Keck II Telescope in late 2026, will be the first facility-class high-contrast thermal-infrared IFS, operating over the 2-5 micrometer wavelength range. The SCALES-DRP, develope…

astro-ph.HEcs.LGhep-ex

A Differentiable Neural Surrogate for Photon Propagation in Neutrino Telescopes

Felix J. Yu, Berthy T. Feng, Nicholas Kamp, Carlos A. Argüelles

Large-volume neutrino telescopes infer neutrino properties from Cherenkov light, but simulating the transport of billions of photons through highly scattering ice or water is computationally costly. We introduce candela, a differentiable SIREN neural field that learns the photon Green's function of the IceCube Neutrino Observatory, a cubic-kilometer detector embedded in Antarctic glacial ice. Given a point-like energy deposit and sensor, it predicts the expected photon yield and full arrival-tim…

astro-ph.EPastro-ph.IM

Retrieving Ocean Glint Reflectance Signatures from Directly Imaged Earth-like Exoplanets

Eleanor Cornish, Tyler D. Robinson

Future space telescopes searching for extraterrestrial life require methods to detect environments that can potentially support life. Liquid water is considered essential for life as we know it and its presence is therefore an important observable when characterizing potentially Earth-like exoplanets. Remotely inferring the presence of surface liquid water on a world from spatially unresolved observations is an outstanding challenge where the detection of ocean glint could provide supporting evi…

astro-ph.EPastro-ph.IM

A Cross-Laboratory Comparison Study of Titan Haze Analogs: Surface Energy II

Eric C. Austin, Xinting Yu, Chao He, Cara Pesciotta, Ella Sciamma-O'Brien, Joshua A. Sebree, Jose Raul Montes-Bojorquez, Adis Husić et al.

The organic haze particles on Titan play important roles in atmospheric cloud formation and aerosol-lake interactions. These processes are strongly influenced by the surface energy of the haze particles, which controls cohesion and wetting behavior. This study presents a comparative analysis of 32 laboratory-produced haze analog samples ("tholins") synthesized across three laboratories. Using contact angle measurements, we determine the total surface energy and its dispersive and polar component…

astro-ph.GA

Star Formation Evolution in Galaxy Pairs: Constraints from Morphological Disturbances and Recent Star Formation Histories

Shaoze Geng, Shuai Feng, Shuhao Chen, Yaotian Duan, Shiyin Shen, Cailu Shi, Linlin Li, Yijin Niu et al.

Galaxy interactions can enhance star formation, but how star formation evolves during galaxy interactions remains poorly constrained by observations. We combine pair separation, morphological disturbance, and recent star formation history to study this evolution. We measure morphological disturbance with the shape asymmetry parameter ($A_{\rm shape}$) using deep images from the DESI Legacy Surveys, and use Galaxy Zoo DESI classifications as an independent test. We infer recent star formation his…

astro-ph.COastro-ph.IM

Implementation of frequency-correlated noise in CMB component separation: Method, Validation, and Early Applications

L. Zapelli, M. Bersanelli, L. P. L. Colombo, A. Mennella, L. G. Bachar, E. Battistelli, I. Bekkaoui, L. A. Bianchi et al.

Parametric component separation methods used in cosmic microwave background (CMB) analyses commonly assume instrumental noise to be uncorrelated between frequency channels. This approximation may become insufficient for experiments whose design naturally introduces cross-channel correlations, such as interferometric or multi-band bolometric systems. This work aims to provide a consistent framework to include frequency-correlated noise in Commander2 and to quantify its impact on component separat…

nucl-thastro-ph.SR

Breakdown of the Plane-Wave Trojan Horse Analysis of the $^{12}\mathrm{C}+{}^{12}\mathrm{C}$ Fusion Reaction: Critical Role of Coulomb Distortions

Akram Mukhamedzhanov

Recently, a new Trojan Horse Method (THM) measurement of carbon-carbon fusion was reported by Li \textit{et al.} [Phys. Lett. B (2026) 140675]. The purpose of the present work is to demonstrate the breakdown of the plane-wave approximation used in the analysis of these data and the critical role of Coulomb distortions in the initial and final states. The reaction mechanism underlying the THM analysis of the $^{12}\mathrm{C}+{}^{12}\mathrm{C}$ fusion reaction using the $^{16}\mathrm{O}+{}^{12}\ma…

astro-ph.HE

Preferential accretion onto eccentric and unequal binary black holes

Stanislav DeLaurentiis, Zoltán Haiman, Magdalena Siwek

Supermassive binary black holes (SMBBHs) are expected to be surrounded by circumbinary disks (CBDs) which affect the binary through gravitational forces and accretion. It has been reported that the binary can experience ``preferential accretion'' where one black hole (BH) out-accretes the other for hundreds of orbits, but this asymmetry has yet to be fully described or understood. In this work, we utilize a suite of 80 SMBBH hydrodynamical simulations with varying mass ratios ($q_b$) and eccentr…

astro-ph.IM

Identifying Casual SETI Transmissions and Ultra-Faint RFI with Cumulant Imaging

Miguel F. Morales

Techniques for identifying radio beacons transmitted by extra-terrestrial civilizations are well advanced. However, the casual broadband emission from standard radio communication is much harder to detect, and counter-intuitively casual Earth radio transmissions are becoming more difficult to identify as we more efficiently utilize the radio spectrum. In this paper we examine the electric-field statistics behind radio communication and re-conceptualize standard radio imaging as the first non-zer…

astro-ph.EP

Circumbinary planets in coplanar triple-star systems: I. Minimum eccentricity variation region

Emmanuel Gianuzzi, Mario Sucerquia, Nicolás Cuello, Cristian Giuppone

We aim to determine the conditions under which Lidov-Kozai oscillations can arise for circumbinary planets in hierarchical triple-star systems, and to identify the orbital regions where competing secular perturbations minimize eccentricity excitation. We analyzed the statistical properties of hierarchical triples from the Multiple Star Catalog to construct representative synthetic configurations. We then performed N-body simulations of circumbinary planets embedded in these systems, systematical…

hep-phastro-ph.SRcond-mat.stat-mechnlin.AO

Stability of Collective Neutrino Oscillations -- A Distributional Approach

Rupak Majumder, Dwaipayan Mukherjee, Shamik Gupta, Basudeb Dasgupta

We study the stability of collective neutrino oscillations using a distributional approach motivated by the statistical mechanics of Kuramoto synchronization. Treating the ensemble of neutrino flavor polarization vectors in the thermodynamic limit $N\to\infty$, we derive an exact nonlinear Fokker--Planck (continuity) equation for the one-body distribution $F(\vec{\mathbf{S}},ω,t)$ on the flavor sphere. This equation admits a two-parameter family of azimuthally symmetric stationary solutions, who…

astro-ph.GA

KKR 18: A Late Arrival Galaxy?

R. Brent Tully, Valentina E. Karachentseva, Igor D. Karachentsev, Gagandeep S. Anand, Maksim I. Chazov, Serafim S. Kaisan, Ehsan Kourkchi, Lidia N. Makarova et al.

KKR 18 is a dwarf irregular galaxy in the Local Void at a distance of 9.46 Mpc. It is gas rich and was experiencing vigorous star formation 20 - 100 Myr ago. Its metallicity is 4% of Solar from an emission spectrum, qualifying is as extremely metal poor (XMP). Its most remarkable characteristic is an extremely deficient Red Giant Branch. This feature is shared with a small number of other dwarf galaxies and it is inferred that they lack ancient stellar components. It is suggested that these are…

astro-ph.GA

Linking orbital history to the quenching of isolated dwarf galaxies

Sophia Um, Devontae C. Baxter, Ethan O. Nadler

Recent discoveries of isolated dwarf galaxies (${M}_{\star}\sim 10^{7-9}~{\rm M}_{\odot}$) with no signs of ongoing star formation have challenged the prevailing notion that these solitary systems are exclusively star-forming. Investigating the origins of isolated quenched dwarfs provides important clues into the dominant processes driving galaxy quenching as a function of environment and stellar mass. In this study, we identify central dwarf galaxies in the Illustris-TNG50 cosmological simulati…

astro-ph.GA

Hint of bimodal Mg-Al anticorrelation in the metal-poor Globular Cluster NGC 4372

Camila Beltrand, Macarena Uribe, Sandro Villanova, César Muñoz

We present a detailed chemical abundance analysis of seven red giant branch stars in the very metal-poor globular cluster NGC~4372, based on high-resolution UVES spectra. Our study aims to characterize the chemical evolution of NGC~4372 and investigate the presence of multiple populations. We derived abundances for 17 elements, including light, iron-peak, $α$, and heavy elements, using both equivalent width and spectral synthesis methods. We find a mean cluster metallicity of [Fe/H]=$-$2.36 $\pm…