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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.IM

Investigation of magnetic-field effects on photomultiplier tubes for the first Large-Sized Telescope of the Cherenkov Telescope Array Observatory

Yukiho Kobayashi, Dai Tateishi, Yuji Sunada, Takuto Kiyomoto, Nobuaki Sasaki, Kazuki Abe, Franca Cassol, Shuichi Gunji et al.

Photomultiplier tubes (PMTs) are widely used in imaging atmospheric Cherenkov telescopes. Their response can depend on the telescope pointing direction through changes in their orientation relative to the geomagnetic field. Such a dependence was indicated during the calibration campaign of the CTAO LST-1. In this work, the LST-1 calibration data are analyzed to quantify the gain dependence in terms of the geomagnetic field, and dedicated laboratory measurements are performed to test the hypothes…

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astro-ph.SR

Multi-thermal Structure of Solar Jets based on Combined EUV and Ha Observations

Lei Huang, Yang Guo, Zining Ren, Mingde Ding

This study investigates the multi-thermal structure of solar jets by combining extreme ultra-violet (EUV) and Ha observations, addressing whether cool and hot components originate from the same jet, their morphological similarities and differences, and the role of mini-filaments. We analyze 70 jet events simultaneously observed by Atmospheric Imaging Assembly (AIA) and Chinese Ha Solar Explorer (CHASE) from 2023 May 25 to 2026 January 15. The events are classified into four types based on whethe…

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astro-ph.GAastro-ph.CO

The extreme Disturbed Galaxy Cluster Sample (eDGeS): Spectroscopy and Dynamical Analysis of the eROSITA-Selected Merging Galaxy Cluster Candidate 1eRASS J025859.4-193727

Anish S. Aradhey, Eleazar R. Carrasco, Alfredo Zenteno, Rogério Monteiro-Oliveira, Facundo A. Gómez, Konstantina Boutsia, Esra Bulbul, Guillermo Damke et al.

Addressing open questions such as the effect of galaxy cluster mergers on the evolution of galaxies and the self-interaction cross-section of dark matter requires the construction of a large, diverse sample of disturbed galaxy clusters. One contribution to such a sample is the extreme Disturbed Galaxy Cluster Sample (eDGeS), an ongoing spectroscopic study of massive disturbed and merging galaxy clusters selected from complementary surveys. Here, we present our first results from the eROSITA-sele…

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gr-qcastro-ph.COastro-ph.HEhep-ph

Relativistic Stellar Oscillations from Ultralight Dark Matter

Shanae Oishi, Christopher Reyes, Jeremy Sakstein

Ultra-light dark matter, composed of bosons behaving as classical waves, can resonantly excite stellar oscillations. In this work, we investigate this phenomenon in relativistic stars, showing that $\ell=0$ fluid modes can be excited. We derive a framework for calculating the mode amplitude and apply it to neutron stars to predict the associated surface temperature fluctuations; the resulting signal lies beyond current observational sensitivities. We discuss prospects for extending this approach…

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astro-ph.GAastro-ph.SR

Honoring Paris Pişmiş' Legacy: Uniform Astrophysical Properties of 14 Understudied Clusters from Gaia DR3

Seliz Koç, Neslihan Alan, Furkan Akbaba, Olcay Plevne

Open clusters are fundamental tracers of the chemical and dynamical evolution of the Galactic disc. This study presents a systematic characterisation of 14 understudied open clusters from the Pismis catalogue, selected for a well-defined stellar sequence in Gaia DR3 and spanning a wide range of ages and distances. Using high-precision Gaia DR3 astrometry, we provide a high-fidelity modernisation of these historical discoveries while testing our analytical framework across diverse stellar populat…

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astro-ph.HE

Lepto-hadronic modeling of blazars associated with well-reconstructed high-energy neutrino events

Leonard Pfeiffer, Margot Boughelilba, Simone Garrappa, Sara Buson, Massimiliano Lincetto, Annette Bremer

The association of active galactic nuclei (AGN) with high-energy neutrinos has been studied through population and individual source analyzes, but whether these associations reflect physical processes or chance coincidences remains open. Blazars, AGN with relativistic jets aligned with the line of sight, spatially consistent with IceCube high-energy events, offer a natural framework to address this question. Combining multifrequency observations with physically motivated emission models allows u…

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astro-ph.SR

Energy redistribution during 2D oscillatory reconnection

Luiz A. C. A. Schiavo, Jordan Talbot, Gert J. J. Botha, Ben Snow, Daniel Johnson, Madeleine L. Combrinck, James A. McLaughlin

Magnetic reconnection is a fundamental energy release mechanism in solar and space plasmas. However, the distribution of released magnetic energy among kinetic and internal (thermal) energy during time-dependent reconnection remains largely unexplored. This work aims to study energy conversion in magnetohydrodynamics via oscillatory reconnection (OR) at a 2D magnetic null point. Using a shock-capturing code, we identify three families of shocks: termination shocks, slow-mode deflection shocks, a…

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astro-ph.GA

Extreme Enrichment at Cosmic Dawn: Three FeII-Strong Quasars at z > 6 from the JWST Aether survey

Anniek J. Gloudemans, Emanuele Paolo Farina, Roberto Decarli, Klaudia Protušová, Fabrizio Arrigoni Battaia, Eduardo Bañados, Aaron J. Barth, Silvia Belladitta et al.

We present three outliers on the quasar main sequence at z>6, as revealed by JWST/NIRSpec IFU observations from the Aether survey, a program targeting ~200 quasars at cosmic dawn. The quasars, J0216-5226, J0320-3521, and J1429+5447, exhibit exceptionally strong FeII emission and weak H$β$ and [OIII] lines, indicating rapid chemical enrichment within the first Gyr of cosmic history. Their FeII strengths ($R_{\rm{FeII},\lambda4570} \equiv \rm{EW}_{\rm{FeII}}/\rm{EW}_{\rm{H}β}$) range between ~2.5-…

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gr-qcastro-ph.IMcs.LG

Deep Learning Detection of Beyond-General-Relativity Deviations in Gravitational-Wave Signals: A Detection-Threshold Study with Real LIGO Noise

Muhammad Adnan Shahzad

We study machine-learning detection of controlled beyond-General-Relativity (beyond-GR) deviations in gravitational-wave signals, using both synthetic aLIGO-PSD noise and real LIGO H1 detector strain. Three deviation families are applied to General-Relativistic inspiral-merger-ringdown waveforms: amplitude modulation, phase modulation, and frequency modulation, each parameterized by a dimensionless strength coefficient $β$. A hybrid classifier combining a one-dimensional convolutional neural net…

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astro-ph.GAastro-ph.SR

From observing strategies to velocity dispersion bias: forward modeling unresolved binaries in ultra-faint dwarf galaxies

Xiaowei Ou, Andrew B. Pace, Nitya Kallivayalil, Amery Gration, Christopher T. Garling, Nathan R. Sandford, Lina Necib, Niusha Ahvazi et al.

Ultra-faint dwarf galaxies (UFDs) in the Milky Way are ideal probes of low-mass galaxy formation and dark matter because they are highly dark-matter dominated. In the lowest-mass systems, however, unresolved binary orbital motion complicates dynamical mass estimates by inflating measured velocity dispersions and biasing the interpretation of the inferred masses. We develop a flexible forward-modeling pipeline, the Binary Observation Simulator, to generate mock multi-epoch radial-velocity observa…

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astro-ph.GAastro-ph.SR

Characterizing the hierarchical structure of filaments I. On the origin of the length-mass (L-M) scaling relation

Rahul Patel, Daniel Seifried, Alvaro Hacar

Aims. Filamentary structures in molecular clouds are widely recognized as fundamental components of star formation. Observations report a length-mass relation of the form $L \propto M^α$ with $α\simeq 0.5$. We characterize this relation in simulated molecular clouds and investigate the influence of hierarchical fragmentation and spatial resolution. Methods. We apply a two-step filament identification method to high-resolution 3D hydrodynamical and magnetohydrodynamical simulations from the SILCC…

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astro-ph.GAastro-ph.SR

Star clusters as tracers of the perturbed southern outer disk of the Large Magellanic Cloud

Matías Chiarpotti, Andrés E. Piatti, Denis M. F. Illesca, Roberto Butrón

The complex interaction history between the Large and Small Magellanic Clouds (L/SMC) has left significant imprints on their structural and chemical evolution. In this work, we use a sample of 70 star clusters located in the southern outer disk of the LMC ($R > 5^{\circ}$) to trace the magnitude of these tidal perturbations. Using deep $g,i$ photometry from the SMASH DR2 survey and the Automated Stellar Cluster Analysis (ASTeCA) code, we provide a homogeneous determination of cluster ages, metal…

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astro-ph.GA

Sub-arcsecond imaging of HCN and CN in the Orion Bar. UV-driven warm Nitrogen chemistry in dense environments

M. Zannese, J. R. Goicoechea, S. Cuadrado, J. Pety, M. Gerin, E. Chapillon

Rotationally excited HCN and CN lines, due to their high critical densities, are often used as tracers of gas densities. ALMA, with its high spectral and spatial resolution, provides unique access to the spatial morphology and kinematics of HCN and CN emission to study the substructures of the molecular cloud edges. We present new sub-arcsecond imaging of HCN 4-3 and CN 3-2 lines to probe the density structure in the Orion Bar. We study their spatial distribution and compare them to other existi…

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astro-ph.SRastro-ph.GA

Extragalactic Multi-Band Exploration of Red Supergiants (EMBERS): Pipeline, Source Classification, and Bolometric Properties of 101,219 Red Supergiants from James Webb Space Telescope Imaging

Aswin Suresh, Charles D. Kilpatrick, Wen-fai Fong, Maria R. Drout, Daichi Hiramatsu, Luca Izzo, Wynn V. Jacobson-Galán, Armin Rest et al.

The evolution of red supergiants (RSGs), especially in their final stages before exploding as hydrogen-rich Type II supernovae (SNe), remains poorly understood, owing to small samples of well-characterized stars in the Local Group. We present the largest population study of RSGs to date using $\sim10^5$ stars with bolometric parameters inferred from archival James Webb Space Telescope/Near-Infrared Camera (NIRCam) imaging of 15 galaxies within 20 Mpc. We also present jwst123, a newly-developed g…

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astro-ph.SRastro-ph.EP

A Grid of Contribution Functions to Help the Interpretation of Time-resolved Observations of Brown Dwarfs

Myrla Phillippe, Theodora Karalidi, Elena Manjavacas, Natalia Oliveros-Gomez, Daniel Apai, Jonathan Fernandez, Kieran M. Manjrawala

We present a grid of thermal emission contribution functions and their corresponding atmospheric spectra model for cloudy and cloud-free brown dwarfs, spanning effective temperatures $T_{\rm eff} \in [500, 2000]$ K, surface gravities $\log g = [3.5, 5.5]$ [cgs], sedimentation efficiencies $f_{\rm sed} = 1, 2, 3, 4$ and 8, and eddy diffusion coefficients $\log K_{\rm zz} = [6, 11]$. We use temperature-pressure profiles from the Sonora Diamondback models in conjunction with the picaso radiative tr…

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astro-ph.IMphysics.ed-ph

Gravitas: A Browser-Based Astrophysics Laboratory for Prediction, Measurement, and Discovery

Carl Ziegler

Astronomy students are often asked to reason about systems that cannot be handled in a laboratory, evolve over inaccessible timescales, or reveal themselves only through indirect measurements. Gravitas is a free, browser-based astrophysics environment designed to turn those limitations into opportunities for experimentation. Its version 1.0.0 release combines a configurable gravitational sandbox with 59 ready-to-run scenarios and 22 guided investigations comprising 636 steps and roughly 15-19 ho…

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astro-ph.SRastro-ph.EP

Mapping Molecular Ion Distributions in a Diverse Sample of Protoplanetary Disks

Deryl E. Long, L. Ilsedore Cleeves, Charles J. Law, Fred C. Adams, Dana E. Anderson, Sean M. Andrews, Edwin A. Bergin, Jane Huang et al.

Observations of ionization-tracing molecules in protoplanetary disks suggest that their ionization environments are diverse due to varying degrees of cosmic ray modulation, stellar activity, and environmental differences that alter the impact of ionizing radiation. To better understand ionization chemistry in disks, we present the largest survey of resolved observations of molecular ions to date. Using new and archival ALMA observations we detect HCO+, H13CO+, N2H+, and DCO+ toward seven protopl…

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astro-ph.GA

MSA-3D: A Diversity of Dust Attenuation Profiles Across the Epoch of Thin Disk Emergence

Ivana Barišić, Tucker Jones, Naveen Reddy, Matthew Malkan, Ryan Sanders, Alaina Henry, Ayan Acharyya, Kevin Bundy et al.

We present spatially resolved measurements of dust attenuation and star formation in 18 main-sequence star-forming galaxies at z$\sim$1 from the MSA-3D survey, obtained by mapping the Balmer emission lines at $\sim$1 kpc resolution with JWST/NIRSpec's MSA in a slit-stepping strategy. We investigate the diversity of radial attenuation profiles, and how the spatial variation affects attenuation and star formation rates (SFR) derived from single-aperture measurements. We find a notable diversity am…

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astro-ph.GA

Reconstructing the Projected Dark Matter Field across 0.1-100 Mpc Scales from the SDSS Survey

Kunyao Zhao, Yingjie Peng, Dingyi Zhao, Xiaohu Yang, Luis C. Ho, Kai Wang, Jing Dou, Zeyu Gao et al.

Dark matter sets the gravitational environment in which galaxies form and evolve, but cannot be observed directly. We present a conditional diffusion model that reconstructs the projected dark matter density field from the galaxy stellar-mass density field for direct application to galaxy surveys. The model is trained on CAMELS and validated on the independent IllustrisTNG300-1 simulation. Halo masses inferred from the reconstructed projected-aperture measurements agree well with the correspondi…

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astro-ph.EPastro-ph.GA

JWST Reveals Refractory-Rich Water Ice in Interstellar Comet 3I/ATLAS: Evidence for a Continuum of Grain Properties across Protoplanetary Disks

Silvia Protopapa, Michael S. P. Kelley, Martin A. Cordiner, Stefanie N. Milam, Dennis Bodewits, Steven B. Charnley, Maria N. Drozdovskaya, Sara Faggi et al.

We present JWST/NIRSpec PRISM observations of the interstellar comet 3I/ATLAS obtained on 2025 August 6 (Epoch 1), 2025 December 22 (Epoch 2), and 2026 April 1 (Epoch 3), spanning eight months around perihelion at heliocentric distances of 3.3, 2.4, and 5.7 au, respectively. The spectra reveal a broad 3 $μ$m absorption band together with H$_2$O, CO$_2$, and CO gas emission. Unlike previously reported water-ice-rich Solar System comae, the strong 3 $μ$m absorption is accompanied by weak or absent…

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astro-ph.HEastro-ph.GA

Hydrodynamic Simulations of Eccentric Black Hole Encounters in AGN Discs

Andrew Imai, Henry Whitehead, Bence Kocsis

We investigate close encounters between stellar-mass black holes (BHs) in the gaseous discs of active galactic nuclei (AGNs), during which binary black holes (BBHs) may form. We perform a suite of 483 2D adiabatic viscous hydrodynamic simulations within a shearing box prescription using the Eulerian grid code Athena++. We co-evolve the two embedded BHs with the gas. To probe the dependence of capture on non-circular initial conditions, we vary the initial radial separation $b$, the eccentricity…

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astro-ph.EP

Does HD 3167 Have Planets with Perpendicular Orbits?

Joshua N. Winn, Jack Lubin, Guðmundur Stefánsson, Haochuan Yu, Erik Petigura, Howard Isaacson, Andrew W. Howard, Fei Dai et al.

The two transiting planets of HD 3167 were reported to follow nearly perpendicular paths, with the inner orbit aligned with the stellar equator and the outer orbit nearly polar. This interpretation depends critically on a challenging single-transit detection of the Rossiter-McLaughlin effect of the inner planet. We observed three additional transits of the inner planet with the Keck Planet Finder and analyzed the new data together with two archival ESPRESSO transit datasets. We do not confirm th…

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astro-ph.SRastro-ph.EPastro-ph.HE

Coronal Mass Ejections from Young Suns: An Observational View through the Solar-Stellar Connection

Kosuke Namekata

Kepler and TESS have revealed that magnetically active stars frequently produce flares and superflares, raising the possibility that frequent, fast, and massive coronal mass ejections (CMEs) may affect planetary space weather environments. However, observational constraints on stellar CMEs remain extremely limited. Several diagnostics, including Doppler-shifted spectral lines, coronal dimming, and radio bursts, have been explored mainly for cool dwarfs, while recent observations have begun to ex…

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astro-ph.GAastro-ph.EPastro-ph.SR

Galactic archaeology meets exoplanets: linking stellar birth radii to exoplanet demographics

M. L. L. Dantas, J. J. García-Delgado, I. Rebollido, R. Smiljanic

Stars observed in the solar vicinity were not necessarily born there. Radial mixing can redistribute stellar populations across the Galactic disc, decoupling their present-day locations from the environments in which they formed. We summarise a framework that combines Galactic chemical evolution models with a generalised additive model to infer stellar birth radii. We apply it to 1327 predominantly thin-disc planet hosts with homogeneous ages, \textit{Gaia} DR3 astrometry, and \texttt{SWEET-Cat}…

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

A census of massive eclipsing binaries in the Whirlpool Galaxy

Cheyanne Shariat, Kareem El-Badry, Maude Gull, Daniel R. Weisz, Charlie Conroy, Alessandro Savino

We present a census of massive eclipsing binary (EB) candidates in the Whirlpool Galaxy (M51), a face-on spiral galaxy at 7.5 Mpc with $Z\sim Z_\odot$. Using 34 epochs of red-optical Hubble Space Telescope (HST) photometry and a single epoch of broadband UV-optical photometry, we identify 173 massive EB candidates ($>5~{\rm M_\odot}$) with orbital periods $P_{\rm orb}$=1-30 days. The sample traces young stellar populations across the spiral arms of M51. Joint light-curve and spectral energy dist…

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astro-ph.GA

A model to mini-quench early galaxies by balancing stellar feedback and gas accretion

Judah Luberto, Steven R. Furlanetto

The James Webb Space Telescope (JWST) has discovered a population of low-mass, early galaxies with very low levels of star formation over tens of Myr. These "mini-quenched" galaxies were one of the many surprises from JWST and still require a robust explanation. We seek to explain a few important properties of these galaxies, namely the timescales governing their star formation and quenching. We use a simple model that pairs stellar feedback with the forces binding gas to a $z \sim 6$ galaxy, an…

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astro-ph.HEastro-ph.SR

A Significant Dust Reservoir Uncovered with JWST in the Type Ic SN 1983V More Than 40 Years Post-Explosion

Sophia S. Kressy, Thomas Moore, Ori D. Fox, Nathan Smith, Raphael Baer-Way, Luc Dessart, Michael J. Dulude, W. V. Jacobson-Galán et al.

Searching for late-time emission from supernovae (SNe) is an active field. Infrared (IR) wavelengths are sensitive to thermal emission from dust, which can be used to probe SN contributions to the cosmic dust budget and progenitor mass-loss histories. The older an SN, the more likely it is for any existing dust to have cooled below the detection threshold of most observatories, even JWST. Decades-old IR observations of SNe are therefore exceedingly rare. Here we present fortuitous and serendipit…

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astro-ph.COastro-ph.HE

On the Clustering Bias of Unresolved Gamma-Ray Sources

Bhashin A. Thakore, Marco Regis, Michela Negro, Stefano Camera, Daniel Gruen, Nicolao Fornengo, Aaron J. Roodman

The Unresolved $γ$-Ray Background (UGRB) encodes the collective emission of source populations that are too faint to be detected individually, and its cross-correlation with tracers of the large-scale structure has emerged as a powerful tool to characterize those populations. In this work, we analyze the weak-lensing--UGRB cross-correlation using a reference blazar model. By modeling the relation between blazar $γ$-ray luminosity and host-halo mass, we infer the average linear bias $\langle b(z)…

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astro-ph.SRastro-ph.GA

The T-GEX project. II. Chrono-chemo-dynamic signatures of UV-bright FGK stars

D. Beltrán, M. L. L. Dantas, R. Smiljanic, P. B. Tissera

We compare the ages, chemical abundances, Galactic orbits, and inferred birth environments of 37 T-GEX stars with strong (G1), normal (G2), and intermediate (G3) UV emission. The groups show distinct correlation structures: UV colours correlate with chemical and orbital quantities in G1; G2 has the largest number of significant (anti-)correlations; and no UV-colour correlation reaches the adopted threshold in G3. Most stars have prograde disc-like orbits, while both halo-like objects belong to G…

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hep-phastro-ph.COastro-ph.HE

Collective flavor conversion in dense neutrino plasmas

Damiano F. G. Fiorillo

Compact transient sources, such as supernovae (SNe) and neutron star mergers (NSMs), host a population of thermal neutrinos in their inner cores, which decouple from the dense matter as they stream out. Yet, collisionless does not mean free; their density is large enough to mediate collective waves driven by the coherent weak neutrino--neutrino interaction. These collective waves carry little energy, but crucially they transport flavor. Neutrinos thus form a collisionless plasma with flavor tran…

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