UchUchU

Research Trends

Latest preprints in space engineering and astrophysics.

physics.space-ph

AETHER-P3 Nowcast v1.0: Model Description, Training-Data Construction, and Validation Technical report prepared in support of CCMC onboarding

Ruochen Wang, Xiaoli Bai

AETHER-P\textsuperscript{3} Nowcast v1.0 is a machine-learning-based global thermospheric neutral-density model developed for low-Earth-orbit applications and prepared for onboarding to NASA's Community Coordinated Modeling Center (CCMC). The model provides pointwise neutral-density estimates together with predictive uncertainty using a deep evidential regression framework driven by causal solar, solar-wind, geomagnetic, spatial, temporal, and empirical-model inputs. This report documents the re…

astro-ph.IMcs.CV

NEO-BENCH: A New Multi-Source Benchmark for Generalizable Astronomical Streak Detection

Jiayou He, Jessica Yao

Near-Earth Objects (NEOs) can appear as faint streaks in long-exposure astronomical images. Detecting these streaks across diverse observatories requires methods that remain reliable despite differences in image quality, orientation, sky background, and noise. However, existing detectors are commonly evaluated using data from only one source, providing limited evidence of cross-source generalization. We introduce NEO-Bench, a multi-source benchmark containing 8,376 images from five astronomical-…

astro-ph.SRastro-ph.GA

Elusive helium stars in the gap between subdwarfs and Wolf-Rayet stars III. Formation of the Galactic population of stripped helium stars

L. R. Yungelson, A. G. Kuranov, A. V. Mishakina

Population synthesis based on the grid of pre-computed evolutionary sequences for close binaries is applied to the problem of formation of the Galactic population of stripped helium stars, the remnants of $5 \lessapprox M/M_\odot \lessapprox 24$ primary components of close binaries after RLOF. Stellar rotation is taken into account. For the current star formation rate in the Galaxy $2\,M_\odot yr^{-1}$, the estimate of the number of 1 to $7\,M_\odot$ objects with $T_{eff} \gtrapprox $25000K rang…

astro-ph.GAcond-mat.quant-gasgr-qc

Fractional Bose-Einstein Condensate Dark Matter Cores: Numerical GPP Solutions and SPARC Rotation Curves

Akila Labadi, Mohamed Benarous, Ahmed Hocine

We investigate a fractional Bose Einstein condensate dark matter scenario in which an ultralight bosonic component forms a self gravitating core embedded in a predominantly cold dark matter halo. The stationary GPP system solved numerically beyond the TF approximation leads to energetically bound equilibrium configurations and good phenomenological fits to the selected rotation curves from 30 SPARC galaxies.

hep-phastro-ph.HEhep-th

Solar Capture Tests of Inelastic Dark Matter after the LZ High-Recoil Event

Mattia Di Mauro, Halim Shaikh

The LUX-ZEPLIN (LZ) Collaboration has reported a $248$ keV nuclear-recoil candidate for which endothermic dark matter (DM) gives some of the largest local significances. We study Solar-capture constraints on three simple interpretations: a thermal Higgsino, a thermal pseudo-Dirac fermion with off-diagonal vector interactions, and neutron-philic endothermic spin-dependent scattering through $\mathcal{O}_4$. The canonical full-density thermal Higgsino is excluded: its LZ-preferred splitting near $…

hep-phastro-ph.HEhep-th

Solar Capture Tests of Inelastic Dark Matter after the LZ High-Recoil Event

Mattia Di Mauro, Halim Shaikh

The LUX-ZEPLIN (LZ) Collaboration has reported a $248$ keV nuclear-recoil candidate for which endothermic dark matter (DM) gives some of the largest local significances. We study Solar-capture constraints on three interpretations: a thermal Higgsino, a thermal pseudo-Dirac fermion with off-diagonal vector interactions, and neutron-philic endothermic spin-dependent scattering through $\mathcal{O}_4$. The canonical full-density thermal Higgsino is excluded: its LZ-preferred splitting near $0.38\,\…

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

Calibration of CNEOS Fireball Velocities and the Robustness of Nominally Hyperbolic Events

Volkan Duran, Abraham Loeb

The NASA/JPL CNEOS Fireball Data catalogue provides a near-global record of bright atmospheric entries but does not report per-event velocity covariance. We calibrate its kinematic accuracy using 19 events with independent reference trajectories and use optical, satellite, radar, and infrasound catalogues as source-specific controls. For nine modern high-quality comparisons, the CNEOS-minus-reference speed residual has mean -1.00 km s$^{-1}$ and standard deviation 0.86 km s$^{-1}$; variance deco…

gr-qcastro-ph.HE

Physics-based phenomenological modeling of binary black hole hierarchical formation 2: Autodifferentiable functional inference of hierarchical compact-binary populations

R. O'Shaughnessy, M. Zeeshan, M. Qazalbash

The gravitational-wave (GW) census contains mass and spin structure consistent with contributions from black holes assembled through repeated mergers in dense environments. Connecting that structure to formation physics requires models that are both physically interpretable and tractable within population inference. We construct an autodifferentiable, physics-based phenomenological model in which each dense environment is represented by a coagulation response and a population of such environment…

astro-ph.IM

Chromatic Anisoplanatism in Adaptive Optics: A detailed comparison of theory with numerical simulations

B. Femenía-Castellá, N. Devaney

Context. Chromatic Anisoplanatism arises in Adaptive Optics because atmospheric refraction makes rays of different wavelengths follow different paths through the atmosphere resulting in different wavefronts at the sensing wavelength and the science wavelength, introducing a correction error that grows rapidly with zenith distance. Aims. Using numerical simulations based purely on geometric optical propagation we aim to validate the theoretical framework describing wavefront errors caused by Chro…

astro-ph.EP

An Outer Giant Excites and Constrains the Orbit of $π$ Mensae d

Qunfeng Jiang

The nearby $π$ Mensae system contains the eccentric giant planet b on a 5.7 yr orbit, the 6.27 day transiting sub-Neptune c, and a candidate planet d on a 123 day orbit between them. Published estimates place the eccentricity of d between approximately 0.2 and 0.4. We reanalyze 772 published velocities with three-Keplerian fits and explore three-dimensional b-d dynamics with N-body integrations. The high-eccentricity solution persists when the phase or apsidal prior is widened; exact importance…

astro-ph.GAastro-ph.CO

ADF22-WEB: Massive galaxy formation shaped by cosmic web filaments in the z = 3.1 proto-cluster core

Hideki Umehata, Ian Smail, Charles C. Steidel, Bret D. Lehmer, Kouichiro Nakanishi, Bunyo Hatsukade, Mariko Kubo, Norika Okauchi et al.

We present a census of dust, molecular gas, and galaxy structure in 18 dusty star-forming galaxies (DSFGs) at $z=3.09$ embedded in Ly$α$-traced cosmic web filaments in the core of the SSA22 proto-cluster, using multi-band ALMA, JWST imaging, and JVLA CO(1--0). Using up to six ALMA bands and Herschel/SPIRE data, we construct rest-frame far-infrared spectral energy distributions. The DSFGs span two orders of magnitude in far-infrared luminosity ($L_{\rm FIR}\sim10^{11}$--$10^{13}L_\odot$), with me…

astro-ph.SRastro-ph.IM

PySeshat: A Validated Python Pipeline for Binary-Star Orbit Determination and Al-Wardat Stellar Atmosphere Modeling

R. I. El-Kholy, Z. M. Hayman

Precise stellar masses and physical parameters for binary and multiple star systems require, respectively, well-constrained orbital solutions and independent stellar-atmosphere modeling. Existing open-source software addresses these separately, and hierarchical triple systems additionally require simultaneous fitting of their inner and outer orbits, a treatment few existing tools provide. We present PySeshat, an open-source Python package unifying binary and hierarchical-triple orbit determinati…

astro-ph.HE

Possible Sources of Iron Nuclei in Ultra-High-Energy Cosmic Rays

Anna Uryson

The origin of a cosmic ray particle with an ultra-high energy of 2.44 x 10^20 eV recorded by the Telescope Array is discussed by assuming that it is a heavy nucleus, namely an iron or silicon nucleus. Iron is chosen as a heaviest element in cosmic rays, while silicon is chosen to find out how much the theoretical results obtained vary with the mass of the heavy nucleus. Assuming extragalactic origin of the particle with such energy, the constraints on the distances to possible sources are analys…

astro-ph.HEgr-qc

CoportSL: A Contribution-constrained Hybrid Slow-light Framework for Time-dependent Polarized GRMHD Imaging

Fan Zhou, Jiewei Huang, Yuehang Li, Minyong Guo, Bin Chen

Fast-light approximations neglect fluid evolution along rays, whereas slow-light modeling is indispensable for recovering the true magnetohydrodynamic state. However, full slow-light radiative transfer for extended general relativistic magnetohydrodynamic (GRMHD) sources requires simultaneous access to many fluid snapshots and is memory-intensive. We introduce CoportSL, the first contribution-constrained hybrid slow-light framework for time-dependent full-Stokes imaging. It uses emission, absorp…

astro-ph.HEastro-ph.GA

Chandra X-ray imaging and IC/CMB model for the inner jet of PKS 0637-752

Jaya Maithil, Daniel A. Schwartz, Aneta Siemiginowska, Diana M. Worrall, Preeti Kharb

We present the X-ray surface brightness maps of the jet from the quasar PKS 0637-752, using two epochs of archival Chandra observations (1999 and 2017). We present, for the first time, a model of the faint inner jet extending from 3.4 to 7 arcsec from the core, interpreting its X-ray emission as inverse Compton scattering of cosmic microwave background photons by the synchrotron-emitting relativistic electrons. The inner jet contrasts with the bright outer part of the jet, dominated by several d…

astro-ph.SR

Stage-dependent superhump waveform evolution and non-stationary positive-superhump timing in the near-period-gap dwarf nova YZ Cancri

Zhibin Dai, Xuefei Chen, Zhanwen Han

We present a photometric and timing study of the near-period-gap SU~UMa-type dwarf nova YZ~Cancri, based on nearly continuous Transiting Exoplanet Survey Satellite (TESS) photometry and long-baseline ground-based observations. Our main observational result is that the positive-superhump (SH) waveform follows a repeatable, stage-dependent sequence during superoutbursts (SOs). In the two well-covered TESS SOs, and consistently in the long-baseline ground-based SO sample, the plateau waveform evolv…

astro-ph.IM

Generating radio continuum survey maps of arbitrary size with latent diffusion models

Tobias Vičánek Martínez, Marcus Brüggen

Radio surveys provide exponentially increasing amounts of observational data, which requires the development of novel data reduction and analysis methods. To this end, realistic simulations of observational data provide controlled environments for testing and developing new methods. Diffusion models excel at synthesizing realistic image data, but are limited by size constraints and high computational demands. We implemented a latent diffusion model (LDM) to synthesize realistic radio survey map…

astro-ph.IMastro-ph.EPphysics.opticsphysics.space-ph

Mechanisms of Electrostatic Charge Formation and Retention in Lunar Regolith

Minhyeok Kim, Hyun Jung Kim, Sang H. Choi, Ashley Daeun Jung

As the Artemis program advances toward the lunar south pole and permanently shadowed regions (PSRs), understanding lunar charging is increasingly important for protecting astronauts, robotic systems, instruments, and infrastructure. Persistent darkness, cryogenic temperatures, low regolith conductivity, and long charge-relaxation times may allow energetic-particle-induced charge to accumulate beneath the surface. This Technical Memorandum addresses a key unresolved question: how is electrostatic…

astro-ph.GA

A Direct DESI--SDSS Two-Fibre Test of Aperture Bias in Optical Emission-Line Diagnostics

Shihong Liu, Yu Rong

Fixed angular apertures sample different physical regions of nearby galaxies and can therefore bias optical emission-line diagnostics. We use 20,545 high-confidence emission-line galaxies observed by both the Dark Energy Spectroscopic Instrument (DESI) and the Sloan Digital Sky Survey (SDSS) as a two-fibre experiment, in which the DESI 1.5 arcsec fibre is nested within the SDSS 3 arcsec fibre. To isolate aperture effects from line-measurement systematics, we refit every spectrum using the same e…

astro-ph.GA

A Direct DESI--SDSS Two-Fibre Test of Aperture Bias in Optical Emission-Line Diagnostics

Shihong Liu, Yu Rong

Fixed angular apertures sample different physical regions of nearby galaxies and can therefore bias optical emission-line diagnostics. We use 20,545 high-confidence emission-line galaxies observed by both the Dark Energy Spectroscopic Instrument (DESI) and the Sloan Digital Sky Survey (SDSS) as a two-fibre experiment, in which the DESI 1.5 arcsec fibre is nested within the SDSS 3 arcsec fibre. To isolate aperture effects from line-measurement systematics, we refit every spectrum using the same e…

astro-ph.IMastro-ph.GA

DustRover: A Python Package for Modelling Dust Extinction Curves (Phase I)

Amir E. Bazkiaei, Tayyaba Zafar, Nuria P. F. Lorente, Anilkumar Mailvaganam, Arihant Raidani

We introduce DustRover, an open-source Python package designed to model dust extinction curves using multi-wavelength regimes. DustRover supports optical/infrared spectroscopy, broadband photometry, and X-ray data within a unified framework, enabling robust analysis of dust extinction curves in distant galaxies. The software features a modular architecture that strictly decouples data management, dust models, and Markov Chain Monte Carlo (MCMC) based statistical fitting. The package is highly us…

astro-ph.IMastro-ph.GA

PERRY: A Human-in-the-Loop GUI for Precision Alignment of MUSE Data

Amir E. Bazkiaei, Brent Miszalski, Jesse van de Sande, Nuria P. F. Lorente, Simon O'Toole, Kate Sheng

The Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope produces high-dimensional data-cubes where even minor astrometric misalignments between multiple exposures can introduce severe artifacts and compromise data quality. While automated pipelines provide a crucial baseline, subtle offsets require human intervention. To address this, we introduce PERRY, an interactive, Python-based Graphical User Interface (GUI) explicitly designed for the visual inspection and manual fine-tuni…

stat.MLastro-ph.COastro-ph.IMcs.AIcs.LG

Recovering Weak Signals with Normalizing Flows

Sarod Yatawatta

In many scientific disciplines, weak signals of interest are obscured by dominant nuisance signals that are several orders of magnitude stronger. Recovering these weak signals requires subtracting the dominant ones; however, this calibration process inherently distorts or partially suppresses the underlying signal of interest. To address this problem, we propose the use of normalizing flow models to reconstruct calibration-affected weak signals. By leveraging the statistical invariance of the ta…

astro-ph.HEgr-qcnucl-th

Detectability of bulk viscosity effects on post-merger gravitational wave signals from binary neutron star mergers

Zhenyu Zhu, Michail Chabanov, Richard O'Shaughnessy

We investigate bulk viscosity (BV) effects on post-merger gravitational wave (PMGW) signals from binary neutron star (BNS) mergers and their detectability using realistic equation of state (EoS) posteriors constrained by recent progress in gravitational-wave (GW) and X-ray observations, as well as neutron skin thickness measurements. A linear fitting formula based on recent BNS simulations with BV is used to estimate the peak frequency shift of the PMGWs caused by BV effects. Subsequently, we ev…

astro-ph.HEgr-qcnucl-th

Constraining the Equation of State of Neutron Stars with third-generation Gravitational Wave detectors

Zhenyu Zhu, Richard O'Shaughnessy

We investigated the impact of the number of binary neutron star merger events and neutron star (NS) mass distributions on constraining the equation of state (EoS), tidal deformability and radius of NSs, as well as the nuclear parameters, using binary neutron star inspiral gravitational wave signals with third-generation detectors. We generate simulated gravitational wave signals and compute the Fisher information matrix for each event after the number of events and mass distribution models are g…

astro-ph.SRastro-ph.HE

IPHAS J190812.63+045728.1: A deeply eclipsing, X-ray bright cataclysmic variable with frequent outbursts

Raimundo Lopes de Oliveira, Albert Bruch, Koji Mukai, A. S. de Araujo, Guilherme P. Guimarães, Ted Leandro de Almeida

We present a multi-wavelength characterization of IPHAS J190812.63+045728.1. Independently discovered by us after being serendipitously observed by XMM-Newton, followed up with optical photometry with SPARC4/OPD and spectroscopy with GMOS/Gemini South, and exploring archival TESS and ZTF observations, we reveal the system to be an eclipsing accreting white dwarf (WD) system with an orbital period of 5.073 h. The deep optical and flat-bottomed X-ray eclipses completely occult the WD and the accre…

astro-ph.SR

Coordinated Coronagraphic Observations from Proba-3 and Aditya-L1: Investigating CME Energetics in the Inner Corona

Anjali Agarwal, Wageesh Mishra, R. Ramesh, V. Muthu Priyal, A. N. Zhukov, Jagdev Singh, Nat Gopalswamy, Soumyaranjan Khuntia et al.

Constraining the plasma properties and energetics of coronal mass ejections (CMEs) in the inner corona is essential for understanding their early evolution, yet remains challenging because of limited observations. We investigate the mass and density evolution, and energy partitioning of two CMEs observed on 2025 September 14 and 16, and assess the potential of coordinated Proba-3/ASPIICS and Aditya-L1/VELC observations to constrain CME energetics in the low corona. We present the first coordinat…

astro-ph.GAcs.CVcs.LG

Deep learning from the crowd Fundamentals of morphological galaxy classification

Luis Enrique Sucar, Carlos del Burgo, Jonathan Serrano-Pérez

Aims. The objective of this work is to adapt a deep neural network model to perform galaxy morphological classification trained from crowd annotations, considering the training scheme, the agreement between the annotators, and the hierarchy. Methods. We use Galaxy Zoo 1 as our experimental testbed and trained a convolutional neural network (CNN) for the automatic classification of galaxies' morphologies. We analyze the impact of the following aspects on the classification accuracy and training e…

astro-ph.GAastro-ph.SR

Interstellar Complex Organic Molecules and Molecular Outflows in NGC 1333 IRAS 4B and 4B' Observed Using NOEMA

C. C. Sarver, M. M. Giese, D. C. Lis, S. L. Widicus Weaver

We present interferometric observations with the Northern Extended Millimeter Array (NOEMA) of NGC 1333 IRAS 4B and 4B', two young stellar objects (YSOs) within the Perseus molecular cloud. YSOs, especially Class 0 protostars, are rich in gas-phase interstellar complex organic molecules (iCOMs), but relatively little is known about the spatial distribution of these important prebiotic molecules. Various molecules were imaged within IRAS 4B and the surrounding area in the 145 GHz spectral range,…

astro-ph.GAastro-ph.SR

Interstellar Complex Organic Molecules and Molecular Outflows in NGC 1333 IRAS 4B and 4B' Observed Using NOEMA

C. C. Sarver, M. M. Giese, D. C. Lis, S. L. Widicus Weaver

We present interferometric observations with the Northern Extended Millimeter Array (NOEMA) of NGC 1333 IRAS 4B and 4B', two young stellar objects (YSOs) within the Perseus molecular cloud. YSOs, especially Class 0 protostars, are rich in gas-phase interstellar complex organic molecules (iCOMs), but relatively little is known about the spatial distribution of these important prebiotic molecules. Various molecules were imaged within IRAS 4B and the surrounding area in the 145 GHz spectral range,…