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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.IM

First results for second generation SiSeRO CCD devices

Abigail Y. Pan, Declan O'Neill, Kevan Donlon, Peter Orel, Sven Herrmann, Steven Allen, Marshall W. Bautz, Tanmoy Chattopadhyay et al.

The Astro2020 Decadal recommended the development of a suite of next generation astronomical observatories spanning the X-ray to near-IR spectrum. These programs require fast, extremely low noise detectors to fulfill their science goals. To address this technology gap, Stanford X-ray Astronomy and Observational Cosmology (XOC) group, MIT Lincoln Laboratory (MIT-LL), and MIT Kavli Institute (MKI) are advancing Single electron Sensitive Read Out (SiSeRO), a multiband detector technology capable of…

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

Nancy Grace Roman Space Telescope Wide Field Instrument: Bright Point Source Saturation Response and Persistence Properties from Thermal-Vacuum Testing

Dana R. Louie, Robert F. Wilson, Thomas Barclay, Joshua E. Schlieder, Nicholas Bond, Evan Bray, Mario Cabrera, Stephanie Cheung et al.

The Nancy Grace Roman Space Telescope's Wide Field Instrument (WFI) will observe hundreds of thousands of bright stars across its Core Community Surveys, particularly in the dense stellar fields of the Galactic Bulge Time Domain Survey (GBTDS). Sources brighter than ~17th magnitude will saturate WFI detector pixels in typical survey exposures, with the brightest stars deeply saturating large pixel regions and potentially producing persistence signals that may impact subsequent observations. Prio…

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astro-ph.GA

The Next Generation Virgo Cluster Survey (NGVS). II. A Catalog of Galaxies in the Virgo Cluster

Laura Ferrarese, Patrick Cote, Lauren A. MacArthur, Joel C. Roediger, John P. Blakeslee, Michele Cantiello, Jean-Charles Cuillandre, Puragra Guhathakurta et al.

The Next Generation Virgo Cluster Survey (NGVS) is a deep, high resolution imaging campaign that used the 1 deg$^2$ MegaCam instrument on the Canada-France-Hawaii Telescope to carry out a comprehensive optical survey of the Virgo cluster, from its core to its virial radius. The NGVS covers a contiguous area of 104 deg$^2$ (8.63 Mpc$^2$ at the 16.5 Mpc distance of Virgo) in the $u^*$-,$g$-,$i$-, and $z$-band, with additional limited coverage in $r$. In this paper, we present the final catalog of…

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astro-ph.EPastro-ph.IM

Precise Determination of the Metallicity and C/O of WASP-39~b From a Single JWST Instrument Mode with Phase-Resolved Cross-Correlation Retrievals

Arjun B. Savel, Eliza M. -R. Kempton, Erin M. May, Matthew C. Nixon, Jegug Ih, Katherine A. Bennett, Joost P. Wardenier

Measuring atmospheric metallicities and C/O ratios is a key goal of JWST exoplanet science, given their proposed link to planet formation. Achieving this goal has previously been shown to require broad wavelength coverage ($\sim$1--5 $μ$m), typically demanding multiple instrument modes to complete the molecular inventory. Here, we show that the multi-instrument requirement can be circumvented using phase-resolved cross-correlation retrievals at native pixel resolution -- an approach more typical…

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astro-ph.EPastro-ph.GA

Characterizing Microlensing Planetary System OGLE-2014-BLG-0676L with High-Resolution Image Constrained Light Curve Modeling

Asahi Idei, Naoki Koshimoto, Daisuke Suzuki, Kansuke Nunota, David P. Bennett, Ian A. Bond, Jean-Philippe Beaulieu, Takahiro Sumi et al.

We present an analysis that incorporates high-resolution Keck adaptive optics (AO) imaging into microlensing light-curve modeling for the planetary microlensing event OGLE-2014-BLG-0676. Using Keck AO observations obtained 6.3 years after the event, we directly resolved the lens and source. The Keck images reveal a tension, in that the $K$-band source flux is $0.52 \pm 0.22$ magnitudes brighter than predicted by previously reported light-curve models. By incorporating the Keck imaging constraint…

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astro-ph.GA

Star formation powers optical line emission from the CGM

Huanian Zhang, Lizhi Xie, Zhijie Qu, Dennis Zaritsky, Luis C. Ho, Min Bao, Fabio Fontanot, Michaela Hirschmann et al.

Using integral field spectroscopy, we explore the disk-halo interface, or the inner circumgalactic medium (CGM), of individual galaxies by constructing and analyzing emission-line maps for a large sample (72) of normal, low-redshift galaxies spanning three orders of magnitude in stellar mass and four orders in star formation rate (SFR). We find a steep turnover occurring at $(1-2) R_e$ in the H$α$, [O {\small II}], and [O {\small III}] line emission radial profiles. Beyond this radius, the slope…

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astro-ph.EP

Late-infall-induced formation of giant planets, multi-generational planetesimals, and disk substructures

Haichen Zhao, Tommy Chi Ho Lau, Joanna Drążkowska, Tilman Birnstiel, Sebastian M. Stammler

Late infall can replenish the building materials of planets in protoplanetary disks and dramatically alter their structural evolution. The resulting pressure bumps effectively accumulate dust, facilitate grain coagulation, and trigger planetesimal formation via the streaming instability. In this work, we investigate the potential for planetesimal and planet formation, as well as the emergence of observable substructures, in disks undergoing late-stage infall. We utilize a comprehensive modeling…

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astro-ph.GAastro-ph.SR

Discovery of an Unbound Flyby Companion of UBC 63: In the Immediate Aftermath of a Close Encounter

Samrat Biswas, Biman J Medhi, Sergio Messina, Zhanpeng Zhu, Songmei Qin, Sukanta Deb, A. H. Sheikh, H. S Das et al.

We re-investigate the open cluster UBC 63 using the Gaia DR3 data and show that, rather than being a single cluster as previously classified, it is a compelling candidate for a double cluster undergoing an unbound flyby interaction. A GMM decomposition performed in the 5D astrometric space reveals the two statistically distinct components, namely UBC 63A (98 members, Age = 21 $\pm$ 4 Myr) and UBC 63B (148 members, Age = 562 $\pm$ 43 Myr). A significant age difference of $Δ\mathrm{Age} = 541 \pm…

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gr-qcastro-ph.HE

Search for continuous gravitational waves from the pulsar J0435+3233

Brian McGloughlin, Jing Ming, Maria Alessandra Papa, Kartikey Sharma, Reinhard Prix, Benjamin Steltner, Heinz-Bernd Eggenstein, Na Wang et al.

We perform a search for continuous gravitational waves from J0435+3233 using LIGO O4a public data. J0435+3233 is unique among millisecond pulsars as it exhibits an exceptionally large spin-down and marks the first pulsar observed to date with a spin-down larger than $10^{-12}$ Hz/s in the sub $10$ ms spin period range, making it a potentially strong source of continuous gravitational waves. We target signals at exactly twice the rotation frequency, a narrow band around this frequency, and also s…

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astro-ph.EP

A Self-Consistent 3D Hydrodynamic Model for Helium Transit Signatures in Evaporating Hot Jupiters

Anselmo Falorca, Aline Vidotto

The HeI triplet line (1083 nm), together with hydrodynamic models, can be used to characterize atmospheric escape of exoplanets. However, most of the available models cannot capture the three dimensional (3D) physics of escaping atmospheres, such as tidal forces and the interaction with stellar winds. To investigate how 3D effects affect the helium transit signature, we update our 3D atmospheric evaporation model to self-consistently solve the hydrodynamic equations together with the atomic hydr…

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astro-ph.EP

A Self-Consistent 3D Hydrodynamic Model for Helium Transit Signatures in Evaporating Hot Jupiters

Anselmo Falorca, Aline Vidotto

The HeI triplet line (1083 nm), together with hydrodynamic models, can be used to characterize atmospheric escape of exoplanets. However, most of the available models cannot capture the three dimensional (3D) physics of escaping atmospheres, such as tidal forces and the interaction with stellar winds. To investigate how 3D effects affect the helium transit signature, we update our 3D atmospheric evaporation model to self-consistently solve the hydrodynamic equations together with the atomic hydr…

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astro-ph.IMphysics.flu-dyn

Per Astronomix ad Astra: High-Order Differentiable (Magneto)hydrodynamics with Energy-Conserving Self-Gravity

Leonard Storcks, Nils Thuerey, Tobias Buck

We present astronomix, a performant differentiable (magneto)hydrodynamics simulator written in Python/JAX. We demonstrate how automatic differentiation, validated against hand-derived analytical functional derivatives and finite differences, enables inverse modeling over millions of parameters and allows for sensitivity and stability analysis as well as correct eigenmode initialization. The differentiability of astronomix furthermore enables training machine-learning models inside the simulator.…

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gr-qcastro-ph.IM

Post-Newtonian Global Conservation Laws in the Presence of Sensitive Bodies

Timothy Clifton, Asta Heinesen, Oliver Pitt

The parameterized post-Newtonian (PPN) approach is the state of the art formalism for performing theory independent tests of weak-field gravity, and for constraining possible deviations from Einstein's theory. Within this framework, global conservation laws are useful for the calculation of dynamics and for giving meaning to parameters. In this paper we extend the concept of semi-conservative and fully-conservative theories of gravity to include situations in which compact astrophysical bodies a…

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astro-ph.IMgr-qc

An Unsupervised Search for Novel Instrumental Glitches in LIGO O4a: Multi-Scale Sensitization, Empirical Physical Vetoes, and Rate Upper Limits

Luca Cirfeta

The fourth observing run (O4) of Advanced LIGO, Virgo, and KAGRA presents unparalleled sensitivity, rendering unsupervised pipelines highly vulnerable to the non-stationary domain shift of the detectors' noise manifolds. We present DANTE V3, concluding a longitudinal investigation into unmodeled anomalies during early O4a. By expanding to a multi-scale geometric framework (0.5 s to 4.0 s), we amplify morphological sensitivity, extracting 10,372 unique candidates. To mitigate domain-shift artifac…

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astro-ph.IMgr-qc

An Unsupervised Search for Novel Instrumental Glitches in LIGO O4a: Multi-Scale Sensitization, Empirical Physical Vetoes, and Rate Upper Limits

Luca Cirfeta

The fourth observing run (O4) of Advanced LIGO, Virgo, and KAGRA presents unparalleled sensitivity, rendering unsupervised pipelines highly vulnerable to the non-stationary domain shift of the detectors' noise manifolds. We present DANTE V3, concluding a longitudinal investigation into unmodeled anomalies during early O4a. By expanding to a multi-scale geometric framework (0.5 s to 4.0 s), we amplify morphological sensitivity, extracting 10,372 unique candidates. To mitigate domain-shift artifac…

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astro-ph.HEastro-ph.GAastro-ph.SRnucl-exnucl-th

Quantifying the Information Gain from Future High-Precision Radius Measurements for Identifying Twin Neutron Stars

Bao-An Li, Xavier Grundler

Twin neutron stars (NSs), characterized by identical gravitational masses but different radii, are among the most promising astrophysical signatures of a strong first-order hadron--quark phase transition in supradense matter. We investigate how increasingly precise NS radius measurements improve the Bayesian inference of twin-star observability using mock radius data for a canonical $1.4\,M_\odot$ NS. Radius uncertainties are varied from the current level of about $0.9$ km to the $\approx 0.1$ k…

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astro-ph.GAastro-ph.IMastro-ph.SR

The science of the cycle of matter in our Galaxy with the SKA

Marc Audard, Ke Wang

Exploring how matter cycles through the Galaxy, from the birth of stars in dense interstellar clouds to the ejection of matter and energy during a star's final stages-requires a multi-faceted approach. Radio observations are essential to reveal the intricate interactions at play. By studying our Galaxy in detail, we can use it as a model to better understand these processes in galaxies as well. The Square Kilometre Array offers unique capabilities in wide-field, high-sensitivity, high-resolution…

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astro-ph.IMastro-ph.HEcs.CV

Co-addition and Subtraction of Undersampled Images

Matan Schlanger, Barak Zackay

In astronomical imaging surveys, repeated observations of the same sky patches are taken in order to obtain deeper images and detect new sources. This is the case in the search for many transient phenomena, such as supernovae, gravitational wave (GW) optical counterparts and other cataclysmic variables. In many such surveys some of the images are undersampled, meaning that the pixel size is too large, and the image suffers from aliasing. For undersampled images, both co-addition of the images an…

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astro-ph.GA

Comparing the Near-infrared Spectral Energy Distributions from Different Stellar Population Synthesis Models with SPHEREx Observations

Jeong Hwan Lee, Minjin Kim, Woong-Seob Jeong, Yujin Yang, Daniel C. Masters, Kyuseok Oh, Bomee Lee, Zhaoyu Huai et al.

While stellar population synthesis (SPS) models have been widely used for spectral analysis in optical wavelengths, their characteristics remain uncertain in the near-infrared (NIR) due to a relative lack of observed NIR spectra. The spectrophotometric data from SPHEREx are well-suited for investigating the performance of SPS models in the NIR, thanks to its wide wavelength coverage over $0.7-5.0~{\rm μm}$. In this work, we compare the observed SPHEREx data of SDSS compact galaxies, including 2,…

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astro-ph.GA

Ergodicity of FIRE: star formation variations within and between simulated galaxies

Fraser M. Smith, Robert J. Thacker

We investigate the ergodicity of star formation in simulated galaxies from the FIRE-2 (Feedback In Realistic Environments) project. We restrict ergodicity considerations to being related to deviations from the star-forming main sequence (SFMS), and in turn whether ensemble averages across populations match time-averaged star formation histories (SFHs) based on simulated observable properties. We find that in these high-resolution simulations the deviations of individual galaxies from the SFMS te…

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astro-ph.SR

Evidence for elemental diffusion in the eclipsing binary star AI Phoenicis

Pierre F. L. Maxted, Nicholas Storm, Andreas J. Korn, Marília Carlos, Matthew R. Gent, Sviatoslav B. Borisov, Paula Jofré, Maria Bergemann et al.

AI Phe is an eclipsing binary star with an orbital period of 24.6 days for which the surface gravity and effective temperature are known from direct measurements to very high precision and accuracy. We have obtained high-quality spectroscopy of the K0IV star during the total eclipse of the F7V companion, and also obtained spectra with a very high signal-to-noise ratio for this star and its F7V companion using the spectral disentangling technique. We have used these spectra to measure the abundan…

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astro-ph.HE

The Complete Catalog of Gamma-Ray Transients Observed by GRBAlpha & VZLUSAT-2 CubeSat Missions

Marianna Dafcikova, Jakub Ripa, Andras Pal, Norbert Werner, Michaela Duriskova, Yasushi Fukazawa, Martin Kolar, Laszlo Meszaros et al.

We present the largest sample of gamma-ray transients observed by any CubeSat mission so far. Observations were acquired by a 1U CubeSat GRBAlpha, the smallest astrophysical space observatory, and a 3U CubeSat VZLUSAT-2. Both missions were technological pathfinders and carried a novel CsI scintillator-based detector read-out by silicon photomultipliers. They operated on Sun-synchronous low Earth orbits below 550 km for about four years; GRBAlpha between March 2021 and June 2025 while VZLUSAT-2 b…

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astro-ph.SRastro-ph.GAastro-ph.IM

Probabilistic Stellar Age Estimation for Gaia XP Stars with NGBoost

Xiaokun Hou, Wenbo Wu, Gang Zhao, Haining Li, Jingkun Zhao

Stellar age is a fundamental quantity for Galactic archaeology, but reliable age estimation for large stellar samples remains challenging. In this work, we develop an uncertainty aware NGBoost framework for stellar age estimation using Gaia XP-derived atmospheric parameters and chemical abundances. Different from the standard NGBoost model, we modify the loss function by incorporating the uncertainties of the training age labels. We further use a Monte Carlo strategy to quantify the influence of…

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astro-ph.IMastro-ph.CO

gevolution 2.0: GPU-accelerated relativistic N-body simulations for cosmology

Julian Adamek, Øyvind Christiansen

High-performance computing is increasingly dominated by hardware acceleration using Graphics Processing Units (GPUs). To take advantage of this long-term trend, we implement a major overhaul of the parallelisation approach in the relativistic particle-mesh N-body code gevolution. The new version 2.0 of gevolution employs three layers of parallelisation: MPI for scalability on a distributed memory system, shared memory parallelisation on each MPI rank using OpenMP, and offloading all compute inte…

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astro-ph.SRastro-ph.IM

Solar, Heliospheric and Ionospheric Physics: Pathfinders, Precursors and SKAO Perspective

Pietro Zucca, Rohit Sharma, Divya Oberoi, Eduard Kontar, John Morgan, Peter Gallagher, Sven Wedemeyer, Biagio Forte et al.

The Solar, Heliospheric and Ionospheric (SHI) Physics Science Working Group of the Square Kilometre Array Observatory (SKAO) addresses the full chain of plasma processes linking the solar corona to the terrestrial environment. This overview chapter synthesises 16 topical contributions to Advancing Astrophysics with the SKA-II, spanning the quiet and active solar atmosphere, eruptive phenomena, heliospheric turbulence and solar-wind diagnostics, ionospheric science, stellar-solar connections, and…

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astro-ph.GA

Spatio-kinematical structure of the Galactic Nuclear Stellar Disk revealed in VLBI astrometry of circumstellar masers

Hiroshi Imai, Kohei Kurahara, Huib J. van Langevelde, Maria J. Rioja, Richard Dodson

SKA-VLBI astrometry will enable us to measure up to thousands of three dimensional motions of OH masers associated with circumstellar envelopes (CSEs) of OH/IR stars in the Nuclear Stellar Disk (NSD) and sites of high mass star formation in the Central Molecular Zone (CMZ) of the Galactic Center (GC). It is expected that the spatio-kinematical distribution of those OH masers should indicate the existence of a ring structure in the NSD, which has formed as a result of outward propagation of star-…

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astro-ph.HEastro-ph.GA

Black hole spin-mass correlation and vector resonant relaxation in gaseous star clusters: the origin of GW231123?

Zacharias Roupas

During the formation of a star cluster a spin-mass correlation of stellar black holes is generated as they grow via accretion of the residual gas. Moreover, the black hole spin tends to be anti-aligned with its orbital angular momentum in the cluster. We show that GW231123, reported by the LIGO-Virgo-KAGRA (LVK) collaboration, lies on our predicted high-mass, high-spin plateau of the spin-mass correlation with positive Bayesian evidence over the LVK prior. Furthermore, vector resonant relaxation…

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astro-ph.SR

Fast and periodic propagating disturbances along coronal loops detected with EUI on board Solar Orbiter

A. Dolliou, S. Mandal, K. Barczynski, T. Van Doorsselaere, D. Berghmans, C. Froment, F. Auchère, P. Antolin et al.

Recent high-resolution observations from the Solar Orbiter mission can help detect the indirect signatures of heating at the smallest scales. In this work we measure the properties and investigate the physical origin of propagating disturbances (PDs) in the intensity at the smallest resolvable scales with Solar Orbiter/EUI along coronal loops. We used two sequences of EUI/HRIEUV at high spatial (down to 125 km per pixel) and temporal resolutions (5 s of cadence). We placed slits along 13 active…

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

Revealing a multi-zone circumnuclear dust response in UGC~11487 through phase-resolved WISE W1--W2 diagnostics

I. O. Izviekova, O. V. Kompaniiets, I. B. Vavilova

Mid-infrared (MIR) flares provide a direct probe of dust reprocessing in obscured tidal disruption event (TDE) candidates when the primary optical or ultraviolet flare is weak, missed, or strongly attenuated. We present a phase-resolved analysis of the WISE/NEOWISE W1-W2 evolution of the MIR-selected TDE candidate UGC 11487/WTP14adeqka over 2014-2024. We combine timing, colour, and flux diagnostics with phenomenological modelling, hydrodynamically motivated clumpy dust-echo calculations, and an…

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astro-ph.IM

DESTINY: a new binding-energy-resolved astrochemical framework. Self-Consistent Competitiveness using Branched Absorbing Markov Chains

Maria Groyne, Cedric Baijot, Michaël De Becker

Under cryogenic interstellar conditions, the amorphous structure of interstellar ice results in binding-energy distributions (BEDs) per species. However, only few studies attempted their inclusion in astrochemical models. This paper introduces DESTINY, a deterministic astrochemical framework designed to incorporate BEDs while self-consistently accounting for the competition among activated surface processes. The framework is currently constrained to a monolayer. Surface processes initiated by su…

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