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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.GA

First Light and Assembly of GalaxieS (FLAGS) I: The JWST/NIRCam Number Counts and IGL as Constraints on Galaxy Formation Models

Jack C. Turner, Stephen M. Wilkins, Aswin P. Vijayan

JWST observations have been used in conjunction with SED fitting to infer the physical properties of galaxies throughout cosmic time, revealing tensions with the predictions of theoretical models. However, the biases associated with this process are poorly understood, which limits its true constraining power. We introduce the First Light and Assembly of GalaxieS (FLAGS) series, which will leverage forward modelling to confront models with more reliable direct observables. We describe the consist…

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astro-ph.GAastro-ph.SR

GLOW II: A Census of Oxygen in Low-Mass Galaxies

Kristen B. W. McQuinn, O. Grace Telford, Andrey V. Kravtsov, Joseph Burchett, Roger Cohen, Laura Hunter, Evan D. Skillman, Julia Roman-Duval et al.

Oxygen is forged by stars and redistributed through galaxies by feedback-driven outflows, leaving a record of star formation and the baryon cycle imprinted on its present-day abundance and distribution. The Galaxies Losing Oxygen via Winds (GLOW) project quantifies the production, distribution, and retention of oxygen in 37 low-mass, low-metallicity, gas-rich galaxies in the nearby universe (D 0.5) and within 1 Mpc of a massive galaxy (Mstar>10^9 Msun), indicating environment likely affects the…

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astro-ph.GAastro-ph.SR

GLOW I: Comprehensive Measurements of Gas-Rich, Star-Forming, Low-Mass Galaxies in the Nearby Universe

Kristen B. W. McQuinn, O. Grace Telford, Roger Cohen, Liese van Zee, Laura C. Hunter, Madison Smith, Evan D. Skillman, Benjamin Williams et al.

Gas-rich, star-forming, low-mass galaxies in the nearby universe are powerful laboratories for studying baryonic physics in detail including: stellar mass assembly, stellar feedback, chemical enrichment, and the interplay of the interstellar medium with star formation. Investigating these disparate yet interconnected processes requires data obtained by myriad observatories. Here, we present a comprehensive atlas of uniformly processed data on 37 low-mass galaxies within 6 Mpc. The atlas includes…

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gr-qcastro-ph.IM

The G347.3-0.5 outlier from O3: a follow-up case study for continuous gravitational-wave candidates

L. Mirasola, F. Amicucci, M. Carrio, D. H. T. Cheung, M. A. Ferrer-Martinez, E. Goetz, D. Keitel, A. M. Knee et al.

We report a multi-pipeline follow-up study of the continuous gravitational-wave (CW) outlier identified by the Ming et al. Einstein@Home directed search for the young supernova remnant G347.3-0.5 (containing the central compact object RXJ1713.7-3946). The outlier was initially identified in LIGO data from the O3a observing run and followed up with the addition of O3b and O4a data by the Einstein@Home pipeline, with O4a producing weaker evidence. Here, we show extended data quality checks and res…

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astro-ph.HE

Wild behaviour near the finish line: the Type Ibn SN 2020able and its stratified environment

L. Tartaglia, E. Cappellaro, G. Valerin, A. Pastorello, S. Benetti, A. Reguitti, L. Tomasella, P. Lundqvist et al.

We present spectrophotometric observations of the Type Ibn supernova SN~2020able, along with a comprehensive analysis and modelling of its evolution. The transient occurred in SDSS J092602.93+243115.1, a faint host galaxy characterised by significantly sub-solar metallicity ($12+\log(\rm{O/H})\simeq8.28\,\rm{dex}$). The early photometric evolution and high peak luminosity ($L_{peak}\simeq4.4\times10^{43}\,\rm{erg}\,\rm{s^{-1}}$) indicate an efficient conversion of ejecta kinetic energy into radi…

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astro-ph.HEhep-phhep-th

Constraints on magnetic monopoles from X-ray observations of neutron stars

Mainak Mukhopadhyay, Daniele Perri, Edward W. Kolb

Magnetic monopoles are captured efficiently by neutron stars, and if they catalyze nucleon decay, the decay products would thermalize and generate observable X-ray surface emission. We use archival Chandra, XMM-Newton, and Swift-XRT data for old isolated millisecond pulsars to place conservative limits on the Galactic monopole flux ($F_M$). For a benchmark cross-section of $σ_{Δ\rm B} \sim 10^{-27}\ {\rm cm^2}$, our constraint as a function of monopole mass $m_M$ is given by $F_{\rm M}(m_M) \les…

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gr-qcastro-ph.HEastro-ph.IM

Celephais: efficient spectral initial data code for precessing compact binaries

Hao-Jui Kuan

Large numerical-relativity surveys require compact-binary initial data that are both spectrally accurate and inexpensive to construct, including for systems with unequal masses and misaligned spins. We present \celephais, a compact-object initial-data code built on the \texttt{Kadath} spectral library, that constructs binary-neutron-star and black-hole--neutron-star initial data without imposing equatorial symmetry. The method exploits the sparse structure of the globally coupled multi-domain Ja…

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astro-ph.COastro-ph.GA

HST imaging, pipeline modeling, and time-delay predictions of 2 triply-imaged and 15 quadruply-imaged lensed quasars

William Sheu, Tommaso Treu, Adriano Agnello, Timo Anguita, Simon Birrer, Daniel Gilman, Xiaosheng Huang, Richard G. McMahon et al.

The Hubble-Lemaître tension remains a significant challenge in modern cosmology, exhibiting a discrepancy between early-Universe cosmic microwave background measurements and local distance ladder observations. Strong lensing time-delay cosmography provides an independent, geometric probe of $H_0$ that can help resolve this discrepancy. Although hundreds of lensed quasars have been discovered, only a handful have been analyzed due to the resource-intensive follow-up required to measure precise ti…

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astro-ph.COastro-ph.GA

HST imaging, pipeline modeling, and time-delay predictions of 2 triply-imaged and 15 quadruply-imaged lensed quasars

William Sheu, Tommaso Treu, Adriano Agnello, Timo Anguita, Simon Birrer, Daniel Gilman, Xiaosheng Huang, Richard G. McMahon et al.

The Hubble-Lemaître tension remains a significant challenge in modern cosmology, exhibiting a discrepancy between early-Universe cosmic microwave background measurements and local distance ladder observations. Strong lensing time-delay cosmography provides an independent, geometric probe of $H_0$ that can help resolve this discrepancy. Although hundreds of lensed quasars have been discovered, only a handful have been analyzed due to the resource-intensive follow-up required to measure precise ti…

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

A clear detection of proper motion confirms that the claimed $\mathbf{z\simeq32}$ galaxy candidate, "Capotauro'', is a Y-type brown dwarf

F. -Y. F. Liu, D. J. McLeod, B. J. Sutlieff, T. J. Dupuy, J. S. Dunlop, X. Chen, R. J. McLure, H. -H. Leung et al.

The compact red source ``Capotauro'', discovered in deep JWST imaging in 2025, has been suggested as a possible galaxy candidate at redshift $z\simeq32$ on account of its extreme NIRCam colours. However, given the lack of evidence that this source is spatially resolved, a very cool brown dwarf, at a distance consistent with the scale-height of the Milky Way stellar disc ($\simeq 500$ pc), provides an alternative explanation of the observed photometry. Here we exploit new medium-band NIRCam imagi…

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astro-ph.SR

White Dwarf Kicks via Episodic Mass Ejection from Red Giant Stars

Jim Fuller

Recent observations have found evidence that white dwarf (WD) stars receive a kick of $\sim$1 km/s as the envelopes of their red giant progenitors are expelled. We show that these kicks can arise from asymmetric and episodic mass loss of red giant stars. Based on simple hydrodynamic models of red giant mass loss, each mass ejection event likely expels of order $\sim \! 10^{-4} \, M_\odot$, imparting a small and randomly oriented kick to the star, with the net kick to the WD arising from a combin…

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astro-ph.COastro-ph.IMhep-phhep-th

Sensitivity of Next-Generation CMB Surveys to Neutrinos and Other Light Relics

Cynthia Trendafilova, Srinivasan Raghunathan, Benjamin Wallisch, Joel Meyers, Kevork N. Abazajian, Edoardo Altamura, Carlo Baccigalupi, Kimberly K. Boddy et al.

Neutrinos and other light relics leave characteristic imprints in the cosmic microwave background anisotropies, making their observation a sensitive probe of the particle content and thermal history of the early universe. The energy density in these relativistic species is parameterized by their effective number $N_\mathrm{eff}$. Measuring this parameter at the percent level, which is a long-standing science goal of CMB-S4 and other experiments, would test a wide range of well-motivated physics…

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astro-ph.COastro-ph.GA

Simplified treatment of kinematic corrections to the SZ effect using the boost operator approach

Alex Hoey, Jacob Long, Jens Chluba

The Sunyaev-Zeldovich (SZ) effects provide a potent cosmological probe of the large-scale structure in the universe. Here, we present a simplified derivation of the kinematic corrections to the relativistic thermal SZ effect using the boost operator approach. By first performing the thermal average inside the moving electron cloud frame, the thermal and peculiar motion contributions can be naturally separated, leading to a significant simplification of the scattering calculation. The angular dep…

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astro-ph.HE

Core-Collapse Supernova detections from Einstein Telescope within the Milky Way

I. F. Giudice, A. L. De Santis, M. T. Botticella, M. Branchesi, G. Pastorelli, L. Girardi, L. Izzo, E. Cappellaro et al.

Core-collapse supernovae are key drivers of galaxy evolution and promising sources of gravitational waves, which provide a unique probe of the physics driving their explosion mechanism. Third-generation detectors, such as the Einstein Telescope, will dramatically improve the prospects for detecting these signals. This study assesses the capability of the Einstein Telescope, alone and in synergy with next-generation detectors such as Cosmic Explorer, to detect gravitational waves from core-collap…

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astro-ph.IM

Closing the loop on-sky with a vector-Zernike wavefront sensor using a convolutional neural network as phase reconstructor

Francisco Oyarzún, Mathieu Motte, Cedric-Taissir Heritier, Benjamin González, Rodrigo Muñoz, Vincent Chambouleyron, Marie Angelie Alagao, Arnaud Striffling et al.

Context: The new giant segmented mirror telescopes will use adaptive optics to reach the fundamental limits in resolving power. To accomplish this, new wavefront sensors (WFS) have been designed to fulfill the requirements, but they may require non-linear reconstruction techniques to operate given the nature of the signal of the WFSs Aims: In this article we show that it is possible to use non-linear reconstructors to extend the dynamic range of one of the most sensitive wavefront sensors far be…

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astro-ph.IM

Telemetry is a Sensor: Opportunistic Wavefront Estimation for the James Webb Space Telescope

Lahav Buzi, Yoav Y. Schechner, Aviad Levis, Jason J. Wang

Space telescopes maintain optical alignment through periodic, resource-intensive wavefront calibration, leaving the optical state unobserved between corrections. We propose treating onboard engineering telemetry as an opportunistic wavefront sensor. Specifically, the high-cadence thermal and pointing signals already recorded by the James Webb Space Telescope may suffice to recover spatially resolved optical path difference at nanometer precision, without dedicated measurements. Our framework use…

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astro-ph.GA

Tracing the early Milky Way thin disc with the Gaia-ESO Survey

Carlos Viscasillas Vázquez, Sofia Randich, Riano Escate Giribaldi, Leda Berni, Laura Magrini, Maria Tsantaki

The origin of metal-poor stars on thin-disc-like orbits remains an open question in Galactic archaeology and provides important constraints on the earliest phases of Milky Way disc formation. We aim to identify and characterise metal-poor stars with thin-disc-like kinematics observed in the Gaia-ESO Survey, using Gaia DR3 orbital parameters, spectroscopic information, isochrone ages, and detailed chemical abundances. Out of 1784 turn-off stars, we identify one metal-poor candidate with [Fe/H] =…

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astro-ph.SRastro-ph.EP

Host--Non-host Differences in Stellar Chemistry, Activity, and Birth Radius: Hints of Distinct Formation Environments for Earth-like Planets and Sub-Neptunes

Xunzhou Chen, Tiancheng Sun, Yuxi, Lu, Liu Long, Zixuan Lu

Host-star properties provide important clues to planet formation and evolution, yet it remains unclear whether the observed differences between planet-hosting stars and stars without detected planets reflect genuine signatures of planet formation or underlying differences in stellar populations. Using a homogeneous sample of 28,383 Kepler-LAMOST-Gaia dwarf and subgiant stars, including 629 host stars with 865 planets, we compare host stars with age-mass matched non-host stars after correcting fo…

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astro-ph.GA

CO Structures with Narrow Lines in Nearby Quiescent Regions

Ruilin Xia, Yang Su, Shiyu Zhang, Xuepeng Chen, Ji Yang, Yan Gong, Yuehui Ma, Yan Sun et al.

Using CO data from Phase I of the Milky Way Imaging Scroll Painting (MWISP) survey, we present a systematic study of molecular structures with narrow lines. We identify 57 CO structures, most of which exhibit low densities and subsonic/transonic turbulence. Among them, structures with large projected areas and diffuse, sheet-like geometries are identified as veil clouds. The low LSR velocities and the concentration of these CO structures toward both the Galactic center (e.g., Ophiuchus, Aquila)…

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gr-qcastro-ph.IM

Spotlight searches for continuous gravitational waves triggered on radiometer candidates in LIGO O4a data

Alan M. Knee, Keith Riles, Ling Sun

We report on a follow-up search for continuous gravitational waves (CWs) targeting sub-threshold candidates from the O4a LIGO-Virgo-KAGRA (LVK) all-sky all-frequency (ASAF) directed radiometer analysis. We analyze a total of $562$ ASAF candidates using Advanced LIGO data from the first part of the fourth LVK observing run. Each candidate comprises a narrow $1/32$ Hz frequency band paired with a ${\sim}13$ deg$^2$ sky pixel, defining the search parameter space for our analysis. Our search pipelin…

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gr-qcastro-ph.HEnucl-th

Oscillations of Dissipative Neutron Stars: The Impact of Hyperonic Reaction Rates

Suprovo Ghosh, Alexander Haber, Nils Andersson, Andrew Rhys Counsell

Tidal excitations of stellar oscillation modes during binary neutron-star inspirals offer a powerful probe of the composition of dense matter at supranuclear densities. Chemical equilibration plays a crucial, but often neglected, role in stellar perturbation calculations. If the chemical equilibration timescale is comparable to the oscillation timescale, then viscous effects can damp the modes. If the reactions are fast, some modes can completely disappear since their restoring force vanishes. T…

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math.DSastro-ph.EPastro-ph.IMcs.GRmath.NA

GPU-Accelerated Orbit Propagation with High-Fidelity Solar Radiation Pressure Modeling

Leandro Zardaín, Ariadna Farrés, Anna Puig, Kevin Muntal, Albert Mir

Solar Radiation Pressure (SRP), the force exerted by photons emitted by the Sun, is one of the main non-gravitational perturbations affecting spacecraft trajectories, making its accurate modeling essential for high-fidelity orbit propagation. While physically-based ray-tracing models improve SRP accuracy, their computational cost becomes a limitation during numerical integration, where the SRP force must be evaluated repeatedly throughout the trajectory propagation. This paper investigates the i…

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astro-ph.GAastro-ph.CO

Testing dark matter models and modified gravity theories with spatially resolved HI observations

Federico Lelli, Antonino Marasco, Timothy A. Davis, Nathan Deg, Jonathan Freundlich, Gyula I. G. Jòzsa, Peter Kamphuis, Pavel E. Mancera Piña et al.

Understanding the nature of dark matter (DM) is one of the most pressing questions of modern physics. The flat rotation curves of galaxies, especially the extended HI rotation curves from radio observations at 21 cm, played a key historical role to establish the DM problem and continue to be a major tool to test different galaxy formation models, particle DM models, and modified gravity theories. The SKA observatory will revolutionize the study of HI rotation curves thanks to its unprecedented a…

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astro-ph.HEastro-ph.SR

Multi-dimensional NLTE radiative transfer for a double detonation Type Ia explosion model in the photospheric phase

F. P. Callan, L. J. Shingles, S. A. Sim, C. E. Collins, J. M. Pollin, R. Pakmor, S. Gronow, F. K. Roepke et al.

Previous radiative transfer calculations have shown that both multi-dimensionality and NLTE (non local thermodynamic equilibrium) effects impact the synthetic observables predicted for Type Ia supernova explosion models. Here we carry out a 2D NLTE radiative transfer simulation in the photospheric phase for a double detonation model with a 1 M$_{\odot}$ carbon-oxygen core and 0.02 M$_{\odot}$ helium shell. The predicted observables demonstrate that departures from both spherical symmetry and loc…

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astro-ph.IMphysics.ins-det

WST, the Wide-field Spectroscopic Telescope: dispersing elements

Andrea Bianco, Michele Frangiamore, Anna Brucalassi, Dimitri Buffat, Corentin Cudennec, Kjetil Dohlen, Alexandre Jeanneau, David Lee et al.

The Wide-field Spectroscopic Telescope (WST) is a proposed 12-m class facility entirely dedicated to spectroscopic surveys, combining a high-multiplex multi-object spectrograph operating at low (MOS-LR) and high (MOS-HR) spectral resolution with a giant panoramic integral-field spectrograph (IFS), all three operating in parallel. Diffraction gratings are the key dispersing elements of all three instruments and, given the very large number and size of the units required, drive critical trade-offs…

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astro-ph.GA

Discovery of the Distant, Ultra-Faint Milky Way Satellite Aquarius IV with the Vera C. Rubin Observatory Early Data Preview 2

William Cerny, Aashay Pai, Alex Drlica-Wagner, Andrew B. Pace, Peter S. Ferguson, Marla Geha, Chin Yi Tan, Sasha Campana et al.

We present the discovery of Aquarius IV (Rubin J2201$-$0234) -- the first ultra-faint Milky Way satellite to be identified using data from the Vera C. Rubin Observatory. This system was detected at $\sim$8$σ$ significance using Rubin Early Data Preview 2 (EDP2) photometry and independently confirmed at $\sim$6$σ$ significance in archival Dark Energy Camera imaging. Jointly fitting its morphology and distance, we find that Aquarius IV is a low-luminosity ($M_V=-1.9^{+0.6}_{-1.0}$), compact ($r_{1…

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astro-ph.IMastro-ph.GA

SDSS-V Local Volume Mapper (LVM): Dithered Data Cube Reconstruction with 3dcubegen

H. J. Ibarra-Medel, A. Z. Lugo-Aranda, R. de J. Zermeño, Sebastián F. Sánchez, Lesly Castañeda-Carlos, J. Eduardo Méndez-Delgado, K. Kreckel, Roeland P. van der Marel et al.

The Sloan Digital Sky Survey V (SDSS-V) Local Volume Mapper (LVM) is conducting an unprecedented wide-field integral field spectroscopic survey of the Milky Way, the Magellanic Clouds, and nearby galaxies using a strategy based on multiple dithered observations to achieve full spatial coverage, improved spatial sampling, and enhanced spectral depth. However, the scientific exploitation of these observations requires a robust methodology to combine the individual row-stacked spectra (RSS) into ho…

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astro-ph.HEastro-ph.IM

Generation of Correlated Time Series for X-ray Astronomy Applications

Seth Rowan Larner, Michael A. Nowak, Jörn Wilms

Cross-spectral methods have become essential for studying accretion physics in X-ray binaries and active galactic nuclei, where coherence and phase lag measurements constrain physical models and reveal variability components invisible in power spectra alone. Recent multi-Lorentzian fitting techniques have uncovered new quasi-periodic features through joint analysis of power spectra and cross-spectra, but testing these methods requires synthetic data with realistic statistical properties. We pres…

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astro-ph.EP

Orbital-Period Determination As an Indispensable Tool to Study the Pedigree of a Sungrazing Comet

Zdenek Sekanina

Among some 4500 Kreutz sungrazers known, the orbital period has been established to better than about +/-20 years only for C/1882 R1, C/1963 R1, C/1965 S1, C/2011 W3, and C/2026 A1. I describe solutions to a range of intriguing problems involving the orbital-period determination. A helpful, but computer-intensive routine is a detailed investigation of derived orbital periods as a function of the last observation used, which allows one to filter out effects of activity (the case of C/2026 A1) or…

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astro-ph.IMphysics.optics

CCAT: Optical Design of the 410 GHz Prime-Cam Module

Tilak M. Patel, Tanner Buck, Anthony Huber, Eve M. Vavagiakis, James Burgoyne, Scott Chapman, Ben Keller, Jenna E. Moore et al.

Prime-Cam is a first-generation instrument for the Fred Young Submillimeter Telescope (FYST), enabling wide-field, multi-frequency observations for cosmology, line-intensity mapping, and galaxy studies. We present an optical performance study for a candidate 410 GHz broadband module designed to field approximately 21,000 polarisation-sensitive kinetic inductance detectors (KIDs). The three-lens silicon design was adapted from the SO LATR design and used for the existing 280 and 350 GHz Prime-Cam…

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