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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.HEhep-ph

High-energy neutrinos from shocked circumnuclear material around optically-bright and infrared-only tidal disruption events

Mainak Mukhopadhyay, Shigeo S. Kimura, Tatsuya Matsumoto

Tidal disruption events (TDEs) can launch sub-relativistic outflows that drive shocks into the surrounding circumnuclear material (CNM), providing a natural site for cosmic ray (CR) acceleration and high-energy neutrino production through hadronuclear ($pp$) interactions. We model this emission for optically bright and infrared (IR)-only TDEs, the latter motivated by a recently identified population of luminous IR transients with weak or absent optical counterparts, consistent with TDEs embedded…

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astro-ph.IM

LeoNet: A Machine Learning Method for Binary Pulsar Classification

Zhaocheng Gong, Jack White, Zeyu Yang, Jayanta Roy, Karel Adamek, Wesley Armour

Binary pulsars provide valuable laboratories for testing theories of gravity, but orbital Doppler shifts complicate their detection. Fourier-domain acceleration and jerk searches address this challenge via matched filtering, but at substantial computational cost. We present LeoNet, a convolutional neural network that uses ten learnable filters to extract features of signals affected by Doppler shifts. The resulting ten-channel feature map provides a compact, lower-dimensional alternative to an e…

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astro-ph.HEhep-ph

Towards Retrieval Augmented Generation in High-Energy and Astroparticle Physics

Jacky Kumar, Sajan Kumar

The high-energy and astroparticle physics literature has grown into an enormous body of knowledge. Gaining a comprehensive understanding of this literature is an important step in research, but is a challenging task. Before making meaningful advances, it is important to establish what has already been done and identify open questions. However, this process is becoming increasingly difficult given the sheer volume of publications. Conducting a focused literature survey on a narrow topic is partic…

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astro-ph.HEastro-ph.IM

Optimal Pulsar Timing Array Strategies with the Deep Synoptic Array

Tyler Cohen, Paul B. Demorest, Jeremy G. Baier, Ryan S. Lynch, Scott M. Ransom, Michael T. Lam, Gabriella Agazie, Akash Anumarlapudi et al.

Pulsar timing array (PTA) experiments have seen evidence for a nanohertz-frequency gravitational wave background (GWB) through coordinated radio timing observations of millisecond pulsars. The significance of this evidence is expected to grow and the GWB's progenitor(s) uncovered with continued observations, especially as the next generation of radio telescopes comes online. We present a framework for simulating timing observations of a set of pulsars with a set of telescopes to predict the per-…

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astro-ph.EP

Correlations between the Carbon-to-Oxygen Ratio and the Orbital and Physical Properties of Exoplanets

Noah Ferich, Robert Royer, Cody Shakespeare, Jason H. Steffen

Studies suggest that protoplanetary disks around stars with high carbon-to-oxygen (C/O) ratios can produce terrestrial planets with carbon-dominated compositions instead of silicon-dominated ones. While previous work studied the evolution of these disks and the planets that form within them, none analyze in detail how the differences in the surface density profiles of these disks could affect the architectures and iron and siderophile contents of exoplanetary systems. Here, we present a new stud…

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astro-ph.IM

Near-Noiseless Single-Photon Detection in the Infrared with a Megapixel Semiconductor Array for Low-Background Astronomy

Guillaume Huber, Pavaman Bilgi, Charles-Antoine Claveau, Shane Jacobson, Ian Baker, Daniel Owton, Vincent Isgar, Chris Maxey et al.

Sensor noise is a fundamental barrier to low-flux astronomical imaging and spectroscopy, where the ideal sensor would unambiguously distinguish individual photon arrivals. While optical semiconductor arrays can reach single-photon sensitivity, comparable performance in the infrared has largely required superconducting detectors. These must be operated at temperatures near absolute zero and require substantially more power, introducing major system-level challenges. HgCdTe avalanche photodiodes o…

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astro-ph.HEastro-ph.SR

Early Emergence of SSS emission in RS Oph

J. -U. Ness, J. P. Osborne, M. Orio, S. Starrfield, S. Mitrani, E. Behar

Early in the 2006 outburst of the recurrent nova RS Oph, Swift detected the onset of the super-soft-source (SSS) phase. An XMM-Newton observation on day 26.1 revealed an unusual soft X-ray spectrum containing transient narrow emission features that could not be identified with known transitions and are atypical of SSS spectra. We analyse a new XMM-Newton observation obtained at a comparable stage of the 2021 outburst and compare it with spectra from other epochs and with similar novae. A blackbo…

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nucl-thastro-ph.HE

Coexistence of strange quark stars and neutron stars: metastability and nucleation in proto-neutron stars

Mirco Guerrini, Giuseppe Pagliara, Luca Passarella, Alessandro Drago

If strange quark matter (SQM) is absolutely stable, hadronic neutron stars (NSs) and strange quark stars (QSs) may coexist in the so-called two-families scenario. A key issue is explaining how hadronic NSs can survive as long-lived metastable objects, rather than promptly converting into stable QSs. Since all NSs are born as hot proto-neutron stars (PNSs), a necessary condition for their existence is that the conditions for conversion, triggered by the nucleation of the first critical SQM drople…

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astro-ph.COastro-ph.IM

ROBIN-PIP: Robust Bayesian Field-Level Inference with Physics-Informed Priors

Ludvig Doeser, Simon Ding, Guilhem Lavaux, Jens Jasche

Accurately extracting information from galaxy surveys, particularly at non-linear scales, requires increasingly complex and flexible forward models of the observed galaxy distribution. A key component is the galaxy bias relation, which connects the underlying matter distribution to observed galaxies and requires more expressive representations than those currently incorporated into Bayesian field-level inference. Certain parameterized models for this mapping can be overparameterized, with indivi…

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astro-ph.SR

Unresolved triples in the open cluster NGC 2437 (M 46) confirmed by the KMOS VVVX-GalCen Spectroscopic Survey

D. Minniti, T. Palma, C. O. Obasi, M. Gómez, R. K. Saito, J. G. Fernández-Trincado, J. Alonso-García, E. R. Garro et al.

Recent optical and near-IR photometric databases like Gaia data release 3 (DR3) and the VISTA Variables in the Vía Láctea eXtended (VVVX) ESO public survey allow the exploration of candidate unresolved multiple systems (binaries, triples, quadruples, etc.) in nearby clusters, that need spectroscopic confirmation. NGC 2437 (M 46) is a benchmark open cluster with well determined physical parameters. Its relative proximity (D=1.6 kpc) makes this cluster an ideal laboratory to measure the fractions…

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physics.plasm-phphysics.space-ph

Normal-Field Evolution and the Breakdown of Classical Tearing in Current Sheets

Grzegorz Kowal, Diego A. Falceta-Gonçalves

Classical resistive tearing theory assumes a prescribed current-sheet equilibrium, but a finite normal magnetic field can evolve the background on the tearing timescale. For a transversely pressure-balanced Harris profile of initial half-thickness $a$ and asymptotic reconnecting-field magnitude $B_0$, threaded by uniform $B_n$ ($ξ=B_n/B_0$), we derive an exact evolution in ideal magnetohydrodynamics: counter-propagating Alfvenic fronts broaden the neutral layer and generate a central sheet-paral…

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astro-ph.HE

AT2018hyz: Predictions for a Sky Projection from a Delayed Off-Axis Jet

Ranadeep Ghosh Dastidar, Paul C Duffell

Initially discovered optically, Tidal Disruption Event (TDE) AT2018hyz was first detected in radio 972 days later. The continued monitoring of the event revealed a late-time (1370-2160 days) radio brightening. The source for this radio brightening has been associated with an afterglow originating from an off-axis jet or a delayed mildly relativistic outflow. In this work, we explored the conditions required for a delayed off-axis jet to explain the observed radio brightening. We find that the co…

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astro-ph.HE

The X-ray and optical emission of the intermediate polar Swift J0614.0+1709

Nikita Rawat, Domitilla De Martino, David A. H. Buckley, Koji Mukai, Martina Veresvarska, Zackery A. Irving, Simone Scaringi, Nicola Masetti et al.

We present the first detailed X-ray and optical study of the intermediate polar Swift J0614.0+1709 based on a pointed XMM-Newton observation complemented by long-term optical photometry from TESS. A strong coherent modulation at the white dwarf spin period was detected in X-rays, with a period of $\sim$1411 s, confirming the magnetic nature of the system. The X-ray spin pulse exhibits a pronounced energy dependence, with the modulation amplitude decreasing towards higher energies, consistent wit…

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astro-ph.SR

Theoretical RR Lyrae Instability Strip from MESA-RSP Pulsation models and updated BaSTI Evolutionary Tracks

M. Deka, M. Marconi, R. Molinaro, A. Bhardwaj, S. Cassisi, E. Luongo, G. De Somma, I. Musella et al.

RR Lyraes (RRLs) are important tracers of old stellar populations and crucial distance indicators. To complement large variability surveys such as Gaia and Rubin-LSST, the topology of the RRL instability strip (IS) and their period-luminosity-metallicity (PLZ) and period-Wesenheit-metallicity (PWZ) relations need to be updated using state-of-the-art stellar evolution and pulsation models. We employ the updated set of BaSTI horizontal-branch (HB) evolutionary models, with finer sampling in effect…

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astro-ph.HE

Generation of UL-Axions by a Kerr Black Hole. Part III: The fate of its Axion Wind

Guy Pelletier

In two previous articles, we have explained how super-massive Kerr Black Holes in the nucleus of an active galaxy or quasar can generate a large amount of axion particles in their magnetosphere. In that third part, we explore the possibility of observable dynamics resulting from some interaction of an axion wind with the baryonic matter and the axionic Dark Matter in the surroundings of the closest AGNs. The axions that we have considered are the same as those Ultra Light Axions favored in cosmo…

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astro-ph.GA

The Impact of Simulation Resolution on Dwarf Galaxy Stellar Stream Populations in FIRE

Yasmine J. Meziani, Nondh Panithanpaisal, Robyn E. Sanderson, Andrew Wetzel, Pratik J. Gandhi, Philip F. Hopkins, Adriana Dropulic

Cosmological simulations allow us to study galaxy-progenitor stream populations, allowing comparisons with observations to constrain galaxy formation physics. Previous work found that present-day galaxy-progenitor streams in FIRE have larger pericenters than observed in the MW, which might indicate that they tidally disrupt at larger distances, where the Galactic tides are weaker, than in the MW. One possible explanation is that they tidally disrupt too quickly because of limited resolution. At…

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astro-ph.GA

The Impact of Simulation Resolution on Dwarf Galaxy Stellar Stream Populations in FIRE

Yasmine J. Meziani, Nondh Panithanpaisal, Robyn E. Sanderson, Andrew Wetzel, Pratik J. Gandhi, Philip F. Hopkins, Adriana Dropulic

Cosmological simulations allow us to study galaxy-progenitor stream populations, allowing comparisons with observations to constrain galaxy formation physics. Previous work found that present-day galaxy-progenitor streams in FIRE have larger pericenters than observed in the MW, which might indicate that they tidally disrupt at larger distances, where the Galactic tides are weaker, than in the MW. One possible explanation is that they tidally disrupt too quickly because of limited resolution. At…

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astro-ph.IM

Measuring the linear gain performance for the OrcaQuest CMOS imaging sensor

Zain Azama, Aditya Khandelwal, Ryan Dungee, Ting S. Li, Sarik Jeram, Shaojie Chen

The OrcaQuest CMOS sensor by Hamamatsu Photonics has been found to exhibit a non-linear gain curve at low exposure times. This effect is characterized through the various exposure tests and data reduction pipelines detailed in this report, and a more accurate gain characterization curve is provided. Such data can be used to provide more consistent measures of pixel gain, linearity, and high framerate images.

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cs.DLastro-ph.IM

Best practices in software citation

Phil R. Van-Lane, Floor S. Broekgaarden, Daniel S. Katz, Bhavesh Patel, Pengyin Shan, Jonathan Starr, Samantha Teplitzky, Peter K. G. Williams et al.

Software is both a foundational tool and a primary output of modern computational research, yet citation practices for software remain inconsistent, incomplete, and rarely machine-actionable. Existing infrastructure designed for paper and data citation does not adequately serve the distinct needs of software citation, leaving a gap that impedes reproducibility, misattributes scholarly credit, and obscures the labor embedded in research pipelines. Drawing on a NASA-funded community workshop held…

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astro-ph.GAastro-ph.SR

Star Formation Mitosis: The Effects of Particle Splitting on the Star Formation Outcome

Shivan Khullar, Michael Y. Grudić, Christopher D. Matzner, Philip F. Hopkins, Norman Murray, Claude-André Faucher-Giguère

Particle splitting can increase the dynamic range in Lagrangian astrophysical simulations by several orders of magnitude. However, such methods can introduce numerical noise that may affect the rate of convergence, particularly for collapse problems where fragmentation could be artificially suppressed or enhanced. Thus it is necessary to determine how these errors propagate to key quantities of interest, and to correct or mitigate them where possible. Using GIZMO's MFM-MHD method, we perform a s…

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astro-ph.IM

Prototyping the Next-Generation Spectrograph for Space Exploration: Digital Micromirror Device-based Multi-Object Spectrograph (DMD-MOS) Calibration and Performance Assessment

Jiayi Emma Xu, Sarik Jeram, Shaojie Chen, Ting S. Li, Ziang Chen, Zain Azam, Adi Khandelwal, Mark Barnet et al.

Abandoning the traditional approaches to multi-object spectrographs, the Digital Micro-mirror Device-based Multi-Object Spectrograph (DMD-MOS) leverages a robust, elegant method for creating multi-object spectroscopy slit masks through use of a DMD, which is an array of microscopic flat mirrors where each micro-mirror can be addressed to physically flip between two discrete angles. We have designed two optical channels for DMD-MOS - one for each of these two positions: 1) an imaging channel that…

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astro-ph.HE

X-ray Through Radio Observations and Modeling of the Soft X-ray Flash GRB 250419A

Genevieve Schroeder, Anna Y. Q. Ho, Gavin P. Lamb, Tanmoy Laskar, Daniel A. Perley, Ore Gottlieb, Tomas Ahumada, Igor Andreoni et al.

Soft X-ray flashes (XRFs) are predicted from a variety of hypothesized phenomena, including "dirty fireballs" (relativistic jets with significant baryon loading), and gamma-ray bursts viewed marginally off-axis. For a given burst, detailed multiwavelength observations are necessary for distinguishing between possible progenitor scenarios, but the number of XRFs with such data remains small. Here we present X-ray, optical, and radio (mm to cm) data of GRB 250419A, an XRF (with peak energy $E_p<4\…

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astro-ph.IM

Automated multi-stressor optical fiber focal ratio degradation and throughput characterization system for future massive multiplex spectroscopic survey

Daksh Singh, Ting S. Li, Sarik Jerma, Shaojie Chen

Future spectroscopic survey facilities such as Spec-S5 and the Wide-Field Spectroscopic Telescope (WST) will contain more than 25,000 optical fibers. Characterizing the focal ratio degradation (FRD) and throughput of these fibers is essential for spectroscopic calibration, sky subtraction, and overall instrument performance, but manual testing of such large fiber populations is prohibitively time-consuming. In this work, we present an automated multi-stressor optical fiber characterization platf…

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astro-ph.HE

A Multi-Wavelength Picture of the Surprisingly Short 2024/25 Outburst from EXO 0748-676

Amy H. Knight, Lauren Rhodes, Noel Castro Segura, Douglas J. K. Buisson, Aru Beri, David M. Russell, Kevin Alabarta, Maria C. Baglio et al.

After sixteen years in quiescence, EXO 0748-676 unexpectedly returned to outburst in March 2024. However, in stark contrast to its previous outburst (1985 - 2008), EXO 0748-676 returned to quiescence in January 2025, after ~ 10 months in outburst. Here, we collate data from nine observing facilities, covering wavelengths from radio to X-ray, to provide the first multi-wavelength study of the 2024/25 outburst. Unlike the 1985 outburst, both the rise and decay are fully captured at X-ray and optic…

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astro-ph.GAastro-ph.SR

The star formation history of Orion is structured and episodic

Alena Rottensteiner, João Alves, Stefan Meingast, Sebastian Hutschenreuter, Núria Miret-Roig, Josefa Großschedl, Cameren Swiggum, Sebastian Ratzenböck et al.

The propagation of star formation throughout a molecular cloud complex can tell us much about its physical drivers and the importance of environmental versus intrinsic processes. We reconstruct the star formation history (SFH) of the Orion star-forming complex using the highest-resolution age map currently available. It comprises 47 co-spatial and co-moving groups identified by the SigMA clustering algorithm, with homogeneously derived ages and group memberships. We find four periods of increase…

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astro-ph.GAastro-ph.HE

The impact of relativistic AGN jets on realistic galaxy cluster environments

K. Hervella-Seoane, M. Perucho, S. Planelles, J. M. Martí, V. Quilis

Context. Low-power FRI-like radio jets dominate the AGN population, yet the main mechanism of heating the intracluster medium (ICM) and its efficiency remain a matter of debate. Aims. We investigate the impact of intermediate-power FRI-like relativistic jets on the inner region of realistic ICM, focusing on the role of weak shocks on heating and the environmental coupling in regulating energy deposition. Methods. We present six three-dimensional relativistic-hydrodynamic simulations of (1e44 - 1…

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astro-ph.IMastro-ph.HE

NASA ASTRA White Paper : A Chandra Successor in the 2030s

C. S. Reynolds, E. Hodges-Kluck, E. A. Kara, M. Koss, K. Madsen, E. Miller, B. Williams, S. Allen et al.

Chandra established that soft X-ray spectral imaging with approximately 1 arcsec angular resolution is an essential tool for almost every area of astrophysics, from the early Universe to ice chemistry in protoplanetary disks. While Chandra continues to deliver groundbreaking science, it lacks the sensitivity to be the counterpart to JWST, Roman, Rubin, LISA, ngVLA, ALMA, IceCube, NewAthena, ELT, and other upcoming large facilities. Here we highlight the scientific potential of a Chandra successo…

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astro-ph.SR

Eppur binaria non è esclusa: Pulsations in CZ Tuc appear to be tidally excited by its veiled companion

Piotr A. Kołaczek-Szymański, Patryk Iwanek, Jim Fuller, Dorota M. Skowron, Grzegorz Pojmański, Igor Soszyński

Long secondary periods (LSPs), observed in about one-third of pulsating red giants, remain unexplained despite decades of study, with binarity and non-radial oscillations as the leading competing hypotheses. If LSP variables are indeed interacting, eccentric binary systems consisting of a red giant and a substellar object, tidally excited oscillations (TEOs) would be expected to appear in a fraction of them. Therefore, detection of TEOs offers an independent test of the binary scenario that has…

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astro-ph.GAastro-ph.CO

LIGHTS. Limitations of Far-Infrared Tracers for Galactic Cirrus Mitigation in the Era of Ultra-Deep Imaging

Ouldouz Kaboud, Ignacio Trujillo, Ignacio Ruiz Cejudo, S. Zahra Hosseini-ShahiSavandi, Mireia Montes, Sergio Guerra Arencibia, Mauro D'Onofrio, Dennis Zaritsky et al.

Current and forthcoming deep optical imaging surveys are reaching surface brightness levels fainter than 30 mag/arcsec$^2$, where Galactic cirrus emission becomes a significant contaminant. This poses a major challenge for the study of extremely low-surface-brightness extragalactic structures. We investigate the relationship between far-infrared emission, as traced by the Herschel 250 $μ$m band, and optical surface brightness in the Sloan \textit{g}- and \textit{r}-bands. We find that, for Galac…

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astro-ph.IMastro-ph.CO

Inferring radio beams from sparse sampling patterns: a case study with the Murchison Widefield Array

Michael J. Wilensky, Aman Chokshi

Accurate primary-beam models are essential for high-dynamic-range radio experiments, particularly searches for the redshifted 21-cm signal from the Epoch of Reionisation, where beam errors can couple bright foreground emission into the faint cosmological measurement. Using reprocessed satellite observations we infer the 137-MHz, zenith-pointed power beams of Murchison Widefield Array receiving elements. We develop two complementary Bayesian approaches for quantifying departures from nominal elec…

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