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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.SR

Hbeta Spicules, Small-scale Jets, and Hbeta Microflashes: Sub-arcsecond Dynamic Events and their Magnetic Origins in the Lower Solar Chromosphere Observed by DKIST

Navdeep K. Panesar, V. Aparna, Sanjiv K. Tiwari, Alphonse C. Sterling, Ronald L. Moore, J. M. da Silva Santos

We examine an on-disk solar quiet region of enhanced magnetic network using Hbeta images from Daniel K. Inouye Solar Telescopes (DKISTs) Visible Broadband Imager (VBI) and line-of-sight magnetograms from DKISTs Visible Spectro-Polarimeter (ViSP). We also compare the ViSP magnetograms with co-aligned co-temporal line-of-sight magnetograms from the Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI). We find:(i) Two types of chromospheric jet-like features: Hbeta spicules, and…

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gr-qcastro-ph.HE

Binary-black hole spin population results may be driven by prior degeneracies

Noah E. Wolfe, Asad Hussain, Jack Heinzel, Salvatore Vitale

Gravitational waves carry information on the spins of merging binary-black holes. The orientations of their spins relative to their orbits ("tilts")---while challenging to measure---differentiate the astrophysical formation mechanisms by which merging black hole binaries may form. Multiple analyses have reported tentative evidence that black hole spins are preferentially oriented in the plane of the binary orbit. We show that these results are likely extrapolated from more easily measurable "eff…

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astro-ph.HEastro-ph.IM

Teglon: A Pixel-Level Pipeline for Galaxy-Informed Gravitational-Wave Follow-up Planning and Efficiency Analysis

D. A. Coulter, P. Darc, C. D. Kilpatrick, R. J. Foley, P. McGill, S. D. Wyatt, R. Hausen

We describe Teglon, an open-source database and analysis pipeline engineered to optimize the search for electromagnetic (EM) counterparts to gravitational wave (GW) sources. Teglon constructs a 3D galaxy completeness metric from an input galaxy catalog and convolves it with the 3D localization volume of a GW event, producing an updated posterior map informed by known galaxy distributions. Using Teglon, users can ingest arbitrary instrument footprints --- or download them directly from the Treasu…

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astro-ph.EP

WASP-43b TESS Phase Curve Mapping: Evidence for a Hot Interior

Maura Lally, Ryan C. Challener, Elspeth Lee, Nikole Lewis

Phase-curve mapping probes various atmospheric properties depending on wavelength: thermal phase curves are dominated by atmospheric emission, while visible and near-infrared phase curves include reflected light. The measured planetary phase curve offset--the longitudinal offset of the hemisphere of peak brightness from the substellar point--is therefore sensitive to differing atmospheric processes in emission-dominated vs. reflection-dominated bands. In particular, planets with partial western-…

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astro-ph.GAastro-ph.CO

BIND (Baryonic INpainting with Deep learning): A Field-level Emulator for Galaxy Groups and Clusters

Max E. Lee, Shy Genel, Zoltan Haiman, Greg L. Bryan, Christopher C. Lovell, Boryana Hadzhiyska

Baryonic feedback is a dominant source of systematic uncertainty for upcoming weak-lensing surveys, but current tools for modeling its effect rely on spherical approximations and density profiles calibrated almost entirely on two-point statistics. We introduce BIND (Baryonic INpainting with Deep learning), a conditional flow-matching model that learns a field-level mapping from dark-matter-only halos to their hydrodynamical counterparts. BIND is trained on halos from the 1024 paired hydrodynamic…

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astro-ph.GAastro-ph.SR

Predictions for astrometric microlensing in Gaia

Zofia Kaczmarek, David Sweeney, Łukasz Wyrzykowski, Ulrich Bastian

ESA's astrometric space mission Gaia is uniquely positioned for microlensing studies thanks to its all-sky coverage and simultaneous astrometric and photometric observations. In Gaia Data Release 4 (DR4), astrometric time series will be published for the first time, providing a rich dataset for isolated stellar remnant searches. In anticipation of DR4, we prepared tools for fitting photometric and 1D astrometric measurements. We tested the recovery of true event parameters and population distrib…

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astro-ph.GAastro-ph.CO

Probing dynamics of extreme galaxies I. Dark matter content in ultra-diffuse galaxies

Filippo Bouchè, Chiara Buttitta, Saboura Zamani, Enrichetta Iodice, Salvatore Capozziello, Vincenzo Salzano, Marcello Miranda, Enrico Maria Corsini et al.

We investigate the internal structure of two galaxies from the LEWIS sample: the ultra-diffuse galaxy UDG-1 and the extended dwarf LSB-6. Both show coherent stellar rotation combined with a non-negligible fraction of random motion, with no signs of ongoing disturbance. This is the first attempt to constrain the dynamics and dark matter physics of rotation-supported UDGs through integral-field stellar kinematics. We model the galaxies as stellar spheroids with typical dwarf-like thickness embedde…

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astro-ph.HE

Detection of hard X-ray pulsations in non-ULX X-ray pulsar 3X J0042 in M31

Ketan Rikame, Biswajit Paul

We report the detection of hard X-ray pulsations from the M31 accreting non-ULX X-ray pulsar 3X J0042 (3XMM J004232.1+411314) using archival NuSTAR observations. The source has a spin period of ~3 s and an orbital period of ~4.15 hr, with coherent pulsations previously detected only in XMM-Newton observations. We reanalyse all five publicly available NuSTAR observations by correcting the photon arrival times for binary motion and optimizing the orbital epoch and projected semi-major axis. Cohere…

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astro-ph.EPastro-ph.IM

Sorting a mess I: Addressing velocity-axis correlation of cross-correlation functions. A census of atomic and ionised species in KELT-9b's atmosphere

Nicholas W. Borsato, Brian Thorsbro, Jens Hoeijmakers, Daniel B. Zucker, Stefan Pelletier, Bibiana Prinoth

Ultra-hot Jupiters (UHJs) are the most extreme class of close-in gas giants. We combine 13 transit observations of KELT-9b from six high-resolution spectrographs spanning 316-960 nm to conduct a census of atomic and ionised species in its atmosphere using cross-correlation. We introduce an agnostic strategy to mitigate velocity-axis correlation bias in parameter uncertainties. A forward model of the cross-correlation function (CCF) and a Monte Carlo bootstrap of flux uncertainties measure the CC…

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astro-ph.HE

Strong Black Hole Natal Kicks in Magnetized Accretion-Powered Explosions

Sean E. Li, Ore Gottlieb, Brian D. Metzger

Asymmetric stellar explosions impart an impulse, or natal kick, to their compact remnants by linear momentum conservation. Black hole (BH) natal kicks are often assumed to be weaker than neutron star kicks because of greater mass accretion, and they are harder to constrain observationally because isolated BHs are electromagnetically faint. Using 3D general-relativistic magnetohydrodynamic simulations lasting up to ~30 s, we show that BHs formed from the collapse of rapidly rotating massive stars…

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gr-qcastro-ph.HEphysics.class-ph

Wave optical imaging of an oscillating electric dipole orbiting a black hole

Filipe Nazaré, João S. Santos, Vitor Cardoso, José Natário

We study the electromagnetic radiation and wave-optical imaging of an oscillating electric dipole orbiting a Kerr black hole. We derive the effective 4-current associated with a pointlike oscillating electric dipole in curved spacetime, and use black hole perturbation theory to compute the resulting radiation field at future null infinity, from first principles. We then develop a wave-optical imaging framework for a moving electromagnetic source in curved spacetime. We obtain images of an orbiti…

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astro-ph.EPastro-ph.HE

Energy deposition in planetary and exoplanetary atmospheres induced by cosmic rays

Jesse Polman, Ingo Leya

Cosmic rays can significantly alter the abundances of certain species in the upper layers of planetary atmospheres, especially in terms of their biosignatures. To fully understand the extent of this effect, it is essential to accurately model the interactions of cosmic rays with planetary magnetic fields. We used the CosmicTransmutation code to study the effect of a planetary magnetic field on the flux of galactic cosmic rays and stellar energetic particles. We found that both particle sources a…

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astro-ph.IM

The CHIME/FRB Outriggers: Commissioning the Hat Creek Outrigger and an Updated Calibration Scheme for Mitigating RFI

Mattias Lazda, Nina V. Gusinskaia, Gurman Sachdeva, Shion Andrew, Juan Mena-Parra, Mandana Amiri, Bridget C. Andersen, Alyssa Atkinson et al.

This work presents commissioning of the Hat Creek Outrigger (HCO), a dual-polarization 256-element radio interferometer that is part of the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) Outrigger project. Driven by a complex radio-frequency interference (RFI) environment that consistently contaminates $\sim40\%$ of HCO's usable bandwidth, we implement an improved calibration scheme using Gaussian Process Regression to recover complex gain solutions over RFI contamin…

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astro-ph.GA

Emulator-Assisted Calibration of a Semi-Analytic Galaxy Formation Model for the Roman Galaxy Redshift Survey

Andrew Robertson, Andrew Benson

Mock catalogues for the Roman Galaxy Redshift Survey benefit from galaxy populations whose physical properties and emission-line observables are predicted within a single galaxy-formation framework. We present an emulator-assisted calibration of the semi-analytic model Galacticus for this purpose. Because direct posterior exploration with Galacticus is computationally prohibitive, we train Gaussian-process emulators to predict the observables entering the calibration likelihood. We calibrate the…

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astro-ph.IMcs.CLcs.DL

More than half of recent astronomy papers are written with language-model assistance

Serat M. Saad, Yuan-Sen Ting

Language models leave a distinctive vocabulary in the prose they help write, and we measure how much of the astronomy literature now carries it. From the full text of 207,111 astro-ph papers spanning 2015 to mid-2026, we count those words in each paper and model the counts, in proportion to paper length, as a mixture of assisted and unassisted writing in a hierarchical Bayesian model. Papers from before 2020 calibrate the unassisted rate, and the 392 papers that disclose model use calibrate the…

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astro-ph.IM

A data processing pipeline for the WINTER near-infrared surveyor using the $\texttt{mirar}$ framework

Viraj Karambelkar, Robert Stein, Danielle Frostig, Saarah Hall, Mansi M. Kasliwal, Tomás Ahumada, Michael W. Coughlin, Thomas Culino et al.

We present the data reduction and transient detection pipeline for the Wide-field Infrared Transient Explorer (WINTER) surveyor and report its on-sky performance. The WINTER camera utilizes cost-effective InGaAs sensors as alternatives to traditional IR sensors, and is mounted on a dedicated 1-m robotic telescope at Palomar Observatory. The WINTER camera has six detectors producing a combined field-of-view of 1.2 sq. deg. equipped with y, J, and shortened-H bands. WINTER saw first light in June…

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astro-ph.IMastro-ph.EP

Small-Body Science with the Nautilus Space Observatory: From Cislunar Space Resilience to Mapping the Kuiper-Belt-to-Oort-Cloud Transition

J. de Wit, A. Y. Burdanov, P. McGill, D. Apai, S. N. Hasler, S. Cambioni

A new generation of space-based observatories can transform small-body science from the local Earth-Moon environment to the Solar System's dynamical frontier, where planetary control gives way to Galactic tides and stellar encounters. Mapping this frontier would reveal how planetesimals were scattered during giant-planet formation, how many primordial bodies survived in distant reservoirs, and whether large objects remain undiscovered in the inner Oort Cloud. At the same time, meter- to decamete…

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astro-ph.IM

Performance Comparison of the Nonlinear Curvature and Shack-Hartmann Wavefront Sensors in Strong Turbulence

Sam J. Potier, Arlene J. Aleman, Justin R. Crepp, Stanimir Letchev

Strong turbulence induces spatial variations in beam intensity that hinder the reconstruction process of many commonly deployed adaptive optics (AO) systems that use gradient-based wavefront sensors (WFS), such as the Shack-Hartmann wavefront sensor (SHWFS) and pyramid wavefront sensor. The nonlinear curvature WFS (nlCWFS) uses Fresnel diffraction to extract wavefront phase and amplitude information, suggesting that it may be able to operate under challenging turbulence conditions. In this work,…

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astro-ph.GA

The kinematics of tadpole galaxies at intermediate redshift $z \sim 0.4 - 1.5$

Manish Kataria, Kanak Saha, Bruce Elmegreen

Galaxy morphology and kinematics encode complementary information about the assembly history of galaxies, but the extent to which they evolve in tandem remains unclear. Tadpole galaxies, characterized by their distinct head-tail morphology and pronounced asymmetry, provide an ideal laboratory for investigating whether strongly asymmetric galaxies can exhibit ordered galaxy-scale kinematics. In this work, we present a detailed analysis of the ionized-gas kinematics of 20 morphologically selected…

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hep-phastro-ph.COastro-ph.GAastro-ph.HEastro-ph.SR

Implications of Inelastic Dark Matter for Primordial Dark-Star Evolution: Kinematic Thresholds and Nonthermal Capture

Qinxun Li, Shengyi Liu

The recent 248-keV nuclear recoil candidate reported by LUX-ZEPLIN has renewed interest in endothermic inelastic dark matter, motivating us to examine its capture in primordial dark stars. Relative to the conventional elastic-capture picture in dark star evolution, endothermic capture adds two qualitative features. First, it opens only after the growing star crosses a compactness threshold, expressed as a kinematic radius $R_{\rm kin}\proptoμ_χM_\star/δ$ set by the stellar mass, the dark-matter-…

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astro-ph.EP

A Candidate Innermost Fifth Planet In the HR 8799 System Revealed By JWST NIRISS Aperture Masking Interferometry

Jayke S. Nguyen, Louis Desdoigts, Alexandra Z. Greenbaum, Benjamin J. S. Pope, Max Charles, Quinn M. Konopacky, Kaitlyn Hessel, Dori Blakely et al.

We detect a candidate fifth planet in the HR 8799 system, directly imaged with the JWST/NIRISS Aperture Masking Interferometer (AMI). The detected source lies just above a $3σ$ contrast curve at a contrast of $\sim2\times10^{-4}$ in the F380M filter at a projected separation of $\sim150$ mas, corresponding to a few-to-several Jupiter mass planet at an orbital radius of $\sim 7$au. The separation of the candidate is compatible with absolute proper-motion constraints from Gaia and Hipparcos assumi…

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astro-ph.IMastro-ph.CO

Beyond the BLUE I: the advantage ceiling - how much can any estimator beat the matched filter in mm/submm survey data?

Kaustuv Basu

Convolutional neural networks are increasingly used to measure source amplitudes in survey maps, often with claims of outperforming the matched filter. That filter is the best linear unbiased estimator (BLUE) for any noise of a given covariance, and minimum-variance unbiased outright when that noise is Gaussian and known, so an advantage requires a covariance that varies from image to image, or noise that is non-Gaussian. We introduce a single number, the advantage ceiling eta >= 1, that quantif…

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astro-ph.GA

ACES VIII: A Survey of Compact, High-Velocity Features Observed in CS(2-1)

Dani R. Lipman, Jakub Poznanski, Savannah R. Gramze, Claire E. Cook, Cara Battersby, Jennifer Wallace, Pablo García, Samantha Adams et al.

The extreme kinematics of the Milky Way's Central Molecular Zone (CMZ) are influenced by processes such as dynamical shearing, cloud collisions, and stellar feedback. These events are visible in molecular data as vertically spiked features in position-velocity (PV) diagrams referred to as high velocity dispersion compact clouds (HVCCs). Using ALMA CMZ Exploration Survey (ACES) CS (2-1) molecular data, we identify a total of 235 HVCC candidates, 163 of which are visually identified, and an additi…

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astro-ph.SRphysics.plasm-phphysics.space-ph

Wave Emission and Absorption in a Near-Sun Proton-Cyclotron Wave Storm

Kristopher G Klein, Daniel Verscharen, Mihailo Martinovic, Niranjana, Ali Rahmati, Roberto Livi, Davin Larson, Michael Stevens et al.

Quantification of energy transport and dissipation in weakly collisional heliospheric plasmas that are far from local thermodynamic equilibrium is an outstanding scientific problem. A central challenge is determining how non-Maxwellian velocity-space structure affects damping and emission of coherent ion-scale waves, especially compared to simplified analytical models for background plasma velocity distributions. In this work, we study the damping and emission of parallel-propagating proton cycl…

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physics.space-ph

Cascade models of anisotropic turbulence in magnetized plasma of solar wind

A. Bershadskii

We present a physical framework for Alfvénic solar wind turbulence in which the plasma is modeled as discrete domains with local rotational symmetry about the domain-mean magnetic field. Using this symmetry, we construct minimalist cascade models governed by two characteristic time scales, nonlinear and Alfvénic, associated, respectively, with the perpendicular and parallel directions relative to the domain-mean magnetic field. Within this partial symmetry, we also characterize the anisotropy of…

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astro-ph.IMastro-ph.HE

Wide Field Localization Using Fixed Modulation Collimators

Steven E. Boggs

Rapid, precise localization of gamma-ray bursts (GRBs) requires continuous wide-field imaging at hard X-ray and soft gamma-ray energies. We develop a fixed (non-rotating) modulation-collimator architecture to address this challenge. A bigrid collimator, a pair of aligned, periodic slit grids in front of a simple, non-imaging photon-counting detector, transmits an off-axis source through a triangular fringe pattern whose local angular position, the source phase, is recovered from simultaneous cou…

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astro-ph.EPastro-ph.SR

From spirals to rings: dust dynamics in gravitoturbulent protoplanetary discs after late infall

Clément Baruteau, Steven Rendon Restrepo, Gaylor Wafflard-Fernandez, Sebastián Pérez, Zhaohuan Zhu, Hans Baehr, Farzana Meru, Jean-François Gonzalez et al.

Substructures appear to be a common trait of all extended protoplanetary discs. They are found notably in discs still surrounded by ambient, possibly infalling material. In this study, we revisit the observational signatures of gravitational instability (GI) in the dust and gas emission of protoplanetary discs. We focus on discs undergoing a short-lived episode of late infall that triggers spirals via GI, in order to investigate the long-term dynamics of millimetre-sized dust. We performed 2D hy…

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astro-ph.SRphysics.space-ph

On the 3D Magnetic Structure of Coronal Mass Ejections Through the Solar Corona

Erika Palmerio, Michal Ben-Nun, Tibor Török, Cooper Downs, Viacheslav S. Titov

The magnetic fields that make up the internal structure of coronal mass ejections (CMEs) are thought to be organised in a flux rope configuration, consisting of twisted magnetic fields that wind about a central axis. Remote-sensing observations of CMEs show a wide range of morphologies, dynamics, and evolution, including rotation, non-uniform expansion, deflection, and interaction with the ambient solar wind. In-situ measurements, however, typically consist of a single 1D spacecraft trajectory t…

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astro-ph.GA

Extending the Little Red Dot population at intermediate redshift with VIPERS

Krzysztof Lisiecki, Krzysztof Hryniewicz, Francesco Pistis, Michał J. Michałowski, Aidan P. Cotter, Maciej Koprowski, Miguel Figueira, Agnieszka Pollo et al.

Little red dots (LRDs) are a recently identified population of compact, red sources characterised by a distinctive V-shaped UV-to-optical continuum and broad emission lines. Their physical structure and evolution remain uncertain, while their properties at intermediate redshifts are largely unexplored. We identify and characterise LRD-like sources at 0.5 0.5, bridging local and high-redshift studies. Their abundance, compact morphology, environmental properties, and multi-wavelength emission pro…

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astro-ph.GA

From stardust to interstellar grain growth in the first galaxies: a cosmological transition in dust evolution near z ~ 8.9

Denis Burgarella, Tom J. L. C. Bakx, Raffaella Schneider, Hiddo S. B. Algera, Chloe Aurin, Tim Dewachter, Clarke Esmerian, Luca Graziani et al.

When and how did dust begin to shape galaxies? Motivated by the identification of an apparent redshift break in galaxy dust masses, suggesting substantially lower dust masses at $z \gtrsim 9$, we investigate dust enrichment during the first billion years of cosmic history. We aim to determine whether the observed evolution marks a transition in the dominant dust-production mechanism and to identify the physical conditions under which such a transition is expected to occur. Using JWST, ALMA, and…

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