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Research Trends

Latest preprints in space engineering and astrophysics.

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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astro-ph.HEastro-ph.GA

Associating binary black holes with galactic centres using lensed gravitational waves

Laura Uronen, Tian Li, Qiuhan He, Justin Janquart, Thomas Collett, Léon V. E. Koopmans, Otto Hannuksela

Binary black holes (BBHs) have been theorised to form through various different channels, but current LIGO-Virgo-KAGRA (LVK) sky locations make the direct study of formation channels a challenge. Association of strongly lensed BBHs to their hosts has been shown to be possible with current detector networks at upgraded sensitivity and survey telescopes like Euclid, with localisations that can reach sub-galactic scales in the source plane. With Hubble Space Telescope-like high-resolution imaging,…

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astro-ph.GA

Cosmic-ray electron propagation in the peculiar barred spiral galaxy NGC 2442

Shengtao Wang, Xiaohui Sun, Volker Heesen, George Heald, Jiangtao Li, Chao-Wei Tsai, Stefan W. Duchesne, Andrew J. Battisti et al.

Face-on spiral galaxies offer a favorable geometry for studying magnetic-field structures and cosmic-ray (CR) propagation because projection effects and structural overlap are reduced. We investigate cosmic-ray electron (CRE) transport in the nearby face-on spiral galaxy NGC 2442 and assess how its environment and magnetic-field structure influence propagation. We combine radio continuum (RC) observations from ASKAP at 943 MHz, MeerKAT at 1.28 and 1.7 GHz, and ATCA at 5 GHz with optical H$α$ and…

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astro-ph.GA

The solar Galactocentric distance and local kinematic parameters from Gaia DR3 using Bottlinger's equations

D. V. Odynets, V. S. Akhmetov, S. I. Denyshchenko

The solar Galactocentric distance, $R_0$, together with the local kinematic parameters of the Milky Way, provides fundamental constraints on the Galactic structure and rotation. Their accurate determination has become possible with the hight astrometric precision of Gaia DR3 catalogue. We determine the Galactocentric distance, the Solar peculiar motion components $(u_0,v_0,w_0)$, and the local angular velocity of Galactic rotation, $ω_0$, using a self-consistent approach based on Bottlinger's eq…

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physics.hist-phastro-ph.HE

The Crab Nebula progenitor: recovering the 1054 AD supernova event as galactic Gamma-ray burst

Costantino Sigismondi, Remo Ruffini

In 1054 AD a daytime star appeared in the constellation of Taurus, for three weeks, and it was reported in various sources from Europe to China/Japan: it was one of the few documented galactic supernovae of the last two millenia. This paradigm has been established about sixty years ago, as the comprehension of the physics of supernovae progressed with enough observational data. The Gamma-ray bursts were discovered in the same period, but only in the past few years have their observations become…

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gr-qcastro-ph.HE

Testing Source Dependence in Gravitational-Wave Tests of General Relativity with Mutual Information

Yi-Fan Wang

Phenomenological deviation parameters used in gravitational-wave tests of general relativity need not represent universal fundamental properties of the sources. Instead, a deviation parameter can be a derived quantity that depends on source properties. Apparent violations of general relativity arising from waveform systematics or data-quality issues can also depend on source properties. In addition to diagnosing individual events, it is helpful to identify systematic trends at the population lev…

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astro-ph.HE

Anisotropic wind in tidal disruption events

Paola Martire, Elena Maria Rossi, Nicholas Chamberlain Stone, Elad Steinberg, Itamar Giron

Over the coming years, the number of tidal disruption events (TDEs) is expected to substantially increase with observations from the Vera Rubin Observatory (g and r band) and {\it ULTRASAT} (near UV) wide-field surveys. These future samples have great promise to characterize the bottom end of the massive black hole mass function, but existing detections of intermediate mass black hole TDEs are primarily in X-rays, leaving their optical/UV emission largely unexplored. We present a time- and angle…

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astro-ph.SR

MHD Modelling of magnetic reconnection heating and jets in the solar corona

P. Pagano, C. Argiroffi, F. Reale, A. Petralia, G. Cozzo, P. Testa

Magnetic reconnection is seen as the lead mechanism to explain the persistent and bursty heating of the solar corona that keeps its thermal structure. Lately the observations and modelling of magnetic reconnection outflows, i.e. nanojets, has empowered our capabilities to scrutinise this mechanisms, however more needs to be understood on the relation between the energetic and kinematic events. The aim of this paper is to study in details the properties of the heating events (nanoflare) and the k…

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astro-ph.HE

The first MeerKAT S-band globular cluster pulsar survey

Rouhin Nag, Marta Burgay, Alessandro Ridolfi, Federico Abbate, Andrea Possenti, Paulo C. C. Freire, Scott M. Ransom, Miquel Colom i Bernadich et al.

Globular clusters are efficient factories of recycled pulsars, but searches toward high-dispersion-measure (DM) clusters can be strongly limited near 1 GHz by dispersive smearing and interstellar scattering. We present the first MeerKAT S-band (nu ~ 2.4 GHz) pulsar survey of 14 globular clusters. High time- and frequency-resolution observations were searched using segmented acceleration and jerk techniques, followed by candidate folding and targeted folding with available timing ephemerides. We…

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