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Research Trends

Latest preprints in space engineering and astrophysics.

gr-qcastro-ph.HE

What Fraction of Extreme Mass Ratio Inspirals That Merge After the LISA Mission Ends Are Detectable?

Daniel J. Oliver, Aaron D. Johnson, Jonathan E. Thompson, Curt J. Cutler

Stellar-mass compact objects spiraling into massive black holes in galactic nuclei (referred to as "extreme-mass-ratio inspirals", or EMRIs) will be an important class of sources for the Laser Interferometer Space Antenna (LISA). A stellar-mass compact object can radiate in the millihertz band for years to decades before it plunges into its massive black hole, so a substantial fraction of the EMRIs that LISA can detect will still be inspiraling when the mission ends. We calculate what fraction o…

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astro-ph.EP

Whole-disk Photometric and Colorimetric Phase Curves of Earth with the Clementine Lunar Orbiter

Chase Cooper, Tyler D. Robinson, L. C. Mayorga, Jason W. Barnes, Lily Robinthal

The phase curve on a planetary object can reveal key details about its atmosphere and surface, including the presence of surface liquid oceans. Phase curves for Earth can inform the search for habitable surface environments on terrestrial exoplanets, but such phase curves are quite rare. The Clementine lunar orbiter made 3,744 observations of the Earth between February and May of 1994. These observations spanned phase angles between 3.4 and 139.1 degrees. From these data, we produce phase curves…

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astro-ph.GAastro-ph.COhep-ph

How well do integral-of-motion distribution functions describe Milky Way-analogue halos?

Jason Kumar, Louis E. Strigari

We study the dark-matter phase space distribution of Milky Way-mass halos in the Auriga simulations, considering both hydrodynamic and dark-matter-only runs. In a spherically averaged potential, we test whether the coarse-grained distribution function can be approximated as a function of the integrals of motion $E$ and $L$. We find that $f(E,L)$ provides a useful description of the simulated halos: although the deviations from this form are formally statistically significant, the median fraction…

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astro-ph.HEastro-ph.IM

Assessing the detectability and identification of pulsar halos with H.E.S.S. and CTAO

Karim Sabri, Yves Gallant, Justine Devin

Pulsar halos are a class of extended gamma-ray sources, resulting from inverse Compton scattering of ambient photons by electrons and positrons believed to have escaped confinement in a pulsar wind nebula. First identified by HAWC towards PSR J0633+1746 and PSR B0656+14, a growing number of pulsar-powered gamma-ray sources is proposed as candidate halos. Using a model of isotropic diffusion, we assessed the ability of current-and-future generation imaging atmospheric Cherenkov telescopes to char…

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astro-ph.EP

Cool, Cloudy Nights on an Ultrahot Neptune: A Panchromatic NIRISS/NIRSpec Transmission Spectrum of LTT 9779 b

Sarah Stamer, Diana Dragomir, Annabella Meech, Joshua D. Lothringer, Reza Ashtari, Jonathan Brande, Vivien Parmentier, Ian J. M. Crossfield et al.

Studies of planets that reside in the hot Neptune desert allow us to gain insight into how their atmospheres survive the intense flux from their host stars. One such member of that population, LTT 9779 b, is unique in that it has a confirmed atmosphere across various multi-wavelength studies, although results regarding the planet's atmospheric content differ. We present a panchromatic ($λ= 0.63 - 5.165$ $μ$m) JWST transmission spectrum of LTT 9779 b's atmosphere, including a re-reduction of prev…

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hep-phastro-ph.COastro-ph.GA

LMC-Perturbed LZ Dark Matter Landscape

Nassim Bozorgnia, Samantha Contreras, Graciela B. Gelmini, Alvine C. Kamaha, Javier Reynoso-Cordova, Yongheng Xu

The local dark matter (DM) velocity distribution is significantly altered by the gravitational impact of the Large Magellanic Cloud (LMC), which creates a high-velocity tail. We evaluate how the LMC reshapes the DM landscape for a wide variety of theoretical models in light of the recent putative LZ DM event. We show that the LMC-induced velocity shifts substantially modify the parameter space for inelastic endothermic DM models across a broad range of possible interactions, driving the viable r…

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astro-ph.HEnucl-th

What We Have Learned from NICER About Neutron Star Radii

M. C. Miller

The cores of neutron stars have a combination of density, temperature, and neutron-proton asymmetry that cannot be replicated in laboratories or understood using first-principles quantum chromodynamics. Thus, observations of neutron stars are necessary to understand this regime. In particular, precise and accurate measurements of neutron star radii are highly informative about cold, catalyzed matter at a few times nuclear saturation density. X-ray observations with NASA's Neutron star Interior C…

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astro-ph.SRastro-ph.EP

PHAROS: Panchromatic spectral energy distributions of solar-like stars across evolutionary stages

Viktor Sumida, Raissa Estrela, Eric Mamajek, Pin Chen, Adriana Valio

Panchromatic stellar spectral energy distributions (SEDs) provide the wavelength-dependent irradiation fields required for studies of exoplanet atmospheres, photochemistry, atmospheric escape, and habitability. We present PHAROS, the Panchromatic Habitable-world Archive of Radiation from Observed Solar-like stars, a first release of fifteen component-traceable SEDs for nearby FGK stars spanning adopted ages of 0.26--6.5\,Gyr. The catalogue covers 0.5--5000\,nm and combines archival \textit{XMM-N…

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astro-ph.GA

MEGATRON: The Physical Origins of Steep UV Slopes at High Redshift

Harley Katz, Nicholas Choustikov, Aayush Saxena, Corentin Cadiou, Martin P. Rey, Jeremy Blaizot, Alex J. Cameron, Fergus Cullen et al.

The ultraviolet (UV) spectral slope, $β$, serves as a fundamental probe of stellar population properties and interstellar medium conditions in galaxies. At high redshift, a small sample of galaxies have been confirmed to have extremely blue spectral slopes of $β<-2.8$, as measured directly from spectroscopy. One explanation for such galaxies is that they are leaking copious amounts of ionizing photons such that these photons are never processed into the nebular continuum and we are observing the…

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astro-ph.HEphysics.plasm-ph

Fast Radio Bursts from Induced Upscattering. I. Magnetar Polar Fireballs

Rei Nishiura, Kunihito Ioka, Bing Zhang

The extreme brightness temperatures of fast radio bursts (FRBs) demand a coherent process that converts magnetar burst energy into millisecond radio emission. We propose that FRBs can be produced within magnetar magnetospheres by induced (stimulated) upscattering in a relativistic fireball outflow. In this paper, we focus on induced Compton upscattering in an electron--positron fireball launched from the polar region of a magnetar. Radiation from the X-ray burst accelerates the polar fireball ou…

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astro-ph.EP

Binary tidal evolution as a sculptor of circumbinary planet architectures

Mario Sucerquia, Nicolás Cuello, Gaspard Duchêne

Circumbinary planets (CBPs) are expected to form in circumbinary discs and migrate towards the disc inner cavity, often near the binary stability boundary. Yet the observed population is not strictly marginally stable: excluding extreme systems, the typical offset is $Δ\equiv a_{\rm p}/a_{\rm crit}=1.22^{+0.18}_{-0.07}$, suggesting post-formation evolution may shape present-day architectures. We test whether secular evolution of close binaries can contribute to this displacement. Using high-accu…

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physics.space-phphysics.comp-phphysics.geo-ph

Temporal Correlation between Ionospheric Storm-Enhanced Density Plume and Plasmaspheric Plume Occurrence

Xiangning Chu, Shunrong Zhang, Jacob Bortnik, Naomi Maruyama, Jerry Goldstein, Kausik Chatterjee, David Malaspina, Phil Erickson et al.

We present a statistical evidence of a temporal correlation between ionospheric storm-enhanced density (SED) and plasmaspheric plumes during magnetic storms. We identified SED plumes in 75 storms between 2010-2024 with sufficient total electron content (TEC) coverage. We also identified plasmaspheric plumes during these storms using a plasmapause asymmetry (PPA) index derived from the machine-learning-based DEN3D model. We found that all SED plumes coincided with plasmaspheric plumes. The start…

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astro-ph.IM

Comparing Active Anomaly Detection Frameworks: From Light Curves to Images

Sreevarsha Sreejith, Robert C. Nichol

The increasing volume and complexity of data from modern astronomical surveys are making comprehensive visual inspection increasingly impractical, motivating automated methods for identifying rare and unusual objects. Active anomaly detection (A-AD) combines unsupervised anomaly detection with iterative user feedback, allowing searches to adapt to scientific interests while retaining sensitivity to unexpected objects. We systematically compare three A-AD frameworks, Astronomaly, Protege, and Pin…

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astro-ph.COastro-ph.GA

Constraining Reionization with Persistent Homology: a Novel Summary Statistic for Wide-Field Lyman-$α$ Emitter Observations

Michael M. Wyatt, Nikolaos Triantafyllou, Steven R. Furlanetto, Hiroya Umeda, Samuel Gagnon-Hartman, Andrei Mesinger, Masami Ouchi

The spatial clustering of Lyman-$α$ emitters (LAEs) is one of the most promising observables for constraining reionization. In this work, we introduce persistent homology, a popular tool in topological data analysis, and specifically the Betti-0 curve as a summary statistic to characterize the clustering of LAEs. We compare the performance of the Betti-0 curve against the angular correlation function (ACF) and void probability function (VPF) by quantifying their ability to constrain the global n…

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astro-ph.GA

CHAMPS: Data Reduction and Detection of ~3300 Dusty Galaxies at 1.2 mm

Felix Martinez, Jeyhan S. Karaltepe, Andreas L. Faisst, Arianna S. Long, Jorge A. Zavala, Caitlin M. Casey, Jed McKinney, Ezequiel Treister et al.

We present the reduction and source catalogs for the \textit{COSMOS High-$z$ ALMA-MIRI Population Survey} (CHAMPS), the largest Atacama Large (Sub)Millimeter Array (ALMA) blank field survey to date at 0.2\,deg$^2$. With observing frequency centered at $250\, $GHz ($1.2\,$mm) and bandwidth of 7.5 GHz, CHAMPS covers the JWST/NIRCam+MIRI footprint in the COSMOS field, taking advantage of the rich, multiwavelength ancillary datasets in COSMOS ranging from X-ray to radio. The majority of the CHAMPS s…

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astro-ph.HEastro-ph.IM

First Detection of the Doppler Shift of X-ray Photons Due to a Telescope's Orbital Motion

Stephen DiKerby, Shuo Zhang

We have detected for the first time the redshifting and blueshifting of X-ray photons due to the orbital motion of an X-ray telescope around the Earth. Current and planned X-ray telescopes like XRISM/Resolve and NewAthena can achieve energy resolutions $R = E / ΔE \approx 1000$, requiring spectroscopic calibration of physical effects such as the local standard of rest and the orbit of the Earth around the Sun. We construct an a priori method for detecting a heretofore unexamined effect: the modu…

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astro-ph.EP

The Dense, Rocky Core of Haumea Revealed by Satellite Dynamics

Benjamin Proudfoot, Darin Ragozzine, Will Grundy, Flavia Rommel, Bryan Holler

The icy dwarf planets in the outer solar system are among the most enigmatic bodies known, showing activity ranging from atmospheric resurfacing to possible cryovolcanism. Yet the study of their interiors remains largely theoretical, with few empirical measurements to guide our understanding. The orbits of their moons offer a way to break this deadlock, providing a direct probe of dwarf planet interiors. Here we present a detailed investigation of Haumea's interior derived from the motion of its…

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astro-ph.GA

Snapshots of r-process production in the Milky Way disk

Sarah G. Kane, Stephanie Monty, Madeleine McKenzie, HanYuan Zhang, Sven Buder, Terese Hansen, Tadafumi Matsuno, Jason Sanders et al.

Stars enhanced in heavy neutron capture elements like europium (Eu) provide a window into the rarest and most exotic nucleosynthetic events. Most Eu-enhanced stars discovered thus far are found among metal-poor populations, with $\mathrm{[Fe/H]} 0.7$) in the Milky Way disk with metallicities in the range $-0.87<\mathrm{[Fe/H]}<-0.21$ identified from among $74\,717$ stars in the GALAH survey. 14 of these stars additionally have $\mathrm{[Ba/Eu]}<0$, marking enhancement from the rapid neutron capt…

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gr-qcastro-ph.COastro-ph.HE

Stochastic gravitational-wave background from subsolar neutron stars in collapsar disks

Valerio De Luca, Loris Del Grosso, Emanuele Berti

The fragmentation of the neutrino-cooled accretion disks that surround the black holes formed in collapsars has recently been proposed as an astrophysical channel for the production of neutron stars with masses well below the standard core-collapse floor. These disk-born objects merge either with one another or with the central black hole, and the superposition of all such mergers across cosmic history sources a stochastic gravitational-wave background. In this work we compute the energy density…

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astro-ph.GA

MOCSS: Multi-Object Coronagraphy for JWST/NIRSpec Slitless Spectroscopy

Mason S. Huberty, Claudia Scarlata, Matthew J. Hayes, Alaina Henry, Danielle A. Berg, Vieri Cammelli, Richard Ellis, Anne E. Jaskot et al.

We present an experimental JWST/NIRSpec observational method to obtain $R\gtrsim1000$ G140M/F100LP slitless spectroscopic observations. This "Multi-Object Coronagraphy for Slitless Spectroscopy" (MOCSS) technique involves opening essentially all microshutters on NIRSpec simultaneously while closing shutters corresponding on-sky with known bright objects. Through observations of the Hubble Ultra Deep Field, we demonstrate the discovery potential of these deep, high resolution observations without…

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astro-ph.GAastro-ph.HE

An Off-Nuclear Tidal Disruption Event Discovered At Late Times: The Case Of TDE 2023mfm

Itai Sfaradi, Ryan Chornock, Yuhan Yao, Erica Hammerstein, Jean Somalwar, Raffaella Margutti, Huei Sears, Robert Stein et al.

We present the discovery and analysis of the optically selected tidal disruption event (TDE) 2023mfm, which originates from a wandering massive black hole (MBH) in a massive ($\sim 10^{11} \,$M$_{\odot}$) galaxy hosting a central low-luminosity active galactic nucleus (AGN). Our analysis of the ZTF, Lick, Keck, Swift, Chandra, XMM-Newton, HST, and VLA observations reveals that TDE 2023mfm is a TDE-H from a $10^{6.2 \pm 0.5}\,$M$_{\odot}$ black hole which is offset by $0.66 \pm 0.02$" from the ce…

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astro-ph.GA

A Systematic Assessment of Total Stellar Mass Measurements with Spatially Resolved Photometry and Medium Bands at 1 < z < 9: The Impact of Mass-to-Light Variations and Outshining

Naadiyah Jagga, Adam Muzzin, Visal Sok, Vivian Yun Yan Tan, Ghassan Sarrouh, Kartheik Iyer, Yoshihisa Asada, Chris J. Willott et al.

JWST NIRCam spatially resolved photometry enables studies of galaxies' stellar populations and stellar masses on sub-kpc scales. We use JWST (CANUCS, Technicolor, JUMPS) and HST data, covering wide- and medium-band UV-IR filters to study the stellar mass bias between spatially resolved and integrated photometry of $\sim$3000 galaxies at 1 $ 10^{\mathrm{-8.5}}$ yr$^{\mathrm{-1}}$. For these high-sSFR galaxies, the median offset reaches $Δ\log_{\mathrm{10}} (M_{\ast})$ $\sim$ -0.36 dex with the la…

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astro-ph.SR

Beyond what's observed: hierarchical inference of Gaia astrometric compact-object binaries

Natsuko Yamaguchi, Kareem El-Badry, Reed Essick, Amanda Farah, Cheyanne Shariat, Sahar Shahaf

Astrometry from the Gaia mission has revealed a large and homogeneous population of binaries containing compact objects, including more than 3000 white dwarf--main sequence (WDMS) binaries with orbital periods of $P_{\rm orb}\sim100$--$1000$ d. Most of these binaries likely underwent mass transfer from asymptotic giant branch donors, but their evolutionary histories remain uncertain. We develop a hierarchical Bayesian inference model to constrain the intrinsic properties of the Gaia WDMS binary…

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astro-ph.HE

Hierarchical Bayesian Inference on the intrinsic event rate of Type I gamma-ray bursts from the {\it Fermi}/GBM catalogue

Cao Tian-Yong, Yi Shu-Xu, Du Yun-Fei, Yorgancioglu S. Emre, Xiong Shao-Lin

The intrinsic event-rate of Type I gamma-ray bursts (GRBs) as a function of redshift, provides a probe for binary neutron star (BNS) mergers population. However, the above-mentioned inference is complicated by instrumental selection effects, the lack of redshift measurements for the majority of GRBs, and uncertainties in jet geometry. In this work, we applied a hierarchical Bayesian inference framework to the {\it Fermi}/GBM Type I GRB catalogue to reconstruct the underlying event-rate populatio…

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astro-ph.GA

CHAMPS: The COSMOS High-Redshift ALMA-MIRI Population Survey - A New Census of the Dusty Early Universe

Andreas L. Faisst, Felix Martinez, Jeyhan S. Kartaltepe, Manuel Aravena, Caitlin M. Casey, John D. Silverman, Sune Toft, Ezequiel Treister et al.

Understanding how dust forms and evolves over cosmic time is a key open problem in extragalactic astrophysics. Galaxies in the early Universe were once thought to be mostly dust-poor, but recent discoveries of heavily dust-obscured galaxies near the Epoch of Reionization challenge models of early dust production and raise new questions about the true cosmic star formation rate density. In this paper, we present the COSMOS High-Redshift ALMA-MIRI Population Survey (CHAMPS), which sheds light on t…

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astro-ph.COastro-ph.GAhep-ph

Enhanced density fluctuations: consequences for stellar dynamics and dark matter substructure

Wenzer Qin, David E. Kaplan, Neal Weiner

Enhanced density fluctuations form early dark matter halos, which serve as early gravitational potential wells for baryons. These baryons can then condense to form stars and black holes at high redshifts, $1+z \gtrsim 100$. Larger density fluctuations result in denser halos with higher virial temperatures; hence, a halo at a mass that is below the threshold for forming stars under standard astrophysical expectations may form astrophysical objects if its initial density is higher than expected, a…

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astro-ph.HEastro-ph.GAgr-qc

Bayesian Evidence for Inspiraling Hotspot Motion in the Galactic Center

Pablo Ruales, Maciek Wielgus, Delilah E. A. Gates, Alejandro Cardenas-Avendano

During flaring episodes, polarimetric observations of the Galactic Center black hole Sagittarius A* (Sgr A*) reveal evolving, loop-like trajectories in the Stokes Q-U plane, the so-called Q-$U loops. Keplerian models of transiently energized orbiting features, hotspots, have been employed to reproduce these polarimetric signatures. In this work, we develop a Bayesian framework to infer the time-dependent kinematics of the hotspot from polarized light curves, using a general prescription for its…

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astro-ph.IM

Divergence-free magnetohydrodynamics on a moving mesh

Volker Springel, Alexander C. Mayer, Rüdiger Pakmor

Magnetic fields are ubiquitous in the Universe and play an important role in many astrophysical processes, such as star formation and the evolution of galaxies. Hydrodynamical simulation methods that account for ideal magnetohydrodynamics (MHD) are however challenged by the need to achieve numerical stability and physical consistency. Both can be compromised by the occurrence of non-vanishing local divergence errors in the magnetic field. Different approaches to either eliminate or reduce these…

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astro-ph.SR

The long period radio transient ASKAP J1448-68 is a cataclysmic variable

Geoffrey Mo, Akash Anumarlapudi, Iris de Ruiter, Kareem El-Badry, David L. Kaplan, Antonio C. Rodriguez, Ilaria Caiazzo, Kaitlyn Shin et al.

Wide-field time-domain radio surveys have recently unveiled a new class of Galactic radio emitter: long period radio transients (LPTs). Despite the rapid pace of discovery, their origins remain poorly understood, with two main theories emerging: slowly spinning magnetars or binary white dwarfs (WDs) with magnetic interactions. All three LPTs with well-characterised optical counterparts are WDs in binary systems, but even within that class there is diversity, with one accreting and two detached s…

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astro-ph.GAastro-ph.CO

COSMOS-3D: Diverse Environments and Hot-dust Signatures among Dusty Star-forming Galaxies at $z$ = 4.9-7.2

Siwei Zou, Manuel Aravena, Shaoze Geng, Romain A. Meyer, Jianwei Lyu, Jaclyn B. Champagne, Jia-Sheng Huang, Andreas L. Faisst et al.

Dusty star-forming galaxies (DSFGs) are expected to trace early massive-halo assembly, but the connection between dust-obscured star formation, morphology, hot dust, and environment remains unclear at $z$>4. We combine JWST/NIRCam F444W grism spectroscopy from COSMOS-3D with MIRI F1000W/F2100W imaging and a mixed ALMA-selected and ALMA-followed dusty-galaxy sample from CRISTAL, CHAMPS, REBELS, and A3COSMOS to study 18 DSFGs or DSFG candidates at z=4.9-7.2. We compare their environments with the…

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