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Research Trends

Latest preprints in space engineering and astrophysics.

gr-qcastro-ph.HEhep-th

Tidal Love numbers of multi-state Boson stars

Xin-Lei Zhao, Jun-Ru Chen, Yong-Qiang Wang

In this paper, we calculate the tidal Love numbers of multi-state boson stars (MSBSs) composed of ground state and first excited state complex scalar fields. Under synchronized and nonsynchronized frequency conditions, the background solutions of MSBSs are classified into single-branch and double-branch types. The field functions, ADM mass, and binding energy of different solutions are discussed. We then calculate the quadrupolar ($\ell=2$) electric and magnetic tidal Love numbers for branches c…

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astro-ph.EP

Setting the Stage: The Early History of the Solar System

Antgona Segura, Rachel L. Smith, Myriam Telus, Edward Schwieterman, Rachel Osten, Sukrit Ranjan

This article reviews the early history of our solar system from an astrobiological perspective and presents evidence from meteorites and astronomical observations. The purpose is to trace the formation of key molecules that participated in the building blocks of life. The Sun and its planetary system started from a section of a molecular cloud that collapsed into a protoplanetary disk. In the center of the protoplanetary disk, the protosun heated the surrounding material. The dust and gas inheri…

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astro-ph.EPastro-ph.SR

Stellar Activity, Exoplanet, Habitability, Planetary Atmospheres

Antígona Segura, Manuel Güdel, Konstantin Herbst, Dibyendu Nandy, Arghyadeep Paul, Raissa Estrela, Allison Youngblood

This chapter will review the deep connection of planetary habitability and stellar irradiation. We present the long-term stellar evolution as one of the drivers of atmospheric escape and climate changes on exoplanets, as well as the chemistry driven by stellar UV and stellar energetic particles. Habitability is presented in the context of short and long-term stellar variability and evolution to layout what we understand and what we need to know about stellar irradiation to constrain our planetar…

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astro-ph.EPastro-ph.SR

Stellar impact on exoplanetary atmospheric evolution and habitability

Antígona Segura, Manuel Güdel, Konstantin Herbst, Dibyendu Nandy, Arghyadeep Paul, Raissa Estrela, Allison Youngblood

This chapter will review the deep connection of planetary habitability and stellar irradiation. We present the long-term stellar evolution as one of the drivers of atmospheric escape and climate changes on exoplanets, as well as the chemistry driven by stellar UV and stellar energetic particles. Habitability is presented in the context of short and long-term stellar variability and evolution to layout what we understand and what we need to know about stellar irradiation to constrain our planetar…

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gr-qcastro-ph.HEhep-th

Structural morphology and the gravitational arrow of time

Julian Barbour, Francisco S. N. Lobo, Maria I. R. Lourenço

The Newtonian $N$-body problem in the zero-energy, zero-linear-momentum, and zero-angular-momentum sector provides a time-reversal-invariant setting in which generic complete solutions possess a Janus point and exhibit a gravitational arrow on both branches away from it. The dimensionless variety $V$, a global scale-invariant measure of clustering contrast, is not pointwise monotonic but fluctuates while growing between rising bounds away from the Janus region. Central configurations are critica…

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astro-ph.EP

Neptune's Inner Moons and Rings Are Exposed Icy Body Interiors

M. Ryleigh Davis, Matthew Belyakov, Ian Wong, Zachariah Milby, Michael E. Brown

Neptune's single large moon, Triton, is accompanied by a set of dusty rings and small moons whose composition and origin are uncertain. Using the James Webb Space Telescope, we observed Neptune's rings and three moons: Larissa, Galatea, and Proteus. Remarkably, these moons and rings have spectra that are distinct from other outer solar system objects and show no evidence of water ice, despite hosting deep 3 micron OH absorption bands. Additionally, Larissa, Galatea, and the rings show a composit…

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astro-ph.HE

JWST Spectra Indicate a Large Mass of Postshock Dust Formed by SN 2010jl

Nathan Smith, Melissa Shahbandeh, Ori D. Fox, Thomas Moore, Jennifer E. Andrews, Thomas G. Brink, Eli Dwek, Michael Engesser et al.

We present new JWST mid-IR spectra and ground-based optical spectra of the lingering source at the position of SN 2010jl, which was a relatively nearby superluminous Type IIn supernova having strong interaction with circumstellar material (CSM). Early-time data showed evidence of dust, interpreted as either pre-existing CSM dust, or as newly formed dust in the SN ejecta and post-shock region. At 13 yr post explosion, JWST reveals a strong MIR excess from warm dust, with broad features at 10-15 $…

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astro-ph.GA

Stellar photoionisation modelling in SYNTHESIZER

Aswin P. Vijayan, Stephen M. Wilkins, Sophie L. Newman, Christopher C. Lovell, William J. Roper, Sabrina Berger, Thomas Harvey, Jack C. Turner et al.

Emission from photoionised gas surrounding young stellar populations ($H\text{II}$ regions) provides critical diagnostics of the physical conditions in star forming galaxies. This emission constrains the gas properties, the nature of ionising sources, and generates essential features for determining galaxy redshifts. To leverage spectroscopic observations to test galaxy formation models, it is essential to incorporate these emissions into synthetic datasets. Here, we present the integration of p…

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astro-ph.HEgr-qc

On the triple nature of the PSR J0435+3233 system

Paulo C. C. Freire, Colin J. Clark, Cees G. Bassa, Guillaume Voisin, Rutger van Haasteren, Lars Nieder, Benjamin W. Stappers

Context. The recent pulsar timing ephemeris of PSR J0435+3233 indicates that this millisecond pulsar (MSP) has a spin-down rate that is much higher than observed in other MSPs and challenges our understanding of the formation and evolution of MSPs. Aims. We propose that this system is a hierarchical triple, and that the high spin-down rate is caused by varying acceleration due to a tertiary in a wide orbit. Methods. We use pulsar timing methods with radio and gamma-ray observations of PSR J0435+…

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astro-ph.IMastro-ph.SRphysics.space-ph

Compton Polarimeter Prototype for the CUbesat Solar Polarimeter (CUSP) mission

Nicolas De Angelis, Andrea Alimenti, Riccardo Campana, Mauro Centrone, Giovanni De Cesare, Ettore Del Monte, Sergio Di Cosimo, Enrico Costa et al.

The space-based CUbesat Solar Polarimeter (CUSP) mission aims to measure the linear polarization of solar flares in the hard X-ray band (25-100 keV) by means of a dual-phase Compton polarimeter. CUSP will allow to study the magnetic reconnection and particle acceleration in the flaring magnetic structures of our star with its unprecedented sensitivity to solar flare polarization. CUSP is a project under development as part of the Alcor Program of the Italian Space Agency aimed at developing new…

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astro-ph.IMphysics.optics

Testing of machine learning wavefront sensing algorithms on the Tiny Observatory for Telescope Optimization (TOTO) testbed

Sanchit Sabhlok, Solvay A. Blomquist, Maggie Y, Kautz, Debstuti Biswas, Kevin Derby, Jaren N. Ashcraft, Hyukmo Kang et al.

Phase retrieval techniques are utilized to correct low order wavefront aberrations originating from misalignments of the optical system in space based telescope concepts. Traditional phase retrieval involves observation of the Point Spread Function (PSF) and a diversity measurement, usually focus diversity although other measures are possible, to reconstruct the incident wavefront at the science detector. We consider a Machine Learning model trained originally on simulated data, and then augment…

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astro-ph.IM

Tiny Observatory for Telescope Optimization (TOTO): testing algorithms for autonomous on-orbit alignment for space-based telescope systems

Solvay A. Blomquist, Sanchit Sabhlok, Hyukmo Kang, Maggie Y. Kautz, Simran Agarwal, Heejoo Choi, Alexandra Kupersmith, Adam Schilperoort et al.

The Tiny Observatory for Telescope Optimization (TOTO) is an optical testbed designed to evaluate the efficacy of autonomously driven alignment algorithms for space-based telescope systems. For space-based missions, active control of the telescope alignment on-orbit offers potential to relax passive alignment requirements and reduce on-ground verification activities. TOTO is used to evaluate and verify simulation work of two primary alignment algorithms, Stochastic Parallel Gradient Descent (SPG…

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astro-ph.HEastro-ph.IM

Radio Follow-Up of Einstein Probe Fast X-Ray Transients

Carmen Choza, Joe S. Bright, Francesco Carotenuto, Alex Pollak, Rob Fender, Andrew Siemion

Fast X-ray transients (FXTs) are brief, luminous bursts of soft X-ray emission whose physical origins remain uncertain. The Einstein Probe (EP) mission has recently enabled prompt discovery of these events, providing opportunities for rapid multi-wavelength follow-up. We present a coordinated radio observing campaign targeting 20 FXTs detected by the EP in 2024. The core consists of 59 epochs with the Allen Telescope Array (ATA), sampling post-burst timescales from $\sim$1 to $\sim$65 days and r…

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astro-ph.IMastro-ph.EPastro-ph.GAastro-ph.SR

PhoPS: An automated photometric pipeline for survey-era astronomy

Orhan Erece, Yucel Kilic

Modern astronomical surveys produce large volumes of imaging data together with highly accurate astrometric and photometric reference catalogues, creating a need for automated, robust, and instrument-independent reduction pipelines. We present PhoPS (Photometry and Astrometry of Point Sources), an open-source Python pipeline for fully automated astrometric calibration and photometric reduction of stellar and moving Solar System targets. PhoPS dynamically generates local Gaia DR3 astrometric inde…

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astro-ph.HE

Binary neutron star populations across cosmic time: the impact of binary stellar evolution uncertainties

Mathieu Venet, Irina Dvorkin

We investigate the impact of uncertainties in binary stellar evolution on the formation efficiency and cosmological merger rate of BNS systems. In particular, we aim to determine whether robust signatures of binary evolution can be identified across a broad range of metallicities. We perform a systematic exploration of 72 binary evolution models using the population synthesis code COSMIC. We vary four key parameters controlling the onset and efficiency of common-envelope evolution, the natal kic…

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astro-ph.GAastro-ph.HE

Cosmic Pairs: A DESI Census of Dual and Offset AGN as Precursors to Massive Black Hole Binaries

Ekaterine Dadiani, Antonella Palmese, Yihao Zhou, Nianyi Chen, Tiziana Di Matteo, Alejandro Eróstegui, Mar Mezcua, Jessica Nicole Aguilar et al.

We present a systematic census of dual and offset active galactic nuclei (AGN) using spectroscopic data from the first data release (DR1) of the Dark Energy Spectroscopic Instrument (DESI). After correcting for observational systematics, our final sample contains $>7,000$ dual AGN and 27,000 galaxy pairs containing one AGN over the redshift range $0 \lesssim z \lesssim 3.6$. This sample expands the known dual AGN sample by $\sim 1-2$ orders of magnitude at $0.2 \lesssim z \lesssim 0.4$, includes…

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astro-ph.GA

Exploring the Limits of Spectral Line Stacking in Spectral Line Data and Application Toward the Detection of Bulk $^{13}$C Enrichment of Aromatics in TMC-1

Miya Duffy, Ryan A. Loomis, Martin S. Holdren, Andrew Lipnicky, D. Archie Stewart, Gabi Wenzel, Ci Xue, Annapoorani Hariharan et al.

The formation history of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium remains a topic of active debate, with proposed mechanisms ranging from high-temperature stellar ejecta processes to low-temperature chemistry within molecular clouds. Recently, the identification of small PAHs in the cold, dark cloud TMC-1 has provided some circumstantial evidence of the latter. If these are formed in situ, their isotopic ratios, particularly $^{12}$C/$^{13}$C, should reflect the local,…

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astro-ph.EP

High-Resolution Dayside Spectroscopy of the Ultra-Hot Jupiter WASP-178b with GHOST/Gemini South

Caitlin E. Bell, Emily K. Deibert, Adam B. Langeveld, Ernst de Mooij, Ray Jayawardhana, Laura Flagg, Jake D. Turner

We present high-resolution dayside spectroscopy of the ultra-hot Jupiter WASP-178b obtained with the Gemini High-resolution Optical SpecTrograph (GHOST) at the Gemini South Observatory. The observations cover pre- and post-eclipse orbital phases, lasting approximately 9 hours in total, and represent the first published high-resolution optical dayside emission spectroscopy of WASP-178b's atmosphere, complementing previous near-infrared dayside spectroscopy. We verify the presence of a thermal inv…

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astro-ph.IM

Laboratory characterization of iLocater

Marcelo Tala Pinto, Marshall C. Johnson, Julia Brady, Xavier Lesley-Saldaña, Jonathan Crass, Allie Renshaw, Michael Engelman, Brian Sands et al.

iLocater is a diffraction-limited, fiber-fed spectrograph designed for the Large Binocular Telescope (LBT), which targets high-precision radial velocity measurements in the near-infrared. Prior to deployment, comprehensive laboratory characterization was essential to validate instrument performance and inform alignment strategies. This paper presents results from four key areas of lab characterization: (1) adjustment and optimization of detector orientation to optimize spectrum alignment with th…

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astro-ph.EPastro-ph.SR

A Systematic Trend in the Observed vs. Predicted Radii of Transiting Brown Dwarfs

Thomas G. Beatty

Transiting brown dwarfs provide a direct empirical test of substellar evolutionary models, and with more than 50 now known we can carry out this test at the population level. We compared the observed masses and radii of 31 field-age, weakly irradiated transiting brown dwarfs to the Sonora Diamondback, Sonora Bobcat, and ATMO 2020 grids, and a subset of 23 of them to the irradiated models of Mukherjee et al. (2026). In every comparison we find a radius-dependent trend, with fits of $R_{\rm pred}$…

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physics.opticsastro-ph.IMphysics.acc-ph

New techniques for high-resolution imaging and high-precision wavefront sensing via masked-aperture interferometry

Nithyanandan Thyagarajan, Bojan Nikolic, Chris Carilli, Laura Torino, Ubaldo Iriso

Achieving high-angular-resolution imaging on subarcsecond scales is fundamentally limited by wavefront aberrations imparted by the propagation medium and by optical elements along the light path. Accurate recovery of source structure at these fine angular scales therefore relies on precise, real-time sensing and correction of wavefront aberrations. Drawing inspiration from radio interferometry, we have developed different approaches using masked apertures that directly measure both the amplitude…

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hep-exastro-ph.SR

First Experimental Bounds on Transverse Plasmon Solar Axions with ANAIS-112

S. J. Hollick, M. Giannotti, J. Ruz, J. K. Vogel, R. M. Alkaddah, J. Amaré, J. Apilluelo, S. Bharat et al.

Solar axion-like particles (ALPs) can be resonantly produced through the conversion of transverse plasmons in the magnetic field of the solar interior, introducing a production mechanism complementary to the conventional Primakoff process. In this Letter, we report the first experimental search for solar ALPs produced through this mechanism. Using an exposure of 625.75 kg$\times$yr from ANAIS-112, we search for the annual modulation of the flux induced by the variation of the Earth--Sun distance…

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astro-ph.HE

Exploring cosmic magnetism with gamma-ray burst afterglow emission

Paolo Da Vela, Davide Miceli, Lara Nava, Giancarlo Ghirlanda

The nature and origin of magnetic fields on cosmological scales are still unclear. Magnetic fields detected in galaxies and galaxy clusters are typically interpreted as the result of the amplification of weak seed fields, but their nature remains largely unknown with two scenarios considered: the cosmological and the astrophysical origin. Signatures of magnetization in cosmic voids from observations of very high energy (VHE, E > 100 GeV) photons from extragalactic sources can provide crucial res…

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astro-ph.HE

Relativistic effects of PSR~J1856--0039 double neutron star system in a 2.36-hour compact orbit

Z. L. Yang, J. L. Han, W. Q. Su, P. F. Wang, C. Wang, T. Wang, D. J. Zhou, Yi Yan et al.

Compact double neutron star (DNS) systems are unique laboratories for testing gravitational theories and studying DNS mergers. Here we report the properties of a new DNS system, PSR J1856--0039, discovered in the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The pulsar is mildly recycled with a period of 23.4~ms in a compact eccentric orbit ($e=0.106$) with an orbital period of 2.36 hours. By following up FAST observations, we measured the relativistic effects, including the orbi…

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astro-ph.IMastro-ph.EPastro-ph.SR

Commissioning and on-sky performance verification of iLocater

Marshall C. Johnson, Marcelo Tala Pinto, Jonathan Crass, Brian Sands, Jackson Datkuliak, Sai Vidyud Senthil Nathan, Justin R. Crepp, Michael Engelman et al.

iLocater is a high-resolution near-infrared extreme precision radial velocity (EPRV) spectrograph that was deployed to the Large Binocular Telescope (LBT) in June 2026. iLocater operates over $λ=966-1312$ nm with a median resolving power of $R=205,000$ as measured in the laboratory. We present the commissioning and initial on-sky verification program using solar and night-time observations at the LBT. First light was achieved on 27 June 2026, and nearly 150 on-sky spectra have now been recorded.…

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astro-ph.GA

An Exploratory Analysis of New Large Gaia-informed Quasar Samples in SDSS-V

Shir Aviram, Benny Trakhtenbrot, Tom Dwelly, Scott F. Anderson, Sean Morrison, Michael Eracleous, Yue Shen, Mara Salvato et al.

Quasars are luminous objects that provide insights into the physics and evolution of supermassive black holes (SMBHs) and their accretion flows, galaxy evolution, and even cosmology. In this study, we present an exploratory study based on the ongoing fifth generation of the Sloan Digital Sky Survey (SDSS-V) and its unique dual-hemisphere, wide-field, and multi-object spectroscopic capabilities, with the aim of creating a comprehensive, all-sky quasar sample. The targets were selected through two…

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astro-ph.IM

The Calibration System of the iLocater Spectrograph

Sai Vidyud Senthil Nathan, Jonathan Crass, Julia E. Brady, Mark Derwent, Marcelo Tala Pinto, Brian Sands, Jackson Datkuliak, Jonathan Shover et al.

iLocater is a new near-infrared, extreme precision radial velocity (EPRV) instrument delivered to the Large Binocular Telescope in the summer of 2026. The instrument utilizes single-mode fibers (SMFs) for light transmission, including its calibration systems. We present an overview of the iLocater calibration system, detailing the specific sources and the hardware required to inject calibration light into the SMFs. Furthermore, we discuss the hardware that efficiently switches between these sour…

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astro-ph.SRastro-ph.GAastro-ph.IM

PANTERA. I. Hunting for the Most Metal-Rich Stars in the Solar Neighborhood with High-Resolution Spectroscopy

Serat M. Saad, D. M. Rowan, K. Z. Stanek, Ilya Ilyin, Benjamin J. Fulton, Howard Isaacson, Jessica Lu

We present PANTERA (Project for Astrophysical Nucleosynthesis and Targeted Exploration of metal-Rich Abundances), a high-resolution spectroscopic survey of the most metal-rich stars in the solar neighborhood. In this first paper, we report iron abundances for 56 metal-rich stars, selected from Gaia DR3 XP spectrophotometric metallicities. These targets were observed with the PEPSI spectrograph on the Large Binocular Telescope (LBT), the Levy spectrograph on the Automated Planet Finder (APF) tele…

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astro-ph.HEastro-ph.COhep-ph

Semi-analytic Inference of Satellite Densities in the Cold Dark Matter Model Part II. Implications for Dark Matter Indirect Detection Constraints

Kailash Raman, Dylan Folsom, Manoj Kaplinghat, Mariangela Lisanti, Benjamin R. Safdi

Dwarf galaxies provide excellent targets to search for signals of dark matter annihilation or decay. Using a calibrated semi-analytic model and the latest stellar kinematic data (presented in Part I), this paper updates the astrophysical J-factors for the Milky Way's dwarf spheroidal galaxies. We infer the probability distributions for the J-factors of 39 dwarfs by conditioning a population of subhalos, generated with the SatGen semi-analytic satellite model, on either a dwarf's kinematically de…

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astro-ph.SRastro-ph.GA

The T-GEX project. I. Stealth UV-bright Sun-like stars in the Galaxy as candidate contributors to the UV upturn

M. L. L. Dantas, D. Beltrán, R. E. Giribaldi, R. Smiljanic, P. R. T. Coelho, P. B. Tissera

We constructed the Tiny Gaia-ESO + GALEX (T-GEX) catalogue by combining Gaia-ESO spectroscopy, Gaia DR3 astrometry, GALEX UV photometry, and 2MASS and AllWISE infrared measurements for 37 stars. Astrometric and spectroscopic quality cuts minimise obvious multiplicity and spectral peculiarity, although unresolved companions cannot be excluded. We classified the stars relative to the empirical FGK UV-normal locus, applied a 3-component Gaussian mixture model in the FUV-NUV versus NUV-$G$ plane, me…

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