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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.GA

Precise C-N-O Abundances of Individual Galaxies in the First Billion Years from Ultra-Deep, Rest-UV-to-Optical JWST Spectroscopy

Raunaq Singh Rai, Guido Roberts-Borsani, Ryan Sanders, Alice E. Shapley, Leonardo Clarke, Pascal A. Oesch, Daniel Schaerer, Rui Marques-Chaves et al.

We present ultra-deep JWST/NIRSpec $R\sim1000$ spectroscopy of nine star-forming galaxies at $z=6.0-8.3$ in the GOODS-N field, drawn from the Origins of Metal Enrichment in Galaxies at cosmic dAwn (OMEGA) survey. Paired with ancillary ultra-deep G140M observations, the G395M integrations from OMEGA yield continuous rest-frame UV-to-optical coverage and the full suite of diagnostics needed for precise characterisations and measures of the chemical abundances of these systems. Crucially, the auror…

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astro-ph.GAastro-ph.CO

Massive Population III Galaxies Near a GN-z11 Analog: The Role of the Baryon-Dark Matter Streaming Velocity

Eli Visbal, Greg L. Bryan, Ryan Hazlett

Recently the James Webb Space Telescope (JWST) detected Hebe, a Population III (Pop III) candidate located ${\sim}3$ kpc in projection from the massive $z=10.6$ galaxy GN-z11. This raises the question of whether Pop III star formation is expected in the vicinity of massive high-redshift galaxies or whether it would be prevented by early metal enrichment. We address this with a semi-analytic model of Pop III and metal-enriched star formation applied to a zoom-in N-body simulation of a highly over…

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astro-ph.IM

Refactoring the SIXTE simulator: Towards a more modular code base

Christian Kirsch, Maximilian Lorenz, Lea Dauner, Esin G. Gülbahar, Karan Pal, Neo Reinmann, Jakob Stierhof, Philipp Thalhammer et al.

The SIXTE (SImulation of X-ray TElescopes) software is a general end-to-end simulation toolkit for X-ray observations, covering the full observation process from source photon generation to detector readout and the production of high-level output files. It is the official simulator for existing and future X-ray missions, such as \textit{eROSITA}, \textit{NewAthena}, \textit{THESEUS} and \textit{AXIS}. Originally being designed as a simulator for \textit{eROSITA}, the addition of new instrument a…

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astro-ph.IM

Refactoring the SIXTE simulator: Towards a more modular code base

Christian Kirsch, Maximilian Lorenz, Lea Dauner, Esin G. Gülbahar, Karan Pal, Neo Reinmann, Jakob Stierhof, Philipp Thalhammer et al.

The SIXTE (SImulation of X-ray TElescopes) software is a general end-to-end simulation toolkit for X-ray observations, covering the full observation process from source photon generation to detector readout and the production of high-level output files. It is the official simulator for existing and future X-ray missions, such as eROSITA, NewAthena, THESEUS and AXIS. Originally being designed as a simulator for eROSITA, the addition of new instrument and telescope types over several years has mad…

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astro-ph.GA

Diverse Metallicities in Protoclusters at $z \sim 3.4$ detected by Deep Learning

Yoshihiro Takeda, Nobunari Kashikawa, Kei Ito, Jun Toshikawa, Mariko Kubo, Rieko Momose, Yongming Liang, Takehiro Yoshioka et al.

We present spectroscopic follow-up observations with Subaru/MOIRCS of four protocluster candidate regions identified by the deep-learning model PCFNet. In three candidate regions, we confirm four protoclusters at $z =$ 3.316, 3.403, 3.408 and 3.425, exhibiting galaxy density peaks over five times the uniform distribution. The detection rate of confirmed members aligns with PCFNet's predictions, underscoring its effectiveness. Analysis of spectral energy distributions (SEDs), incorporating up to…

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astro-ph.IMastro-ph.COastro-ph.GA

Source--Line Associations in JWST/NIRSpec Dense-Shutter Spectroscopy

Zihao Wu, Daniel J. Eisenstein, Francesco D'Eugenio, Erica Nelson, Benjamin D. Johnson, Andrew J. Bunker, Zhiyuan Ji, Pierluigi Rinaldi et al.

We demonstrate the feasibility of source--line association in JWST/NIRSpec dense-shutter spectroscopy, with $\sim$2000 sources observed simultaneously per pointing regardless of spectral overlap. While JWST wide-field slitless spectroscopy (WFSS) can disentangle overlapping spectra using two grisms with perpendicular dispersion directions, NIRSpec can achieve this using gratings with different dispersions. Compared with WFSS, NIRSpec dense-shutter spectroscopy offers substantially higher sensiti…

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astro-ph.SR

V405 Draconis: A Deep Contact Binary with a Tertiary Companion and a Quadruple System Candidate

Maksym Yu. Pyatnytskyy, Ivan L. Andronov

We continued our analysis of the O-C diagram of the EW-type eclipsing binary V405 Dra using recently available data. We refined the orbital parameters of the third body responsible for the short-period oscillations in the O-C curve, obtaining $P_3=513.12(20)$ d, $a_{12}\sin i_3=0.3862(15)$ AU, and $e_3=0.1690(48)$. Assuming a total mass of $1.56$ $M_\odot$ for the eclipsing binary, the minimum mass of the third body is estimated to be about $0.5$ $M_\odot$. We also investigated the complex long-…

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astro-ph.IM

Diffusion Models for Polarimetric Reconstruction of Circumstellar Environments in Correlated Speckle Noise

Quentin Villegas, Laurence Denneulin, Simon Prunet, André Ferrari, Éric Thiébaut, Maud Langlois

High-contrast polarimetric imaging of circumstellar disks is severely limited by stellar leakage and speckle noise. Building upon the RHAPSODIE framework for polarimetric inverse problems, diffusion-based methods have shown promising results by replacing classical regularization with learned priors. However, RHAPSODIE's white noise assumption fails to capture the spatial correlation structure of atmospheric and instrumental speckles. We extend this framework to handle speckle fluctuations, which…

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astro-ph.GA

Extreme MgII Emission in Recently-Quenched Galaxies: A New Sample of Intermediate-Redshift Post-Starburst Quasars from the DESI Early Data Release

Margaret E. Verrico, Aayan Verma, K. Decker French, David J. Setton, Omar Almaini, Jenny E. Greene, Stephanie LaMassa, Yuanze Luo et al.

Post-starburst galaxies are galaxies which have recently and rapidly shut off star formation. AGN activity is often invoked to explain this rapid quenching, but most post-starburst selection methods select against optical AGN, motivating searches for "post-starburst quasars." We present DESI observations of ten post-starburst quasars with significant MgII emission ($L_{\text{MgII}} \geq 3 \times 10^{41}$ erg/s). This is the first sample of post-starburst quasars to be selected from a post-starbu…

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astro-ph.GAastro-ph.CO

ViCTORIA project: A pilot study of the M49 region in the Virgo cluster in polarisation

A. Spasic, A. Benati, M. Brüggen, H. W. Edler, F. De Gasperin, V. Gustafsson, P. Serra, A. Bonafede et al.

Large-scale magnetic fields permeate the Intracluster Medium (ICM) of galaxy clusters. Understanding these fields gives an insight into the origin of cosmic magnetic fields and the interaction of cluster galaxies with the ICM. Using MeerKAT observations of the Virgo cluster as part of the ViCTORIA project, we probe magnetic fields via Rotation Measure (RM) synthesis. The aim of this work is to characterise the magnetic fields in and around the infalling group M49 in the Virgo cluster. We will pr…

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astro-ph.GAastro-ph.IM

The 2MIG isolated AGNs -- 4. Linking hot-dust reverberation to spectroscopically predicted BLR scales in IC~5287 and Mrk~845

I. O. Izviekova, I. B. Vavilova, O. V. Kompaniiets, O. Zamora, R. Clavero

We investigate the relation between directly measured hot-dust reverberation scales and spectroscopically predicted broad-line region (BLR) scales in the isolated Seyfert galaxies IC~5287 and Mrk~845 (MCG+09-25-022), combining ZTF optical light curves, WISE/NEOWISE monitoring, and archival SDSS spectroscopy. Both nuclei show BWB optical variability, RWB MIR behaviour, and delayed MIR responses consistent with circumnuclear dust reprocessing. For IC~5287, interpolated cross-correlation function a…

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astro-ph.GA

Probing Spatial Variations in IGM Transmission: Higher Ly$α$ Visibility in an H$α$-Selected Galaxy Overdensity at $z\simeq6.2$

Shunta Shimizu, Nobunari Kashikawa, Junya Arita, Ryo Emori, Kohei Inayoshi, Akio K. Inoue, Kei Ito, Satoshi Kikuta et al.

The visibility of Ly$α$ emission during the epoch of reionization depends on both galaxy properties and the transmission of Ly$α$ photons through the intergalactic medium (IGM). Using JWST/NIRCam F470N imaging, we identify a prominent projected overdensity of H$α$ emitters (HAEs) at $z\simeq6.2$ in CEERS field. We use Subaru/HSC NB872 imaging to measure their Ly$α$ fluxes and compare the Ly$α$ visibility of galaxies within $2'$ of the density center with that of galaxies outside this region. The…

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astro-ph.IM

Stellar interferometry with a K-band integrated optics beam combiner instrument at the CHARA Array - I. First on-sky fringes for CHARIOT

Aline N. Dinkelaker, Kévin Barjot, Nic Scott, Aurélien Benoît, Narsireddy Anugu, Alyssa V. Mayer, Jacopo Siliprandi, Robert R. Thomson et al.

We present the instrument description and the first on-sky observations for the new CHara ARray Integrated Optics Testbench (CHARIOT) at the CHARA Array. CHARIOT is a 2-telescope proof-of-concept instrument that utilises a fibre-connectorised beam combiner fabricated by ultrafast laser-inscription in Infrasil quartz glass, which presents low-OH contamination and high transparency over the whole K-band. With its fibre-connected architecture, CHARIOT is designed as a plug-and-play testbed instrume…

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astro-ph.GAcond-mat.mtrl-sci

Photoelectron and electron microscopy investigation of laboratory grown Mg-silicate space dust analogues

Steffen Friis Holleufer, Mie Andersen, Frederik Granzow Doktor, Lars Eric Borchert, Martin Wibrand Larsen, Duncan S. Sutherland, Zheshen Li, Alexei Preobrajenski et al.

The atomic structure at the surface of interstellar silicate dust particles likely plays a key role in a variety of chemical processes occurring in star- and planet-forming regions of the interstellar medium (ISM). Here, we use the photoelectric effect to characterize, in situ, the local chemical structure of Mg-silicate nanoparticulate films, and ex situ electron microscopy to trace changes to morphology resulting from different starting compositions. Nanoparticulate films are prepared via co-d…

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astro-ph.SR

A First Global Full-Vector Coronal Magnetic Field Inference Using MLSO CoMP and UCoMP Observations

Alin Razvan Paraschiv, Zihao Yang, Daniela Adriana Lacatus, Momchil Molnar

Building on recent advances in coronal spectropolarimetry, seismology, and magnetic-field inferences of Z. Yang et al. (2024) and A. R. Paraschiv (2026), we present the first application of the CLEDB IQUD inversion methodology to Mauna Loa Solar Observatory CoMP and UCoMP observations. Using spectropolarimetric IQU measurements together with coronal seismology derived magnetic field BPOS constraints, we recover vector magnetic field solutions across the off-limb solar corona accessible to the ob…

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physics.space-phastro-ph.EPastro-ph.SRphysics.comp-phphysics.plasm-ph

Spectral Properties of Solar Wind Charge Exchange from Earth's Magnetospheric Boundaries: MHD and Test Particle Simulations

A. Ramachandran, R. T. Desai, H. L. Norman, Y. Tong, D. Bewicke, S. Nitti, J. A. Carter, J. P. Eastwood et al.

The Solar Wind Charge Exchange (SWCX) mechanism, where X-rays can be generated through interactions between heavy, highly charged solar wind ions and neutral atoms, offers an opportunity to observe the large-scale transfers of energy and momentum through the Sun-Earth system. In this study, we simulate SWCX signatures from Earth's outer boundaries using Gorgon global magnetohydrodynamic (MHD) simulations combined with kinetic particle-based simulations which we call the X-ray Imaging of the Magn…

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astro-ph.HE

Investigating signatures of extinct PeVatron activity in supernova remnants IC 443 and W51 C

Silvia Celli, Giovanni Morlino

Context. Supernova remnants (SNRs) are renewed sources of non-thermal particles and the main contributors of Galactic cosmic rays (CRs). Recent ultra-high energy (UHE) gamma-ray data from middle-aged SNRs, such as IC 443 and W51 C, highlight the key role of these systems for particle acceleration. Understanding SNR contribution to PeV CRs requires a detailed modelling about how accelerated particles escape their shocks and are released inside the Galaxy. Aims. We aim at critically assessing the…

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astro-ph.IM

I2C@2024: an interferometric imaging contest in 2024

Florentin Millour, Mathis Houll{é}, Jeremy Perdigon, Julien Drevon, Ryan Norris, Rebecca Proni, Alexis Matter, Ferreol Soulez et al.

Images in optical long-baseline interferometry have seen a boost in the recent years thanks to new techniques and recipes invented by the community. These images are more and more used for science interpretation and not only illustration, and their fidelity has improved significantly, thanks mainly to the increase in the number of telescopes used in interferometers. The focus today is to improve their reliability and dynamic range. With this contest, we follow up the quest introduced in 2004 of…

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astro-ph.COastro-ph.GAastro-ph.IMastro-ph.SR

MATISSE in the era of GRAVITY+

Florentin Millour, Anthony Soulain, St{é}phane Lagarde, Alexis Matter, Valentin Fleury, Farin Drewes, Mathis Houll{é}, Jules Scigliuto et al.

MATISSE, the mid-infrared spectro-interferometric imager of the Very Large Telescope Interferometer (VLTI), has been feeding on the light corrected by the GRAVITY+ Adaptive Optics (GPAO) systems since the retirement of MACAO on the four Unit Telescopes in 2024. We report the assessment of the new MATISSE performance with GPAO, based on commissioning observations obtained in 2024 and 2025 and compared with archival MACAO observations of the same stellar sources. The instrumental visibility transf…

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astro-ph.IM

The best of all worlds: gravitational-wave transient detection with multiple pipelines

Nikolas Moustakidis, Theofilos Moustakidis, Deep Chatterjee, Anastasios Tefas, Erik Katsavounidis

The search for gravitational-wave transients (modeled and unmodeled) as performed by the LIGO-Virgo-KAGRA collaborations and the broader community typically involves multiple detection algorithms, often redundant and sometimes complementary. We here address the problem of combining such detection algorithms in order to maximize the noise vs signal discrimination power of such an astrophysical search that utilizes multiple analysis pipelines. Using a machine learning approach, we construct a neur…

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astro-ph.SRastro-ph.HE

First results from PADRE/MeDDEA: X-rays from a flare and its CME

Muriel Zoë Stiefel, Säm Krucker, Olivier Limousin, Niharika Godbole, Gwendoline Marc, Amir Caspi, Kyle Gregory, Ace Stratton et al.

The MeDDEA hard X-ray spectrometer onboard NASAs PADRE CubeSat operates four flight-spare detectors from the Solar Orbiter/STIX instrument. This paper aims to evaluate the accuracy of the MeDDEA calibration and to demonstrate that MeDDEA data are ready for scientific exploitation. Using the first joint observations between MeDDEA and STIX, we investigate faint HXR emission associated with an escaping CME relative to the emission from the full flare. The first large flare observed by MeDDEA is an…

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astro-ph.GA

Far-Ultraviolet diffuse emission as a tracer of Galactic extinction at the North Galactic Pole

Swagat Bordoloi, P. Shalima, Rupjyoti Gogoi, Jayant Murthy, Oleg Malkov

Interstellar extinction at high Galactic latitude is often traced by thermal dust emission, but the conversion from infrared surface brightness to reddening is sensitive to grain properties and temperature. We test dust-scattered far-ultraviolet (FUV) and near-ultraviolet (NUV) diffuse emission as a high-resolution extinction tracer towards the North Galactic Pole (NGP), where E(B-V) 70 deg and compare them with the Planck E(B-V) map at matched resolution. A direct pixel-to-pixel regression give…

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astro-ph.HEphysics.plasm-ph

Jet Forecast: Timing of Discrete Jet Ejections of Stellar-Mass Black Holes Anticipated via X-ray Properties

Toshihiro Kawaguchi, Kazutaka Yamaoka

The radio -- soft $γ$-ray data of the Galactic black hole binary XTE J1859+226 showed that discrete jets are launched when the inner radius of the accretion disk ($R_{\rm in}$) rapidly approaches the innermost stable circular orbit (ISCO). Given the correlations among the X-ray fractional variability amplitude (rms), $R_{\rm in}$, and the X-ray hardness, previous phenomenological findings related to jet ejections (``jet line'' and sharp drops of rms) also indicate that the rapid shrinkage of $R_…

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astro-ph.EP

Surveying exogenous species in Saturn with ALMA. II. Detecting and Mapping HCN

T. Fouchet, T. Cavalié, R. Moreno, S. Guerlet, E. Lellouch, D. Bardet

Several external sources (the rings, the satellites, cometary impacts, interplanetary dust particles) supply material to the upper atmosphere of Saturn. The signature of this external influx has been documented on the ionospheric electronic and ionic densities, and in the stratosphere on oxygenated molecules (CO, CO2, H2O). We search for the chemical signature of the external sources in nitrogen-bearing species in Saturn's stratosphere. We have targeted the HCN(4-3) rotational line and mapped it…

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astro-ph.HE

From Choked to Successful: The Role of Black Hole Spin in Collapsar Jet Breakout

Rushikesh Sonawane, Krishna Kumar, Shabnam Iyyani

Long gamma-ray bursts (LGRBs) are believed to originate from the core collapse of massive Wolf-Rayet (WR) stars, leading to the formation of a spinning black hole that powers a relativistic jet. The prompt emission is produced once the jet emerges from the stellar envelope. We perform 2D axisymmetric RHD simulations using the PLUTO code to model semi-self-consistent, accretion-powered jets launched by Kerr black holes. For the two progenitor models, we adopt black hole masses of $4 M_{\odot}$ an…

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astro-ph.EP

Planetesimal formation facilitated by streaming instability in weak pressure bumps

Magnus S. Sørensen-Taylor, Anders Johansen, Troels Haugbølle

Planetesimal formation via the streaming instability of small pebbles in protoplanetary discs requires enhanced solid concentrations relative to the solar metallicity, $Z\simeq 0.01$. We investigate here whether pile-ups in weak axisymmetric pressure bumps are sufficient to trigger strong particle concentrations via the streaming instability. Using high-resolution 2D shearing box simulations with millimetre-to-centimetre pebbles, we explore the behaviour of the streaming instability in the prese…

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astro-ph.EP

Planetesimal formation facilitated by streaming instability in weak pressure bumps

Magnus S. Sørensen-Taylor, Anders Johansen, Troels Haugbølle

Planetesimal formation via the streaming instability of small pebbles in protoplanetary discs requires enhanced solid concentrations relative to the solar metallicity, $Z\simeq 0.01$. We investigate here whether pile-ups in weak axisymmetric pressure bumps are sufficient to trigger strong particle concentrations via the streaming instability. Using high-resolution 2D shearing box simulations with millimetre-to-centimetre pebbles, we explore the behaviour of the streaming instability in the prese…

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astro-ph.GA

Exploring the observed properties of JWST Little Red Dots with cosmological simulations and dust radiative transfer

Saksham Chandna, Fabio Di Mascia, Simona Gallerani, Stefano Carniani, Pierluigi Rinaldi, Roberta Tripodi, Milena Valentini, Alessia Tortosa et al.

JWST has uncovered compact high-redshift (z>=4) sources, dubbed Little Red Dots (LRDs), characterised by a distinct V-shaped continuum. Their nature remains debated since broad-line AGN signatures coexist with non-AGN continua, marked by weak X-ray and mid-IR emission. We investigate which properties of LRDs naturally emerge within simulations of massive AGN host galaxies and which require additional physics. We post-process two cosmological zoom-in simulations of the same massive halo, one incl…

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astro-ph.EPastro-ph.SR

Activity in White Dwarf Debris Disks II: WISE Mission Traces a Decade of Disk Evolution and Persistence

Hiba Tu Noor, Jay Farihi, Scott J. Kenyon

This study presents multi-epoch photometry from the Wide-field Infrared Survey Explorer to investigate variability in white dwarf debris disks, utilizing the full 14.5 yr mission datasets pre- and post-cryogen. Unambiguous variations are detected across the bulk of the 52 confirmed dusty white dwarfs and are consistent with universal variability after correcting for the sensitivity of WISE relative to Spitzer. Some disk light curves exhibit trends such as possible oscillations, sudden brightenin…

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astro-ph.GA

DREAMS: Taking the Temperature of a Massive Galaxy at z ~ 11

L. Parente, E. Vanzella, M. Messa, A. Zanella, K. Nakajima, M. Ouchi, R. A. Windhorst, M. Talia et al.

We present a detailed photometric and spectroscopic analysis of Janus-11, a $z=10.7933 \pm 0.0006 $ galaxy magnified by a factor 1.6 by the galaxy cluster MACS J0416. It was observed with JWST/NIRCam as part of the PEARLS program and with JWST/NIRSpec MSA as part of the DREAMS program. It has M$_{\rm UV}=-19.78^{+0.12}_{-0.11}$, and its stellar mass of log(M*/M_sun) = 8.75 (+0.08/-0.10) places it among the most massive known $z>10$ galaxies, while its $A_V=0.54\pm0.09$ mag and UV slope of $β=-1.…

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