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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.HE

Simulation of advective accretion flows around black holes under various outer boundary conditions

Rajiv Kumar, Seong-Jae Lee

We simulated various accretion disc structures with viscous hydrodynamic (HD) flow around a black hole (BH). We found that the structure of the accretion disc is significantly influenced by changes in the physical parameters of the initial inflowing gases. These physical parameters can be called outer boundary conditions (OBCs) at the outer-accretion boundary and represented on an OBC plane, which is primarily divided into hot-mode and cold-mode inflowing gases. We found smooth and shocked flows…

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astro-ph.EPastro-ph.SR

A metallicity sweet spot for disc fragmentation and planet formation

Ethan J. Carter, Dimitris Stamatellos, George Blaylock-Squibbs, Alison Young, Ken Rice

Fragmentation of gravitationally unstable discs offers an alternate formation mechanism for gas giant planets and brown dwarfs on wide orbits. Metallicity plays a key role in disc evolution from the onset of gravitational instability to the formation of planets. We aim to determine the effect of metallicity on disc fragmentation and on the properties of disc-instability planets. We model gravitationally unstable discs with varying metallicity ($0.01-10 \,\rm Z_{\odot}$) using the Smoothed Partic…

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astro-ph.HEastro-ph.CO

Automatically distinguishing Rubin transients from AGN using variability metrics

Dylan Magill, Matt Nicholl, Philip Wiseman, Charlotte R. Angus, Paige Ramsden, Christopher Frohmaier, Sjoert van Velzen, Vysakh Anilkumar et al.

Stochastic variability of active galactic nuclei (AGN) can produce contaminants in the search for explosive extragalactic transients (such as supernovae and tidal disruption events). In the new era of the Rubin Observatory's Legacy Survey of Space and Time (LSST), previously uncatalogued AGN, especially those with luminosity near the survey detection limits, are expected to produce a flood of detections that have the potential to contaminate surveys targeting other transients, leading to ineffic…

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physics.hist-phastro-ph.SR

Could John Ellard Gore have pre-empted the Hertzsprung-Russell diagram?

Jeremy Shears

John Ellard Gore (1845-1910) was an Irish amateur astronomer, prolific science writer and civil engineer. He was an inaugural member of the British Astronomical Association when it was founded in 1890 and was invited to become the first Director of its Variable Star Section. Through careful reasoning, Gore reached remarkably modern conclusions about the nature of stars, including their sizes, distances and luminosities. This paper explores whether he might have been able to produce an early form…

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astro-ph.IM

Millimeter and sub-millimeter characterization of polymers used for infrared filters in high-sensitivity cryogenic microwave telescopes

Miranda Eiben, Rustam Balafendiev, Thomas Gascard, Jon E. Gudmundsson

Vacuum windows and infrared filters are important transmissive optical components in millimeter receivers, as they hold out the atmosphere and reduce radiative loading on cold stages, thereby improving cryogenic performance. However, the complex optical properties of the materials commonly used for windows and filters are poorly characterized, particularly in-band and in the sub-millimeter regime. The absorption and scattering properties of these materials are becoming increasingly important for…

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astro-ph.GA

Size-Mass Relation Shows Its Colours: Contrasting Physical Imprints of Galaxy Evolution in Rest-Frame UV and Optical

Angelo George, Marcin Sawicki, Ivana Damjanov

The galaxy size-mass relation (SMR) is a key scaling relation used to constrain the physical processes that build galaxy structure, yet it is almost always measured in a single rest-frame optical band, where the light traces the bulk of the old stellar mass. Tracing younger populations with flux-weighted ages of ~100-500 Myr and low-metallicity stars, the rest-frame near-ultraviolet opens a new stellar window on this scaling relation. Because each process redistributes the light of young and old…

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hep-exastro-ph.IMgr-qcphysics.atom-phphysics.ins-det

Technical Proposal for the Atom Interferometer CERN Experiment (AICE) Facility

Gianluigi Arduini, Nadja Augst, Mark G. Bason, Charles Baynham, Andrea Bertoldi, Gianfranco Bertone, Diego Blas, Daniela Bortoletto et al.

We present the technical proposal for the Atom Interferometer CERN Experiment (AICE), a $\mathcal{O}(100)$ m vertical atom interferometer to be installed against the wall of the PX46 access shaft to the LHC. AICE is conceived as a versatile and flexible long-baseline atom-interferometry facility whose primary scientific goal is probing for bosonic ultralight dark matter (ULDM) in a mass range inaccessible to other experiments, with a secondary goal of pioneering the exploration of gravitational…

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astro-ph.HE

Multi-zone Modeling of Blazar Jets: Constraints from GeV-Optical Correlation and Short-Timescale Variability

Arit Bala, Kaustav Mitra, Ritaban Chatterjee

We have developed a multi-zone model of blazar jet emission, in which the emission region contains many cells with individual magnetic fields and electron energy distributions. Nonthermal emission from radio to $γ$-rays is generated by electrons accelerated by shocks passing through the region via synchrotron and inverse-Compton (IC) processes. The optical and GeV variability at days-to-months time-scale simulated from our model are strongly correlated with no significant time lag, as observed i…

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astro-ph.SR

A generalized quadratic balance relation for nonradial nonadiabatic pulsations

Jan Zalewski

We derive a generalized quadratic balance relation for linear nonadiabatic, nonradial stellar pulsations, starting from a sesquilinear amplitude analogue of the pressure-volume-rate work. The derivation requires neither weak nonadiabaticity nor averaging over a pulsation cycle. The relation is expressed in terms of work, generalized norm and boundary contributions and is subsequently recast into kinetic-energy-power form $\mathcal{P}+ΔB=2\Re(σ)E_{\rm kin}$. The volume power is decomposed into a…

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astro-ph.GA

The Total and Polarized Radio Emission from the Innermost Jets of a High-Redshift Quasar and a Candidate at Parsec-Scale Resolution

Bence Husvéth, Krisztina É. Gabányi, Tao An, Sándor Frey, Jun Yang, Iván Agudo, Yingkang Zhang

High-frequency very long baseline interferometry (VLBI) polarimetry probes synchrotron-emitting plasma closer to the central engines of radio-loud active galactic nuclei (AGNs), but observations above 43 GHz are technically demanding. We present 22-GHz European VLBI Network observations of the $z=4.31$ quasar J1510+5702 and J1606+3124, whose published spectroscopic redshift, $z=4.56$, is uncertain; a photometric estimate gives $z_{\rm phot}=0.9\pm0.1$. For the published $z>4$ redshifts, 22 GHz c…

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astro-ph.EP

Looking for TRAPPIST-1 external planets' emission in JWST archival data

Louis-Julien Cartigny, Alice Maurel, Elsa Ducrot, Taylor J. Bell

The TRAPPIST-1 system has been thoroughly observed with JWST. Unfortunately, stellar contamination issues strongly limit the interpretation of transit observations. As for emission observations, only the two closest planets have been observed through five dedicated JWST programs. We gathered all these emission observations and tried to detect the combined emission of the external planets in previous JWST MIRI observations of TRAPPIST-1; this paper presents our approach and our results. We could…

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astro-ph.GA

Hector Galaxy Survey: Falling in Between - Infalling Galaxies in the Midst of the Abell 3667 Merger

Oğuzhan Çakır, Matt Owers, Gabriella Quattropani, Mina Pak, Stefania Barsanti, Joss Bland-Hawthorn, Julia Bryant, Scott Croom et al.

Whether cluster mergers enhance ram pressure stripping (RPS) and accelerate member galaxy evolution remains an open question. Here, we investigate galaxy populations in the nearby merging cluster Abell 3667 ($z\simeq0.0553$) using spatially resolved data from the Hector Galaxy Survey. We define an RPS sample combining Hector-selected galaxies with ionised gas disturbances (e.g., asymmetric tails or truncated disks) and supplementary, optically identified jellyfish galaxies lacking Hector data. M…

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astro-ph.SRastro-ph.IM

An Empirical Effective-Temperature Calibrations for Galactic B/A Supergiants

N. L. Vaidman, A. S. Miroshnichenko, Sh. T. Nurmakhametova, S. Danford, S. A. Khokhlov, I. M. Izmailova, Ch. T. Omarov, S. V. Zharikov et al.

We present empirical effective temperature Teff calibrations for Galactic supergiants of spectral types B5-A5 based on optical spectra. The relationships were derived from a reference sample with adopted literature temperatures and use equivalent widths, central line depths, and ratios of selected spectral features as temperature indicators. Quadratic relationships are established for individual diagnostics and their ratios. Collectively, the calibrations span a Teff interval from 8 400 K to 14…

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astro-ph.HE

Hybrid disc geometry for shocked accretion flows: Unveiling QPOs in black hole X-ray binaries

Monu Singh, Sudip Kumar Garain, Santabrata Das

We investigate the efficacy of semi-analytical global accretion solutions in capturing the flow properties observed in two-dimensional numerical simulations of shocked accretion onto black holes. A comparative analysis reveals that no single disc geometry adequately matches the simulation profiles across the entire radial domain. The pre-shock region exhibits closer agreement with the conical disc geometry, while the post-shock region is better described by the vertical equilibrium disc, where e…

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astro-ph.SRastro-ph.EPastro-ph.GA

Investigating the properties of nearby young moving groups using GaiaDR3

Mamta Lad, Ujjwal Krishnan, Blesson Mathew, Raksha Olakal, Arun Roy, Sreeja Kartha, Vineeth Valsan

Moving groups, which are gravitationally unbound collections of stars spread over large portions of the sky, pose challenges to their identification. Analyzing the three-dimensional spatial motion of stars is one method to identify their members. Despite several studies in the past, a reliable and conclusive catalog of moving group stars is currently lacking. Our objective is to present a most recent and updated catalog of nearby young moving group (NYMG) candidates in the solar neighborhood and…

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astro-ph.GAastro-ph.SR

Kinematics and Dynamics of the Open Cluster NGC 2302

Yuna Lee, Jongsuk Hong, Beomdu Lim

Open clusters are ideal observational testbeds to understand the dynamics of stellar systems. We present a dynamical study of the young open cluster NGC 2302. The latest Gaia data and $UBVIJHK_s$ photometric data are used in this study. A total of 117 stars are selected as the genuine members using the Gaia data. This cluster is, on average, reddened by $ = 0.24 \pm 0.06$ (s.d.). The ratio of total-to-selective extinction ($R_V$) in the direction of NGC 2302 is $2.8 \pm 0.1$. The cluster distanc…

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

Beyond Idealized PAHs: Infrared Signatures of Carbon-Chain Defects from Shock Synthesis

Xiaoting Tan, Zhao Wang, Zu-Jia Lu, Houda Haidar, Dimitra Rigopoulou

Polycyclic aromatic hydrocarbons (PAHs) are widely recognized as carriers of the aromatic infrared bands (AIBs). However, most spectral models rely on idealized structures that fail to capture the energetic environments of interstellar PAH formation. This work investigates the infrared (IR) signatures of PAHs formed under shock conditions and explores whether produced defective structures can explain observational features unpredicted by standard, idealized models. We combine two-stage reactive…

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astro-ph.HE

On coordinate frames relevant for pulsar physics

Jyotijwal Debnath, Manjari Bagchi

Pulsars can be either isolated or binary (or even in triple) systems. Observational features of pulsars are used to probe various aspects of fundamental physics, including emission mechanism, gravitational physics, etc. Theoretical models of various phenomena need different coordinate frames. Often different physical processes affect each other and we need to use multiple coordinate frames and relations between those. This short review presents an extensive set of coordinate frames and relations…

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astro-ph.HE

Time-dependent Evolution of Proton Spectra in Supernova Remnants and Their Contribution to Galactic Cosmic Rays

Jun-Yu Shen, Hou-Dun Zeng, Qiang Yuan

Recent $γ$-ray observations indicate that the proton spectra of supernova remnants (SNRs) are well described by broken power laws, with both the spectral break energy, $E_{\mathrm{br}}$, and the low-energy spectral index, $α$, exhibiting systematic evolution with SNR age. The physical origin of these evolutionary trends and their implications for the Galactic cosmic-ray (CR) population remain poorly understood. In this work, we develop the temporal evolution model for protons in SNRs by extendin…

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astro-ph.GAastro-ph.HE

A model for the enhanced production rate of early-type hypervelocity stars in the Galactic halo

Chunyang Cao, F. K. Liu, Xian Chen, Shuo Li

About twenty late B-type hypervelocity stars (HVSs) traveling faster than the Galactic escape velocity have been discovered in the Galactic halo, many of which were ejected from the Galactic center (GC). Recently, we have advocated that these HVSs most likely formed in the nuclear star cluster (NSC) $150$--$500\, \rm{Myr}$ ago and were predominantly ejected via the gravitational slingshot of a past intermediate-mass black hole (IMBH) orbiting the supermassive black hole (SMBH) Sgr~A$^{*}$. Here…

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astro-ph.GAastro-ph.CO

The MAGPI Survey: Emission Line Products Data Release and the Role of Spectroscopic Aperture Covering Fraction on the Balmer Decrement-Stellar Mass Relation

A. J. Battisti, E. G. M. Muller, E. Wisnioski, J. T. Mendel, C. Foster, C. D. P. Lagos, K. E. Harborne, I. U. Aalia et al.

The Middle Ages Galaxy Properties with Integral field spectroscopy (MAGPI) survey is a Large Program on the European Southern Observatory Very Large Telescope using the MUSE instrument. This paper presents the data release for the MAGPI emission line products and includes emission line maps for 836 galaxies at $0.05\leq z_\mathrm{spec}\leq 0.424$ ($\mathrm{H}α$-window) and aperture-based emission line measurements for 2,607 galaxies at $0.05\leq z_\mathrm{spec}\leq 1.50$ (upper bound is [OII] cu…

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astro-ph.EPastro-ph.SR

Stellar Abundances as Probes of Rocky Exoplanet Interiors: The Mantle Composition and Mineralogy of GJ 486b

Harshit Krishna, Asmit Gupta, Sneha Bhowmik, Chandan K. Sahu, Sudipta Mridha, Liton Majumdar

Over the past three decades, hundreds of rocky exoplanets have been discovered. Some of these show atmospheric signatures indicative of diverse chemical compositions. Interpreting these atmospheres requires a physically grounded understanding of planetary interiors, as interior composition and mineralogy govern the formation and evolution of secondary atmospheres. Rocky terrestrial exoplanets are expected to inherit the refractory composition of their host stars, providing a direct pathway to co…

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astro-ph.HE

An invariant energy release hierarchy in a repeating fast radio burst

X. Yang, S. B. Zhang, Y. Li, D. Xiao, W. L. Zhang, J. -J. Wei, J. -J. Geng, J. -S. Wang et al.

Fast radio bursts (FRBs) are luminous millisecond radio transients whose physical origin remains unsettled. A key diagnostic is whether their burst-energy distributions retain characteristic physical scales that are intrinsic and temporally stable within an individual engine. Here we report a 3.2-year monitoring campaign of the hyperactive repeater FRB~20220529 with FAST and Parkes, yielding more than 1,300 bursts spanning nearly five orders of magnitude in spectral energy density. The cumulativ…

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astro-ph.GA

Dynamics of tidal dwarf galaxies in the system Arp 72

Osvan M. Portilla-Narvaez, Javier Zaragoza-Cardiel, Gisela N. Ortiz-León, Y. D. Mayya, Beverly J. Smith, Chandreyee Sengupta, Mark L. Giroux, S. Comerón et al.

Some interactions between galaxies produce tidal tails primarily composed of material from their disks. Within these tails, concentrations of gas and stars can form, resembling dwarf galaxies. These tidal objects often begin to form stars and become dynamically independent of their parent galaxies, leading to their classification as Tidal Dwarf Galaxies (TDGs). By definition, TDGs should consist solely of baryonic material, with a negligible dark matter fraction. In this study, we analyze the dy…

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physics.space-phastro-ph.EPphysics.plasm-ph

Evolution of lunar wake potentials: structure, energy conversion, and their imprints on velocity distributions

Xin An, Vassilis Angelopoulos, Jasper S. Halekas, Terry Z. Liu, Shaosui Xu, Andrew R. Poppe, Ferdinand Plaschke

We study the evolution of electric potentials in the lunar wake. The wake potential exhibits two distinct spatial scales. The macroscopic scale arises from solar wind expansion into the vacuum, with a potential length-scale growing with distance from the Moon; the microscopic scales arises from ion acoustic shocks near the wake center, with transition layers spanning tens of local Debye lengths. This two-scale potential mediates energy conversion between ions and electrons during wake refilling.…

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astro-ph.EPastro-ph.GA

The Inbound Gas and Dust Evolution of Interstellar Comet 3I/ATLAS from Optical Spectroscopy and Multi-band Photometry

Toni Santana-Ros, Alexey Sergeyev, Oleksandra Ivanova, Sofiia Mykhailova, Johannes Markkanen, Igor Luk'yanyk, Tomasz Kwiatkowski, Dagmara Oszkiewicz et al.

Interstellar objects (ISOs) provide direct constraints on the composition and evolution of extrasolar planetary systems. As the third confirmed ISO, comet 3I/ATLAS offers a rare opportunity to study pristine material from another star system. We present a systematic multi-band monitoring campaign conducted from 2025 July to September. To minimize systematic uncertainties, we utilized a homogeneous dataset of SDSS $g', r', i', z_s$ and Johnson-Cousins $BVR$ imaging obtained with MuSCAT3/4 on the…

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astro-ph.IM

The Atacama Cosmology Telescope: Passband Measurements with an Analysis of Systematic Errors

Thomas Alford, Rahul Datta, Erminia Calabrese, Steve K. Choi, Shannon M. Duff, Adriaan J. Duivenvoorden, Joseph Golec, Matthew Hasselfeld et al.

We present measurements of the spectral response of the four Advanced ACTPol (AdvACT) multichroic detector arrays, which observed in frequency bands centered near 30, 40, 90, 150, and 220 GHz. The passbands were measured with a Fourier transform spectrometer (FTS) combined with coupling optics that direct and match the output of the FTS to the AdvACT receiver. We perform optical simulations of the FTS and coupling optics in order to model frequency-dependent systematic effects in this system. We…

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astro-ph.IM

The Atacama Cosmology Telescope: Passband Measurements with an Analysis of Systematic Errors

Thomas Alford, Rahul Datta, Erminia Calabrese, Steve K. Choi, Shannon M. Duff, Adriaan J. Duivenvoorden, Joseph Golec, Matthew Hasselfeld et al.

We present measurements of the spectral response of the four Advanced ACTPol (AdvACT) multichroic detector arrays, which observed in frequency bands centered near 30, 40, 90, 150, and 220 GHz. The passbands were measured with a Fourier transform spectrometer (FTS) combined with coupling optics that direct and match the output of the FTS to the AdvACT receiver. We perform optical simulations of the FTS and coupling optics in order to model frequency-dependent systematic effects in this system. We…

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astro-ph.HE

Modeling the Gravitational Wave Signal from the X-ray Pulsar Her X-1

I. D. Markozov, G. K. Pimenov, A. A. Mushtukov

The paper is devoted to modeling the gravitational waves from the X-ray pulsar Her X-1. The neutron star is considered as a freely precessing ellipsoid. The gravitational wave signal is calculated in the quadrupole approximation. The $h_{\times}$ and $h_{+}$ polarization profiles are constructed for the precession parameters of the neutron star in Her X-1 measured in up-to-date works. The possibility of signal detection with the DECIGO telescope is assessed. The formulas for the semi-analytical…

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astro-ph.HE

High-Redshift Type Ia Supernovae Exhibit Enhanced Calcium Abundances

Xingzhuo Chen, Ulisses Braga-Neto, Lifan Wang

Type Ia supernovae (SNe Ia) are major contributors to cosmic chemical enrichment, and their elemental abundances provide a probe of progenitor properties and explosion physics across cosmic time. We employ an artificial intelligence-assisted inversion technique to analyze spectra of high-redshift SNe Ia from the Supernova Legacy Survey and of gravitationally lensed SNe Ia observed by the James Webb Space Telescope, extending the sample to redshift 2.05. We find a positive correlation between SN…

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