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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.GA

Irreducible-Mass Growth and Extractable Energy in a Self-Gravitating Blandford-Znajek Engine

Remo Ruffini, Giorgio Sonnino

Wang recently constructed a self-gravitating split-monopole Blandford-Znajek engine and obtained its secular horizon mass and angular-momentum loss rates. We determine the previously unknown consequences of this evolution: the growth of the irreducible mass, the division of rotational work between outgoing electromagnetic power and horizon dissipation, and the lifetime-integrated energy removed from the horizon. For fixed magnetic flux and impedance matching, one half of the instantaneous rotati…

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astro-ph.IM

CosmicPAH-IRDB: A Web Application for Including Anharmonicity in Simulated PAH Spectra for Astrophysics

Louan de Bentzmann, Christine Joblin, Karine Demyk, Giacomo Mulas, Dominique Toublanc, Vincent Marty, Axel Pérignon, Mickaël Boiziot et al.

Advances in infrared observations with the James Webb Space Telescope (JWST) call for new tools to exploit the information associated with the Aromatic Infrared Bands (AIBs), now observed in both distant galaxies and the embryos of planetary systems. The AIBs contain information about their carriers as well as the excitation conditions, making them powerful probes of the chemical and physical conditions of their environments - if their spectral information can be decoded. While large datasets of…

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physics.plasm-phphysics.space-ph

A Magnetothermodynamic Theory of Energy Transport In Collisionless Plasmas

Dominic Payne

Presented here is an exploratory conceptual framework with the aim of describing electromagnetic and thermal energy transport and transfer in collisionless plasmas in a coherent way, starting from an arrow-of-time perspective. That is, arguments about the transport of energy are fundamentally based on the idea that systems tend to fill the phase space available to them. First, we describe electric fields, magnetic fields, and plasma particles as interacting subsystems that are thermodynamically…

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astro-ph.IM

Project management of the Canadian Hydrogen Observatory and Radio-transient Detector

Dallas Wulf, Matt Dobbs, Brian Hoff, Michael Rupen, Kendrick Smith, Keith Vanderlinde

The Canadian Hydrogen Observatory and Radio-transient Detector (CHORD) is a new drift-scan radio interferometer operating from 300-1500 MHz, optimized for 21cm intensity mapping, 21cm galaxy detection, pulsars, and transient detection and localization. The full instrument will feature a core array of 512 six-meter dishes, plus two 64-dish outriggers at several thousand kilometer baselines. The project is nearing completion of the first 64-dish sub array, which will enable commissioning activitie…

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astro-ph.HE

Extreme AGN Variability in WISE: Powerful Flares and Candidate Tidal Disruption Events in AGN

Satya Teja Anuraag Upadhyayula, Daniel Stern, Kishalay De, Christos Panagiotou, Matthew J. Graham, K. E. Saavik Ford, Barry McKernan, Murray Brightman et al.

We present first results from a systematic study of extreme mid-infrared variability of active galaxies across the $>10$-year baseline of the Wide-field Infrared Survey Explorer (WISE) mission. WISE, which observed the full sky with a six-month cadence, is sensitive to transient events in both unobscured and obscured galaxies. This paper focuses on extreme flares in active galactic nuclei (AGNs). Previous studies identified flares such as tidal disruption events (TDEs) in inactive galaxies, typi…

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astro-ph.COastro-ph.GA

Energy deposited by black holes in the hot X-ray gas of elliptical galaxies, groups and clusters

A. Cattaneo, S. Ettori

Galaxy groups show entropy excesses $ΔS$ with respect to theoretical expectations from models and simulations with purely gravitational heating. We determine the heat $Q_{\rm heat}\simeq TΔS$ deposited by non-gravitational sources into the hot gas of elliptical galaxies, groups and clusters, and to compare it with the energy output of their central black holes (BHs). We adopt a simple model for the hot gas with only one free parameter: the core entropy. We calibrate the core entropy on the obser…

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astro-ph.COastro-ph.GA

Energy deposited by black holes in the hot X-ray gas of elliptical galaxies, groups and clusters

A. Cattaneo, S. Ettori

Galaxy groups show entropy excesses $ΔS$ with respect to theoretical expectations from models and simulations with purely gravitational heating. We determine the heat $Q_{\rm heat}\simeq TΔS$ deposited by non-gravitational sources into the hot gas of elliptical galaxies, groups and clusters, and to compare it with the energy output of their central black holes (BHs). We adopt a simple model for the hot gas with only one free parameter: the core entropy. We calibrate the core entropy on the obser…

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astro-ph.GA

The MWA Interestingly Deep AStrophysical (MIDAS) Survey: Survey Description and First Data Release

S. Paterson, N. Seymour, N. Hurley-Walker, T. J. Galvin, S. W. Duchesne, J. Morgan, T. M. O. Franzen

We present the deepest MWA survey to date, targeting the GAMA9 and GAMA23 survey fields at 215.68 MHz. With a bandwidth of 30.72 MHz, the two images cover ${\sim}1250\text{ deg}^2$ for the GAMA9 field and ${\sim}850\text{ deg}^2$ for the GAMA23 field, with an angular resolution of ${\sim}60''$. The GAMA9 image was formed from 1 282 2-min snapshot observations (42.7 hours) and the GAMA23 image from 1 701 observations (56.7 hours) achieving depths of $0.923 \pm 0.003$ and $0.331 \pm 0.001$ mJy/bea…

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astro-ph.GA

Semiresolved Stellar Populations as Distance Indicators

Ignacio Martín-Navarro, Patricia Iglesias Navarro, Francesco La Barbera, Alexandre Vazdekis, Michael A. Beasley, Marc Huertas-Company, ChangHoon Hahn, Luis Peralta de Arriba et al.

Galaxy distances are central to our understanding of the Universe. Despite the success of existing approaches, independent and complementary methods remain valuable for testing systematic effects and extending the applicability range of different distance metrics. Here we demonstrate that the spectrum of an individual semi-resolved stellar population encodes direct information about its distance and that valuable distance constraints can, in principle, be obtained by combining multiple independe…

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astro-ph.SR

The quiescent states of V745 Sco and V3890 Sgr: VLT/X-shooter and Swift/XRT+UVOT observations

Bor Jamnik, Ulisse Munari, Nicola Masetti, Gregor Traven, Manica Perko

Symbiotic recurrent novae are symbiotic binaries in which multiple thermonuclear outbursts have been observed. Only four such systems are currently known in the Galaxy: T CrB, RS Oph, V745 Sco, and V3890 Sgr. They provide convenient laboratories for studying accretion and binary interaction in symbiotic novae during quiescence. We characterise the quiescent states of the less-studied systems V745 Sco and V3890 Sgr and compare their properties with those of T CrB and RS Oph. We analyse VLT/X-shoo…

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astro-ph.EP

Transiting Planetary Systems with Distant Giant Companions Remain Moderately Coplanar

Guang-Yao Xiao, Huan-Yu Teng, Xiumin Huang, Fabo Feng, Dong Lai, Fei Dai, Yu-Juan Liu

The mutual inclination between inner planets and distant giant companions provides an important probe of planetary system formation and dynamical evolution, yet direct measurements of this quantity remain scarce. We combine radial velocity (RV) observations with Hipparcos--Gaia astrometry to constrain the orbital architecture of 19 planetary systems hosting at least one transiting inner planet and one outer giant companion. Using a hierarchical Bayesian framework, we infer the population-level d…

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astro-ph.HEastro-ph.IM

Reconstruction of anomalous air showers with SKA-Low

Vital De Henau, Sjoerd Bouma, Justin Bray, Stijn Buitink, Arthur Corstanje, Edwin Dickinson, Tjibbe Gottmer, Brian Hare et al.

Double-bump showers are a surprising class of extensive air showers (EAS) predicted by Monte Carlo simulations, which, so far, no experiment has been able to directly detect. They occur when a high-energy secondary particle, the leading particle, travels significantly farther than the rest, creating a distinct double-peaked longitudinal profile. The unique radio footprint of double-bump showers, characterized by multiple pulses in the signals and interference patterns in the frequency spectra, e…

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astro-ph.HEastro-ph.IM

Reconstruction of anomalous air showers with SKA-Low

Vital De Henau, Sjoerd Bouma, Justin Bray, Stijn Buitink, Arthur Corstanje, Edwin Dickinson, Tjibbe Gottmer, Brian Hare et al.

Double-bump showers are a surprising class of extensive air showers (EAS) predicted by Monte Carlo simulations, which, so far, no experiment has been able to directly detect. They occur when a high-energy secondary particle, the leading particle, travels significantly farther than the rest, creating a distinct double-peaked longitudinal profile. The unique radio footprint of double-bump showers, characterized by multiple pulses in the signals and interference patterns in the frequency spectra, e…

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astro-ph.GAphysics.chem-ph

Collisional excitation of cyclopentadiene by helium. A complete set of rate coefficients and astrophysical applications

Sándor Demes, François Lique, Marcelino Agúndez, José Cernicharo

Complex organic molecules, including large cyclic species, are prevalent in interstellar space and play a key role in various astrochemical processes. Cyclopentadiene (c-C5H6) is a five-membered cyclic hydrocarbon recently detected in TMC-1 and some other interstellar molecular clouds. While accurate spectroscopic data were available, collisional rate coefficients for its rotational transitions were missing so far, introducing a potential limitation in the interpretation of the observations. Thi…

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astro-ph.IM

HEL1OS on Aditya-L1 Mission: Operations, Data Processing and Monitoring of Sun in Hard X-rays

Ravishankar B. T., Manju Sudhakar, Srikar Paavan Tadepalli, Kiran Kumar Kalisetti, Madhavan R. Menon, Anand Jain, Reenu Palawat, Brajpal Singh et al.

HEL1OS (High Energy L1 Orbiting X-ray Spectrometer) is the hard X-ray spectrometer on-board Aditya-L1 solar mission, monitoring the Sun continuously in the hard X-ray band of 8 keV to 150 keV from the vantage observation platform around the Sun-Earth Lagragian Point 1 (L1). HEL1OS was commissioned in end of October, 2023 and the final instrument configuration was set by end of June, 2024 after all the performance verifications. The instrument always operates in the event mode, and the down-linke…

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astro-ph.HE

AGN X-ray coronae at high luminosity: A broadband study of RBS 229 and PG 1407+265

Alessandro Leonardo Lai, Stefano Bianchi, Andrea Marinucci, Enrico Piconcelli, Francesco Ursini, Elena Bertola, Giorgio Lanzuisi, Pierre-Olivier Petrucci et al.

Context. The X-ray emission of active galactic nuclei (AGNs) is commonly interpreted as arising from Comptonisation in a hot corona above the accretion disc. A prominent soft X-ray excess is also observed in many sources and is often explained by a warm Comptonising layer. Aims. We investigate the X-ray-emitting coronae of the luminous radio-quiet quasars PG 1407+265 ($z=0.94$) and RBS 229 ($z=0.334$), testing whether a two-corona scenario consistently describes their broadband spectra. Methods.…

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astro-ph.IM

4MOST Low Resolution Spectrographs Characterization in Chile

Florence Laurent, Didier Boudon, Eric Daguise, Remi Giroud, Aurelien Jarno, Alexandre Jeanneau, Andreas Kelz, Jens-Kristian Krogager et al.

4MOST, the 4m Multi Object Spectroscopic Telescope, is the optical, fibre-fed, MOS facility for the VISTA telescope at ESO's Paranal Observatory in Chile. Its main science drivers are in the fields of galactic archeology, high-energy physics, galaxy evolution and cosmology. The 4MOST consortium consists of several institutes in Europe and Australia under leadership of the Leibniz-Institut fur Astrophysik Potsdam (AIP). This paper focuses on the successful testing, installation and technical comm…

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astro-ph.GA

Slow stellar halo rotation as a signature of disc flips and GES-like mergers

Kirill Batrakov, Alis J. Deason, Francesca Fragkoudi, Thomas Tomlinson, Azadeh Fattahi, Vasily Belokurov

The stellar halo of the Milky Way (MW) exhibits a weak net prograde rotational signal ($v_φ \lesssim 25$ km~s$^{-1}$), yet its origin remains unexplained. To investigate this, we use the Auriga cosmological simulation suite of MW-mass haloes to probe the rotation of stellar haloes over the redshift range $z_{\mathrm{red}}=0-2.5$. The rotational signal is found to persist over this redshift range. We show that satellite progenitors of the stellar halo exhibit a non-uniform distribution of infall…

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astro-ph.SR

A wavelet-based model of magnetic turbulence over a Parker spiral field

Andrea Larosa, Francesco Pucci, Francesco Malara, Oreste Pezzi, Silvia Perri, Gaetano Zimbardo, Giuseppe Nisticò, Federica Chiappetta et al.

The propagation of Solar Energetic Particles (SEPs) through the heliosphere is strongly influenced by solar-wind magnetic turbulence, which governs particle scattering, field-line wandering, and cross-field transport. These processes shape SEP intensity profiles, anisotropies, and arrival times. Because heliospheric turbulence spans a vast range of scales, direct numerical simulations cannot capture its full spectrum. Synthetic turbulence models provide an efficient alternative by generating fie…

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astro-ph.GA

The Physical Conditions of Low-Mass Galaxies at z=3.5-7.0 from JWST Spectroscopy: The Behaviour of Spectral Line Ratios with Burstiness

Ryan A. Cooper, Karina I. Caputi, Alessandro Marconi, Anna Feltre, Edoardo Iani, Pierluigi Rinaldi, Guillaume Desprez, Harley Katz et al.

We present a study of the physical conditions of galaxies at redshifts $z=3.5-7.0$, based on emission-line diagnostics of JWST NIRSpec spectra for 1889 star-forming sources spanning more than 4~dex in stellar mass. We find that the median H$α$/H$β$ and [OIII]/H$β$ are constant throughout these redshifts, indicating a slow evolution of the interstellar medium conditions from the Epoch of Reionization to Cosmic Noon. The stellar-mass evolution of these line ratios follow the expected trend for che…

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astro-ph.GA

The Physical Conditions of Low-Mass Galaxies at z=3.5-7.0 from JWST Spectroscopy: The Behaviour of Spectral Line Ratios with Burstiness

Ryan A. Cooper, Karina I. Caputi, Alessandro Marconi, Anna Feltre, Edoardo Iani, Pierluigi Rinaldi, Guillaume Desprez, Harley Katz et al.

We present a study of the physical conditions of galaxies at redshifts $z=3.5-7.0$, based on emission-line diagnostics of JWST NIRSpec spectra for 1889 star-forming sources spanning more than 4~dex in stellar mass. We find that the median H$α$/H$β$ and [OIII]/H$β$ are constant throughout these redshifts, indicating a slow evolution of the interstellar medium conditions from the Epoch of Reionization to Cosmic Noon. The stellar-mass evolution of these line ratios follow the expected trend for che…

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astro-ph.IM

Exploring reinforcement learning to enhance focal-plane wavefront control for vortex coronagraphs

Iremsu Taskin, Jalo Nousiainen, Gilles Orban de Xivry, Olivier Absil, Markus Kasper

High Contrast Imaging (HCI) on ground-based telescopes suffers from phase aberrations on the observed wavefront caused by atmospheric turbulence. Adaptive Optics (AO) systems are adept at correcting these aberrations, but fall short in the correction of non-common path aberrations (NCPAs). NCPAs arise because the wavefront sensor (WFS) measures and corrects a wavefront that is different from that affecting the science images, thus requiring additional intervention. This work makes use of focal-p…

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astro-ph.EPastro-ph.IM

Optical Colors as Compressed Spectral Information for Trans-Neptunian Objects

Hsing-Wen Lin, Larissa Markwardt, Kevin Napier, Fred Adams, Renu Malhotra, David Gerdes

Broadband optical colors have long been recognized as tracers of the surface spectral properties of trans-Neptunian objects (TNOs), yet their relationship to near-infrared (NIR) spectra has not been quantitatively characterized. We construct an empirical optical-NIR spectral manifold from JWST spectroscopy of 40 TNOs and 8 Neptune Trojans and interpret broadband photometry as compressed representations of this manifold. Using the spectral manifold as a prior, the model conditions on observed bro…

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astro-ph.GA

Sulphur within the extreme environment of the central molecular zone of NGC 253: a chemical modelling approach

M. Bouvier, K. M. Dutkowska, S. Viti, J. G. Mangum, E. Behrens, C. Eibensteiner

Sulphur(S)-bearing species are ubiquitous in Galactic star-forming regions, from dense cold cores to outflows and shocks linked to protostellar activity. A recent observational study investigated the origin of S-bearing species towards the central molecular zone (CMZ) of NGC 253 and showed that Sulphur emission is linked to the presence of forming stars. However, more extensive modelling of these observations are required to determine the exact origin of the Sulphur emission (e.g. shock or therm…

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astro-ph.EP

Current water trapping micro-habitats on the surface of Mars

Anna Bognar, Bernadett D. Pal, Akos Kereszturi

This paper presents a conceptual model exploring how liquid water could be maintained in direct contact with hypothetical microorganisms during warm daytime periods on Mars. Hygroscopic surface salts (e.g., NaCl, CaCl$_2$, Ca(ClO$_4$)$_2$, gypsum, MgSO$_4$) can absorb water vapor and form liquid solutions; however, daytime exposure normally causes rapid drying. We propose a mechanism where diurnal temperature fluctuations drive thermal expansion and contraction cycles that open and close micro-c…

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astro-ph.HEgr-qc

Constraints on Buchdahl-Inspired Gravity from Future Pulsar Timing near Sgr A*

Jian-Ming Yan, Tao Zhu, Zong-Kuan Guo, Zhao Li

Future pulsar timing observations near Sgr~A* offer a unique probe of gravitational physics in the vicinity of a supermassive black hole. We forecast the ability of such measurements to constrain a Buchdahl-inspired $R^2$ gravity, parameterized by a single deviation parameter $ε$, using a timing framework that self-consistently integrates orbital dynamics with light-propagation delays and preserves the full timing solution across the observing span. Through Fisher-matrix forecasts for a represen…

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astro-ph.GA

The fraction of clumpy star-forming galaxies in nearby galaxies from CLAUDS and HSC-SSP

Jürgen J. Popp, Hugh Dickinson, Stephen Serjeant, Lucy F. Fortson, Tobias Géron, Vihang Mehta

Massive, star-forming clumps are regions of intensive star-formation that are commonly observed in high-redshift ($z > 1$) galaxies. Observations of low-redshift clumpy galaxy analogues are rare but the availability of wide-field galaxy survey data makes the detection of large clumpy galaxy samples much more feasible. We present a population of 12,790 star-forming clumps detected in a mass-complete sample of 5,395 star-forming galaxies (SFGs) at redshifts $z\leq0.32$, located in the XMM-LSS, E-C…

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astro-ph.SR

Integrated Mass Loss for Very Metal-poor Stars: Asterosesimic Red Giant Masses of K2 Globular Cluster NGC 5897

Csilla Kalup, László Molnár, Madeline Howell, Attila Bódi, András Pál

Mass loss in low-mass stars during the red giant branch (RGB) and early asymptotic giant branch (EAGB) phases plays a key role in shaping stellar evolution, yet its dependence on stellar parameters such as metallicity remains poorly constrained, with observational studies yielding conflicting trends. We present the first asteroseismic analysis of RGB and EAGB stars in NGC 5897, the most distant and metal-poor globular cluster observed by the Kepler space telescope during the K2 mission. We detec…

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astro-ph.HE

Complex Lags from Simple Physics

Benjamin Ricketts, Gregoire Marcel

X-ray timing information produced through Fourier analysis from the variable emission of black hole X-ray binaries has been used for several decades to provide key insights into the physical setup of these systems not measurable with spectroscopy. In particular, quasi-periodic oscillations within these systems have been of particular interest and remain the source of great debate on how they come about. We investigate the timing products of simple toy models of QPO variability to provide more in…

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astro-ph.HE

Complex Lags from Simple Physics

Benjamin Ricketts, Gregoire Marcel

X-ray timing information produced through Fourier analysis from the variable emission of black hole X-ray binaries has been used for several decades to provide key insights into the physical setup of these systems not measurable with spectroscopy. In particular, quasi-periodic oscillations within these systems have been of particular interest and remain the source of great debate on how they come about. We investigate the timing products of simple toy models of QPO variability to provide more in…

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