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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.SRastro-ph.GA

The nearby Type II supernova 2024ggi beyond 600 days: circumstellar interaction and dust formation

L. Ferrari, G. Folatelli, C. P. Gutiérrez, A. Méndez, C. Ashall, K. Medler, K. Ertini, H. Kuncarayakti et al.

The Type II SN 2024ggi is one of the nearest core-collapse SNe to have exploded in recent decades. Its proximity has enabled extensive multiwavelength monitoring from early times through the nebular phase. Signatures of late-time interaction between the SN ejecta and hydrogen-rich circumstellar material (CSM) have recently been reported. Here we extend its study using late-time optical photometry and spectroscopy from 570 to 820 d after explosion. We investigate the emergence and evolution of la…

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astro-ph.EPastro-ph.SR

JWST Imaging of Edge-on Protoplanetary Disks. V. Flux Ratio Reversal and Disk-edge Structure in the Flying Saucer

Jie Ma, Karl R. Stapelfeldt, Marion Villenave, Gaspard Duchêne, François Ménard, Ryo Tazaki, Youcef I. Bouarour, Greta Guidi et al.

We present near- and mid-infrared broadband imaging observations of the edge-on protoplanetary disk 2MASS J16281370-2431391, a.k.a. the 'Flying Saucer', obtained with NIRCam and MIRI on board JWST. These data are combined with archival optical and near-IR broadband imaging from HST, millimeter dust continuum emission from ALMA, and optical lightcurves from the K2 and TESS for a comprehensive multi-wavelength study. The JWST observations reveal a reversal of the flux ratio between the two reflect…

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cs.HCastro-ph.IM

Particle Selection in Virtual Reality

Boaz Keren-Gil, James Gain, Lucia Marchetti, Patrick Marais, Alexander Sivitilli

Point-cloud representations of 3D data are used in many fields, from astronomical surveys of galaxies to medical imaging and laser scans of buildings. A task common to all of these is interactive selection: picking out a meaningful subset of points for closer analysis. The data is inherently 3D, yet the traditional workflow uses a 2D mouse on a 2D projection and inherits the limitations of a flat screen. This paper compares Virtual Reality (VR) and desktop environments for 3D particle selection,…

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astro-ph.IMastro-ph.EPastro-ph.GA

Extinction by non-spherical particles with the Nanoparticle Transition Matrix Code: perspectives for interstellar medium and exoplanetary atmospheres

G. La Mura, G. Mulas, M. A. Iatì, C. Cecchi-Pestellini, G. Aresu, S. Rezaei, R. Saija

The Transition Matrix formalism (T-matrix) offers an optimal solution to the problem of radiation scattering and absorption by particles characterized by a high degree of chemical and structural complexity. However, its application to particle models composed by large numbers of constituents has been classically limited by the substantial computational burden of the method. As a consequence, the investigation of light scattering and absorption processes, in cases where particle asymmetry and non…

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astro-ph.GA

R(V) parameter of the dust extinction curve: mapping based on hot stars and connections to diffuse interstellar bands

R. Lallement, J. L. Vergely, N. L. J. Cox

Favored carriers of the Diffuse Interstellar Bands (DIBs) are carbonaceous molecules whose constituents have been presumably expelled by dying stars along with those of dust grains. The parallel evolution of DIB carriers and grains and their potential interplay are unknown. We assembled published R(V) measurements of 505 hot stars. We inverted a catalog of extinction data based on Gaia XP spectra and NIR photometry, and used the resulting new 3D extinction map to locate the opaque areas responsi…

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hep-phastro-ph.HEhep-th

Cosmic Colliders in Binary Blazars Probing Ultra-High-Energy Particle Physics

Giorgio Galanti

While terrestrial colliders and fixed-target cosmic-ray interactions are bounded at center-of-mass (CM) energies $\sqrt{s} \lesssim \mathcal{O}(10^5)\,\text{GeV}$, we demonstrate that bound sub-parsec binary blazars form broad-band, beam-beam hadronic ``Cosmic Colliders'', overcoming such limitation. Driven by modest jet misalignments ($θ_{\rm mis} \sim 1^\circ - 6^\circ$), co-streaming proton beams collide at CM energies reaching $\sqrt{s} \sim 10^{10}\,\text{GeV}$ - six orders of magnitude abo…

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astro-ph.COastro-ph.GA

The Cosmic Radio Dipole and Observer Effects in SKA all-sky surveys

D. Bertacca, L. Böhme, B. Bottazzi Baldi, C. Burigana, M. Y. Elkhashab, C. L. Hale, S. von Hausegger, H. R. Klöckner et al.

The Square Kilometre Array (SKA) will observe our Universe on the largest scales and so enable the study of fundamental assumptions in cosmology, such as cosmic homogeneity and isotropy. Observations over recent years have reaffirmed an unexpected challenge to the Cosmological Principle first seen in measurements of the cosmic radio dipole. This dipole anisotropy is thought to be caused by our local observer motion, however, it is observed to be about three times larger than predicted, with sign…

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astro-ph.HEastro-ph.COastro-ph.GAhep-ph

Indirect Dark Matter Detection in the Multi-Messenger Era: Experiments, Systematics, Anomalies, and Prospects for Discovery

Muad Ghaith, Khaled Obaideen

Indirect searches for dark matter (DM) span gamma rays, charged cosmic rays, neutrinos, X-rays, radio emission, the cosmic microwave background (CMB), and the 21~cm signal, but reported constraints and anomalies vary in evidential strength. This critical review synthesizes peer-reviewed literature from January 2000 through October 2026 using a structured search strategy. We assess observations through a framework linking particle interactions and halo source terms to propagation or cosmological…

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astro-ph.HEastro-ph.IMhep-ex

An end-to-end experimental pipeline for automated track identification for paleo-detectors

Claudio Galelli, Alessandro Testi, Lorenzo Caccianiga

Paleo-detectors aim to exploit the damage tracks left in natural minerals by cosmic messengers over geological times to reconstruct past fluxes of energetic particles. For cosmic rays, the expected signal is abundant, and the tracks are micron-scale, so they can be revealed by etching and read out with conventional optical microscopy; what remains challenging is turning a bulk sample into a calibrated track-length spectrum that can be quantitatively confronted with theoretical predictions. In th…

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astro-ph.GAastro-ph.HEastro-ph.IM

A Quest for Changing-State AGNs

Kasra Mokhtarpour, Vicki Sarajedini

We use Gaia Data Release 3 (DR3) light curves to identify photometrically selected changing-state active galactic nucleus (CSAGN) candidates. We employ unsupervised deep learning and anomaly detection methods to identify unusual patterns of variability in the light curves of 872,228 AGNs with known variability. We find that 8,504 light curves show anomalous behavior. Among these, 682 sources show evidence for two-state photometric behavior during the Gaia DR3 observing baseline. These 682 CSAGN…

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astro-ph.COastro-ph.HEhep-phhep-th

Self-Interacting Dark Matter: From Particle Physics Theories to Structure Formation Simulations

Martin Rosenlyst, Vinh Tran, Oliver Zier, Xuejian Shen, Mark Vogelsberger, Thejs Brinckmann, Mads T. Frandsen, Jesús Zavala et al.

We develop a unified theory-to-simulation framework for self-interacting dark matter (SIDM), connecting microscopic dark-sector physics to nonlinear structure formation. We systematize particle-physics ingredients of representative SIDM models and map microscopic parameters and interactions onto structure-formation simulation inputs. These include internal-state populations and reaction networks, velocity- and angle-dependent cross sections, inelastic and dissipative energy exchange, decay rates…

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astro-ph.COastro-ph.HEhep-phhep-th

Self-Interacting Dark Matter: From Particle Physics Theories to Structure Formation Simulations

Martin Rosenlyst, Vinh Tran, Oliver Zier, Xuejian Shen, Mark Vogelsberger, Thejs Brinckmann, Mads T. Frandsen, Jesús Zavala et al.

We present a unified theory-to-simulation framework for self-interacting dark matter (SIDM), combining a self-contained introduction to its particle-physics foundations and representative benchmark models with an explicit, systematic mapping to simulation inputs and validated numerical implementations in the moving-mesh code AREPO-2. We characterize representative elementary and composite dark-sector models through their particle content, symmetries, interactions, production mechanisms, and cons…

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astro-ph.GA

Unveiling the Hot Interstellar Medium in Nearby Galaxies with eROSITA

Roman Laktionov, Manami Sasaki, Elias Kyritsis, Andreas Zezas, Steven Hämmerich, Fiona Knies, Jörn Wilms, Frank Haberl et al.

Diffuse X-ray emission in galaxies originates from stellar-feedback-heated gas and unresolved compact sources. We investigate its thermal component and the scaling of X-ray luminosity with star formation rate (SFR), including galaxies with very low SFRs. We analyzed eROSITA/SRG data from the four all-sky surveys (eRASS:4) for a blind, volume-limited sample of 140 galaxies within 25 Mpc from the Updated Nearby Galaxy Catalog (Karachentsev et al. 2013), cross-matched with HECATEv2 (Kyritsis et al.…

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astro-ph.IM

Initial Performance Tests of MASTA for Wide-Field Narrowband Imaging

Mingxuan Xu, Jiang-Tao Li, Li Ji, Chen Zhang, Yantian Zhu

Wide-field narrowband imaging provides an efficient approach for mapping low-surface-brightness line emission over large angular scales. We present initial performance tests of Multi-Application Survey Telescope Array (MASTA) for narrowband imaging. Using commissioning data obtained with the QHY461 and COSMOS-8K cameras, we characterize the basic reduction procedure, photometric calibration, image quality, and point-source detection limits. The measured surface-brightness and point-source detect…

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astro-ph.HE

Double Detonations on a Moving Mesh with $\texttt{Cattails}$: Characterizing Early Reddening in SNe Ia

Dillon Hasenour, Paul Duffell, Abigail Polin

Type Ia supernovae are useful as cosmological distance indicators and are significant sources of chemical enrichment in galaxies, but much about their origins remains uncertain. The double detonation explosion mechanism is one promising model for these transients. We present a suite of thermonuclear hydrodynamic double detonation models of sub-Chandrasekhar mass white dwarfs spanning thin to thick helium shells. Thin shell models produce light curves and spectra consistent with normal Type Ia su…

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astro-ph.GAastro-ph.HEgr-qc

Evidence for Hierarchical Turbulent Scaling in Nearby Star-Forming Galaxies

Luna Maria Scipio, Fernando A. N. Santos, Jay Armas

We find recurring signatures of intermittency in molecular-gas velocities from cloud to galactic scales. In 31 selected galaxies from PHANGS-ALMA, velocity-centroid exponents through sixth order show nonlinear order dependence and nearly linear relations between consecutive exponents across galaxies. Positive estimated offsets from single-exponent scaling occur in all 52 galaxies with a valid power law fit and 99 of 100 clouds. A generalized She-Leveque hierarchy accommodates these signatures, s…

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astro-ph.SR

TESS flares and chromospheric variability in the Pleiades, the Hyades, and Praesepe

A. Görgei, K. Vida, B. Seli, K. Oláh, P. Sági, B. Schmercz, R. M. Roettenbacher, Zs. Kővári et al.

Magnetic activity is a result of the interaction between rotation and dynamo processes in cool stars with outer convection zones. Since open cluster members share a common age, distance, and chemical composition, they provide an opportunity to study the magnetic activity of cool stars in a controlled astrophysical context. We used 120s cadence observations from the Transiting Exoplanet Survey Satellite (TESS) to study the flare activity of stars in three open clusters with different ages: the Pl…

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astro-ph.GA

Environmental Dependence of Satellite Planarity and Orbital-Pole Coherence around Milky Way Analogues in a Hydrodynamical Cosmological Simulation

Peng Wang, Yu Luo, Jiang Chang, Xi Kang, Shi Shao

We examine whether the unusual spatial flattening and orbital-plane coherence of the Milky Way's classical satellites are connected to the Galaxy's location in the cosmic web. We compare the 11 classical satellites with the 11 most massive satellites of 11,922 Milky Way-mass hosts in the TNG300-1 hydrodynamical simulation. We measure flattening with both the simple inertia tensor (SIT), which retains radial information, and the reduced inertia tensor (RIT), which isolates angular anisotropy. Orb…

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astro-ph.SRastro-ph.EP

An Intermediate-orbit Brown Dwarf Confirmed with Astrometry+Radial Velocity Joint Analysis, and the Eccentricity Distribution of Brown Dwarfs Across Different Locations

Lei Ren, Tianjun Gan, Yifan Xuan, Shude Mao, Shigeru Ida, Guang-yao Xiao, Fabo Feng, Enric Pallé et al.

Intermediate-orbit ($\sim 1$ AU) brown dwarfs with absolute mass measurements are essential for understanding the evolution of substellar objects. Although such systems remain rare, their number is now being enlarged thanks to astrometry. Here, we present the absolute mass measurements for HD 203771B, a massive brown dwarf orbiting a K dwarf ($M_\ast=0.79\pm0.08\ M_\odot$) with a period of 1140 days on an eccentric ($e\approx0.5$) and inclined ($i\approx 130^{\circ}$) orbit. Through joint analys…

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astro-ph.IM

Institutional broadening of the Japanese astronomy and astrophysics research community during 1996-2025

Hideaki Fujiwara

Using bibliometric data from publication records, we investigate the institutional broadening of Japanese astronomy and astrophysics over 1996-2025. The number of Japan-affiliated publications increased from 588 to 2,156, and the number of unique participating Japanese institutions increased from 123 to 227, indicating a nominal broadening of the institutional base. However, institution-publication links remained concentrated among leading institutions, and the effective number of institutions,…

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astro-ph.EP

An updated view of Jupiter's UV main auroral emission: large-scale analysis of UV and particle data from Juno's first 60 orbits

Linus Head, Denis Grodent, Bertrand Bonfond, Nicholas Kruegler, Ali Sulaiman, George Clark, Bilal Benmahi, Guillaume Sicorello et al.

The properties and origins of Jupiter's UV main auroral emission are, at present, not yet fully understood, particularly the extent to which its two distinct zones, the Zone-I and Zone-II aurora, originate from a common source. In this work, remote-sensing and in-situ data from the Juno spacecraft are used to investigate and produce maps of the average properties of the main emission over Juno's first 60 orbits. It is found that the peak in mean energy of electrons precipitating in the main emis…

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stat.MLastro-ph.COastro-ph.IMcs.LG

$\texttt{NFDiag}$: High-dimensional MCMC Convergence Diagnosis with Normalizing Flows

Kutay Nazlı, Elena Sellentin

Accurately assessing the convergence of Monte Carlo Markov Chains is crucial for ensuring their validity in Bayesian inference problems. However, convergence assessment in high dimensions is known to be difficult, due to most convergence diagnostics becoming insensitive beyond a few dozen parameters. Conventional convergence statistics analyze marginal distributions which in high dimensions neglects increasing levels of information from the joint and conditional probability distributions. Thus w…

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astro-ph.HE

The Thousand-Pulsar-Array programme on MeerKAT - XX. Co-existing interacting periodicities and polarization modulation in PSR J1901-0906

Jui-An Hsu, Patrick Weltevrede, Geoff Wright, Michael J Keith, Aris Karastergiou, Xiaoxi Song

We present a comprehensive analysis of the complex subpulse modulation in PSR J1901-0906 using data from the Thousand-Pulsar-Array (TPA) programme. Our analysis reveals the coexistence of three distinct periodicities in the subpulse modulation of both profile components, which obey a beat relation. We also detect additional spectral beat features caused by the modulation of these co-existing periodicities by investigating the Fourier phase correlation in two-dimensional fluctuation spectra. More…

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astro-ph.GA

Identifying the principal mechanism of star formation feedback

Chong Li, Rouyu Li, Keping Qiu, Marko Krco, Di Li, Hongchi Wang, Xin Lyu, Yan Duan et al.

Feedback from massive stars regulates the formation of next-generation stars and planets and thus shapes the evolution of galaxies, yet observational evidence capable of determining which mechanism dominates the feedback process has long been lacking. Here,we present a large-scale HI survey toward Orion A$.$ With an unprecedented sensitivity and superior resolution, FAST (Five-hundred-meter Aperture Spherical radio Telescope) reveals a well-defined heart-shaped expanding HI bubble, enshrouding t…

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astro-ph.SR

Aditya-L1 and SDO Observations of a Confined X-Class Flare with an EUV Late Phase: Thermal and Nonthermal Emission, Magnetic Topology, and Flux Rope Confinement

Vishwa Vijay Singh, Bhuwan Joshi, N. P. S. Mithun

We study a long-duration, confined X2.0-class solar flare exhibiting three distinct episodes of HXR emission, along with an accompanying EUV late phase. A key highlight of this work is the novel observations from the high-resolution solar X-ray spectrometers SoLEXS and HEL1OS onboard Aditya-L1, providing insights into the evolution of thermal and non-thermal emissions. Simultaneous EUV observations from AIA/SDO in hot channels, combined with multi-band X-ray light curves, reveal a two-stage conf…

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astro-ph.HEastro-ph.GAastro-ph.SR

Blackbody evolution and circumstellar medium properties of broad-lined H-rich superluminous supernovae

Tuomas Kangas, Takashi Nagao, Uliana Pylypenko, Steve Schulze, Lin Yan

Broad-lined H-rich superluminous supernovae (SLSNe II) tend to show signs of interaction, including a UV excess compared to a blackbody function. However, a quantitative analysis of the CSM configuration and the UV excess has so far not been performed for most of the literature sample. Additionally, SN 2023gpw showed signs of asymmetry in its peculiar blackbody and spectral evolution, raising the question of whether similar properties can be found in other SLSNe II. We aim to characterize the ci…

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astro-ph.GA

Nearly pristine gas in a galaxy 1 billion years after the Big Bang

Sarah E. I. Bosman, Frederick B. Davies, Louise Welsh, Emanuele P. Farina, Prakash Gaikwad, Benedetta Spina, Barun Maity, Ryan Cooke et al.

Excitation of carbon and oxygen ions is the primary mechanism by which collapsing gas clouds dissipate heat to form new stars. At early cosmic times, in galaxies with chemically pristine gas, many stars are expected to have masses far larger than the mass of our sun due to the deficit in these elements. We searched for ultra-metal-poor galaxies using their spectroscopic absorption signatures in front of bright background quasars, employing the new GHOST high-resolution spectrograph. Here we repo…

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astro-ph.SR

SiO Maser Line-width Diagnostics of AGB Stars and Red Supergiants: The RSG-adjacent Region in the FWZI--Luminosity Plane

Qiu-Yu Tao, Jun-ichi Nakashima, Yong Zhang, Zehao Zhang, Jia-Yong Xie, Chang Liu

We investigate whether SiO maser line profiles can distinguish asymptotic giant branch (AGB) stars from red supergiants (RSGs) and identify unusual AGB-classified sources near the RSG regime. We compiled 2,956 detected SiO maser spectra for 1,551 objects and constructed reference samples of 1,068 O-rich AGB stars and 36 RSGs. The full width at zero intensity (FWZI) was reliably measured for 1,020 AGB stars and 32 RSGs. AGB stars are concentrated at narrow line widths: 81.5% have FWZI 15 km s^-1…

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astro-ph.SRastro-ph.EP

From the QBO to Rieger-type periods: Explaining extreme solar events by tidally triggered magneto-Rossby waves

F. Stefani, G. M. Horstmann, G. Mamatsashvili, T. Weier

It has recently been demonstrated that the occurrence of extreme solar events is governed by a phase-stable period close to 1.723 years (629.29 days). According to our previously developed tidally-synchronized solar dynamo model, this is one of the periods resulting from two-planet spring tides exerted by the tidally dominant planets Venus, Earth and Jupiter, which trigger magneto-Rossby waves in the solar tachocline. Overall, the squared sum of these three waves incorporates nine periods rangin…

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astro-ph.IMastro-ph.HE

Unveiling photometric transients with the ILMT and their follow-up using DOT

Priyanshi Kumari, Bhavya Ailawadhi, Talat Akhunov, Monalisa Dubey, Naveen Dukiya, Sara Filali, Paul Hickson, Gokul Singh Mehra et al.

The two 4-m class telescopes at the Devasthal site in India are complementary: the 4-m International Liquid Mirror Telescope (ILMT) is dedicated to the discovery of new transient phenomena, which can be followed up using the 3.6-m Devasthal Optical Telescope (DOT) for their optical characterisation. The ILMT continuously surveys a $22.3^\prime \times 22.3^\prime$ wide strip of the zenith sky. A dedicated transient detection and classification pipeline, PyLMT, based on optimised image subtraction…

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