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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.HE

Discovery of a 62-min long-period transient with near-orthogonal rotator geometry

Scott D. Hyman, Natasha Hurley-Walker, Dale A. Frail, Emil Polisensky, W. M. Cotton

We report the serendipitous discovery of J155543.7$-$563102 (hereafter LPT J1555$-$5631) with a period of 62.2 min in MeerKAT and ASKAP survey data. The source emitted bright (10-30 mJy), steep-spectrum ($α\sim-1.5$), highly polarized radio pulses during a 15-hr active window in May 2022, with no other quiescent or pulsed emission detected before or after over $\sim5$ years. The mean light curve exhibits two alternating pulses per cycle. A main pulse (MP) and an interpulse (IP) separated by $Δφ=…

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astro-ph.HE

Discovery of a 62-min long-period transient with near-orthogonal rotator geometry

Scott D. Hyman, Natasha Hurley-Walker, Dale A. Frail, Emil Polisensky, W. D. Cotton

We report the serendipitous discovery of J155543.7$-$563102 (hereafter LPT J1555$-$5631) with a period of 62.2 min in MeerKAT and ASKAP survey data. The source emitted bright (10-30 mJy), steep-spectrum ($α\sim-1.5$), highly polarized radio pulses during a 15-hr active window in May 2022, with no other quiescent or pulsed emission detected before or after over $\sim5$ years. The mean light curve exhibits two alternating pulses per cycle. A main pulse (MP) and an interpulse (IP) separated by $Δφ=…

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hep-phastro-ph.HE

Sub-MeV gamma-ray lines from an endothermic interpretation of the LZ recoil candidate

Maíra Dutra, Jacinto P. Neto, Clarissa Siqueira

Endothermic upscattering of heavy dark matter offers a compelling interpretation of the high-energy nuclear-recoil candidate recently reported by LUX-ZEPLIN (LZ), with a characteristic recoil energy $E_R \propto δ$, where $δ$ is the mass splitting between the dark matter states. Cosmological and experimental constraints motivate the depletion of the primordial heavier state, which can be regenerated in the Galactic halo. We show that, if the heavier state decays radiatively, the same mass splitt…

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astro-ph.SRphysics.hist-ph

Carrington's Last Sunspot Drawing in 1870

Hisashi Hayakawa, E. Thomas H. Teague

Richard Christopher Carrington carried out extensive sunspot observations from 1853 to 1861 and left numerous scientific legacies. However, despite his fame, consulting his original manuscripts, we have found Carrington's last sunspot drawing, which he never published. We date this drawing 23 Dec 1870, when Carrington was based at his Churt Observatory. The drawing allows us to count 3 sunspot groups and 10 individual sunspots and measure the group positions at N14° W37°, N11° W46°, and S08° W08…

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astro-ph.GA

Constraining the Light Curves of Magnified Stellar Events at z ~ 0.725

Carter Meyerhoff, Hayley Williams, Rafael Ortiz, Gibson B. Bowling, Rogier A. Windhorst, Zach Borowiak, Hunter Sparks, Charles L. Steinhardt et al.

Extreme magnification by lensing galaxy clusters allows the detection of high-luminosity stars during cluster caustic transient events at cosmological distances. The Dragon Arc at z=0.725 is a frontier target for identifying transient events due to its high frequency of microlensing events, and so far >100 of these events have been detected. The high frequency of events and high cadence of observations allow for the measurement of minimal flux variation between epochs, and therefore the magnific…

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astro-ph.IMastro-ph.CO

Lidar-monitoring of atmospheric fluctuations for millimeter-wave astronomical observations

Jacques Delabrouille, Patrick Chazette, Étienne Burtin, Christophe Chailan, Josquin Errard, Shamik Ghosh, Manuel Gonzalez, John Groh et al.

Ground-based millimeter-wave astronomical observations suffer from strong contamination by the emission of inhomogeneous water vapor in the Earth's atmosphere. This emission reduces the observing efficiency and data quality even from a high-altitude, dry location such as the Atacama plateau in Chile. We propose to continuously monitor atmospheric water vapor with a co-pointing dedicated Raman lidar system. We show, with numerical simulations and proof-of-concept observations, how a synergistic u…

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astro-ph.IMastro-ph.GAastro-ph.HE

A Probabilistic Method for Estimating VLBI Jet-Component Ejection Epochs. Application to MOJAVE 15 GHz VLBA Kinematics

Vladislav A. Makeev, Yuri Y. Kovalev, Cecilia Degli Agosti, Daniel C. Homan

Ejection epochs of parsec-scale jet components in active galactic nuclei (AGN), tracked with Very Long Baseline Interferometry (VLBI), are commonly estimated by extrapolating fitted trajectories back to the VLBI core. However, trajectory uncertainties, non-radial motion, acceleration, and the finite size and position variability of the core can make such estimates uncertain and restrict usable samples. We develop a probabilistic framework for estimating VLBI-component ejection epochs, including…

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hep-phastro-ph.SRhep-exhep-th

Constraining Ultra-Light Vector Bosons via Solar Neutrino Oscillations: The Gauged $L_μ- L_τ$ Model and Prospects for JUNO and XLZD

Ilídio Lopes

We present an extension of the Standard Model based upon the gauged $U(1)_{L_μ- L_τ}$ symmetry, featuring an ultra-light vector boson that couples to the difference of muon and tau lepton numbers. This anomaly-free construction, historically motivated by the muon's anomalous magnetic moment, is employed here as an independent phenomenological framework for solar neutrino physics. Through kinetic mixing with the photon, the $Z^\prime$ boson generates an effective matter potential within the solar…

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astro-ph.GAastro-ph.CO

Constraining the galaxy-halo connection at $z>10$ using the neighbors of UV-bright galaxies

Ivan Nikolić, Charlotte A. Mason

JWST has discovered an overabundance of UV-luminous galaxies compared to extrapolations from pre-JWST galaxy formation models. Distinguishing between proposed theoretical explanations requires constraining the halo masses of these systems, which can be probed through clustering. However, at $z>10$, low galaxy number densities render traditional clustering measurements challenging. We introduce a novel formalism that uses information about the local environments ($\lesssim$2 arcmin) of individual…

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astro-ph.HEastro-ph.CO

Observations of Repeating Tidal Disruption Events

Iair Arcavi, Thomas Wevers

The disruption of stars by supermassive black holes (SMBHs) as tidal disruption events (TDEs) can produce transient flares across the electromagnetic spectrum. Such flares can be used to probe SMBH properties, accretion physics and stellar dynamics in galactic nuclei. However, it can be difficult to distinguish TDE flares and those arising from other accretion phenomena around SMBHs, such as active galactic nuclei disk instabilities. Repeated flares from the same location can be produced by eith…

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

Synthesis of organo-phosphorous species in space: the reaction of P$^+$ with C$_2$H$_2$

Matteo Michielan, Jorge Alonso de la Fuente, Roland Thissen, Christian Alcaraz, Nicolas Solem, Cristina Sanz Sanz, Susana Gómez Carrasco, Miroslav Polášek et al.

Despite its low cosmic abundance, phosphorus is a bioessential element whose prebiotic availability and incorporation into biomolecules remain open questions. Only a few phosphorous containing molecules with P to C bonds have been detected in astronomical environments (CP, CCP, HCP). More complex species have been proposed, but their formation and destruction pathways remain poorly constrained. Gas-phase ion molecule chemistry involving P cations may contribute to organophosphorus formation, par…

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gr-qcastro-ph.HEhep-ph

Stochastic gravitational-wave background from self-interacting superradiant clouds

Yin-Da Guo, Richard Brito, Chen Yuan

Gravitational-wave (GW) observations offer a powerful probe of new fundamental fields. One well-motivated source is black hole (BH)--boson cloud systems, in which an ultralight scalar field forms a cloud around a rotating BH via superradiance and emits long-lived nearly monochromatic GWs. In this work, we compute the stochastic GW background (SGWB) from such systems, extending previous work by including scalar self-interactions, and discuss its detectability with next-generation ground-based GW…

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astro-ph.HEastro-ph.GA

Evidence for an extended Galactic proton component beyond the cosmic-ray knee

Jieshuang Wang

The cosmic-ray (CR) \textit{knee} at a few petaelectronvolts (PeV) is commonly associated with the acceleration limit of Galactic protons. Recent detection of multi-PeV photons from the microquasar Cygnus X-3 suggests proton acceleration to tens of PeV. However, the contribution of such type of sources to CRs remains unclear. Here we analyse proton and helium spectral data spanning from 0.1 to 1000~PeV and find that the knee strongly disfavours a single terminal cutoff. Full-spectrum analyses in…

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physics.space-phastro-ph.EPastro-ph.SR

An autonomous approach to model daytime behavior of sub-ionospheric VLF signals over short and medium propagation paths in India

Sayak Chakraborty, Tamal Basak, Sourav Palit, Sandip K. Chakrabarti

We present an autonomous model to simulate the daytime variation of sub-ionospheric Very Low Frequency (VLF) signal amplitude, beginning with the computation of the D-region electron density by numerically solving the electron continuity equation (ECE). From the resulting altitude-dependent electron density profile (Ne), we extract Wait's ionospheric parameters (h' and beta) using a log-linear fitting method. The study focuses on two VLF propagation paths (one short and one medium in length) in…

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astro-ph.SRastro-ph.EPphysics.space-ph

Modeling of the variability of D-region ionospheric electron density during solar cycle-24

Sayak Chakraborty, Sourav Palit, Semontee Deb, Tamal Basak

Solar cycle variation of earth's atmosphere, particularly the ionosphere is of particular interest in the field of space science and space weather studies. In this article, we present the outcome of our detailed quantitative study on solar cycle variation of lower ionospheric properties using numerical investigation. First, we seek to model and compare the collective D-region ionization rates (q's) due to the individual contributions from the ionizing sources, namely, (a) solar extreme ultraviol…

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astro-ph.GA

Barred Galaxies in MaNGA: Stellar Mass Dependence and Black Hole Growth

Chandan Watts, Sudhanshu Barway

This study investigates the role of internal structures, such as stellar bars and active galactic nuclei (AGN), in shaping galaxy evolution using 7,408 galaxies (2,641 barred) from the SDSS-IV MaNGA survey. Our analysis spans a wide stellar mass range, from dwarf to massive galaxies, examining how internal and environmental processes regulate galaxy evolution. Galaxies are categorized by morphology (ellipticals (E), lenticulars (S0s), early-type spirals (ETS), and late-type spirals (LTS)), envir…

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astro-ph.GA

CHANG-ES XLII: Cosmic-Ray Electron Transport and the Spatially Resolved Radio-SFR Relation in Edge-on Galaxies

Jianghui Xu, Volker Heesen, Jiang-Tao Li, Guilin Liu, Rainer Beck, Li-Yuan Lu, Yang Yang, Jayanne English et al.

Radio continuum emission traces star formation in galaxies, but cosmic-ray electron (CRE) propagation between the disk and halo complicates this connection. We present a wide-band, spatially resolved analysis of 19 nearby edge-on galaxies, combining LOFAR observations at 144 MHz with CHANG-ES VLA imaging at 1.575, 3.0, and 6.0 GHz, and hybrid H$α$+22 $μ$m star formation rate (SFR) maps. All maps are convolved to a common 2.1 kpc resolution for pixel-by-pixel analysis of the nonthermal spectral i…

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astro-ph.HEastro-ph.SR

Testing Spin Prior Assumptions of Binary Black Hole Parameter Inference and Their Astrophysical Implications

Chen-He Wu, Wei-Hua Guo, Shu-Jin Hou, Yuan-Zhu Wang, Ying Qin

With the growing number of binary black hole (BBH) candidates in the Gravitational-Wave Transient Catalog 5.0 (GWTC-5.0), an increasing number of BBH systems with distinct properties have been reported. The individual spins are relatively less constrained in the parameter estimations for most events. While the LIGO-Virgo-KAGRA Collaboration (LVK) adopts a uninformative spin prior by default, some binary evolution scenarios have strong predictions on component spins. In this work, we perform Baye…

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hep-phastro-ph.HEastro-ph.SR

Probing Solar Chameleons with XENONnT Ionization-Only Data

Guan-Wen Yuan

Screened scalar fields provide a possible connection between dark energy and laboratory-scale new physics while remaining compatible with existing fifth-force constraints. Solar production offers a direct probe of these models, and ionization-only measurements extend the sensitivity of liquid-xenon detectors into the sub-keV regime. We present the first search for solar chameleons using low-energy S2-only data, based on the 7.83 tonne-year XENONnT ionization-only data set. The predicted electron…

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astro-ph.EP

The July 2023 Outburst of Comet 12P/Pons-Brooks: Observations and Modeling of Dust Coma and Arc Structure

Hitoshi Hasegawa, Mitsunori Tsumura, Shin-ichi Watanabe, Hiroki Akisawa, Jun-ichi Watanabe

We conducted continuous imaging observations of comet 12P/Pons-Brooks, which has experienced multiple outbursts since 2023 July. Among these, we determined the dust coma expansion velocities and the occurrence times for three outbursts. The outburst on 2023 July 20.39$\pm$0.05 had an expansion velocity of 207.5$\pm$0.1 [unit]. The outburst on 2023 November 14.52$\pm$0.10 had an expansion velocity of 305.8$\pm$13.7 [unit], and the outburst on April 2.23$\pm$0.06, 2024 had an expansion velocity of…

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astro-ph.EP

The July 2023 Outburst of Comet 12P/Pons-Brooks: Observations and Modeling of Dust Coma and Arc Structure

Hitoshi Hasegawa, Mitsunori Tsumura, Shin-ichi Watanabe, Hiroki Akisawa, Jun-ichi Watanabe

We conducted continuous imaging observations of comet 12P/Pons-Brooks, which has experienced multiple outbursts since 2023 July. Among these, we determined the dust coma expansion velocities and the occurrence times for three outbursts. The outburst on 2023 July 20.39$\pm$0.05 had an expansion velocity of 207.5$\pm$0.1 m s$^{-1}$. The outburst on 2023 November 14.52$\pm$0.10 had an expansion velocity of 305.8$\pm$13.7 m s$^{-1}$, and the outburst on April 2.23$\pm$0.06, 2024 had an expansion vel…

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astro-ph.EP

On the Secular Evolution of Inclinations Among the Classical Belt TNOs

Dallin Spencer, Darin Ragozzine, Kat Volk, Renu Malhotra

Proper orbital elements have been used in diverse ways to study the dynamical architecture of transneptunian objects (TNOs), providing insights into Solar System evolution and migration theories. In this paper, we present the numerically-computed proper elements of all known TNOs. We then compare their distribution with the distribution of proper elements of a large synthetic sample generated to study the secular behavior of TNOs in the Classical belt region in an effort to better understand cer…

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astro-ph.IMastro-ph.SR

Error Propagation from Integral Moments and Spectral Derivatives of Stokes Profiles to Magnetic Observables

Roberto Casini

We aim to derive convenient analytic estimations of magnetic inference errors, which can be used to inform and facilitate the creation of the science-traceability matrix of a polarimetric instrument. In order to do this, we study the general problem of the propagation of Poissonian noise in polarized light signals to derived data products of the Stokes profiles, namely integral moments of arbitrary orders and spectral derivatives of the intensity. In particular, we derive the errors on the longi…

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gr-qcastro-ph.IM

Gravitational-Wave Modulation of Atomic Spontaneous Emission: Electrodynamical Theory, Quadrupolar Redistribution, and Rydberg Cavity Metrology

Sohrab Rahvar

Studying Gravitational Waves (GWs) provide a unique probe of the interplay between quantum matter and the dynamics of spacetime. We develop a QED framework for spontaneous emission in the presence of a weak classical GW by quantizing the electromagnetic field in a linearized gravitational background. We show that a passing GW dynamically phase-modulates vacuum electromagnetic modes, dressing photon states into a Floquet ladder of sidebands separated by the GW frequency. While the total spontaneo…

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astro-ph.EPastro-ph.SR

Worlds Next Door. V. A Candidate Solar System Scale Super-Jupiter in the 61 Cygni Binary System

Aniket Sanghi, Billy Quarles, Andrea S. J. Lin, Cheyanne Shariat, Pierre Kervella, James Mang, Dimitri Mawet, Mark R. Giovinazzi et al.

We present new constraints on a candidate third companion in the 61 Cygni binary system-one of the closest neighbors to our solar system (3.5 pc), the first stars to have a measured parallax, and two of the most favorable targets for habitable zone exo-Earth searches with future direct imaging missions. Kervella et al. (2022) first identified the candidate based on a 4.4$σ$ tangential velocity anomaly in the system determined using Hipparcos and Gaia DR3 astrometry of the A and B components. We…

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astro-ph.SR

SolRaT: polarized spectral line modeling with multi-term and multi-level atoms

Ivan I. Yakovkin

The interpretation of polarized spectral lines requires models that combine statistical equilibrium with polarized radiative transfer accounting for atomic polarization, the Hanle effect, and Zeeman and Paschen-Back splitting. The aim is to provide an open-source Python implementation of the irreducible spherical tensor formalism of Landi Degl`Innocenti and Landolfi (2004), hereafter LL04, for forward synthesis of Stokes profiles with interchangeable atomic descriptions. SolRaT solves the statis…

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astro-ph.IM

Making Euclid VIS Imaging AI-Ready: A Scalable Pipeline for Morphology, Anomaly Detection, and Similarity Search

Jinhui Xie, Yunfei Xu, Zhen Zhang, Lang Chen, Chenzhou Cui

The Euclid mission is delivering an unprecedented volume of high-resolution galaxy imaging, posing new challenges for standardized and reproducible reuse across morphological analyses. We present a scalable pipeline that converts released VIS cutouts into standardized $224\times224$ model inputs and uses a pretrained DINOv2 ViT-S/14 feature extractor to construct a 365,513-row, 384-dimensional cutout-and-embedding product from the Galaxy Zoo Euclid (Q1) catalogue. Initial production of the 365,5…

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astro-ph.HE

Pulse profiles of tall accretion columns in X-ray pulsars

Bagration Megrelishvili, Pavel Abolmasov

Accreting X-ray pulsars (XRPs) are strongly magnetized neutron stars (NSs) distinguished by a periodic variability pattern related to the rotation of their magnetospheres (pulsations). Many of these objects show complex asymmetric pulse profiles that are difficult to explain in the framework of existing models. We calculate the pulsations of X-ray radiation from a magnetized NS in the regime of supercritical accretion, when the radiation shock wave is high above the NS surface, and the observed…

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astro-ph.EP

Pre-accretional irradiation of comet 67P/Churyumov-Gerasimenko constituents

Inès Sansberro, Nicolas Fray, Hervé Cottin, Cécile Engrand, Donia Baklouti, Christelle Briois, Anaïs Bardyn, Henning Fischer et al.

Comets are thought to have largely preserved the primordial material from which they formed. Therefore, cometary studies provide important clues about the processes involved in the formation of the Solar System. During the last weeks of ESA's Rosetta mission, the COSIMA (COmetary Secondary Ion Mass Analyser) instrument performed a series of measurements, which involved long-term sputtering of dust particles captured from comet 67P/Churyumov-Gerasimenko. These post-sputtering analyses revealed th…

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astro-ph.HE

Global Spline Fit: A unified data-driven view of the cosmic-ray spectrum and mass composition from GeV to the highest energies

Anatoli Fedynitch, Kozo Fujisue, Hans Dembinski, Ralph Engel

The energy spectrum and mass composition of cosmic rays are measured by two complementary classes of instruments: space- and balloon-borne detectors that resolve individual elements up to sub-PeV energies, and ground-based air-shower observatories that extend the reach to beyond $10^{11}$ GeV but resolve only broad mass groups. The Global Spline Fit (GSF) is a data-driven model that combines both into a single, self-consistent description of the flux of all elements from hydrogen to nickel. The…

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