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宇宙工学・惑星科学・宇宙物理の最新プレプリント。

astro-ph.SRastro-ph.EP

Re-evaluating solar irradiance reconstructions: No evidence for large secular trends

Theodosios Chatzistergos, Natalie A. Krivova, Mathew J. Owens, Tatiana A. Egorova

Most current irradiance reconstructions suggest only a modest secular increase in TSI between the 1700 and 1986 activity minima ($<1$ Wm$^{-2}$). However, 2 models, the CHRONOS and Penza et al. (2024; PEA24) models, suggest substantially larger changes of 2.1-5.9 Wm$^{-2}$. Although the two models differ in their architecture, both use cosmogenic isotope records combined with neutron monitor data to describe the long-term irradiance variability. However, cross-calibrating modulation potential re…

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astro-ph.HE

Black-Hole Spin Measurements from X-ray Reflection Spectroscopy: Quality Criteria and Community Recommendations

Javier A. Garcia, Riley Connors, Laura W. Brenneman, James F. Steiner

X-ray reflection spectroscopy provides one of the most powerful electromagnetic methods for measuring the dimensionless spin of accreting black holes. It has yielded spin constraints for stellar-mass black holes in X-ray binaries and supermassive black holes in active galactic nuclei, and is central to the science goals of current and future X-ray observatories. However, the technique is subject to observational and modeling systematics, including continuum-reflection degeneracy, limited spectra…

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astro-ph.IM

Using Muon Rings for the Calibration of the Cherenkov Telescope Array: An Analytical Solution for the Dual-Mirror Telescope Using Vector Geometry

Markus Gaug, Víctor Giráldez-Segalàs, Fiona Redmen

The analysis of ring images produced by muons in Imaging Atmospheric Cherenkov Telescopes (IACTs) provides a powerful and precise method for calibrating the optical throughput of the instrument and monitoring its optical point-spread function. To date, analytical solutions have been derived for single-mirror telescopes with reflectors assumed flat. However, a complete analytical description of the Cherenkov light produced by muons and detected by a dual-mirror telescope - accounting for both the…

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astro-ph.HEastro-ph.IM

CRESCENDO II: Spectral cosmic rays with improved energy losses and realistic supernova seeding

Daniel Karner, Ludwig M. Böss, Klaus Dolag, Ildar Khabibullin

Context. Cosmological simulation codes with subgrid models for cosmic rays (CRs) help us better understand their impact on baryonic feedback and non-thermal radiation in galaxies and galaxy clusters. An accurate numerical description requires a spectrally resolved treatment of the CR population, because virtually all transport, acceleration and loss processes depend on energy. Aims. We advance the treatment of CR electrons and protons in the on-the-fly spectral CR solver CRESCENDO in OpenGadget3…

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astro-ph.GA

The chemodynamical signature of coherent metal-poor inflow and enriched recycled accretion in the cool circumgalactic medium

Glenn G. Kacprzak, Jerrard Doran, Sameer, James Farrington, Jane C. Charlton, Nikole M. Nielsen, Kaustubh R. Gupta, Christopher W. Churchill et al.

The azimuthal and kinematic structure of the CGM is often interpreted as planar accretion and bipolar outflows, yet direct metallicity evidence for this picture remains ambiguous. We combine cloud-by-cloud ionisation modelling with galaxy rotation kinematics for 21 galaxies from the Multiphase Galaxy Halos Survey to investigate how metallicity depends on azimuthal angle and angular momentum. We find that low-ionisation clouds kinematically consistent with disk rotation have ~0.5 dex lower metall…

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astro-ph.HEastro-ph.SRhep-ph

Multiwavelength study of non-thermal emission in the Swift J1834.9-0846/W41 region

Manoel F. Sousa, Rita C. Dos Anjos, Vitor de Souza

We investigate the origin of non-thermal emission from the Swift J1834-0846/W41 region by modeling its broadband spectral energy distribution from radio to TeV energies within leptonic and lepto-hadronic frameworks using Markov Chain Monte Carlo sampling. Motivated by morphological studies of HESS J1834-087 suggesting a two-component TeV structure, we explore a single extended source scenario and a configuration comprising a central point-like component embedded within extended emission. Purely…

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astro-ph.GAastro-ph.HE

VENUS: an ultra-faint galaxy hosting the metal-poor type II supernova at $z=5.13$ Witnessing the initial metal enrichment with extremely frequent core-collapse supernovae?

Yoshihisa Asada, Seiji Fujimoto, Joseph F. V. Allingham, David A. Coulter, Conor Larison, Matthew R. Siebert, Gabriel Brammer, Dan Coe et al.

We present the first characterization of the host galaxy of a recently discovered type IIP SN at $z=5.13$ (SN Eos). SN Eos and its host galaxy are gravitationally lensed and multiply imaged. The total magnification $μ\sim53$ enables spatially resolving the system, allowing us to localize the core-collapse supernova (CCSN) position and to characterize its local environment within an early galaxy. Our observation reveals that the host is an ultra-faint ($M_{\rm UV}=-14.4\pm0.3$ mag) Lyman-$α$ emit…

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astro-ph.HE

X-Ray Timing Properties of the Black Hole Candidate IGR J17091-3624 During the 2022 Outburst Onset with AstroSat

Sree Bhattacherjee, Biplob Sarkar

We present the evolution of rapid X-ray timing variability in the black hole X-ray binary IGR J17091-3624 during the initial phase of its 2022 outburst using a ~3-day-long AstroSat observation. Utilizing the high time-resolution capability of the Large Area X-ray Proportional Counter, we perform a comprehensive study of the evolution of Type-C quasi-periodic oscillations (QPOs) throughout the observation. The QPO centroid frequency evolves from 3.30 to 7.78 Hz, accompanied by the broad-band nois…

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astro-ph.EP

The exozodi spectral effect: Residual habitable zone dust may bias exoEarth characterization

Miles H. Currie, Christopher C. Stark, Eleonora Alei, Aki Roberge

All exoplanetary systems are expected to host exozodiacal dust, or exozodi, originating from planetesimals. For many stars, exozodi will likely be the largest source of astrophysical noise in direct observations of terrestrial exoplanets. Nearby Sun-like systems likely have $\gtrsim3$x more habitable zone (HZ) dust than our solar system, which must be removed from direct images and spectra to reveal exoplanet signals. The albedo of this micron-sized dust varies smoothly over VIS -- NIR wavelengt…

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astro-ph.EP

Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone

Collin Cherubim, Shreyas Vissapragada, Tim Cunningham, Annabella G. Meech, David Charbonneau, Robin Wordsworth, Aaron Householder, Johanna Teske et al.

Observations of highly irradiated gas giant exoplanets have shown helium escaping from their atmospheres. There is limited evidence for atmospheres on rocky exoplanets, perhaps because they have already escaped. We report spectroscopic observations of LHS 1140b, a rocky exoplanet that orbits in the habitable zone of a nearby low-mass star. The near-infrared transit spectra show absorption by helium escaping from the planet's atmosphere. Helium absorption is detected in 2024 but not in 2025, indi…

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astro-ph.EP

Tidal evolution of packed moon systems around an Earth-mass planet

Alan Briseño, Billy Quarles, Marialis Rosario-Franco

While missions have long targeted terrestrial exoplanets within the habitable zone of their host stars, the number of exomoon candidates is expected to grow as next generation space-based observatories achieve the photometric sensitivity required to detect their transit signals. Constraining the stability limits of tightly packed moon systems is therefore essential for transit searches and predicting the number of moons around terrestrial planets. In our Solar System, only three moons orbit the…

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astro-ph.HE

Einstein Probe Fast X-ray Transients Extend the Physical Parameter Space of Relativistic Jets

Connery Chen, Yihan Wang, Bing Zhang

Fast X-ray Transients (FXTs) detected by the Einstein Probe (EP) mission possess exceptionally low spectral peak energies compared to typical long (Type II) GRBs. Some of these extragalactic transients show phenomenological similarities to X-ray flashes (XRFs), but the physical origins of FXTs remain uncertain. In this work, we investigate EP-detected FXTs using various jet structures relevant to Type II GRBs and test the hypothesis that these FXTs belong to the intrinsically same population of…

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astro-ph.SR

Positive superhumps in high mass ratio cataclysmic variables driven by apsidal disk precession

Rebecca G. Martin, Stephen H. Lubow, David Vallet, Stephen Lepp

Previously it has been assumed that a cataclysmic variable (CV) disk can only become eccentric and display superhumps if the 3:1 resonance is located within the disk. This requires the binary mass ratio to be $q=M_2/M_1\lesssim 0.33$, where $M_1$ is the mass of the white dwarf and $M_2$ is the mass of the companion star. However, several systems with higher mass ratios have been observed to exhibit positive superhumps, posing a challenge to this picture. We present the first 3D hydrodynamic simu…

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astro-ph.IM

Enhancing WISE Infrared Imaging to Spitzer Resolution Using Deep Learning Super-Resolution

Saeed Rezaee, Shoubaneh Hemmati, Bahram Mobasher, Naveen A. Reddy, Tara Fetherolf, Alexander de la Vega, Sina Miri

We present a deep-learning framework that performs 4.6x spatial super-resolution from WISE W1 (3.4 micron) toward Spitzer IRAC Ch1 (3.6 micron), and characterize its behavior on the COSMOS field. Our sample consists of ~390,000 paired cutouts drawn uniformly within the WISE/Spitzer overlap, with a held-out test set of 83,592 cutouts on which we report all metrics. The framework uses a convolutional neural network (an Enhanced Residual Channel Attention Network) trained with a loss function that…

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astro-ph.SRastro-ph.EP

Preferential alignment of Class 0, Class I protostellar disks in multiple systems across nine nearby molecular clouds

Cheng-Han Hsieh, Aleksey Generozov, Stella S. R. Offner, Héctor G. Arce, Jaime E. Pineda, Michael M. Dunham, Diego Mardones, Dominique Segura-Cox et al.

Protostellar disk orientations in multiple systems provide critical insights into the primary mechanisms that govern the formation of multiple-star systems, their subsequent dynamical evolution, and their impact on planet-forming disks. We present a disk alignment study of 512 Class 0, Class I, and flat-spectrum protostars across nine nearby molecular clouds within 500 pc, utilizing data from the CAMPOS and VANDAM surveys. Our sample includes 74 binaries and 31 high-order multiple systems. We fi…

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astro-ph.IM

Expanding the SPISEA Stellar Population Synthesis Software to the Substellar Regime

Caitlin Begbie, Rachel Street, Katarzyna Kruszynska, Jessica Lu, Matthew Hosek, Natasha Abrams, Macy Huston

We present an extension of the SPISEA stellar population synthesis framework that adds brown dwarfs to the existing range of stellar mass objects, enabling physically consistent modeling of brown dwarfs within synthetic star clusters. Previous versions of SPISEA included limited substellar support, relying on outdated initial mass functions and incomplete atmospheric and evolutionary coverage below the hydrogen-burning limit. This was addressed through the implementation of a modern substellar i…

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astro-ph.COastro-ph.HE

Cosmological $γ$-$γ$ Pair-Production Background

Mika A. Gelowicz, Thomas Siegert, Saurabh Mittal, Laura Eisenberger, Dimitris Tsatsis, Niklas C. Bauer, Rudi Reinhardt, Patrik Ehrmann et al.

The origin of positrons is one of the unsolved puzzles in astrophysics as the majority of sources are still unidentified. The Cosmic Photon Background (CPB) is the isotropic radiation spanning the entire electromagnetic spectrum. Interactions of the CPB with itself may pose a promising source of positrons and secondary emission. We calculate the electron-positron pair production rate from the $γ$-$γ$ pair-production of the CPB with itself for redshifts $z \leq 10$, and determine the annihilation…

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astro-ph.IM

DragonflyPol: Wide-Field Optical Linear Polarimetry with the Dragonfly Telephoto Array (Instrument Description and Commissioning)

Mehrnoosh Tahani, Leo Hollberg, Hiroshi Akitaya, Jaeyeon Kim, Deborah Lokhorst, Roberto Abraham, Pieter van Dokkum, William P. Bowman et al.

We present DragonflyPol, a wide-field optical linear polarimetry capability implemented on the Dragonfly Telephoto Array. DragonflyPol leverages Dragonfly's modular, multi-lens architecture to obtain simultaneous measurements in four linear polarization orientations ($0^\circ$, $45^\circ$, $90^\circ$, and $135^\circ$) across a $\sim5\,deg^2$ field of view, distributed across 44 polarized lens--detector units. Four additional units serve as unpolarized reference channels. We describe a broad rang…

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hep-phastro-ph.HE

Constraining the Coexistence of Primordial Black Holes and Particle Dark Matter with Neutrino Observations

Prolay Chanda, Sagnik Mukherjee, James Unwin

Primordial black holes (PBH) with a uniform mass scale could contribute up to 1\% of the gravitationally inferred dark matter relic abundance and remain consistent with observational limits over a large range of masses. In this case, the vast majority of the dark matter relic abundance is comprised of dark matter particles, such as WIMPs or FIMPs. Particle dark matter gravitationally captured around primordial black holes can form dense minispikes in which the annihilation rate is strongly enhan…

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astro-ph.EPastro-ph.SR

First planetesimals from DESI DR1: 12 highly metal-rich white dwarfs

Paula Izquierdo, Andrew Swan, Boris T. Gänsicke, Jamie T. Williams, Detlev Koester, Nicola P. Gentile-Fusillo, Christopher J. Manser, Laura K. Rogers et al.

Metal-enriched white dwarfs provide a unique insight into the composition of exoplanet interiors. These stars accrete the debris of disrupted planetary bodies, and hence, measuring the stellar parameters and photospheric abundances yields the bulk compositions of the parent bodies. At present, over 1750 debris-accreting white dwarfs are known, but just a few dozen are sufficiently enriched to allow a detailed abundance study. Here we report the analysis of 12 highly metal-enriched white dwarfs o…

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astro-ph.IM

COS2035: Extending COS/FUV Operations Through the 2030s

Marc Rafelski, David Sahnow, Christian I. Johnson, Bethan James, Svea Hernandez, John Debes, Beverly Serrano, Kate Davis et al.

The far-ultraviolet (FUV) detector of the Cosmic Origins Spectrograph (COS) accumulates gain sag where photons land, and without continued mitigation this degradation would render the most used modes unusable. To extend COS FUV operations through the 2030s, the COS team developed the COS2035 strategy, which builds on the existing COS2025 rules with four technical breakthroughs and two new usage policies. First, SPLIT-wavecals decouple wavelength calibration from science exposures and open detect…

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astro-ph.GA

Efficient Interstellar Grain Growth from High Sticking Coefficients on Amorphous Carbon Dust

Clarke J. Esmerian, Duncan Bossion, Francois Dulieu, Saoud Baouche, Alexey Potapov, W. M. C. Sameera, Tom J. L. C. Bakx, Susanne Aalto et al.

Cosmic dust is the solid phase of the interstellar medium (ISM), classically assumed to be composed of carbonaceous and silicate grains with size distributions spanning $\sim 5~Å$ to $\sim 1~μ$m (Weingartner & Draine 2001, Draine & Li 2007, Hensley & Draine 2023). While it constitutes at most order-of-magnitude $\mathbf{1\%}$ of the ISM mass, dust is second only to stars in importance for the observable properties of galaxies (Zavala et al. 2021). Large uncertainties in the efficiency of grain g…

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astro-ph.HEphysics.plasm-ph

Ultra-long simulations of collisionless relativistic shocks in front-comoving frame: evidence for a steady state and its properties

Mikhail Garasev, Evgeny Derishev

We present a series of unprecedently long 2D3V PIC simulations of unmagnetized relativistic $e^{-}e^{+}$-pair shocks performed in a front-comoving frame. By implementing a moving-wall boundary condition in the downstream together with continuous injection at the upstream boundary, we maintain a fixed simulation domain size, opening the way to perform substantially longer simulations. Our longest runs extend beyond $100000\,ω_p^{-1}$, exceeding the duration of the previously published simulations…

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astro-ph.EPastro-ph.HEastro-ph.SR

Hierarchical Three-Body Problem at High Eccentricities = Simple Pendulum, IV: Octupole for Librating Kozai-Lidov Cycles

Ygal Y. Klein

We solve analytically the long-term octupole evolution of \textit{librating} Kozai-Lidov cycles - those with a negative Kozai constant, in which the argument of pericenter librates - in the double-averaged restricted hierarchical three-body problem. Librating cycles reach extreme eccentricities when the normal component of the orbital angular momentum vanishes, just as rotating cycles do, but their slow dynamics was left unsolved: as noted by Katz, Dong \& Malhotra (2011), the azimuth of the ecc…

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astro-ph.EP

The Expected Yield of Venus Zone Terrestrial Planets from PLATO

Stephen R. Kane, Emma L. Miles, Colby M. Ostberg, Erika Kohler, James B. Garvin

The characterization of terrestrial exoplanets and the conditions that lead to divergent climate outcomes is a primary goal of exoplanetary science. The Venus Zone (VZ) provides a framework for identifying planets that may have experienced runaway greenhouse processes similar to Venus, and the statistical properties of such planets bear directly on models of planetary habitability. Here we present a quantitative estimate of the expected yield of VZ terrestrial planets from ESA's PLATO (PLAnetary…

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astro-ph.GA

Chemodynamical evidence of the HR 1614 moving group as a bar resonance

Andreas J. Koch-Hansen, Vladislav Gulaev, Dominik H. Plonka, Camilla Juul Hansen, Andrew McWilliam, Victor P. Debattista, Zdenek Prudil

Moving groups (MGs) are ensembles of disk stars that clump in velocity and action space. A multitude of explanations as to their origin has been attempted, from dissolved star clusters to resonances with the Galactic bar, or other non-axisymmetric perturbations. The object of this work, the old HR 1614 group, has in the past already been shown to not be a disrupted cluster in terms of its broad age and metallicity distribution. Thus its stars have more likely been trapped by the Milky Way bar at…

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astro-ph.HE

Signatures of Black Hole Spin in Horizon-Scale Polarimetry

George N. Wong, Daniel C. M. Palumbo, Zachary Gelles, Andrew Chael

The angular momentum of a black hole, usually expressed in terms of a dimensionless "spin," both shapes the strong-field spacetime and provides a reservoir of rotational energy that can be exchanged with surrounding plasma. Very long baseline interferometry (VLBI) has now begun to resolve polarized emission on event-horizon scales. We distinguish polarimetric signatures of spin arising primarily from photon propagation in the Kerr spacetime from those mediated by horizon-threading electromagneti…

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astro-ph.COastro-ph.GAastro-ph.HE

The topology of the magnetic field in Abell 2255 out to its virial radius. Results from the LOFAR Galaxy Cluster Ultra-Deep Field

A. Botteon, R. J. van Weeren, Y. Hu, F. Vazza, G. Brunetti, K. Rajpurohit, A. Lazarian, T. W. Shimwell et al.

We present the LOFAR Galaxy Cluster Ultra-Deep Field, in which 336 h of LOFAR observations at 120$-$168 MHz have been collected on the nearby ($z=0.080$) cluster Abell 2255. This massive and merging system is known to host spectacular radio emission from both cluster galaxies and the intracluster medium. Previous LOFAR observations revealed pervasive diffuse synchrotron emission extending from the cluster center to its dynamically active outskirts, tracing relativistic electrons propagating in l…

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astro-ph.SRastro-ph.GA

The Open Cluster Chemical Abundances and Mapping Survey: IX. Measuring the Effects of Stellar Diffusion in the Open Clusters NGC 752 and Ruprecht 147 using APOGEE

Diogo Souto, Taylor Spoo, Peter M. Frinchaboy, Katia Cunha, Jamie Tayar, Alessa Ibrahim Wiggins, Natalie Myers

A growing understanding of stellar processes that alter surface chemical abundances over time has opened new avenues for using these changes as probes of stellar properties. On the main sequence and near the turnoff, stellar surface abundances are affected by gravitational settling and radiative acceleration, collectively known as atomic diffusion. In this work, we use SDSS/APOGEE DR17/DR19 data to investigate atomic diffusion in the open clusters NGC~752 and Ruprecht~147, thereby constraining h…

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astro-ph.COastro-ph.GA

Measuring satellite galaxy subhalo masses in redMaPPer clusters with UNIONS weak lensing data

Roman Akhmetshyn, Jack Elvin-Poole, Michael J. Hudson, Isaac Cheng, Thomas de Boer, Sébastien Fabbro, Sam Farrens, Sacha Guerrini et al.

In this work, we present the observed galaxy-galaxy lensing signal of satellite galaxies in rich clusters obtained from the Ultraviolet Near-Infrared Optical Northern Survey (UNIONS). Such observations are crucial for understanding dark matter halo physics and interaction dynamics in the cluster environment. Our goal is to investigate the tidal stripping of cluster subhalos. Theoretical predictions, supported by recent studies, suggest that as satellite galaxies fall into clusters, their dark ma…

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