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Physics Astrophysics

astro-ph Watch Astrophysics

Friday 20 March

High Energy Astrophysical Phenomena

HAWC Study on the Ultra-High-Energy Gamma-Ray Emissions from the Pulsar Wind Nebula G32.64+0.53

R. Alfaro, C. Alvarez, E. Anita-Rangel et al. (+91 more)

Multi-TeV gamma-ray emission around eHWC J1850+001 (a source from the first HAWC catalog of gamma-ray sources emitting above 56 TeV) is spatially coincident with the pulsar wind nebula (PWN) G32.64+0.53, powered by PSR J1849-0001. The absence of counterparts in radio, optical, and GeV energy ranges, contrasted with clear detections in X-rays and very-high-energy (VHE) gamma-rays, is indicative of a non-thermal leptonic origin for the nebula. We apply a systematic analysis pipeline, including a sophisticated model for the Galactic diffuse emission, to 2860 days of data from the HAWC Observatory. Our detailed analysis confirms that the ultra-high-energy (UHE) emission originates from G32.64+0.53, and we measure its spectrum up to 270 TeV with significant emission well beyond 100 TeV. We fit the multi-wavelength observations with a time-dependent leptonic model powered by the pulsar's rotational energy, and the results establish the nebula as a leptonic PeV accelerator, capable of accelerating electrons to a maximum energy of $E_{\mathrm{cut}}\geq2.9~\mathrm{PeV}$ (95% one-sided lower bound). The model also constrains the nebular magnetic field to $4.28 ~\mathrm{\mu G}$, supporting a leptonic PWN origin for the observed UHE emission.
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All authors R. Alfaro, C. Alvarez, E. Anita-Rangel, M. Araya, J.C. Arteaga-Velázquez, D. Avila Rojas, H.A. Ayala Solares, R. Babu, P. Bangale, E. Belmont-Moreno, A. Bernal, K.S. Caballero-Mora, T. Capistrán, A. Carramiñana, F. Carreón, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, P. Desiati, N. Di Lalla, R. Diaz Hernandez, M.A. DuVernois, J.C. Díaz-Vélez, K. Engel, T. Ergin, C. Espinoza, N. Fraija, S. Fraija, J.A. García-González, F. Garfias, N. Ghosh, M.M. González, J.A. González, J.A. Goodman, D. Guevel, J. Gyeong, J.P. Harding, I. Herzog, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, S. Kaufmann, D. Kieda, K. Leavitt, W.H. Lee, J. Lee, H. León Vargas, A.L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J.A. Matthews, P. Miranda-Romagnoli, J.A. Morales-Soto, E. Moreno, M. Mostafá, M. Najafi, A. Nayerhoda, L. Nellen, R. Noriega-Papaqui, N. Omodei, E. Ponce, Y. Pérez Araujo, E.G. Pérez-Pérez, C.D. Rho, A. Rodriguez Parra, D. Rosa-González, M. Roth, H. Salazar, D. Salazar-Gallegos, A. Sandoval, M. Schneider, J. Serna-Franco, M. Shin, A.J. Smith, Y. Son, R.W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, E. Varela, L. Villaseñor, X. Wang, Z. Wang, I.J. Watson, S. Yu, X. Zhang, H. Zhou, C. de León

Solar and Stellar Astrophysics

Precise parameter determination of the open cluster NGC 1647 via asteroseismology of p-mode pulsators

Mingfeng Qin, Jian-Ning Fu, Weikai Zong et al. (+4 more)

Asteroseismology of member pulsators provides a robust physical constraint on cluster parameters by linking internal stellar structures to the global properties of the host cluster. However, the parameters of NGC 1647 remains poorly constrained due to limited investigation, a situation that cluster asteroseismology can significantly refine. In this study, we identified 271 high confidential cluster members in NGC 1647, using HDBSCAN clustering with radial-velocity validation. Its initial age is determined in the range of 1250-280 Myr, derived from isochrone fitting based on multi-survey metallicities extinction-corrected Gaia photometry. Among the members, we found 96 periodic variables from TESS and K2 photometry, including nine p-mode pulsators (five {\delta} Sct and four hybrid {\delta} Sct-{\gamma} Dor stars). Assuming a common cluster age and initial chemical composition, joint asteroseismic modeling is performed based on measured large frequency separations and individual mode frequencies. This yields a metallicity of [Fe/H] = -0.08+0.04-0.01, well consistent with the spectroscopic determinations, and a seismic age of 178+11-9 Myr, more precise than isochrone-based estimates. This work shows the diagnostic potential of {\delta} Sct asteroseismology in young open clusters and establishes a high-precision benchmark for future studies of NGC 1647 and other open clusters.
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All authors Mingfeng Qin, Jian-Ning Fu, Weikai Zong, Tianqi Cang, Antonio Frasca, Gang Meng, Xiran Xie

High Energy Astrophysical Phenomena

A Concept of Next-Generation Atmospheric Cherenkov Telescope Array (NG-ACTA)

Jiancheng Wang and Jirong Mao

The Next-Generation Atmospheric Cherenkov Telescope Array (NG-ACTA) is proposed as a prospective infrastructure for very high energy (VHE) gamma-ray astronomy, consisting of a mixed-aperture array of 88 telescopes with a maximum array diameter of 10 km. The array adopts a three-tier configuration of 30 m large-aperture Large Size Telescopes (LSTs), 12 m medium-aperture Medium Size Telescopes (MSTs), and 6 m small-aperture Small Size Telescopes (SSTs), enabling continuous gamma-ray detection across the full energy band from 20 GeV to 100 TeV. With core advantages of an ultra-low detection threshold ($\leq20$ GeV), ultra-high angular resolution ($\leq0.04^\circ$), ultra-large effective area ($\geq1\times10^5$ m$^2$), extreme cosmic ray background rejection (proton rejection efficiency $\geq99.99\%$), and rapid transient response ($\leq100$ ns trigger latency), NG-ACTA targets the most cutting-edge and transformative fundamental scientific topics in modern astrophysics and particle physics, including VHE gamma-ray astronomy, cosmic ray origin, multi-messenger astronomy, and dark matter as well as new physics tests. The array's scientific goals cover five core fields: particle astrophysics, VHE gamma-ray astronomy, cosmic ray physics, multi-messenger astronomy, and new physics exploration, with six hierarchical and mutually supportive scientific objectives from Galactic to extragalactic sources, steady to transient objects, and conventional objects to dark matter. A comprehensive comparison with international under-construction facilities (e.g., CTAO-North, CTAO-South) and Chinese facilities (e.g., LACT) demonstrates that NG-ACTA leads the world in low-energy threshold, baseline length, background suppression, and multi-messenger rapid response capabilities.
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Instrumentation and Methods for Astrophysics

Furax: A Modular JAX Framework for Linear Operators in Astrophysical and Cosmological Data Analysis

Pierre Chanial, Simon Biquard, Wassim Kabalan et al. (+10 more)

The Framework for Unified and Robust data Analysis with JAX (Furax) is an open-source Python framework for modeling data acquisition systems and solving inverse problems in astrophysics and cosmology. Built on JAX, Furax provides composable building blocks in the form of general-purpose and domain-specific linear operators, along with preconditioners and solvers for their numerical inversion. Domain-specific tools are provided for astrophysical and cosmic microwave background (CMB) data analysis$-$including map-making, instrument modeling, and astrophysical component separation$-$with a modular architecture designed to extend to other fields.
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All authors Pierre Chanial, Simon Biquard, Wassim Kabalan, Wuhyun Sohn, Artem Basyrov, Benjamin Beringue, Alexandre Boucaud, Andréa Landais, Magdy Morshed, Radek Stompor, Ema Tsang King Sang, Amalia Villarrubia-Aguilar, Josquin Errard

High Energy Astrophysical Phenomena · Cross-listed from gr-qc

On the Universal Cuspy Behavior in Black Hole Shadows

Peng Cheng and Si-Jiang Yang

This work investigates the universality of cusp formation in the shadows of compact objects. The emergence of cusps is accompanied by three interrelated phenomena: a topological charge transition, an equal-area law governing the self-intersecting structure, and universal critical scaling behavior. We demonstrate that, because these phenomena originate from the global morphology of the shadow, they are fundamentally independent of specific spacetime metric details and apply across diverse models. These features are systematically analyzed for the Kerr black hole endowed with a running Newton coupling. By extending our framework to rotating traversable wormholes, we confirm that the same universal behavior persists in more general compact objects. Our study uncovers the universality underlying cusp formation, offering a model-independent framework for characterizing possible non-Kerr shadow morphologies.
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Solar and Stellar Astrophysics

Expected evolution of the binary system ATLAS J1138-5139

Jing-Qi Chen, Hai-Liang Chen, Zheng-Wei Liu et al. (+2 more)

ATLAS J1138-5139 is a newly detected ultra-compact double white dwarf (DWD) system which is composed of a $1.02\,M_{\odot}$ carbon-oxygen white dwarf (CO WD) and a $0.24\,M_{\odot}$ helium (He) WD with an orbital period of about 27.68 min, making it one of the shortest-period DWD systems known. The future evolution and final fate of this system remain unexplored. In this work, we investigate the evolution of ATLAS J1138-5139 with the one-dimensional stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA). We find that ATLAS J1138-5139 will evolve into an AM Canum Venaticorum (AM CVn) system in about \sim 6.3 Myr. Afterwards, the transferred material from the He WD companion start to build up to form a He shell near the surface of the CO WD. This accumulated He-shell masses can be up to approximately $0.12\,M_{\odot}$, which is likely to trigger a double-detonation (DDet) explosion of the CO WD. We therefore expect that ATLAS J1138-5139 will likely explode as a type Ia supernova eventually through the DDet explosion mechanism. Moreover, our calculations show that ATLAS J1138-5139 will be a promising target for gravitational-wave (GW) detection by future detectors like LISA, Tianqin and Taiji.
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All authors Jing-Qi Chen, Hai-Liang Chen, Zheng-Wei Liu, Xuefei Chen, Zhanwen Han

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-lat

Vector-channel scattering of dark particles in a Sp(4) gauge theory

Jong-Wan Lee, Ed Bennett, Yannick Dengler et al. (+8 more)

We report new results obtained in our lattice studies of the $Sp(4)$ gauge theory coupled to two fundamental Dirac fermions. This theory provides a candidate for the dynamical origin of dark matter models within the strongly interacting massive particle paradigm. We employ Lüscher's formalism to analyse finite-volume energy levels and study the scattering amplitude of two pseudoscalar states in the spin-1 channel. We present our preliminary findings for a set of ensembles generated within a broad range of (Wilson) fermion masses.
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All authors Jong-Wan Lee, Ed Bennett, Yannick Dengler, Deog Ki Hong, Ho Hsiao, C.-J. David Lin, Biagio Lucini, Axel Maas, Maurizio Piai, Davide Vadacchino, Fabian Zierler

Instrumentation and Methods for Astrophysics

SpecZoo: An AI-Powered Platform for Spectral Analysis and Visualization in Science and Education

Yuan-Hao Pu, Guo-Hong Lei, Yang Xu et al. (+2 more)

Astronomical spectra, which encode rich astrophysical and chemical information, are fundamental to understanding celestial objects and universal laws. The advent of large-scale spectroscopic surveys, generating tens of millions of spectra, presents significant challenges for efficient data processing and analysis. To address these challenges, we develop an AI-powered platform (named “SpecZoo”) for spectral visualization and analysis. This platform integrates modern information technology and machine learning to lower the barrier to spectral data utilization and enhance research efficiency. Its core functionalities include interactive visualization, automated spectral classification, physical parameter measurement, spectral annotation, and multi-band/multi-modal data fusion, all supported by flexible user and data management systems. It has become an essential tool for the National Astronomical Data Center, directly supporting spectral data processing and research for major projects including LAMOST, SDSS, DESI, and so on. Furthermore, the platform demonstrates strong potential for science-education integration, providing a novel resource for cultivating talent in astronomy and data science.
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All authors Yuan-Hao Pu, Guo-Hong Lei, Yang Xu, Xun-Zhou Chen, Hai-Jun Tian

Astrophysics of Galaxies

COSMOS-3D: Black Hole Mass Estimators and Luminosity Functions of Paschen-line AGNs

Danyang Jiang, Linhua Jiang, Shuqi Fu et al. (+13 more)

Near-IR Paschen lines are potentially an excellent tracer of Type 1 AGNs that is hardly affected by dust extinction. JWST allows us, for the first time, to explore Paschen-line objects at redshift z>1. Here we present a study of 62 AGNs with broad Pa$\alpha$ and Pa$\beta$ lines at 1<z<3 using data from the JWST COSMOS-3D program. These AGNs are efficiently selected and identified using NIRCam imaging and grism slitless spectroscopic data. We separate the AGN-host emission with image decomposition and quantify dust attenuation with multi-band data. We construct a calibration sample with optical spectroscopy and use single-epoch, Mg II-based black hole masses ($M_{\mathrm{BH}}$) as an anchor to derive new, Paschen-based $M_{\mathrm{BH}}$ estimators. We obtain three sets of $M_{\mathrm{BH}}$ estimators based on Paschen line luminosities and AGN continuum luminosities at 1 and 2 $\mu$m, respectively. After dust corrections, they are well consistent with each other, and also broadly agree with previous results. With this AGN sample, we further construct the first Pa$\alpha$ and Pa$\beta$ luminosity functions (LFs) of Type 1 AGNs. The derived LFs are 3-5 times higher than those of UV/optical-selected AGNs, indicating that Paschen-selected Type 1 AGNs are more complete. In addition, the intrinsic properties of our AGNs show no dependence on dust reddening, suggesting that the observed reddening is unrelated to the central engine and is thus likely caused by line-of-sight obscuration.
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All authors Danyang Jiang, Linhua Jiang, Shuqi Fu, Zijian Zhang, Jie Chen, Zhiwei Pan, Shengxiu Sun, Fengwu Sun, Luis C. Ho, Jinyi Shangguan, Andreas L. Faisst, Olivier Gilbert, Mingyu Li, Yichen Liu, Zi-Jian Li, Takumi S. Tanaka

Instrumentation and Methods for Astrophysics

The Vera C. Rubin Observatory Prompt Processing System

Krzysztof Findeisen, Kian-Tat Lim, Dan Speck et al. (+4 more)

Vera C. Rubin Observatory's Prompt Processing system will automatically process 10 TB of raw images to produce up to 10 million transient alerts per night. We summarize how Prompt Processing meets its throughput, latency, and reliability requirements and present results from Rubin Observatory Commissioning.
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All authors Krzysztof Findeisen, Kian-Tat Lim, Dan Speck, Hsin-Fang Chiang, Erin Leigh Howard, Ian S. Sullivan, Eric C. Bellm

Thursday 19 March

Earth and Planetary Astrophysics · Cross-listed from physics.ao-ph

A Threshold Model for Micrometeoroid Atmospheric Entry: Filippov Dynamics, Survival Estimates, and Survivor-Only Inverse Limits

Md Shahrier Islam Arham, Prasun Panthi and Min Heo

Micrometeoroids enter Earth's atmosphere at hypervelocity speeds and experience rapid coupling between drag, heating, radiation, melting, ablation, and deceleration. This paper develops a reduced threshold model for the thermal survival boundary of spherical micrometeoroids. The model uses free molecular drag, an exponential atmosphere, projected-area heating, full-sphere radiative cooling, and a surplus-heat ablation rule at the melting temperature. The switching surface $T=T_m$ is treated as a Filippov/complementarity surface. Sustained melting occurs when the local heating-to-radiation ratio exceeds unity. Under the additional Allen–Eggers assumptions of constant radius, constant entry angle, negligible gravity during the main heating interval, and constant transport coefficients, this threshold yields the classical approximate survival scaling $r_0^{\rm crit}\sim v_0^{-3}$. An exact radius-loss identity is obtained along the prescribed Allen–Eggers trajectory, and a perturbative stability estimate explains when this expression approximates the full reduced model. The inverse problem is formulated through a transfer matrix from pre-atmospheric entry bins to observed survivor bins. Entry bins with zero survival probability lie in the survivor-only null space and require external information for reconstruction. The framework gives a compact analytical description of threshold entry survival and identifies the information lost when only surviving particles are observed.
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Instrumentation and Methods for Astrophysics · Cross-listed from q-bio.NC

Ca2+ transient detection and segmentation with the Astronomically motivated algorithm for Background Estimation And Transient Segmentation (Astro-BEATS)

Bolin Fan, Anthony Bilodeau, Frederic Beaupre et al. (+4 more)

Fluorescence-based Ca$^{2+}$-imaging is a powerful tool for studying localized neuronal activity, including miniature Synaptic Calcium Transients, providing real-time insights into synaptic activity. These transients induce only subtle changes in the fluorescence signal, often barely above baseline, which poses a significant challenge for automated synaptic transient detection and segmentation. Detecting astronomical transients similarly requires efficient algorithms that will remain robust over a large field of view with varying noise properties. We leverage techniques used in astronomical transient detection for miniature Synaptic Calcium Transient detection in fluorescence microscopy. We present Astro-BEATS, an automatic miniature Synaptic Calcium Transient segmentation algorithm that incorporates image estimation and source-finding techniques used in astronomy and designed for Ca$^{2+}$-imaging videos. Astro-BEATS outperforms current threshold-based approaches for synaptic Ca$^{2+}$ transient detection and segmentation. The produced segmentation masks can be used to train a supervised deep learning algorithm for improved synaptic Ca$^{2+}$ transient detection in Ca$^{2+}$-imaging data. The speed of Astro-BEATS and its applicability to previously unseen datasets without re-optimization makes it particularly useful for generating training datasets for deep learning-based approaches.
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All authors Bolin Fan, Anthony Bilodeau, Frederic Beaupre, Theresa Wiesner, Christian Gagne, Flavie Lavoie-Cardinal, Renee Hlozek

Astrophysics of Galaxies

The Journey to Dominance: How BCGs Evolve Differently from Other Massive Galaxies

Marcelo C. Vicentin, Michael A. Strauss, Laerte Sodré Jr. et al. (+3 more)

We use the L-GALAXIES semi-analytic model to investigate the evolution of Brightest Cluster Galaxies (BCGs) found in clusters at $\rm z \sim 0$. BCGs are typically located in the central region of galaxy clusters, near the bottom of the potential well, exposing them to different environmental conditions compared to galaxies in the cluster outskirts or in the field. As a result, BCGs may follow a distinct evolutionary path and exhibit unique properties. We study the physical properties and merger histories of galaxies in 180 simulated clusters at $z \sim 0$, considering all cluster members with present-day stellar masses above $10^9 \ {\rm M_\odot}$ as the starting points for tracing their merger trees. We compare this sample of galaxies to a control sample of field galaxies and highlight their differences in evolution across cosmic time. We find that BCGs have distinct stellar mass formation histories compared to other massive galaxies from our control sample. Surprisingly, (proto)BCGs consistently become the most massive galaxy of their structure only at z $\sim$ 1.3. Despite this late dominance, (proto)BCGs are found to inhabit regions with higher galaxy and stellar mass density than the most massive galaxy in the structure throughout their entire history, indicating that their evolution is tightly linked to the environment from early times. These conditions shape a distinct evolutionary path for BCGs compared to other massive galaxies in clusters and in the field, underscoring the unique nature of BCGs.
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All authors Marcelo C. Vicentin, Michael A. Strauss, Laerte Sodré Jr., Robert M. Yates, Pablo Araya-Araya, Doris Stoppacher

Astrophysics of Galaxies

Archaeology of Galactic Nuclei Activity

A.V. Moiseev, A. Arshinova and A.A. Smirnova

Considerable observational evidence suggests that the activity of supermassive black holes in galactic nuclei is transient. The term “active galactic nuclei archaeology” has even been coined. This implies the possibility of reconstructing the history of activity, such as changes in the nuclear luminosity over time across various regions of the electromagnetic spectrum, by analysing how this activity manifested itself on galactic and extragalactic spatial scales. These phenomena include relic radio structures, gas clouds illuminated by the “ionising echo” of past activity, and Fermi/eROSITA bubbles. We provide a review of the results of galactic nucleus activity studies, focusing on its observable impact on the intergalactic medium and circumgalactic environment. Our main focus is on optical observations of ionisation cones and evidence of switching between radiative (ionisation cones) and kinetic (radio jets) modes of nuclear activity.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Observational imprints and quasi-Periodic oscillations of magnetically charged anti-de Sitter black holes

Faizuddin Ahmed, Mohsen Fathi and Ahmad Al-Badawi

In this work, we investigate observable signatures of a magnetically charged Anti-de Sitter black hole in string-inspired Euler-Heisenberg theory. We analyze photon trajectories, the photon sphere, and the resulting black hole shadow. We derive the photon sphere and shadow radii and show that both deviate from the Schwarzschild and Schwarzschild-AdS cases. In particular, the radii decrease monotonically as the magnetic charge parameter $Q_m$ increases, indicating that magnetic charge modifies light propagation near the black hole. We also study neutral and charged particle motion and compute the corresponding epicyclic frequencies. Using the effective potential method, we obtain the specific energy and angular momentum for stable circular orbits and determine the innermost stable circular orbit (ISCO). The presence of $Q_m$ shifts the ISCO radius and alters the orbital structure. The radial, vertical, and orbital frequencies show clear deviations from the Schwarzschild case. Finally, we confront the model with twin-peak quasi-periodic oscillation (QPO) data from stellar-mass, intermediate-mass, and supermassive black hole candidates. A two-dimensional Delta chi-square analysis in the ($r$, $Q_m$) space shows that the best fit corresponds to $Q_m=0$, although finite values remain allowed within confidence levels. At the 1 sigma level, we obtain an upper bound $Q_m/M$ less than about 0.2. These results indicate that while magnetic charge produces measurable theoretical deviations, current QPO data place only moderate constraints on its magnitude.
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High Energy Astrophysical Phenomena

Flux-Averaged Force Multipliers

Sergei Dyda, Randall C. Dannen, Shane W. Davis et al. (+2 more)

We apply novel developments in photoionization modeling and multi-frequency radiation hydrodynamics to the study of line driven AGN disc winds. We use a flux-averaged force multiplier approach to compute the radiation force due to lines for hydrodynamics simulations using 4 frequency bands - infrared (IR), optical (O), ultraviolet (UV) and X-rays. Though line driving is dominated by the UV, contributions from the O and X-ray bands are non-negligible and can lead to enhancements in the wind both in terms of mass flux and outflow velocity. Crucially, these effects are not captured when using a “grey” approach to the radiation modeling in the hydrodynamics, where frequency information is averaged over during the photoionization modeling. These results further strengthen the case for frequency dependent radiation dynamics studies for line driven winds.
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All authors Sergei Dyda, Randall C. Dannen, Shane W. Davis, Daniel Proga, Timothy R. Kallman

Earth and Planetary Astrophysics

A Planetary Illusion's Funeral: Non-detection of a Gaia DR3 Exoplanet Candidate, and the Role of Intermediate-precision Radial Velocities in Gaia Exoplanet Follow-up

Alexander Venner, Chelsea X. Huang, David W. Latham et al. (+4 more)

The detection of exoplanets using astrometry has long been an area of interest, but is fraught with challenges. The Gaia mission is fundamentally reshaping this field thanks to its unprecedentedly precise all-sky astrometric observations. The 2022 release of Gaia DR3 brought the first exoplanets discovered from the Gaia astrometry, including a new candidate around the bright ($V=6.6$) solar-type star HD 12800. However, two years after announcement, the Gaia exoplanet candidate was retracted. In this work we report radial velocity observations of HD 12800 acquired with the TRES spectrograph, which we began immediately after the release of Gaia DR3. Our observations failed to detect the planet candidate; nonetheless, we emphasise that the originally proposed companion would have been easily detected in our radial velocity observations. We conclude with a discussion on the role of intermediate-precision ($\approx$10 m s$^{-1}$) RV spectrographs in the follow-up of Gaia astrometric exoplanet candidates, relevant to the forthcoming release of Gaia DR4. We argue that such observations may play an important role in planet confirmation for stars between approximately $8<G<12$, likely to represent a significant fraction of Gaia exoplanet discoveries.
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All authors Alexander Venner, Chelsea X. Huang, David W. Latham, Samuel N. Quinn, Allyson Bieryla, Andrew Vanderburg, Robert A. Wittenmyer

Astrophysics of Galaxies

Impact of subhalo dynamical friction heating on the formation of the first structures in the universe

Zhenyu Wu, Sadegh Khochfar, Muhammad A. Latif et al. (+2 more)

We present a model for gas heating, driven by dynamical friction from orbiting subhalos within dark matter halos. Using data from the TNG50 simulation, we derive the subhalo mass function and calculate the dynamical friction heating rate for a wide range of halo masses and redshifts from $z = 15$ to 0. Our results show that, by converting gravitational potential energy into thermal energy, dynamical friction is an important mechanism for galaxy quenching in massive halos at low redshifts, consistent with previous studies. Additionally, we find that in the early universe at $z \sim 15$, heating rates can be comparable to the molecular hydrogen cooling rates in metal-free minihalos. This can suppress gas cooling and fragmentation and does increase the critical molecular fraction for Pop III star formation by up to one order of magnitude, thereby making Pop III star formation more difficult. In combination with the Lyman-Werner background, the dynamical friction heating mechanism favors the formation of direct-collapse black hole (DCBH) seeds in atomic cooling halos, even when the average H$_2$ fraction is $\sim 10^{-5}$ during the minihalo progenitor phase. Dynamical friction heating at a fixed host halo mass can vary by two orders of magnitude due to the scatter in the number of subhalos. To capture dynamical friction heating in simulations, it is necessary to resolve subhalos with a subhalo to host halo mass ratio $\psi \gtrsim 0.05$.
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All authors Zhenyu Wu, Sadegh Khochfar, Muhammad A. Latif, Ben Morton, Britton Smith

Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Cosmology and modified GW propagation from the BNS mass function at third-generation detector networks

Dounia Nanadoumgar-Lacroze, Niccolò Muttoni, Michele Maggiore et al. (+1 more)

We perform forecasts for the Hubble parameter H_0 and for the parameter Xi_0 that describes modified gravitational-wave propagation, using information from the binary neutron star (BNS) mass function, for Einstein Telescope (ET), taken either in the triangle or in the “2L” configuration, as well as for detector network made by ET together with a 40-km Cosmic Explorer (CE). We restrict ourselves to BNSs with a large signal-to-noise ratio, SNR>50, which still give O(10^3) events yr-1, and we perform a full joint cosmology-population Bayesian inference. We find that, for ET in isolation, the two ET configurations perform comparably, yielding uncertainties of 12% and 11% on H_0 for the triangular and 2L designs, respectively, and 18% uncertainty on Xi_0 in both cases. For networks including ET and CE, we can constrain H_0 and Xi_0 to precisions of 9% and 6%, respectively. These results should be taken as a very conservative estimate of third-generation detectors' capabilities as a consequence of the high SNR cut. We project the constraints on the Lambda CDM expansion history and find that ET alone (triangular and 2L configurations) achieves its best precision on H(z) at z=0.23 and z=0.28, yielding a 10% and 6% precision, respectively. When CE is added to the network, the precision improves to 4% and 3% at z=0.37 and z=0.38, respectively.
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All authors Dounia Nanadoumgar-Lacroze, Niccolò Muttoni, Michele Maggiore, Michele Mancarella

Astrophysics of Galaxies

Revisiting the Milky Way stellar long bar and the 3 kpc arm

M. Lopez-Corredoira, W. Wu, H.-F. Wang et al. (+1 more)

CONTEXT. One of the most difficult and unexplored regions of the Milky Way is the highly extincted in-plane central region within the Galactic coordinates $10^\circ \lesssim |\ell |\lesssim 30^\circ $, $|b|\lesssim 3^\circ $, where we have the long-bar and 3 kpc arm with intermediate-age stellar population, whose morphological properties are still unclear. AIMS. We aim to advance our knowledge of the morphology of these two components. METHODS. We examined star counts of bright M giants in WISE-4.6$\mu $m and its distribution of distances derived from spectroscopic parallaxes with APOGEE-DR17. We also examined the distribution of distances of young OGLE-O-rich Mira variable stars, and reviewed the literature on red clump distance determination within that area. RESULTS. We corroborate the asymmetry between positive and negative longitudes in in-plane regions, thus confirming the necessity to include a long bar. We obtain an average angle between the major axis of the long bar and the line Sun-Galactic centre of $\alpha =27.4^\circ \pm 1.5^\circ $, aligned with the triaxial bulge and a semi-major-axis length $\approx 4$ kpc. The tips of the long bar are in contact with the elliptical 3 kpc arm, with the major axis again aligned with the bulge and the long bar's major axes, whose tangential lines of sight correspond to $\ell =-22^\circ $ and $\ell=+27^\circ $. In the range of 50 degrees in the sky between these two longitudes, the stellar near 3 kpc arm is clearly detected at heliocentric distances around 5 kpc, and the stellar far 3 kpc arm is tentatively detected at heliocentric distances of 9-12 kpc.
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All authors M. Lopez-Corredoira, W. Wu, H.-F. Wang, F. Garzon

Astrophysics of Galaxies

Survival of the most compact: the life and death of satellite halos in self-interacting dark matter

David Klemmer, Moritz S. Fischer, Kimberly K. Boddy et al. (+2 more)

Self-interacting dark matter (SIDM) models feature short-range interactions between dark matter (DM) particles that lead to larger diversity in the inner parts of galactic rotation curves and potentially unique gravitational lensing signatures. Satellite galaxies and dark subhalos provide a valuable testing ground for such models. We develop a simulation framework to explore subhalo evolution and its gravothermal collapse for velocity- and angle-dependent self-interacting cross section in these SIDM models. Our results are essential for testing these models. We perform N-body simulations, treating the host halo analytically and modelling the scattering-induced subhalo-halo interaction process using virtual host particles, a central innovation of our work. We use the Eddington inversion method to accurately model the local velocity distribution in the halo. Our approach is significantly less computationally expensive than simulations with a fully resolved host, while incorporating tidal stripping and tidal heating. We test both isotropic and forward-dominated self-scattering, which represent limiting cases for the angular dependence of the self-interaction cross section. Environmental effects, especially the scattering-induced subhalo-halo interaction, have a strong impact on the subhalo evolution and drive a complex structural evolution. As a result, SIDM subhalos have a larger range of central densities and density profile slopes compared to collisionless DM. Our cost-efficient simulation framework enables modelling of SIDM subhalos in realistic environments. Our results highlight the necessity of accurately modelling the scattering-induced subhalo-halo interaction to predict SIDM subhalo density profiles. For the SIDM models we investigate, the enhanced diversity in the mass profiles of subhalos would leave an observable imprint on strong lensing systems and satellite galaxies.
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All authors David Klemmer, Moritz S. Fischer, Kimberly K. Boddy, Manoj Kaplinghat, Laura Sagunski

Cosmology and Nongalactic Astrophysics

Cosmological constraints from the DESI DR1 joint power spectrum and bispectrum analysis

S. Novell-Masot, H. Gil-Marín, L. Verde et al. (+48 more)

We derive cosmological parameter constraints from the Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) galaxy clustering data, based on a joint full-shape analysis of the power spectrum multipoles and the bispectrum monopole using the ShapeFit framework. This is the follow-up of our previous work, in which we obtained for the first time constraints on the ShapeFit parameters using the bispectrum of DESI DR1. Here we present the first ShapeFit cosmological inference results using the bispectrum of DESI DR1. We recover values for the matter density parameter and Hubble constant of respectively $\Omega_m=0.310\pm0.012$ and $H_0=[68.92\pm0.97]\,\mathrm{km\, s^{-1} Mpc^{-1}}$, consistent with previous results from the full DESI DR1 dataset that did not use the bispectrum signal. The inclusion of the bispectrum significantly tightens the constraints on the amplitude of fluctuations, reducing the error-bars in $\ln(A_s\times10^{10})$ by approximately 20%, compared to using the power spectrum alone. We also explore extended cosmological models by performing fits for the evolving dark energy equation of state $w_0w_a$, and the sum of neutrino masses $\sum m_\nu$. In these cases, we obtain constraints slightly larger than the ones from previous works from the DESI collaboration, due to not combining the full-shape results with other probes in all tracers. We find no strong evidence of deviations from standard $\Lambda$CDM, with the dark energy equation-of-state remaining within 2$\sigma$ from a cosmological constant $\Lambda$, and the neutrino mass being consistent with the normal hierarchy, $\sum m_\nu<0.1\,[eV]$ at 95% confidence limit. These constraints are broadly consistent with other DESI DR1 analyses, thus validating the robustness of the ShapeFit compression approach and the inclusion of the bispectrum for cosmological inference.
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All authors S. Novell-Masot, H. Gil-Marín, L. Verde, J. Aguilar, S. Ahlen, D. Bianchi, D. Brooks, F. J. Castander, T. Claybaugh, S. Cole, A. de la Macorra, J. Della Costa, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, A. X. Gonzalez-Morales, G. Gutierrez, J. Guy, C. Hahn, H. K. Herrera-Alcantar, K. Honscheid, C. Howlett, M. Ishak, J. Jimenez, R. Joyce, R. Kehoe, D. Kirkby, A. Kremin, C. Lamman, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, S. Nadathur, G. Niz, W. J. Percival, I. Pérez-Ràfols, G. Rossi, L. Samushia, E. Sanchez, E. F. Schlafly, D. Schlegel, M. Schubnell, J. Silber, D. Sprayberry, G. Tarlé, B. A. Weaver, C. Zhao, R. Zhou

High Energy Astrophysical Phenomena · Cross-listed from gr-qc

Recursive Penrose processes in electrically charged black hole spacetimes: Backreaction and energy extraction

Duarte Feiteira, José P. S. Lemos and Oleg B. Zaslavskii

We study a recursive Penrose process and the energy extraction for the decay of electrically charged particles in a Reissner-Nordström black hole spacetime with anti-de Sitter (AdS) asymptotics, incorporating the backreaction on the black hole's mass and charge. A recursive process requires that the decay products are confined in a finite region so that the emitted particles bounce back for further decay. In AdS spacetimes, the confinement arises naturally. Outgoing particles encounter a turning point and are reflected. One may impose a mirror at finite radius, but in AdS, backreaction makes these two confinement methods equivalent. Let $Q_n$ be the black hole charge after $n$ decays, and define $n_{\rm c}$ as the index for which the black hole's charge is zero, $Q_{n_{\rm c}}=0$. For $n_{\rm c}$ integer the black hole's charge decreases and reaches exactly zero after a finite number of decays, terminating the process. However, the last particle turns back, and encountering zero charge, falls into the hole. The final state is a charged black hole whose charge equals the sum of the original black hole and the initial particle charges. For $n_{\rm c}$ noninteger, the black hole charge decreases and can be arbitrarily small, but is never zero. The last allowed decay occurs at $n=n_{c}^-$, where $n=n_{c}^-$ is the greatest integer less than $n_{\rm c}$. Any further decay invalidates the approximations, the particles would carry a charge comparable to the black hole mass, transforming the problem into a two-body problem. The would-be subsequent decay would violate cosmic censorship and the process terminates before any inconsistency arises. In the integer and noninteger cases, the system yields a finite energy gain. Backreaction ensures that the process extracts a finite amount of energy. No black hole bomb occurs, the system works at most as an energy factory.
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High Energy Astrophysical Phenomena · Cross-listed from hep-ph

Toward universal coalescence models for antideuteron production

Mattia di Mauro, Jordan Koechler, Lorenzo Stefanuto et al. (+3 more)

Cosmic-ray (CR) antinuclei, especially antideuteron $\overline{\rm D}$ and antihelium-3 nuclei ${}^3\overline{\rm He}$, are among the most promising messengers for indirect dark matter (DM) searches. This is because secondary production in CR interactions with the interstellar medium is strongly suppressed at kinetic energies $K\simeq (0.1 - 1)$ GeV/$n$, typically one to two orders of magnitude below fluxes expected in standard DM scenarios. From the theoretical side, the formation of $\overline{\rm D}$ and ${}^3\overline{\rm He}$ is governed by coalescence, whose dynamics cannot yet be reliably derived from first principles. Phenomenological approaches therefore introduce effective coalescence parameters, possibly dependent on collision energy and production environment (hadronic versus electroweak). In this work we show that a common set of physically motivated coalescence models can simultaneously reproduce collider data in two qualitatively different regimes: ALICE measurements of (anti)deuteron production in $pp$ collisions at $\sqrt{s}=(0.9 - 13)$ TeV and the ALEPH $\overline{\rm D}$ multiplicity in hadronic $Z$ decays at $\sqrt{s}=m_Z$. We test both simple event-by-event prescriptions based on a relative-momentum cutoff, finding a preferred coalescence scale $p_{\rm coal}\simeq 0.2$ GeV, and quantum-mechanical models in the Wigner formalism. In the latter, a Gaussian bound-state wavefunction gives a best-fit momentum width, corresponding to $\delta\simeq 1.7$ fm, while a parameter-free implementation using the Argonne $v_{18}$ wavefunction (constrained by proton-neutron scattering data) agrees with ALICE spectra at the $\sim 25\%$ level. Overall, our results support an approximately universal coalescence description across energies and production environments, strengthening the theoretical basis for interpreting upcoming CR antinuclei searches.
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All authors Mattia di Mauro, Jordan Koechler, Lorenzo Stefanuto, Francesca Bellini, Fiorenza Donato, Nicolao Fornengo

Earth and Planetary Astrophysics · Cross-listed from physics.space-ph

New Constraints on the Jovian Narrowband Radio Components from Juno/Waves Observations and 3D Geometrical Simulations

Boudouma Adam, Zarka Philippe, Louis Corentin et al. (+2 more)

Measurements of Waves instrument onboard the Juno spacecraft suggest that narrowband kilometric radiation (nKOM; 20-141 kHz) and narrowband low-frequency radiation (nLF; 5-70 kHz) are generated within the plasma near the Io plasma torus (IPT) in low-latitude regions. While these emissions are thought to result from the conversion of the natural modes of the plasma into escaping radio waves, at either the fundamental or the first harmonic of the plasma frequency, there is no consensus on the specific mechanism involved. Using the electron density and the magnetic field data from the Jovian Auroral Distribution Experiment (JADE) and the FluxGate Magnetometer (FGM), we determine the range of frequencies accessible to different wave modes during Juno's crossing of the plasma disk environment. We classify the observed nKOM and nLF according to their propagation modes: trapped (Z-mode or Whistler), escaping (X-mode or O-mode), and undetermined (either trapped or escaping). We apply the 3D numerical modeling method that was developed in Boudouma et al. (2024) to the escaping and undetermined nKOM and nLF observations, deriving macroscopic constraints on the generation mechanisms, wave modes, characteristic frequencies, beaming and source locations. Our results support the interpretation in which high-latitude nKOM is consistent with O-mode, while low-latitude is rather X-mode. Both nKOM and nLF appear to be generated near the fundamental of the plasma frequency, but only nLF shows compatibility with emission near the first harmonic, suggesting the possible coexistence of both linear and nonlinear generation mechanisms.
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All authors Boudouma Adam, Zarka Philippe, Louis Corentin, Imai Masafumi, Briand Carine

Astrophysics of Galaxies

The structure and evolution of the Galactic high-$\alpha$ disc I. Chemical and age orbital cartography

Furkan Akbaba, Danny Horta and Olcay Plevne

We present a comprehensive chemical and age orbital cartography of the Galactic high-$\alpha$ disc using subgiant stars with precise ages, element abundances, and full phase-space information from the LAMOST–Gaia data set. Specifically, we map how average [Fe/H], [$\alpha$/Fe], and age vary across present-day kinematic and orbital coordinates. We analyse the data in full and across mono-abundance populations to measure element abundance-orbital and age-orbital gradients across orbital actions and angular-momenta. Our results show that the high-$\alpha$ disc exhibits clear and coherent gradients in [Fe/H], [$\alpha$/Fe], and age with orbits; these gradients are much stronger and sharper in orbital space than in present-day kinematics, showing that orbital diagnostics recover the intrinsic disc structure of old disc populations more effectively than instantaneous kinematic coordinates. We find that older high-$\alpha$ populations display qualitatively similar element abundance–orbital and age–orbital trends to stars in the low-$\alpha$ disc, although the high-$\alpha$ gradients are generally shallower. The presence of these ordered correlations indicates that the old high-$\alpha$ disc is structured, and preserved a strong fossil record of its early assembly despite the Milky Way's subsequent accretion history. This result implies that later mergers did not fully erase the chemical-orbital and age-orbital structure imprinted during the high-$\alpha$ disc's earliest formation epoch. All together, these findings indicate that the Galactic high-$\alpha$ disc formed mainly through inside-out and upside-down growth.
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Astrophysics of Galaxies

Identifying AGNs from X-ray detections-I: Metallicity calibrations in AGNs with X-ray luminosity as the primary input parameter

Mark Armah, O. L. Dors, Rogério Riffel et al. (+4 more)

We present the first semi-empirical strong-line calibrations to determine metallicity in Active Galactic Nuclei (AGNs) that use the directly observable X-ray luminosity (Lx) instead of the dimensionless ionization parameter ($U$). The calibrations are derived from an extensive grid of photoionization models computed with the Cloudy code, which are compared with observational data of Seyfert nuclei from the Burst Alert Telescope (BAT) AGN Spectroscopic Survey (BASS). In this first paper, we develop new calibrations for two key optical metallicity diagnostics based on the $N2$ and $O3N2$ indices, which are valid in a metallicity range of $8.0 \lesssim 12 + \log({\rm O/H}) \lesssim 9.1\, {\rm or}\, 0.2 \lesssim (Z/Z_{\odot}) \lesssim 2.6$, with precision of $1\sigma \approx 0.22$ dex ($N2$) and $\approx 0.20$ dex ($O3N2$). We systematically investigate the influence of the AGN spectral index $(\alpha_{ox})$, narrow-line region (NLR) gas density $(N_{\rm e})$, the characteristic peak temperature of the Big Blue Bump $(T_{\rm BB})$, and Lx. We find a strong, opposing secondary dependence on Lx for both indices. We demonstrate that neglecting this parameter overlooks systematic offsets intrinsic to the diagnostics, leading to metallicity errors of up to $\sim 1.0 Z_{\odot}$ ($\sim 0.50$ dex), particularly for the least and most luminous sources. This framework offers a more precise characterization of chemical enrichment in the NLRs of AGNs by leveraging their intrinsic X-ray emission to mitigate these systematic biases.
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All authors Mark Armah, O. L. Dors, Rogério Riffel, M. V. Cardaci, G.F.Hägele, Rogemar A.Riffel, J.M.Vílchez

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Formation and Decay of Oscillons in Einstein-Cartan Higgs Inflation

Javier Rubio

We review recent progress in the understanding of the preheating stage of Higgs inflation formulated within the Einstein-Cartan framework of gravity. This setup smoothly interpolates between the metric and Palatini formulations of the theory, leading to a distinctive phenomenology in an intermediate regime. Following the end of inflation, the Higgs field undergoes a non-trivial out-of-equilibrium evolution driven by tachyonic instabilities and nonlinear self-interactions, which fragment the inflaton condensate and give rise to well-localized oscillon configurations. While early studies suggested the formation of long-lived oscillons and the possibility of an extended matter-dominated phase, more recent analyses show that self-interactions at small field values render these objects transient, eventually triggering their decay and the onset of radiation domination. We discuss the implications of this dynamics for the thermal history of the Universe, the inflationary observables, and the generation of stochastic gravitational waves.
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Cosmology and Nongalactic Astrophysics

Half-wave-plate non idealities propagated to component separated CMB $B$-modes

Ema Tsang King Sang, Josquin Errard, Simon Biquard et al. (+4 more)

We assess the impact of non-ideal, continuously rotating half-wave plates (HWPs) on cosmic microwave background (CMB) polarization measurements targeting large angular scale signal. Such hardware solutions are used in or planned for multiple modern CMB efforts, both ground-based, for instance, small aperture telescopes of Simons Observatory or satellite borne, such as LiteBIRD. Using a frequency-dependent parametric model based on the Mueller matrix formalism, we characterize the induced mixing of Stokes parameters. Through end-to-end simulations, we propagate these effects from time-ordered data to cosmology via map-making and component-separation stages, quantifying their impact on the $B$-modes power spectrum and the tensor-to-scalar ratio, $r$. Our analysis shows that neglecting the frequency dependence of a three-layer HWP gives rise to significant polarization leakage, biases foreground spectral parameters, and leads to residual contamination in the recovered CMB maps. To mitigate these effects, we investigate multiple analysis strategies progressively incorporating a more complete description of the instrumental response. At the map-making level, this requires generalizing the standard pointing matrix to account for the full time- and frequency-dependent instrumental response. We find that standard HWP models, reduce the biases only down to $r \sim 10^{-2}$, while a more advanced approach based on a generalization of both map-making and component separation, implemented using JAX, can suppress it down to $r \sim 7 \times 10^{-4}$. Finally, we extend this approach to a time-domain component-separation, enabling a statistically consistent treatment of instrumental response in the presence of time-domain features. We demonstrate its feasibility and validate it by performing a full end-to-end analysis, recovering results in good agreement with the map-based ones.
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All authors Ema Tsang King Sang, Josquin Errard, Simon Biquard, Pierre Chanial, Wassim Kabalan, Wuhyun Sohn, Radek Stompor

Instrumentation and Methods for Astrophysics

High efficiency superconducting filterbank with impedance-defined resolution for millimeter-wave spectroscopy

Oliver Jeong, Michel Piat and Aritoki Suzuki

We present a high efficiency, moderate resolution on-chip superconducting filterbank spectrometer designed for line intensity mapping and broadband wave-like dark matter searches. Existing implementations used by the millimeter-wave community rely on resistive feedline termination for standing wave mitigation which caps the per-channel efficiency $\eta_\mathrm{ch}$ at 50% and utilize microstrip resonators which highly couple the resolving power $\mathcal{R}=\nu/\delta\nu$ and $\eta_\mathrm{ch}$ to thin-film dielectric loss. The architecture presented in this paper addresses these limitations by eliminating the termination resistor and employing niobium coplanar waveguide resonators patterned directly on single-crystal silicon, which fixes the resonator's internal quality factor by the silicon substrate property rather than by the loss tangent of a deposited film. The resolving power is set by the impedance ratio between the resonator and feedline. Electromagnetic and circuit simulations of a ten-channel filterbank near 90~GHz at unity oversampling show $\mathcal{R}=1170$ and $\eta_\mathrm{ch}> 78\%$, with no significant trend in efficiency across channels. A ten-channel prototype, designed for $\mathcal{R}=92\pm5$ and $\eta_\mathrm{ch}=(81\pm3)\%$ over 90–106~GHz with a 560~nm interlayer based on simulations, was fabricated and optically characterized, yielding $\mathcal{R}=208\pm74$ and $\eta_\mathrm{ch}=(77\pm6)\%$. Measured $\eta_\mathrm{ch}$ well above the 50% termination limit, together with demonstrated impedance tuning of $\mathcal{R}$, validate the design principles of this filterbank spectrometer and establishes a route to high-efficiency, high-resolution on-chip spectrometer arrays.
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