High Energy Astrophysical Phenomena
Accretion Geometry of Black Hole X-ray Binaries: Insights from X-ray Observations
Honghui Liu
The
accretion-ejection activities of black holes play a vital role in shaping the Universe. Bright and recurrent black hole X-ray binaries are ideal objects for studying
accretion physics across a wide range of
accretion rates, providing insights into the understanding of their supermassive counterparts. This short review summarizes X-ray techniques capable of measuring
accretion geometry, our current understanding, and open questions. In particular, X-ray spectroscopic studies indicate that the
accretion disk can extend close to the innermost stable circular orbit in the bright hard state. Some hints of disk-corona-jet connections are also discussed.
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Solar and Stellar Astrophysics
Third order correlations and skewness in convection. I. A new approach suitable for three-equation non-local models
F. Kupka
Non-local models of
stellar convection can account for mixing effects in regions adjacent to convectively unstable layers and for changes to the mean temperature structure caused by free, buoyancy driven convection. The physical completeness of such models, however, depends on how third order correlations, which characterize the non-local transport processes, are expressed in terms of second order correlations and the
stellar mean structure. Physical arguments and 3D hydrodynamical simulations were used to develop and test new closure relations for the skewness of the vertical velocity and temperature fields and third order cross-correlations to improve the predictive capabilities of non-local models of convection used in
stellar astrophysics and in other disciplines such as meteorology. The structural form of the closure correlations was developed by a series of physical arguments and their accuracy was evaluated through self-consistency tests based on 3D hydrodynamical simulations for the Sun and a DA type white
dwarf. The new closure relations derived for the skewness of vertical velocity and temperature fields provided improvements of up to an order of magnitude compared to previous models. This allows releasing the full potential of closure relations for the vertical velocity and temperature cross-correlations previously proposed in meteorology as well as the construction of new, more reliable models for the third order moments of vertical velocity and temperature in non-local models of turbulent convection. The new models for the skewness and third order cross-correlations of vertical velocity and temperature permit the construction of non-local models of turbulent convection which remove, among others, several major short-comings of three equation non-local convection models that are based on the downgradient approximation.
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High Energy Astrophysical Phenomena
High-Energy Shock Breakout from Supernovae and Gamma-ray Bursts
Chris L. Fryer, Eric Burns, Joseph M. Colosimo et al. (+2 more)
Cosmic explosions play a critical role in a broad range of astrophysical fields. Although considerable progress has been made to understand the explosive engines and their progenitors, many of the details are not well understood. One of the most powerful electromagnetic probes of the explosive mechanism and the
stellar progenitor is the first burst of
photons emitted from this blastwave as it exits the
stellar photosphere, known as shock breakout (SBO). Our understanding of SBO has evolved considerably in the past decade. Shock heating as the blastwave propagates through the
star and circumstellar material can drastically alter this emission producing a much broader range of potential SBO signals than that predicted by standard analytical approaches. Here we present a semi-analytic approach to model this diverse SBO emission, focused on thermal Bremsstrahlung radiation, which more accurately captures the complexities in Nature over previous treatments. We calculate a range of signals for a range of
supernova and gamma-ray burst types. Our models demonstrate how we can use these signals to place constraints on the nature of the explosive engines and better understand the role SBO can play in
prompt gamma-ray bursts. We study the implications of these results to historic observations, Einstein Probe transients, and in the context of proposed missions. We find that stripped envelope events can be detected serendipitously with survey
telescopes, but type Ia and II SBO detections require fast-pointing X-ray observations in response to early warning alerts from gravitational wave or
neutrino detectors.
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All authors Chris L. Fryer, Eric Burns, Joseph M. Colosimo, Michela Negro, Brendan O'Connor
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Non-Minimal Dilaton Inflation from the Effective Gluodynamics
Pirzada, Imtiaz Khan, Mussawair Khan et al. (+2 more)
We develop a nonminimal dilaton-inflation model in which the inflaton is the lightest scalar excitation of a hidden confining gauge theory. The Migdal–Shifman anomaly-matching action fixes a logarithmic contribution to the scalar potential, $V_{\rm MS}=A\varphi^4[\ln(\varphi/\mu)-1/4]$, with $(A,\mu)$ mapped to the scalar mass and
vacuum condensate.
Embedding this sector in the leading curved-space EFT introduces the independent Wilson coefficients $\lambda$ and $\xi$, and the resulting Einstein-frame dynamics yields a plateau with a calculable anomaly-induced deformation. We analyze the pure MS limit as a baseline, derive the $\mu$–$\lambda$ reparametrization, state finite-window RG-control conditions, and impose both the nonminimal-
gravity cutoff and the intrinsic confining-sector gap. Exact slow-roll scans show that the viable regime combines the usual large-$\xi$ attractor behavior with a logarithmic imprint tied directly to nonperturbative trace-anomaly matching.
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All authors Pirzada, Imtiaz Khan, Mussawair Khan, Tianjun Li, Ali Muhammad
Astrophysics of Galaxies
Comparing dynamical effects of the central bar and the spiral arms in the solar neighborhood
Willian Y. Nacafucasaco, Tatiana A. Michtchenko, Douglas Barros et al. (+1 more)
The dynamical effects on the
stellar motion produced by the
Galactic central bar and the spiral arms perturbations are investigated separately and compared. The
stars from the
Gaia DR3 catalog are selected in the region of observable completeness, which we estimate as $\sim$1 kpc from the Sun. We apply the 2D model of the
Galactic potential consisting of three axisymmetric components, the disk, the bulge, and the dark matter
halo, and two non-axisymmetric components, the central bar and the spiral arms. The
stellar dynamics is studied using analytical and numerical techniques, such as
Hamiltonian topology analysis, the construction of dynamical maps on the representative planes, dynamic spectra, and Poincaré sections. We identify the main dynamical features in the
solar neighborhood (SNd), the corotation (CR) and Lindblad resonances (LRs). By assuming that the main moving groups (MGs) in the SNd originate from the resonances, we compare their locations, structures, and intensities with the theoretical predictions and provide a description of the process involved in the formation of the MGs. In addition, we explore parametric planes by adjusting the values of the pattern rotation speed $\Omega_{p}$ with the positions of the MGs, for both the spiral arms and bar models, and conclude that the spiral arms model shows better results when compared to those of the bar, under the hypothesis of the dynamical origin of MGs.
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All authors Willian Y. Nacafucasaco, Tatiana A. Michtchenko, Douglas Barros, Jacques Lépine
Earth and Planetary Astrophysics
Systematic and Statistical Uncertainties in the Non-Gravitational Acceleration of 3I/ATLAS
F. Spada, M. Królikowska and L. Dones
We present a detailed analysis of the trajectory of interstellar comet 3I/ATLAS, with emphasis on the determination of its non-gravitational acceleration (NGA) parameters and their associated uncertainties. Using astrometric observations spanning both pre- and post-perihelion phases, we compute orbital solutions assuming
gravity-only, symmetric, delayed-peak, and asymmetric outgassing NGA models. To mitigate the effects of heterogeneous astrometric quality and potential tailward biases, we adopt a tiered uncertainty model that inflates the uncertainties of lower-fidelity observations, and assess solution robustness through validation against non-fitted data. We find clear evidence that NGA is required to reproduce the observations. Solutions obtained from pre- and post-perihelion arcs separately, however, yield mutually incompatible NGA parameters, suggesting either sensitivity to residual astrometric systematics or intrinsic limitations of constant parameter outgassing models. For the full data set, the inferred acceleration is in very good agreement with the latest JPL solution, supporting its use for physical interpretation and
nucleus size estimates. Models incorporating delayed or asymmetric activity with respect to perihelion improve the fit relative to a symmetric prescription, suggesting that part of the observed asymmetry may be physical. We conclude that, while the NGA of 3I is robustly determined, systematic uncertainties arising from both residual astrometric biases and simplifications in the outgassing modeling prescriptions exceed the formal fitting errors, and should be taken into account when deriving physical properties such as the
nucleus size.
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Solar and Stellar Astrophysics
High-resolution observations of small-scale activity in coronal hole plumes
Ziwen Huang, L. P. Chitta, L. Teriaca et al. (+5 more)
Plumes have been proposed to channel MHD waves and the
solar wind into the heliosphere. High-speed propagating disturbances (PDs), though well detected in plumes, cannot yet be clearly assigned to MHD waves or to mass flows. Additionally, plume bases as observed in the extreme ultraviolet are riddled with small-scale transients that could be related to the PDs. We study three plumes within an equatorial coronal hole observed by the EUV High Resolution Imager of the Extreme Ultraviolet Imager on board
Solar Orbiter. The properties of the small-scale brightenings at the plume bases are investigated to interpret their nature and possible relation with PDs. We process images with the Difference of Gaussians method to highlight the target brightenings, which are further identified with two different approaches. In the 30-min observation, 50 brightenings are visually selected, which also help set thresholds for automatic detection, where we find 451 brightenings. Their properties, including velocities on the plane of sky (PoS), are analyzed statistically. Potential field extrapolation based on the
magnetic field data from the Polarimetric and Helioseismic Imager on board
Solar Orbiter is used for correcting the PoS velocity to the real velocity along the
magnetic field. We observe that the majority of the base brightenings are small-scale, short-lived, and slightly elongated at the plume bases. They display intricate movements, with most exhibiting velocities in the PoS of less than 10 km/s. Their 3-dimensional velocities are found to be substantially lower than (and difficult to reconcile with) the speeds of PDs. A direct link between base brightenings and PDs remains inconclusive. We propose two possibilities for base brightenings: they may be related to wave-driven Type I spicules or originate from interchange reconnections. Further investigation is required to validate these hypotheses.
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All authors Ziwen Huang, L. P. Chitta, L. Teriaca, R. Aznar Cuadrado, H. Peter, S. K. Solanki, T. Wiegelmann, F. Plaschke
Instrumentation and Methods for Astrophysics
Deep learning-based astronomical multimodal data fusion: A comprehensive review
Wujun Shao, Dongwei Fan, Chenzhou Cui et al. (+3 more)
With the rapid advancements in observational technologies and the widespread implementation of large-scale sky surveys, diverse electromagnetic wave data (e.g., optical and infrared) and non-electromagnetic wave data (e.g., gravitational waves) have become increasingly accessible. Astronomy has thus entered an unprecedented era of data abundance and complexity. Astronomers have long relied on unimodal data analysis to perceive the universe, but these efforts often provide only limited insights when confronted with the current massive and heterogeneous astronomical data. In this context,
multimodal data fusion (MDF), as an emerging method, provides new opportunities to enhance the value of astronomical data and deepening the understanding of the universe by integrating information from different modalities. Recent progress in artificial intelligence (AI), particularly in deep learning (DL), has greatly accelerated the development of
multimodal research in astronomy. Therefore, a timely review of this field is essential. This paper begins by discussing the motivation and necessity of astronomical MDF, followed by an overview of astronomical data sources and major data modalities. It then introduces representative DL models commonly used in astronomical
multimodal studies, the general fusion process as well as various fusion strategies, emphasizing their characteristics, applicability, advantages, and limitations. Subsequently, the paper surveys existing astronomical
multimodal studies and
datasets. Finally, the discussion section synthesizes key findings, identifies potential challenges, and suggests promising directions for future research. By offering a structured overview and critical analysis, this review aims to inspire and guide researchers engaged in DL-based MDF in astronomy.
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All authors Wujun Shao, Dongwei Fan, Chenzhou Cui, Yunfei Xu, Shirui Wei, Xin Lyu
Earth and Planetary Astrophysics · Cross-listed from gr-qc
Analysis of Tidal Perturbations Due to Asymmetric Response of LARES 2 and LAGEOS
Xizhi Hu, Xiaodong Chen, Jianqiao Xu et al. (+3 more)
Earth
tidal perturbations affecting
laser-ranged satellites are critical for refining satellite orbital dynamics modeling, and their accurate computation represents a prerequisite for high-precision fundamental physical effects and geodetic investigations based on satellite orbit analysis. This study focuses on the
tidal perturbations induced by the asymmetric responses of LARES 2 and LAGEOS on their orbital nodes and inclinations. Perturbations induced by a total of 402 (392 2nd and 10 3rd-order) earth tide constituents on the two satellites were calculated, based on Kaula's orbital perturbation theory and Lagrange's planetary equations for satellites, considering the frequency dependence of Love numbers. The asymmetric characteristics of
tidal perturbations between the two satellites were quantitatively analyzed. The minimum resolutions of orbital inclinations and nodes, used as screening thresholds for significant constituents, were derived from the RMS of overlapping orbit differences using orbital geometry and error propagation law. With these thresholds, 83 significant constituents were identified from the 402. The cumulative effect of the 319 minor constituents was further evaluated, and it was found that their total impact, from coherent superposition, noticeably exceeds the thresholds, thus becoming non-negligible. The results of this study provide accurate
tidal perturbation parameters for LARES 2 and LAGEOS, and offer methodological references for the screening of Earth tide constituents in high-precision satellite orbital dynamics research, laying a foundation for subsequent studies on inverting geophysical parameters from satellite orbits and verifying fundamental physical effects, particularly the relativistic Lense-Thirring effect.
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All authors Xizhi Hu, Xiaodong Chen, Jianqiao Xu, Ignazio Ciufolini, Wei-Tou Ni, Antonio Paolozzi
Earth and Planetary Astrophysics
A generalized dipole-segment model for the gravitational field of elongated bodies
A. K. de Almeida Jr, A. F. S. Ferreira, L. B. T. Santos et al. (+6 more)
Context. Various simplified models have been investigated to understand the complex dynamical environment near irregular asteroids. We propose a generalized dipole-segment model (GDSM) to describe the gravitational fields of elongated bodies. The proposed model extends the dipole-segment model (DSM) by including variable pole masses and a connecting rod while also accounting for the spheroidal shape of the poles instead of assuming point masses. Methods. A nonlinear optimization method was employed to determine the model parameters, which minimizes the errors between the
equilibrium points predicted by the GDSM and those obtained using a more realistic approach, such as the polyhedron model, which is assumed to provide the accurate values of the system. The model was applied to three real irregular bodies: the Kuiper belt objects Arrokoth, Kleopatra, and comet 103P/Hartley. Results. The results show that the GDSM represents the gravitational field more accurately than the DSM and significantly reduces computational time and effort when compared with the polyhedron model. This reduction in computational complexity does not come at the cost of efficiency. This makes the GDSM a valuable tool for practical applications. The model was further employed to compute heteroclinic orbits that connect the unstable triangular
equilibrium points of the system. These trajectories, obtained from the intersections of the stable and unstable
manifolds, represent natural pathways that enable transfers between
equilibrium regions without continuous propulsion. The results for Arrokoth, Kleopatra, and 103P/Hartley are consistent and validate the GDSM as an accurate and computationally efficient framework for studying the dynamical environment and transfer mechanisms around irregular small bodies.
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All authors A. K. de Almeida Jr, A. F. S. Ferreira, L. B. T. Santos, F. Monteiro, A. Amarante, E. Tresaco, D.M. Sanchez, C. Gomes, A. F. B. A. Prado
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Minisuperspace Cosmology in Extended Geometric Trinity of Gravity
Emmanuele Battista, Salvatore Capozziello and Stefano Pastore
We investigate Extended
Geometric Trinity of
Gravity at both classical and
quantum cosmological levels using the minisuperspace approach. Adopting Noether
symmetries to select viable models, we examine metric-affine theories of
gravity, in particular the extensions of General Relativity, Teleparallel Equivalent General Relativity and Symmetric Teleparallel Equivalent General Relativity, and show that the equivalence among these different formulations can be restored by including in the Lagrangian the divergence terms that relate their respective
geometric invariants to the
Ricci scalar. Exact cosmological solutions are derived and compared in the different models.
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Cosmology and Nongalactic Astrophysics
First Sardinia Radio Telescope detection of the Sunyaev-Zel'dovich effect at 18.6 GHz
S. Cocchi, F. Loi, M. Murgia et al. (+5 more)
Galaxy clusters imprint a distinctive signature on the
cosmic microwave background through the thermal Sunyaev-Zel'dovich (SZ) effect, which enables to study the intracluster
plasma distribution and makes them powerful cosmological probes. We present the first Sardinia
Radio Telescope (SRT) detection of the SZ effect in the
galaxy cluster MACS J1752+4440 at 18.6 GHz, with a resolution of 0.9'. We detected a decrement in brightness toward the cluster centre, which we attributed to the thermal SZ effect. We modelled the signal using a spherically symmetric $\beta$ model for the electron density distribution and we employed a
Bayesian retrieval to estimate the core radius, central electron density, and $\beta$ parameter of the cluster. We found values consistent with expectations for a
galaxy cluster of the mass of MACS J1752+4440: a core radius of ($160 \pm 30$) kpc, a central electron density of ($2.5^{+0.7}_{-0.5} \cdot 10^{-3}$) cm$^{-3}$, and $\beta$=$0.6\pm0.1$. The mean Compton-$y$ parameter within a radius of 3.5' is $(2.6 \pm 0.3) \cdot 10^{-5}$, higher than the value reported by Planck, which is coherent considering the different resolution of the instruments and the modelling adopted. This work demonstrates the potential of the SRT to detect the onset of the SZ decrement at low frequencies, providing higher angular resolution than current all-sky surveys and enabling an improved reconstruction of the SZ decrement profile and the
plasma distribution in the intracluster medium.
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All authors S. Cocchi, F. Loi, M. Murgia, P. Marchegiani, V. Vacca, F. Govoni, F. Gandossi, G. Rodighiero
Earth and Planetary Astrophysics
Planetary Desert around Compact Binaries: Dynamical Instability Triggered by Resonance-Induced Eccentricity Excitation
Bin Liu and Dong Lai
Compact binaries with orbital periods shorter than about 7 days show an absence of transiting
planets, a feature known as the “circumbinary
planet desert". The physical mechanism behind this desert remains unclear. We investigate its origin by simulating the long-term dynamics of multi-
planet circumbinary systems with evolving inner binaries. Our simulations are based on the single-averaged secular equations that average only over the binary orbital period and fully incorporate
planet-
planet interactions. When an eccentric binary decays via tides, an outer
planet can be captured into resonance advection in eccentricity, a state in which its apsidal precession locks with that of the binary, driving extreme eccentricity growth. While such growth can occur in a binary-single
planet system, the parameter space is limited and may not necessarily induce instability. In a multi-
planet system, however, the excited orbit inevitably crosses those of its neighbors, which triggers violent
planet-
planet scatterings and produces collisions or ejections. Crucially, these mutual gravitational interactions amplify the “localized" instability of a single
planet into a system-wide chain reaction, drastically reshaping the orbital architecture and potentially clearing out the inner regions of planetary systems. Our results suggest that the resonance-induced instability provides a natural explanation for the observed circumbinary
planet desert.
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Cosmology and Nongalactic Astrophysics
Constraining the neutral hydrogen fraction during reionization: Cross-simulation inference using power spectrum and bispectrum
Anoop Krishna, Deepthi Moorkanat, Hiten et al. (+1 more)
The redshifted 21-cm signal is a unique probe of the early universe, particularly the Epoch of Reionization (EoR). While the 21-cm power spectrum has been the primary statistic for parameter inference, it fails to capture the non-Gaussian information in the signal, motivating the use of higher-order statistics such as the bispectrum. We perform a rigorous cross-simulation validation to infer the mean neutral hydrogen fraction ($\bar{x}_{\mathrm{H\,I}}$) by training a neural network on 21cmFAST simulations and applying it to mock observations generated by the ReionYuga code. We first
benchmark the framework in an idealized 21cmFAST-only setting before applying it to the more rigorous ReionYuga–21cmFAST cross-simulation case. Our analysis spans six
redshifts and includes realistic SKA system noise and
cosmic variance, calculated from 50 statistically independent realizations. In the same-code case, the bispectrum yields substantially tighter constraints, whereas in the cross-simulation case the improvement is moderate, with constraints tightened by $\sim 1.4\times$ relative to the power spectrum-only case. The cross-simulation analysis also identifies a persistent systematic discrepancy between inferred and true values that often exceeds the statistical uncertainties, implying that modeling uncertainty remains the dominant limitation. Our results, therefore, indicate that the highly stringent constraints obtained in same-code validation studies may be overly optimistic, and mitigating cross-model systematics is crucial for robust parameter inference in the SKA era.
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All authors Anoop Krishna, Deepthi Moorkanat, Hiten, Rajesh Mondal
High Energy Astrophysical Phenomena
Electron-positron Pair Production in Global GRMHD Simulations of Black Hole Accretion Flows
Ho-Sang Chan, Jason Dexter and Mitchell C. Begelman
We present global, three-dimensional general relativistic magnetohydrodynamic simulations of accreting black holes that incorporate pair physics. Pairs are modeled as a passive scalar that maintains a constant temperature. For high
accretion rate models, we observe a maximum pair fraction of $\sim \mathcal{O}(0.01)$, consistent with those inferred from some X-ray binaries, and identify a `pair void' extending to a few gravitational radii from the black hole. Pair fractions peak in the midplane just outside the plunging region and within a thin strip at the base of the corona. For moderate to high
accretion rate models, pairs are near
equilibrium close to the disk midplane, where the scattering optical depth is high and pair
equilibrium timescales are short, and could be comparable to the Coulomb collision timescale. This suggests the possibility of a pair-regulated coronal temperature. In contrast, the upper corona and jets, where the scattering optical depth is relatively low and pair
equilibrium timescales are long, are populated with pairs that may exceed their
equilibrium value by orders of magnitude. These pairs are transported by advection from the disk, which dominates over local pair processes. This result highlights advection as a significant source of pair injection, which may be relevant for certain X-ray binaries exhibiting $\gamma$-ray signatures. The pair density along the magnetically dominated poles exceeds the Goldreich-Julian density in some models.
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Cosmology and Nongalactic Astrophysics
Parameterizations of the Hubble Constant from the Binned Type Ia Supernova Master Sample: Logarithmic versus Power-law Forms
Maria Giovanna Dainotti, Avik Banerjee, Andre' LeClair et al. (+1 more)
Motivated by the Hubble tension and the increasing debate about the
redshift-dependency in the inferred Hubble constant, we investigate its dependence within the flat $\Lambda$CDM framework using a 20-bin analysis of the Master
Supernovae type Ia (SNe Ia) Sample, considering cases with and without very low-
redshift data. The main quantity studied is $H_0(z)/H_0$, where $H_0$ is the Hubble constant today, and $H_0(z)$ is the binned data-driven estimate of the value of $H_0$ inferred from the SNe Ia data within
redshift intervals at $z > 0$, such that $H_0(0) = H_0$. From the binned analyses, we obtain best-fitting values of $H_0$ and $\Omega_{m0}$, and employ logarithmic and power-law parameterizations, which are statistically consistent within uncertainties over the
redshift range considered. To assess their behavior at earlier epochs, we extrapolate both forms to the
Cosmic Microwave Background radiation (CMB) era ($z\simeq1100$), Big Bang Nucleosynthesis (BBN, $z\sim10^{9}$), and inflationary scales ($z\sim10^{20}$). The reconstructed Hubble constant remains nearly indistinguishable up to the CMB scale, diverges at the few-to-ten percent level around BBN, and differs more substantially when extrapolated to inflationary
redshifts, though these two regimes lie beyond the direct observational constraints. A distinct asymptotic behavior emerges at very-high
redshift: the logarithmic form exhibits a vanishing behaviour of $H_0$ at finite $z$, while the power-law form approaches zero asymptotically as $z \rightarrow \infty$. In future studies, independent high-
redshift observations and extensions beyond $\Lambda$CDM, such as $f(R)$ modified
gravity, could allow a comparative study of the two parameterizations beyond the SNe Ia regime and their high-$z$ physical implications.
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All authors Maria Giovanna Dainotti, Avik Banerjee, Andre' LeClair, Giovanni Montani
Instrumentation and Methods for Astrophysics
Detection and classification of astronomical sources with Astro-RetinaNet in crowded stellar fields
Yibo Yan, Chao Liu, Jiadong Li et al. (+1 more)
Upcoming next-generation sky surveys will detect large number of faint objects with magnitudes larger than 25. When objects are crowded within a limited a field of view, blending becomes unavoidable. Blending leads to the omission of many sources during photometry in these fields, which cause an underestimates of tens of percent in crowded fields, and remains a major challenge for existing source-extraction techniques. Although artificial neural networks had shown promising results in the detection and classification in wide-field surveys, they often fail with severely blended
stars. We developed a robust deep learning model, Astro-RetinaNet, based on the Retinanet
algorithm to detect and classify blended sources in single-band astronomical images. After training and evaluating the performance of our network on simulated images, we find precision of 0.96, 0.89,0.70, 0.50,0.75 for single
star, 2-
star, 3-
star, 4-
star and 5-or-more
star blending cases, respectively, with
star number density $\sim$22000
stars per $\rm arcmin^2$. We compare our method's detection capability and completeness both on CSST simulated NGC 2298 images and HST observed M31 images. In crowded and non-crowded
stellar fields of simulated NGC 2298, our results show that the model can recover $82\%$ and $95\%$ sources respectively at magnitude ($i$ band) of 25, while for SExtractor and Photutils the completeness reduces to $20\%, 59\%$ and $60\%, 88\%$ respectively. In the M31 case, as faint as 27 magnitude ($F814W$) in a crowded field, Astro-RetinaNet detects 2,224 sources, significantly outperforming Photutils and SExtractor by factors of 3.4 and 7.1, respectively.
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All authors Yibo Yan, Chao Liu, Jiadong Li, Feng Wang
Earth and Planetary Astrophysics
2024 YR4: Identification of Possible Precoveries in 2016 IPTF Data
Sam Deen and Derek Lam
2024 YR4 is a 40-100 meter-diameter asteroid and former Torino Scale 3 object which currently has a roughly 4% chance of impacting the Moon on 2032 December 22, an event which recent studies suggest could pose a hazard on Earth due to impact ejecta. We present a search for, and identification of, potential precovery observations of the virtual lunar impactor in Intermediate Palomar Transient Facility (IPTF) survey data, as well as other publicly accessible surveys, dating from 2016. These candidate detections, not accounting for any currently-undetected Yarkovsky forces, predict a perilune of 22001 +/- 49 km and a perigee of 277534 +/- 46 km (relative to the center of each respective body) representing an improvement of > 300 times in the approach distance uncertainty above the existing orbit solution and, if confirmed, decisively ruling out a lunar impact in 2032. Using a matched filter tuned to 2024 YR4's predicted appearance in each image, we find the detection to be significant at Pnull = 5x10-9. The resultant possible orbit solution should be easy to confirm during 2024 YR4's 2028 approach to Earth, potentially greatly reducing the effort required by the planetary defense community at large to characterize 2024 YR4 before its potential lunar impact.
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Astrophysics of Galaxies
Identifying and distinguishing quenching galaxies with spatially resolved star formation in TNG50
Cameron Lawlor-Forsyth, Michael L. Balogh, Elizaveta Sazonova et al. (+3 more)
Using the TNG50 simulation, we determine observationally motivated metrics that can distinguish quenching
galaxies from
star forming
galaxies for $M_{*} \geqslant 10^{9.5}~M_{\odot}$, based on the spatial distribution of their
stellar populations. Quenching
galaxies are not fully quenched but have low levels of ongoing
star formation that decreases over time. The morphological metrics consider the concentration of
star formation, size of the
star forming disk, and characteristic radii that trace sharp truncations of
star formation. These metrics can separate simulated quenching
galaxies based on morphology into populations where
star formation is suppressed inside-out and outside-in. Inside-out quenched
galaxies are more likely to be the most massive
galaxy within their
halo in the field, while outside-in quenched
galaxies are satellites residing in dense environments and begin quenching ${\sim} 1~\text{Gyr}$ after being accreted. Outside-in quenched
galaxies typically take ${\sim} 1.5~\text{Gyr}$ to quench, and inside-out quenched
galaxies can take up to ${\sim} 3.5~\text{Gyr}$, where the duration of quenching is a function of
stellar mass. We find that each population of quenched
galaxy experiences
evolution of their morphological metrics, where the different quenched populations reside in unique locations in parameter space.
Galaxies in the later stages of quenching are more easily distinguished than those in the early stages, when compared to
star forming
galaxies. In addition, inside-out quenched
galaxies can be distinguished compared to outside-in quenched
galaxies, and the progress through the quenching episode can be estimated for both populations. These results have broad implications for distinguishing quenching
galaxies in large
galaxy surveys.
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All authors Cameron Lawlor-Forsyth, Michael L. Balogh, Elizaveta Sazonova, Cameron R. Morgan, Sean L. McGee, Gregory H. Rudnick
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
A Unified Interpretation of Supernova, GRB, and QSO Time Dilation Signals in a Generalized Cosmological Time Framework
Seokcheon Lee
Cosmological time dilation (CTD) serves as a fundamental probe of
cosmic expansion, historically verified through the characteristic (1+z) broadening of Type Ia
supernova (SNe Ia) light curves. However, significant tensions arise when extending this test to other astrophysical regimes. While discrete, event-based transients such as Gamma-Ray Bursts (GRBs) exhibit large scatter in interred time-dilation signatures, analyses of
stochastic variability in persistent sources, specifically
Quasars (QSOs), frequently yield null results. I demonstrate that these discrepancies stem from a previously overlooked distinction between discrete
geometric clocks and continuous thermal emission, presenting a resolution within the framework of Generalized Cosmological Time (GCT). The central premise relies on strictly distinguishing global coordinate time, characterized by a generalized lapse function, from the local proper time measured within gravitationally bound systems. We propose that the progenitors of transients, specifically SNe Ia and GRB central engines, are effectively shielded from background time
evolution due to strong gravitational binding and environmental decoupling. Consequently, they act as standard clocks tracing pure
geometric path dilation, obeying \tau_obs \propto (1+z)^{1-b/4}. Conversely, the lack of dilation in QSOs is derived as a consequence of observing persistent thermal
accretion disks at fixed wavelengths, introducing an intrinsic selection effect (\tau_intr \propto (1+z)^{-2}) that masks the cosmological signal. This framework reconciles the diverse behaviors of transient and persistent sources without modifying local physical laws.
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Cosmology and Nongalactic Astrophysics
Accretion history dependence of the halo depletion radius
Jiale Zhou and Jiaxin Han
We investigate the role of the
accretion history in shaping the depletion radius of dark matter
halos using a large cosmological N-body simulation. We show that the inner depletion radius, rescaled by the virial radius, depends strongly on the recent mass
accretion rate (MAR) measured over a dynamical timescale, while exhibiting only weak dependence on
halo mass. While this dependence mirrors that of the splashback radius and the two radii are tightly correlated, the depletion radius exhibits a more nuanced response to the detailed
accretion mode. Specifically, we find that the dependence on MAR steepens at lower
redshifts, aligning with self-similar spherical collapse models yet contrasting with the behavior of the splashback radius. This
redshift dependence is largely driven by recent major mergers, which tend to suppress the depletion radius in stacked measurements at low
redshift and high
accretion rate. Furthermore, we identify a dichotomy in the drivers of the depletion radius. For slowly accreting
halos, the MAR is the primary dependence, whereas for rapidly accreting
halos, other properties (shape,
spin, concentration, and formation time of the central subhalo) related to the anisotropic or perturbed
accretion mode also play a significant role. These results establish the depletion radius as a sensitive physical probe of the detailed
accretion history of dark matter
halos, complementary to the splashback radius.
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Instrumentation and Methods for Astrophysics
A Particle Detector Array deployed to the Murchison Widefield Array in the Murchison Radio-astronomy Observatory
J.E. Dickinson, J.D. Bray, D. Kenney et al. (+16 more)
We report the design and functionality of the Murchison Widefield Array Particle Detector Array (MWA PDA), an array of eight particle scintillation detectors deployed to Inyarrimanha Ilgari Bundara, the Murchison
Radio-astronomy Observatory (MRO). The purpose of the instrument is to identify
cosmic ray extensive air showers (EAS) occurring over the core of the MWA
radio telescope, and generate a trigger to allow
radio data on the event to be captured and analysed. The system also acts as a pathfinder for a much larger instrument to be deployed in the core of the low-frequency component of the Square Kilometre Array, SKA-Low, by the SKA's ultra-high-energy particles science working group. Here, we describe the instrument and associated infrastructure, which has been verified to comply with the strict
radio-frequency emissions requirements of the MRO, and was deployed in November 2024. We present calibration data, which demonstrates the ability of each detector to identify individual atmospheric
muons at the expected rate, and we characterise the temperature dependence of the system. We describe a sample of 35,500 EAS identified using multi-detector coincidence over a 13-day period, and show how the detector data can be used to reconstruct the arrival directions and approximate energies of these events. We conclude that the PDA can reliably trigger on and reconstruct EAS contained within the $\sim 103 \times 90$ m$^2$ core region, arriving within 20$^{\circ}$ of zenith, at primary
cosmic ray energies above $\sim 4$ PeV. We have also verified that the detector array can generate triggers, allowing the capture of
radio data from the MWA correlator for offline analysis.
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All authors J.E. Dickinson, J.D. Bray, D. Kenney, T. Booler, J. Edgley, D. Emrich, A. Forouzan, T. Gould, A. McPhail, P. Roberts, R.E. Spencer, L. Verduyn, R. Watson, A. Williams, K. Grainge, A. Haungs, T. Huege, C.W. James, S.J. Tingay
Earth and Planetary Astrophysics
Terraforming Mars: Mass, Forcing, and Industrial Throughput Constraints
Slava G. Turyshev
Terraforming Mars can be evaluated with a set of system-level constraints linking (i) target pressures & compositions to required atmospheric inventories, (ii) target surface temperatures to the required radiative control, (iii) inventories &
climate agents to sustained industrial throughput & power over a build time, (iv) persistence against collapse, escape, geochemical sinks. We use order-of-magnitude scalings to compare endogenous CO2 release, synthetic super-greenhouse gases, CO2-H2 collision-induced absorption, engineered aerosols/nanoparticles, orbital mirrors, regional paraterraforming. We find: (1) human-relevant pressures imply exaton-class inventories, because Mars requires 3.89 x 10^15 kg of atmosphere per mbar of global mean surface pressure; (2) accessible endogenous CO2 is best treated as ~10s of mbar resource, with a 20 mbar case yielding <10 K warming under present insolation; (3) mean surface temperatures of 250-273 K require either effective IR opacity of ~2-4 or direct absorbed-
solar forcing of ~100 W/m^2, implying reflector areas of ~10^{13}-10^{14} m^2 together with large deployment, control, durability, replacement burdens; (4) breathable open-surface endpoints are dominated by O2 and N2 inventories and by a minimum oxygenation work exceeding 10^{25} J, implying average build rates of 10^7-10^8 kg/s and average power from multi-100 TW to PW for century-to-millennial build times before inefficiencies and sink filling. We conclude that regional habitability via paraterraforming/covered-area strategies are plausible on near-term industrial scales, whereas no credible open-atmosphere pathway is identified to a Mars permitting pressure-unassisted human exposure or a breathable surface atmosphere without exaton-class volatile supply, multi-century planetary industry, + sustained
climate actuation, retention, durability management, replacement against sinks and loss.
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High Energy Astrophysical Phenomena
Constraining the Pulsar 3D Velocity Distribution: The Impact of Spin-Velocity Alignment
Zheng Li, Xiaojin Liu, Zhi-Qiang You et al. (+2 more)
Quantifying the natal kick distribution of
pulsars is essential for understanding
supernova physics and binary
evolution, yet measurements are historically limited by the lack of radial velocity data. Most previous studies rely on transverse velocities under the assumption of spatial isotropy. In this work, we reconstruct the intrinsic three-dimensional (3D) velocity distribution for a curated sample of 18
pulsars by explicitly incorporating the observational constraint of
spin-velocity
alignment. Using a hierarchical
Bayesian framework that accounts for measurement uncertainties, we compare nine candidate velocity distribution models. We find that a Gamma distribution provides an adequate description of the inferred 3D velocities; however, the modest Bayes factor (1.65 relative to a single Maxwellian) indicates that the current data lack sufficient resolving power to discriminate decisively among the models considered. The Gamma model is characterized by a peak velocity of $237^{+67}_{-84}$ km s$^{-1}$. The reconstructed 3D velocities under
alignment are systematically lower than those inferred under isotropy, indicating that projection effects can bias individual kick estimates high, while leaving the overall population scale largely unchanged within uncertainties. A complementary analysis of 465
pulsars with transverse velocity estimates favors a Log-Normal distribution for the full sample, while isolated young
pulsars remain consistent with a Gamma-like profile. Our results underscore the importance of
geometric assumptions in population inference and highlight the need for larger samples with improved distance and
spin-axis measurements to place tighter constraints on natal kick physics.
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All authors Zheng Li, Xiaojin Liu, Zhi-Qiang You, Jumei Yao, Xing-Jiang Zhu
Earth and Planetary Astrophysics
Rotation Period of C/2006 P1 (McNaught) Through Morphological Analysis with Narrowband Imaging
Vincent Okoth, Cyrielle Opitom, Colin Snodgrass et al. (+2 more)
This study presents findings from narrowband imaging of comet C/2006 P1 (McNaught) using the 3.6-metre New Technology
Telescope (NTT) at La Silla, Chile. Observations commenced on January 27, 2007, 15 days after perihelion, and continued until February 4, with additional sessions from February 25 to 28. Imaging was conducted using the ESO Multi-Mode Instrument (EMMI) in both broadband (B, V, R) and six comet-specific narrowband filters (CN, C3, C2, NH2, blue and red continuum). Various image processing techniques were employed to enhance structural features, including azimuthal mean/median division and subtraction, azimuthal renormalisation, and division by inverse profile, as well as the Larson-Sekanina technique. These enhancements revealed dynamic coma structures, with jets transitioning from spiral patterns to linear or fan-like shapes over time. The consistency of morphological patterns across different processing methods validated their authenticity. The periodic recurrence and temporal
evolution of CN coma features in narrowband images indicate a
nucleus rotation period of 11.8 h, consistent with stable active regions and rotationally modulated outgassing near perihelion.
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All authors Vincent Okoth, Cyrielle Opitom, Colin Snodgrass, Brian Murphy, James E. Robinson
Earth and Planetary Astrophysics
TOI-1080 b: a temperate, rocky planet orbiting a quiet M4V host
Y. Gómez Maqueo Chew, G. Dransfield, K. Barkaoui et al. (+41 more)
We present the detection and validation of a small, temperate transiting
exoplanet orbiting TOI-1080 every 3.9652482$^{+0.0000014}_{-0.0000015}$ days. The host is a quiet M4V
star at 25.6 pc. The
planet signal was first detected by TESS and validated using TESS and ground-based observations. By fitting the available light curves, the
planet radius is measured to be 1.200+- 0.058 Rearth and its
equilibrium temperature of 368$^{+12}_{-10}$ K. With NIRPS radial velocities, we are able to place a 3-sigma upper limit on the mass of TOI-1080 b of 10.7 Mearth. Our injection-recovery tests enable us to discard additional transiting
planets in the TOI-1080 system with radii down to 0.9 Rearth and periods between 0.5 and 7.7 days, and
planets with radii larger than 1.4 Rearth for periods up to 19 days. We demonstrate that it is highly amenable to characterisation of its mass and putative atmosphere. In particular, we find that TOI-1080 b is an exceptional target for the ongoing JWST+HST Rocky Worlds DDT programme, having a priority score that is higher than four out of nine targets currently being investigated by the programme. TOI-1080 b can be added to the sample of nearby
benchmark planets accessible for detailed study with JWST.
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All authors Y. Gómez Maqueo Chew, G. Dransfield, K. Barkaoui, C. Cadieux, E. Ducrot, B. V. Rackham, M. Timmermans, A. J. Burgasser, A. Segura, K. G. Stassun, C. Ziegler, A. Soubkiou, J. M. Almenara, B.O. Demory, M. Gillon, J. M. Jenkins, E. Jofré, A. Khandelwal, S. Páez, R. Petrucci, L. Parc, M. Pichardo Marcano, I. Plauchu-Frayn, U. Schroffenegger, R. Schwarz, T.G. Tan, A. H. M. J. Triaud, Z. Benkhaldoun, X. Bonfils, F. Bouchy, K. A. Collins, F. Davoudi, R. Doyon, M. Gachaoui, M. J. Hooton, E. Jehin, F. J. Pozuelos, M. G. Scott, S. Yalç{\i}nkaya, F. Zong Lang, S. Zúñiga-Fernández, J. R. De Medeiros, J. I. González-Hernández, N. C. Santos