Astronomy and Computing最新文献

{"title":"Exploring the impact of dark energy in Finslerian black hole dynamics and observational features","authors":"J. Praveen,&nbsp;S.K. Narasimhamurthy","doi":"10.1016/j.ascom.2025.100938","DOIUrl":"10.1016/j.ascom.2025.100938","url":null,"abstract":"<div><div>This study explores black hole dynamics within the framework of Finsler geometry, emphasizing the influence of the Finslerian constant <span><math><mi>η</mi></math></span> and the quintessence dark energy parameter <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>. By extending the conventional black hole metric with Finslerian corrections, we employ the osculating Riemannian approach and Barthel connection to derive a novel black hole metric, termed the Finsler Black Hole metric. The research investigates the effects of these modifications on photon trajectories, gravitational lensing, and shadow formation. The findings indicate that increasing <span><math><mi>η</mi></math></span> enhances gravitational lensing, reduces the black hole shadow size, and produces distinct photon ring patterns. The analysis also reveals that the effective potential <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>r</mi><mo>)</mo></mrow></mrow></math></span> significantly influences photon orbits, with higher <span><math><mi>η</mi></math></span> values pulling the photon sphere closer to the black hole. Furthermore, the study examines static and infalling spherical accretion models, showing that variations in <span><math><mi>η</mi></math></span> and <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> substantially impact the intensity distribution and geometry of black hole shadows. The inclusion of the Finslerian vector field <span><math><mi>β</mi></math></span> adds complexity to the gravitational dynamics. These modifications introduce observable features that distinguish Finslerian black holes from those predicted by General Relativity. Additionally, the incorporation of dark energy through <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> is shown to affect gravitational behavior and observable phenomena such as bending angles and critical impact parameters. This work provides a geometrical framework for understanding the interplay between Finsler geometry, dark energy, and black hole physics.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100938"},"PeriodicalIF":1.9,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"cosmosage: A natural-language assistant for cosmology","authors":"Tijmen de Haan","doi":"10.1016/j.ascom.2025.100934","DOIUrl":"10.1016/j.ascom.2025.100934","url":null,"abstract":"<div><div><span>cosmosage</span> is a natural-language assistant intended for a wide audience, from laypersons interested in cosmology to students, teachers, and professional cosmologists. <span>cosmosage</span> provides a novel way to access knowledge and reason about cosmology. Leveraging the power of advanced large language models (LLMs), <span>cosmosage</span> has learned from a vast corpus of open-access source texts, including textbooks and papers. <span>cosmosage</span> is found to be state-of-the-art on the narrow task of answering questions about cosmology, outperforming all general-purpose models. The model parameters and code are publicly available.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100934"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143268283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of periodic orbits in the Copenhagen problem with non-spherical primaries","authors":"O.P. Meena ,&nbsp;P. Sachan ,&nbsp;R. Pratap ,&nbsp;P. Meena","doi":"10.1016/j.ascom.2025.100932","DOIUrl":"10.1016/j.ascom.2025.100932","url":null,"abstract":"<div><div>In the present investigation, we conduct an analysis of periodic orbits within the context of the Copenhagen problem, emphasizing the dynamical behavior of a test particle subjected to the gravitational influence of two primary bodies of equal mass, which are in continuous rotation characterized by a constant angular velocity. By expanding upon the classical framework, we treat the primary bodies as non-spherical entities, thereby introducing the phenomenon of oblateness into the dynamical system under consideration. Employing the methodology of Fourier series, we articulate the characteristics of periodic orbits in proximity to the libration points and systematically evaluate the influence of the orbital parameter <span><math><mi>ɛ</mi></math></span> on the spatial dimensions and temporal periods of these orbits. Through the incorporation of terms extending to the third order in Fourier series method, we present a comprehensive representation of the parameter’s influence on the orbital attributes. The findings indicate that with an increase in <span><math><mi>ɛ</mi></math></span>, the dimensions of periodic orbits experience a substantial expansion, while their temporal periods demonstrate non-linear fluctuations. Variational graphs elucidate the correlation between <span><math><mi>ɛ</mi></math></span> and the time period <span><math><mi>T</mi></math></span>, revealing distinct patterns for the various families of orbits under analysis. Moreover, the oblateness exhibited by the primary bodies engenders significant alterations in the geometrical characteristics, size, and time period of the orbits, thereby underscoring their pivotal influence on the dynamics of orbital motion.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100932"},"PeriodicalIF":1.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emulators for stellar profiles in binary population modeling","authors":"Elizabeth Teng ,&nbsp;Ugur Demir ,&nbsp;Zoheyr Doctor ,&nbsp;Philipp M. Srivastava ,&nbsp;Shamal Lalvani ,&nbsp;Vicky Kalogera ,&nbsp;Aggelos Katsaggelos ,&nbsp;Jeff J. Andrews ,&nbsp;Simone S. Bavera ,&nbsp;Max M. Briel ,&nbsp;Seth Gossage ,&nbsp;Konstantinos Kovlakas ,&nbsp;Matthias U. Kruckow ,&nbsp;Kyle Akira Rocha ,&nbsp;Meng Sun ,&nbsp;Zepei Xing ,&nbsp;Emmanouil Zapartas","doi":"10.1016/j.ascom.2025.100935","DOIUrl":"10.1016/j.ascom.2025.100935","url":null,"abstract":"<div><div>Knowledge about the internal physical structure of stars is crucial to understanding their evolution. The novel binary population synthesis code <span>POSYDON</span> includes a module for interpolating the stellar and binary properties of any system at the end of binary <span>MESA</span> evolution based on a pre-computed set of models. In this work, we present a new emulation method for predicting stellar profiles, <em>i.e</em>., the internal stellar structure along the radial axis, using machine learning techniques. We use principal component analysis for dimensionality reduction and fully-connected feed-forward neural networks for making predictions. We find accuracy to be comparable to that of nearest neighbor approximation, with a strong advantage in terms of memory and storage efficiency. By providing a versatile framework for modeling stellar internal structure, the emulation method presented here will enable faster simulations of higher physical fidelity, offering a foundation for a wide range of large-scale population studies of stellar and binary evolution.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100935"},"PeriodicalIF":1.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of spin in black hole triplets","authors":"A. Chitan ,&nbsp;A. Mylläri ,&nbsp;M. Valtonen","doi":"10.1016/j.ascom.2025.100933","DOIUrl":"10.1016/j.ascom.2025.100933","url":null,"abstract":"<div><div>Spin can influence the dynamics of the already chaotic black hole triplet system. We follow this problem in two sets of simulations: first, the Agekian–Anosova region (or region D), and second, using Pythagorean triangles. We use ARCcode, an N-body code that performs numerical integration of orbits. This code includes post-Newtonian corrections, which we include up to the 2.5th order. In set one of our simulations, we fix the masses of the black holes at 10⁶ M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>. Then we run the simulations first without any spin added and after by initialising spin on one of the black holes. We find that after including spin into the system, 12.9% of the simulations changed outcomes. Either the systems went from having all black holes merging to having a black hole escaping the system, or vice versa. In the second set of simulations, we expanded into Pythagorean triangles as initial positions of black holes, stemming from Burrau’s three-body problem. We varied the masses of the black holes from 10⁰ M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>–10¹² M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>. Black holes in these systems were given spin in normalised units ranging from 0 to <span><math><mo>∼</mo></math></span> 0.95. We find that intermediate mass black holes in the range of 10⁴ M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>–10⁵ M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>, were influenced the most by spin, particularly in their lifetimes. We also find that simulations, initialised as 2-dimensional, become 3-dimensional.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100933"},"PeriodicalIF":1.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compression method for solar polarization spectra collected from Hinode SOT/SP observations","authors":"J. Batmunkh ,&nbsp;Y. Iida ,&nbsp;T. Oba ,&nbsp;H. Iijima","doi":"10.1016/j.ascom.2025.100929","DOIUrl":"10.1016/j.ascom.2025.100929","url":null,"abstract":"<div><div>The rapidly increasing volume of observational solar spectral data poses challenges for efficient and accurate analysis. To address this issue, we present a deep learning-based compression technique using the deep autoencoder (DAE) and 1D-convolutional autoencoder (CAE) models, developed for use on the Hinode SOT/SP data. This technique focuses on compressing Stokes I and V polarization spectra from sunspots in addition to the quiet Sun, offering a wider and more efficient avenue for spectral analyses.</div><div>Our findings reveal that the CAE model surpasses the DAE model in reconstructing Stokes profiles, exhibiting enhanced robustness and achieving reconstruction errors close to the observational noise level. The proposed technique is demonstrated to be effective in compressing Stokes I and V spectra from both the quiet Sun and sunspots, highlighting its potential for transformative applications in solar spectral analyses, including the identification of unique spectral signatures.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100929"},"PeriodicalIF":1.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Confirmation of binary clustering in gamma-ray bursts through an integrated p-value from multiple nonparametric tests of hypotheses","authors":"S. Modak","doi":"10.1016/j.ascom.2025.100931","DOIUrl":"10.1016/j.ascom.2025.100931","url":null,"abstract":"<div><div>The paper applies a new, nonparametric, interpoint distance-based measure to confirm the inherent groups prevailing in the brightest source of light in the universe: gamma-ray bursts. Our effective metric, in association with clustering methods like Gaussian-mixture model-based and <span><math><mi>K</mi></math></span>-means algorithms, resolves the conflict regarding the possibility about existence of more than binary clusters in the gamma-ray burst population. Here we carry out multiple nonparametric statistical tests of hypotheses, as many as the number of bursts available from the ‘BATSE’ catalog. An integrated <span><math><mi>p</mi></math></span>-value achieved from the aforesaid dependent tests solves our concern confirming two groups of short and long bursts.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100931"},"PeriodicalIF":1.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143268282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disentangling transients and their host galaxies with scarlet2: A framework to forward model multi-epoch imaging","authors":"C. Ward ,&nbsp;P. Melchior ,&nbsp;M.L. Sampson ,&nbsp;C.J. Burke ,&nbsp;J. Siegel ,&nbsp;B. Remy ,&nbsp;S. Birmingham ,&nbsp;E. Ramey ,&nbsp;S. van Velzen","doi":"10.1016/j.ascom.2025.100930","DOIUrl":"10.1016/j.ascom.2025.100930","url":null,"abstract":"<div><div>Many science cases for wide-field time-domain surveys rely on accurate identification and characterization of the galaxies hosting transient and variable objects. In the era of the Legacy Survey of Space and Time (LSST) at the Vera C. Rubin Observatory the number of known transient and variable sources will grow by orders of magnitude, and many of these sources will be blended with their host galaxies and neighboring galaxies. A diverse range of applications – including the classification of nuclear and non-nuclear sources, identification of potential host galaxies in deep fields, extraction of host galaxy spectral energy distributions without requiring a transient-free reference image, and combined analysis of photometry from multiple surveys – will benefit from a flexible framework to model time-domain imaging of transients. We describe a time-domain extension of the <span>scarlet2</span> scene modeling code for multi-epoch, multi-band, and multi-resolution imaging data to extract simultaneous transient and host galaxy models. <span>scarlet2</span> leverages the benefits of data-driven priors on galaxy morphology, is fully GPU compatible, and can jointly model multi-resolution data from ground and space-based surveys. We demonstrate the method on simulated LSST-like supernova imaging, low-resolution Zwicky Transient Facility imaging of tidal disruption events, and Hyper Suprime Cam imaging of variable AGN out to <span><math><mrow><mi>z</mi><mo>=</mo><mn>4</mn></mrow></math></span> in the COSMOS fields. We show that <span>scarlet2</span> models provide accurate transient and host galaxy models as well as accurate measurement of host–transient spatial offsets, and demonstrate future applications to the search for ‘wandering’ massive black holes.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100930"},"PeriodicalIF":1.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data based investigation on galaxy formation and evolution theory through statistical techniques","authors":"Prasenjit Banerjee ,&nbsp;Tanuka Chattopadhyay ,&nbsp;Asis Kumar Chattopadhyay","doi":"10.1016/j.ascom.2025.100928","DOIUrl":"10.1016/j.ascom.2025.100928","url":null,"abstract":"<div><div>The present work deals with a large data set of star-forming as well as quiescent galaxies at red shifts ranging from 0 to 4 (0<span><math><mo>≤</mo></math></span>z<span><math><mo>≤</mo></math></span>4). The present selected catalogues of objects have been compiled from the NEWFIRM Medium-Band Survey (NMBS). We have concatenated both the catalogues AEGIS and COSMOS, present in NMBS, one after another to form a master catalog. Several derivable parameters were present in the catalog, but we have limited our choice to the observable as well as the physical parameters of the galaxies. In this paper, we have studied the evolutionary pattern of the galaxies by dividing them into various groups according to red shift, and observing the distributional pattern of those groups. Later, the evolutionary pattern of the galaxies is investigated by examining the size-mass relationship corresponding to these groups and comparing the level of dependence of the parameters under study.</div><div>In order to perform a proper analysis of the data for the above-mentioned objectives, we have used statistical techniques like multiple testing, the Shapiro–Wilk test, independent component analysis, multivariate outlier detection, multivariate kernel density estimation, and kernel regularized least squares method. Two noble findings that have been observed in this work are (a) The galaxy parameters with high red shifts (z <span><math><mo>&gt;</mo></math></span> 3.5) follow a multivariate Gaussian distribution, helping us to infer that high red shift (z <span><math><mo>&gt;</mo></math></span> 3.5) galaxy parameters show more randomness compared to other galaxies with z<span><math><mo>&lt;</mo></math></span>3.5. (b) There is a deviation from the linearity of the covariates in very high-redshift galaxies (z <span><math><mo>&gt;</mo></math></span> 3.5) for modeling log mass as a response variable. The same is also observed with the half-life radius as the response variable, although there exists a linear relationship between the mass and the effective radius of the galaxy. These observations may be treated as new findings of the present study.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100928"},"PeriodicalIF":1.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FRELLED Reloaded: Multiple techniques for astronomical data visualisation in Blender","authors":"R. Taylor","doi":"10.1016/j.ascom.2024.100927","DOIUrl":"10.1016/j.ascom.2024.100927","url":null,"abstract":"<div><div>I present version 5.0 of FRELLED, the FITS Realtime Explorer of Low Latency in Every Dimension. This is a 3D data visualisation package for the popular Blender art software, designed to allow inspection of astronomical volumetric data sets (primarily, but not exclusively, radio wavelength data cubes) in real time using a variety of visualisation techniques. The suite of Python scripts that comprise FRELLED have been almost completely recoded and many new ones added, bringing FRELLED’s operating environment from Blender version 2.49 to 2.79. Principle new features include: an enormously simplified installation procedure, a more modular graphical appearance that takes advantage of Blender 2.79’s improved interface, much faster loading of FITS data, support for larger data sets, options to show the data as height maps in 2D mode or isosurfaces in 3D mode, utilisation of standard <em>astropy</em> and other Python modules to support a greater range of FITS files (with a particular emphasis on higher-frequency radio data such as from ALMA, the Atacama Large Millimetre Array), and the capability of exporting the data to Blender 2.9+ which supports stereoscopic 3D displays in virtual reality headsets. In addition, in-built help files are accessible from each menu panel, as well as direct links to a complete wiki and set of video tutorials. Finally, the code itself is much more modular, allowing easier maintainability and, over the longer term, a far easier prospect of migrating to more recent versions of Blender.</div></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"51 ","pages":"Article 100927"},"PeriodicalIF":1.9,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}