Astronomy and Computing最新文献

{"title":"Grouping and long term prediction of sunspot cycle characteristics-A fuzzy clustering approach","authors":"B.T. Anilkumar (Assistant Professor) ,&nbsp;A Sabarinath (Scientist)","doi":"10.1016/j.ascom.2024.100836","DOIUrl":"10.1016/j.ascom.2024.100836","url":null,"abstract":"<div><p>Based on the pattern recognition algorithm called fuzzy c-means clustering, grouping of sunspot cycles has been carried out. It is found that, optimally the sunspot cycles can be divided in to two groups; we name it as Large Group and Small Group. Based on the fuzzy membership values the groups are derived. According to our analysis, cycles 1,5,6,7,12,13,14,15,16 and 24 belongs to the Small class, where as cycles 2,3,4,8,9,10,11,17,18,19,20,21,22, and 23 belongs to the Large class. Based on the features of each group and its fuzzy cluster center, prediction of cycle 25 is also been made. Also on the periodicity of the occurrence of the groups, a new cyclic behaviour has been found for the occurrences of the identical sunspot cycles. According to our study Cycle 25 belongs to small class and further we predict that the future cycle up to cycle 32 may fall in small group.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141412407","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":"Thermodynamical analysis of Phantom AdS black holes","authors":"","doi":"10.1016/j.ascom.2024.100862","DOIUrl":"10.1016/j.ascom.2024.100862","url":null,"abstract":"<div><p>In this paper, we study phase space analysis, thermodynamical geometries and stability of Phantom AdS black hole (BH). The significance of Phantom AdS BH is examined by stability conditions and divergency. The results of small and large roots and divergency are presented for different values of important parameters, graphically. Moreover, we discuss the thermodynamical geometry by using well known techniques such as Weinhold, and geothermodynamics (GTD), HPEM and Ruppeiner and analyze the structure of Phantom AdS BH. Important Physical Information is obtained by utilizing the scalar curvature and zeros of heat capacity. Furthermore, we discuss the P-V criticality to study the stability of Phantom AdS BH which present some significant and important findings.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141845647","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":"Enhancement of the MATISSE tool for the geological analysis of planetary surfaces: A study on central pit craters on Mercury","authors":"V. Camplone ,&nbsp;A. Zinzi ,&nbsp;M. Massironi ,&nbsp;A.P. Rossi ,&nbsp;F. Zucca","doi":"10.1016/j.ascom.2024.100852","DOIUrl":"10.1016/j.ascom.2024.100852","url":null,"abstract":"<div><p>In this work we present the improved capabilities of MATISSE (Multi-purpose Advanced Tool for Instruments for the Solar System Exploration) tool which is now able to integrate geological maps and analyze specific data based on selected parameters (target, mission, instrument, geological units and area of interest). To demonstrate the effectiveness of this approach we focused on “central pit” craters on Mercury, with particular regard to the ones exposed in the Hokusai, Victoria, and Derain quadrangles.</p><p>The use of MATISSE for this application allowed us for an analysis of these morphologies, confirming a tendency for their location on volcanic terrains. The integrated research approach adopted in this study has proven to be a significant advantage in geological analysis, accelerating the process of data collection and interpretation. In conclusion, this study shows how the continuous evolution of scientific tools devoted to data handling and management based on FAIR principles, such as MATISSE, has the potential to open new perspectives in understanding planetary-scale geological processes.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2213133724000672/pdfft?md5=14329405866db02079ed860ee55a31b3&pid=1-s2.0-S2213133724000672-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141407497","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":"On the effective vibrational temperature of the source using (2)3∏ - X3∏ system of GeC molecule","authors":"","doi":"10.1016/j.ascom.2024.100859","DOIUrl":"10.1016/j.ascom.2024.100859","url":null,"abstract":"<div><p>In this work, the experimental potential energy curves for <span><math><mrow><msup><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow><mn>3</mn></msup><mstyle><mi>Π</mi></mstyle></mrow></math></span> and <span><math><mrow><msup><mrow><mi>X</mi></mrow><mn>3</mn></msup><mstyle><mi>Π</mi></mstyle></mrow></math></span> electronic states of GeC molecule have been constructed by using Rydberg-Klein-Rees (RKR) method. The radiative transition parameters viz., Franck-Condon (FC) factor, r-centroid, electronic transition moment, band strength, relative band strength, Einstein coefficients, radiative lifetime and oscillator strength for the <span><math><mrow><msup><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow><mn>3</mn></msup><mstyle><mi>Π</mi></mstyle><mo>−</mo><msup><mrow><mi>X</mi></mrow><mn>3</mn></msup><mstyle><mi>Π</mi></mstyle></mrow></math></span> system of GeC molecule have been estimated for the experimentally observed vibrational levels from Rydberg-Klein-Rees (RKR) potential and the estimated values are tabulated. The estimated effective vibrational temperature found as 5628 K for the <span><math><mrow><msup><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow><mn>3</mn></msup><mstyle><mi>Π</mi></mstyle><mo>−</mo><msup><mrow><mi>X</mi></mrow><mn>3</mn></msup><mstyle><mi>Π</mi></mstyle></mrow></math></span> system of GeC molecule. The radiative transition parameters and effective vibrational temperature are evident that the possible presence of GeC molecule in solar and sunspots atmosphere. Further, these parameters are employed in rationalizations of astrochemical and astrophysical observations.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141849658","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":"A review of unsupervised learning in astronomy","authors":"S. Fotopoulou","doi":"10.1016/j.ascom.2024.100851","DOIUrl":"https://doi.org/10.1016/j.ascom.2024.100851","url":null,"abstract":"<div><p>This review summarises popular unsupervised learning methods, and gives an overview of their past, current, and future uses in astronomy. Unsupervised learning aims to organise the information content of a dataset, in such a way that knowledge can be extracted. Traditionally this has been achieved through dimensionality reduction techniques that aid the ranking of a dataset, for example through principal component analysis or by using auto-encoders, or simpler visualisation of a high dimensional space, for example through the use of a self organising map. Other desirable properties of unsupervised learning include the identification of clusters, <em>i.e.</em> groups of similar objects, which has traditionally been achieved by the k-means algorithm and more recently through density-based clustering such as HDBSCAN. More recently, complex frameworks have emerged, that chain together dimensionality reduction and clustering methods. However, no dataset is fully unknown. Thus, nowadays a lot of research has been directed towards self-supervised and semi-supervised methods that stand to gain from both supervised and unsupervised learning.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2213133724000660/pdfft?md5=4f1896c41ddb28ebaf2391a955843baa&pid=1-s2.0-S2213133724000660-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141483677","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":"Estimation of orbital parameters from (u,v)-coverage for a space radio interferometer","authors":"I.I. Bulygin ,&nbsp;M.A. Shchurov ,&nbsp;A.G. Rudnitskiy","doi":"10.1016/j.ascom.2024.100855","DOIUrl":"https://doi.org/10.1016/j.ascom.2024.100855","url":null,"abstract":"<div><p>Searching for a suitable very long baseline (VLBI) interferometer geometry is a key task in planning observations, especially imaging sessions. VLBI image quality is characterized by <span><math><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow></math></span>-coverage. With one or more radio telescopes located in space, such a task becomes more complex. This paper presents a method of recovering the optimal orbital parameters for space radio telescopes having a given desired <span><math><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow></math></span>-coverage. In turn, this task can be called the inverse of the task of searching for the optimal geometry and orbital configurations of space-ground and pure space VLBI interferometers.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141483697","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":"LCGCT: A light curve generator in customisable-time-bin based on time-series database","authors":"Z. Zhang ,&nbsp;Y. Xu ,&nbsp;C. Cui ,&nbsp;D. Fan","doi":"10.1016/j.ascom.2024.100845","DOIUrl":"https://doi.org/10.1016/j.ascom.2024.100845","url":null,"abstract":"<div><p>In the era of time-domain astronomy, scientists often need to generate light curves with varying time-bin. However, an increase in time resolution typically leads to a substantial increase in data transmission. To enhance the data processing efficiency in time-domain astronomy, we propose a novel time-series data model for storing time-series observation data, and we construct the LCGCT, a tool designed to produce light curves with customisable time bins. To validate our approach, we utilise the 7-year MAXI/GSC (Gas Slit Camera of the Monitor of All-sky X-ray Image) X-ray source catalogue, incorporating its 24-h binned light curves for a comparative analysis with our approach. The results obtained confirm the accuracy and effectiveness of our proposed approach. Subsequently, we compare the storage capacity and query performance of LCGCT with a PostgreSQL-based implementation, and results show that LCGCT conserves 75% of the storage space and achieves three times the query speed. Owing to its noteworthy storage and query performance, our proposed time-series data model-based LCGCT can be used in time-domain astronomical projects with high time resolution.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141540251","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":"TensorFlow Hydrodynamics Analysis for Ly-α Simulations","authors":"","doi":"10.1016/j.ascom.2024.100858","DOIUrl":"10.1016/j.ascom.2024.100858","url":null,"abstract":"<div><p>We introduce the Python program THALAS (TensorFlow Hydrodynamics Analysis for Lyman-Alpha Simulations), which maps baryon fields (baryon density, temperature, and velocity) to Ly<span><math><mi>α</mi></math></span> optical depth fields in both real space and redshift space. Unlike previous Ly<span><math><mi>α</mi></math></span> codes, THALAS is fully differentiable, enabling a wide variety of potential applications for general analysis of hydrodynamical simulations and cosmological inference. To demonstrate THALAS’s capabilities, we apply it to the Ly<span><math><mi>α</mi></math></span> forest inversion problem: given a Ly<span><math><mi>α</mi></math></span> optical depth field, we reconstruct the corresponding real-space dark matter density field. Such applications are relevant to both cosmological and three-dimensional tomographic analyses of Lyman Alpha forest data.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839575","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":"Characterization of ground-based telescope control systems: A systematic mapping study","authors":"S. Carrasco ,&nbsp;P. Galeas ,&nbsp;A. Cravero","doi":"10.1016/j.ascom.2024.100854","DOIUrl":"https://doi.org/10.1016/j.ascom.2024.100854","url":null,"abstract":"<div><p>Telescope operation is exceptionally complex, generally with respect to specialized control and monitoring systems. World-class astronomical facilities usually choose tailored control solutions to meet their specific needs. However, many of these telescopes share a common control architecture composed of a three-layer architecture: a top level for services and communication between software components, an intermediate level for coordination and execution of tasks in real-time, and a low level where the end hardware devices live. The first generations of telescopes also implemented centralized and customized solutions, which later evolved to highly decentralized components based on industrial standards, middleware, and open protocols. This paper reviews control and monitoring technologies used in modern world-class terrestrial observatories.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2213133724000696/pdfft?md5=a2eb6a5bc16e444858e933a463f56886&pid=1-s2.0-S2213133724000696-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141486697","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":"pyC 2 Ray: A flexible and GPU-accelerated radiative transfer framework for simulating the cosmic epoch of reionization","authors":"","doi":"10.1016/j.ascom.2024.100861","DOIUrl":"10.1016/j.ascom.2024.100861","url":null,"abstract":"<div><p>Detailed modeling of the evolution of neutral hydrogen in the intergalactic medium during the Epoch of Reionization, <span><math><mrow><mn>5</mn><mo>≤</mo><mi>z</mi><mo>≤</mo><mn>20</mn></mrow></math></span>, is critical in interpreting the cosmological signals from current and upcoming 21-cm experiments such as the Low-Frequency Array (LOFAR) and the Square Kilometre Array (SKA). Numerical radiative transfer codes provide the most physically accurate models of the reionization process. However, they are computationally expensive as they must encompass enormous cosmological volumes while accurately capturing astrophysical processes occurring at small scales (<span><math><mrow><mo>≲</mo><mi>Mpc</mi></mrow></math></span>). Here, we present <span>pyC</span> <span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> <span>Ray</span>, an updated version of the massively parallel ray-tracing and chemistry code, <span>C</span> <span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> <span>-Ray</span>, which has been extensively employed in reionization simulations. The most time-consuming part of the code is calculating the hydrogen column density along the path of the ionizing photons. Here, we present the Accelerated Short-characteristics Octahedral ray-tracing (<span>ASORA</span>) method, a ray-tracing algorithm specifically designed to run on graphical processing units (GPUs). We include a modern <span>Python</span> interface, allowing easy and customized use of the code without compromising computational efficiency. We test <span>pyC</span> <span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> <span>Ray</span> on a series of standard ray-tracing tests and a complete cosmological simulation with volume size <span><math><msup><mrow><mrow><mo>(</mo><mn>349</mn><mspace></mspace><mi>Mpc</mi><mo>)</mo></mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>, mesh size of <span><math><mrow><mn>25</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span> and approximately <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup></mrow></math></span> sources. Compared to the original code, <span>pyC</span> <span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> <span>Ray</span> achieves the same results with negligible fractional differences, <span><math><mrow><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span>, and a speedup factor of two orders of magnitude. Benchmark analysis shows that <span>ASORA</span> takes a few nanoseconds per source per voxel and scales linearly for an increasing number of sources and voxels within the ray-tracing radii.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934106","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}