{"title":"Observational studies of high-mass star formation","authors":"I. I. ZINCHENKO","doi":"10.17184/eac.8032","DOIUrl":"https://doi.org/10.17184/eac.8032","url":null,"abstract":"<jats:p />","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135665719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on synoptic maps, the orientation and localization (distribution) of coronal bright points (CBP) relative to the polarity line (PL) on the Sun is studied. Preliminary results show that the slope of the CBP angles of the quiet Sun is oriented, in most cases, parallel to the solar equator, while for the CBP of the active Sun it is more randomly distributed. The question of the localization of both types of CBP with respect to active formations and PL is not so clear and requires a more detailed study.
{"title":"Orientation and distribution relative to the polarity dividing line of two types of coronal bright points","authors":"Ch.T. SHERDANOV, S.P. ILYASOV","doi":"10.17184/eac.8036","DOIUrl":"https://doi.org/10.17184/eac.8036","url":null,"abstract":"Based on synoptic maps, the orientation and localization (distribution) of coronal bright points (CBP) relative to the polarity line (PL) on the Sun is studied. Preliminary results show that the slope of the CBP angles of the quiet Sun is oriented, in most cases, parallel to the solar equator, while for the CBP of the active Sun it is more randomly distributed. The question of the localization of both types of CBP with respect to active formations and PL is not so clear and requires a more detailed study.","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135666389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The old and successful idea of using astrophysical systems as laboratories for fundamental physics is becoming extremely popular nowadays. Axions are a remarkable example of Feebly Interacting Particles playing an important role in astrophysical phenomena. It is well-known that stars are powerful axion factories, giving strong constraints on their properties. Aspects of the axion phenomenology in horizontal-branch stars and supernovae are reviewed.
{"title":"A glimpse of axion phenomenology in astrophysics","authors":"Pierluca Carenza","doi":"10.17184/eac.7533","DOIUrl":"https://doi.org/10.17184/eac.7533","url":null,"abstract":"The old and successful idea of using astrophysical systems as laboratories for fundamental physics is becoming extremely popular nowadays. Axions are a remarkable example of Feebly Interacting Particles playing an important role in astrophysical phenomena. It is well-known that stars are powerful axion factories, giving strong constraints on their properties. Aspects of the axion phenomenology in horizontal-branch stars and supernovae are reviewed.","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83460268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Almost at the turn of the 10th century, Ibn al-Haytham (Alhazen) demonstrated that, contrary to the view held by all the scientists of that time, the light received on Earth from the Moon is not the light of the Sun reflected on the surface of the Moon. In the 17th century, Galileo took up the same problem and arrived at almost the same result. This paper discusses the arguments of these two scientists as well as the context in which they are presented and tries to specify both their similarities and their differences.
{"title":"The light of the Moon: Ibn al-Haytham (Alhazen) and Galileo","authors":"Hossein Masoumi Hamedani","doi":"10.17184/eac.7524","DOIUrl":"https://doi.org/10.17184/eac.7524","url":null,"abstract":"Almost at the turn of the 10th century, Ibn al-Haytham (Alhazen) demonstrated that, contrary to the view held by all the scientists of that time, the light received on Earth from the Moon is not the light of the Sun reflected on the surface of the Moon. In the 17th century, Galileo took up the same problem and arrived at almost the same result. This paper discusses the arguments of these two scientists as well as the context in which they are presented and tries to specify both their similarities and their differences.","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91068881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Message of Professor Remo Ruffini, Director of ICRANet, for the Opening Session of the ICRANet–Isfahan Astronomy Meeting","authors":"R. Ruffini","doi":"10.17184/eac.7498","DOIUrl":"https://doi.org/10.17184/eac.7498","url":null,"abstract":"<jats:p />","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86360828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Classification is a popular task in the field of machine learning (ML) and artificial intelligence (AI), and it happens when outputs are categorical variables. There are a wide variety of models that attempt to draw some conclusions from observed values, so classification algorithms predict categorical class labels for use in classifying new data. Popular classification models including logistic regression, decision tree, random forest, support vector machine (SVM), multilayer perceptron, naive bayes, neural networks have proven to be efficient and accurate applied to many industrial and scientific problems. Particularly, application of ML to astronomy has shown to be very useful for classification, clustering and data cleaning. It is because after learning computers, these tasks can be done automatically by them in a more precise and more rapid way than human operators. In view of this, in this paper, we will review some of these popular classification algorithms, and then we apply some of them to the observational data of nonvariable and the RR Lyrae variable stars that come from the SDSS survey. For the sake of comparison, we calculate the accuracy and $F1$-score of the applied models.
{"title":"Analyzing astronomical data with machine learning techniques","authors":"M. H. Zhoolideh Haghighi","doi":"10.17184/eac.7534","DOIUrl":"https://doi.org/10.17184/eac.7534","url":null,"abstract":"Classification is a popular task in the field of machine learning (ML) and artificial intelligence (AI), and it happens when outputs are categorical variables. There are a wide variety of models that attempt to draw some conclusions from observed values, so classification algorithms predict categorical class labels for use in classifying new data.\u0000Popular classification models including logistic regression, decision tree, random forest, support vector machine (SVM), multilayer perceptron, naive bayes, neural networks have proven to be efficient and accurate applied to many industrial and scientific problems. Particularly, application of ML to astronomy has shown to be very useful for classification, clustering and data cleaning. It is because after learning computers, these tasks can be done automatically by them in a more precise and more rapid way than human operators. In view of this, in this paper, we will review some of these popular classification algorithms, and then we apply some of them to the observational data of nonvariable and the RR Lyrae variable stars that come from the SDSS survey. For the sake of comparison, we calculate the accuracy and $F1$-score of the applied models.","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91127659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We summarize a new model that explains the high-energy (photon energies of gigaelectronvolts – GeV) observed in the energetic long-duration gamma-ray bursts (GRBs). The model shows that the gravitomagnetic interaction of a Kerr black hole (BH) with a surrounding magnetic field generates GeV radiation in the vicinity of the BH event horizon extracting the (rotational) energy of the BH.
{"title":"The role of gravitomagnetism in the energy extraction from a Kerr black hole to power the GeV emission of gamma-ray bursts","authors":"","doi":"10.17184/eac.7528","DOIUrl":"https://doi.org/10.17184/eac.7528","url":null,"abstract":"We summarize a new model that explains the high-energy (photon energies of gigaelectronvolts – GeV) observed in the energetic long-duration gamma-ray bursts (GRBs). The model shows that the gravitomagnetic interaction of a Kerr black hole (BH) with a surrounding magnetic field generates GeV radiation in the vicinity of the BH event horizon extracting the (rotational) energy of the BH.","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84166580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the induced gravitational collapse (IGC) paradigm, a carbon–oxygen (CO) star collapses and explodes in a supernova (SN) in the presence of a binary companion, a neutron star (NS). The material ejected in the explosion is gravitationally attracted by the NS, triggering a hypercritical accretion process onto it. For compact systems, the accretion rate could be high enough for the NS to reach its critical mass, collapse in a black hole (BH) and emit an energetic (energy release $gtrsim 10^{52}$ erg) gamma-ray burst (GRB). With the aim to identify the separatrix of systems in which a BH is formed and characterize the observational signatures of the above process, we have performed three-dimensional (3D) smoothed-particle-hydrodynamics (SPH) numerical simulations of the SN expansion in the presence of the NS companion and the evolution of the NS during the accretion process. We here summarize the results of the above simulations for a wide range of the initial conditions of the parameter space.
{"title":"SPH simulations of the induced gravitational collapse","authors":"","doi":"10.17184/eac.7529","DOIUrl":"https://doi.org/10.17184/eac.7529","url":null,"abstract":"In the induced gravitational collapse (IGC) paradigm, a carbon–oxygen (CO) star collapses and explodes in a supernova (SN) in the presence of a binary companion, a neutron star (NS). The material ejected in the explosion is gravitationally attracted by the NS, triggering a hypercritical accretion process onto it. For compact systems, the accretion rate could be high enough for the NS to reach its critical mass, collapse in a black hole (BH) and emit an energetic (energy release $gtrsim 10^{52}$ erg) gamma-ray burst (GRB). With the aim to identify the separatrix of systems in which a BH is formed and characterize the observational signatures of the above process, we have performed three-dimensional (3D) smoothed-particle-hydrodynamics (SPH) numerical simulations of the SN expansion in the presence of the NS companion and the evolution of the NS during the accretion process. We here summarize the results of the above simulations for a wide range of the initial conditions of the parameter space.","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78606117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yu Wang, R. Moradi, M. H. Z. Haghighi, F. Rastegarnia
This article is based on the tutorial we gave at the hands-on workshop of the ICRANet-ISFAHAN Astronomy Meeting. We first introduce the basic theory of machine learning and sort out the whole process of training a neural network. We then demonstrate this process with an example of inferring redshifts from SDSS spectra. To emphasize that machine learning for astronomy is easy to get started, we demonstrate that the most basic CNN network can be used to obtain high accuracy, we also show that with simple modifications, the network can be converted for classification problems and also to process gravitational wave data.
{"title":"Introduction of machine learning for astronomy (hands-on workshop)","authors":"Yu Wang, R. Moradi, M. H. Z. Haghighi, F. Rastegarnia","doi":"10.17184/eac.7535","DOIUrl":"https://doi.org/10.17184/eac.7535","url":null,"abstract":"This article is based on the tutorial we gave at the hands-on workshop of the ICRANet-ISFAHAN Astronomy Meeting. We first introduce the basic theory of machine learning and sort out the whole process of training a neural network. We then demonstrate this process with an example of inferring redshifts from SDSS spectra. To emphasize that machine learning for astronomy is easy to get started, we demonstrate that the most basic CNN network can be used to obtain high accuracy, we also show that with simple modifications, the network can be converted for classification problems and also to process gravitational wave data.","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87454733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A friendly exchange between Professor Remo Ruffini and Professor Yousef Sobouti during the editorial preparation of the Proceedings publication","authors":"","doi":"10.17184/eac.7520","DOIUrl":"https://doi.org/10.17184/eac.7520","url":null,"abstract":"<jats:p />","PeriodicalId":52135,"journal":{"name":"Astronomical and Astrophysical Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72388418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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