Damghan University PressIranian Journal of Astronomy and Astrophysics2322-49249120220401Thermodynamic Phase Transition and Joule Thomson Adiabatic Expansion for dS/AdS Bardeen Black Holes with Consistent 4D Gauss-Bonnet Gravity11729710.22128/ijaa.2022.625.1130ENHosseinGhaffarnejadFaculty of Physics, Semnan Universiy, Semnan, Iran, 35131-191110000-0002-0438-6452ElhamGhasemiFaculty of physics, Semnan UniversityEmadYaraieFaculty of physics, semnan university,MohammadFarsamFaculty of Physics, semnan universityJournal Article20221015Instead of the work \cite{1} given by Glaven and Lin in which in according to the Lovelock theorem it is not applicable for all types of 4-dimensional curved spacetimes of Einstein Gauss Bonnet gravity, authors of the work \cite{2} applied breakdown of diffeomorphism property to present a consistent<br />Einstein-Gauss-Bonnet gravity theory in 4-dimensions. In this work we use the latter model by adding an Ayon-Beato-Garcia type of nonlinear electromagnetic field Lagrangian density to study effects of Gauss-Bonnet coupling constant on the thermodynamic phase transition and Joule-Thomson adiabatic expansion of a 4-dimensional de Sitter/Anti de Sitter Gauss-Bonnet-Bardeen black hole. In fact we will see importance of parameters of this black hole namely the magnetic charge and the Gauss Bonnet coupling constant parameter on its heating-cooling phase transition. Physical importance of this type of black holes is non-singular property which they have and are applicable to study black hole structure of center of galaxies.https://ijaa.du.ac.ir/article_297_9fd982e8039619846d69c62331a81622.pdfDamghan University PressIranian Journal of Astronomy and Astrophysics2322-49249120220401Machine Learning Method for Predicting the Merge and Morphology of Galaxies through Near-Infrared Spectroscopy193029810.22128/ijaa.2022.554.1122ENSamiraMonfaredDepartment of Management, Faculty of social Sciences and Economics, Alzahra University.NedaAbdolvandDepartment of Management, Faculty of Social Sciences and Economics, Alzahra University0000-0003-3623-1284Mohammad TaghiMirtorabiDepartment of Physics, Alzahra University,
Tehran, P.O.Box 1993891176, IranSaeedehRajaee HarandiDepartment of Management, Faculty of Social Sciences and Economics, Alzahra Univerdsity0000-0001-9710-3644Journal Article20220809Astronomy is experiencing rapid growth in the size and complexity of data. This reinforces the development of data-driven science as a useful complement to the current model of model-based data analysis. In spite of this, traditional merger analysis of catalogs is mostly done through visual inspection by trained experts. A method that is not efficient today, because the subjectivity of manual classification has made the result of the process very dependent on the intuition of the analyst and the type and quality of the image. Hence, this study focuses on data processing methods based on Artificial Intelligence (AI) algorithms and investigates the possibility of a pattern among astronomical data to predict the merger of galaxies. The modeling is done in two phases. The first phase deals with the classification between minority and majority classes and the second phase search for any distinction between minority classes. In both phases, various algorithms such as Naive Bayes, Random Forest, and Generalized linear model (GLM) and Neural network are used to ensure the best results according to the research data. The best results for both phases obtained from the implementation of the GLM algorithm with the accuracy of 70.28 % and 76.51% for the first and second phase respectively.https://ijaa.du.ac.ir/article_298_81a2e5b0f87c6a38534099fa65d19bfb.pdfDamghan University PressIranian Journal of Astronomy and Astrophysics2322-49249120220401Hierarchical Classification of Variable Stars Using Deep Convolutional Neural Networks314430210.22128/ijaa.2022.603.1131ENMahdiAbdollahiSchool of Astronomy, Institute for Research in Fundamental Sciences (IPM)NooshinTorabiDepartment of Physics, Sharif University of TechnologySadeghRaeisiDepartment of Physics, Sharif University of TechnologySohrabRahvarDepartment of Physics, Sharif University of Technology0000-0002-7084-5725Journal Article20221101The importance of using fast and automatic methods to classify variable stars for large amounts of data is undeniable. There have been many attempts to classify variable stars by traditional algorithms like Random Forest. In recent years, neural networks as classifiers have come to notice because of their lower computational cost compared to traditional algorithms. This paper uses the Hierarchical Classification technique, which contains two main steps of predicting class and then subclass of stars. All the models in both steps have same network structure and we test both Convolutional Neural Networks (CNN) and Recurrent Neural Networks (RNN). Our pre-processing method uses light curves and period of stars as input data. We consider most of the classes and subclasses of variable stars in OGLE-IV database and show that using Hierarchical Classification technique and designing appropriate preprocessing can increase accuracy of predicting smaller classes, ACep and T2Cep. We obtain an accuracy of 98% for class classification and 93% for subclasses classification.https://ijaa.du.ac.ir/article_302_c2901d4f6a6dc82f720b22a07e388167.pdfDamghan University PressIranian Journal of Astronomy and Astrophysics2322-49249120220401Thermodynamic Phase Transition of Anti De Sitter Schwarzschild Scalar-Tensor-Vector-Black Holes455730110.22128/ijaa.2022.592.1124ENHosseinGhaffarnejadFaculty of Physics, Semnan Universiy, Semnan, Iran, 35131-191110000-0002-0438-6452ElhamGhasemiFaculty of physics, Semnan UniversityJournal Article20220828Instead ofscalar-tensor gravity<br /><br />models which are applicable for<br /><br />description of cosmic inflation with unknown dark sector of<br /><br />matter/energy, at present tense<br /><br />there are presented different alternative<br /><br />scalar-tensor-vector gravities<br /><br />where meaningful dynamical vector fields can support cosmic<br /><br />inflation well without to use dark matter/energy concept. One of<br /><br />these gravity models was presented by Moffat which<br /><br />its modified Schwarzschild black hole solution is used to<br /><br />study thermodynamic phase transition in presence of the AdS space<br /><br />pressure in this article. To do<br /><br />so, we obtained an equation of state which asymptotically reaches<br /><br />to equation of state of ideal gas for large black holes but for<br /><br />small scale black holes we obtained a critical point at phase<br /><br />space where the black hole can be<br /><br />exhibited with a phase transition<br /><br />at processes ofisothermal and<br /><br />isobaric. By looking at diagrams of the Gibbs free energy and the<br /><br />heat capacity at constant pressure which are plotted versus the<br /><br />temperature and the specific volume one can see an inflection<br /><br />point which means that the phase transition is<br /><br />second order type. In fact there<br /><br />is small to large phase transition for the black hole which is<br /><br />equivalent to the Van der Waals liquid-gas phase transition in<br /><br />ordinary thermodynamic systems. The phase transition<br /><br />happens below the critical point<br /><br />in phase space when the gravitational charge of the black hole is<br /><br />equal to its mass.https://ijaa.du.ac.ir/article_301_4f2f95fc8a95d5c3c339c32a5ad413f7.pdfDamghan University PressIranian Journal of Astronomy and Astrophysics2322-49249120220401Chromospheric Jets and Their Properties598330610.22128/ijaa.2022.633.1133ENEhsanTavabiPhysics Department, Payame Noor University (PNU), 19395-3697-Tehran, I. R. of Iran0000-0001-9602-0767SimaZeighamiDepartment of Physics, Tabriz Branch, Islamic Azad University, Tabriz, Iran0000-0002-1246-4473Journal Article20221220In this study we review solar chromospheric jets and characteristics of them. The chromosphere and transition region are the interface between the solar photosphere and the corona, which plays a key role in the formation and acceleration of the solar wind. In recent years, scientists have made great efforts to understand the mechanism of energy transfer in the solar chromosphere and corona. The researchers suggest that the key to solving this problem may lie in understanding the nature of the small-scale transient events that are distributed across the surface of the Sun. Of these, solar spicules are the most prominent small-scale dynamical phenomena in the chromospheric regions that drive relatively cold material from the lower chromosphere to the corona. Spicules can heat the corona both by ejecting hot plasma and by energy transfer by magnetohydrodynamic (MHD) waves. These dynamical structures are formed when photospheric oscillations and convective flow along the magnetic field lines penetrate into the chromosphere.https://ijaa.du.ac.ir/article_306_411f6909bdca7c6f8946abf4259ac358.pdfDamghan University PressIranian Journal of Astronomy and Astrophysics2322-49249120220401The influence of Asymmetric Inflow Reconnection on the Diffusion Region in Resistive Space Plasmas859631910.22128/ijaa.2022.656.1139ENHosseinLotfiFaculty of Physics, University of Tabriz, Iran0000-0002-1135-3552MahboubHosseinpourFaculty of Physics, University of TabrizJournal Article20230214To investigate the effect of asymmetric magnetic reconnection on the<br />development of the diffusion region and growth of magnetic islands induced during<br />reconnection (plasmoids), we use 2-dimensional resistive magnetohydrodynamics sim-<br />ulations. In particular, we consider the strength of the magnetic field and plasma mass<br />density to be dissimilar on both sides of the current sheet. For three cases, the results<br />show that the initial X-point position shifts from the center of the diffusion region to<br />the stronger magnetic field while the plasmoids grow toward the weaker magnetic field.<br />Also, the increase of asymmetry in the magnetic field and plasma mass density leads to<br />the reconnection rate and the growth time of plasmoid instability becoming less. Due<br />to the displacement of reconnection sites in asymmetric cases, the output momentum<br />from these sites does not directly collide with the outflow jets, so the velocity of the<br />outflow jets is lower than in the symmetric case.https://ijaa.du.ac.ir/article_319_2b218650d35858d654f2503a5256fc5f.pdf