Communications of the Byurakan Astrophysical Observatory最新文献_第10页

On the simultaneous generation of radio and soft X-ray emission by AXP 4U 0142+61 AXP 4U 0142+61同时产生的射电和软x射线发射

Communications of the Byurakan Astrophysical Observatory Pub Date : 2021-08-21 DOI: 10.52526/25792776-2021.68.1-114

Z. Osmanov

引用次数: 0

INT monitoring survey of Local Group dwarf galaxies: star formation history and chemical enrichment 本群矮星系的INT监测调查:恒星形成历史和化学富集

Communications of the Byurakan Astrophysical Observatory Pub Date : 2021-01-26 DOI: 10.52526/25792776-2020.67.2-232

Tahere Parto, Shahrzad Dehghani, A. Javadi, E. Saremi, J. V. Loon, H. Khosroshahi, M. Mirtorabi, Hedieh Abdollahi, Mahtab Gholami, S. Hashemi, M. Navabi, Majedeh Noori, Sima T. Aghdam, M. Torki, Mahshid Vafaeizade

{"title":"INT monitoring survey of Local Group dwarf galaxies: star formation history and chemical enrichment","authors":"Tahere Parto, Shahrzad Dehghani, A. Javadi, E. Saremi, J. V. Loon, H. Khosroshahi, M. Mirtorabi, Hedieh Abdollahi, Mahtab Gholami, S. Hashemi, M. Navabi, Majedeh Noori, Sima T. Aghdam, M. Torki, Mahshid Vafaeizade","doi":"10.52526/25792776-2020.67.2-232","DOIUrl":"https://doi.org/10.52526/25792776-2020.67.2-232","url":null,"abstract":"The Local Group (LG) hosts many dwarf galaxies with diverse physical characteristics in terms of morphology, mass, star formation, and metallicity. To this end, LG can offer a unique site to tackle questions about the formation and evolution of galaxies by providing detailed information. While large telescopes are often the first choices for such studies, small telescope surveys that perform dedicated observations are still important, particularly in studying bright objects in the nearby universe. In this regard, we conducted a nine-epoch survey of 55 dwarf galaxies called the \"Local Group dwarf galaxies survey\" using the 2.5m Isaac Newton Telescope (INT) in the La Palma to identify Long-Period Variable (LPV) stars, namely Asymptotic Giant Branch (AGB) and Red Super Giant (RSG) stars. AGB stars formed at different times and studying their radial distribution and mass-loss rate can shed light on the structure formation in galaxies. To further investigate the evolutionary path of these galaxies, we construct their star formation history (SFH) using the LPV stars, which are at the final stages of their evolution and therefore experience brightness fluctuations on the timescales between hundred to thousand days. In this paper, we present some of the results of the Local Group dwarf galaxies survey.","PeriodicalId":412578,"journal":{"name":"Communications of the Byurakan Astrophysical Observatory","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122325829","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}

引用次数: 0

AGN Activity in Brigtest Cluster Galaxies (BCGs) 最亮星系团星系(BCGs)中的AGN活动

Communications of the Byurakan Astrophysical Observatory Pub Date : 2019-12-01 DOI: 10.52526/25792776-2019.66.2-153

S. Fi̇şek, S. Alis, E. K. Ulgen, F. K. Yelkenci

引用次数: 0

Studies of Active Galaxies in Byurakan: Recent Results 比拉坎活跃星系的研究:最新成果

Communications of the Byurakan Astrophysical Observatory Pub Date : 2019-12-01 DOI: 10.52526/25792776-2019.66.2-173

A. Mickaelian, H. Abrahamyan, G. Paronyan, G. Mikayelyan, M. Gyulzadyan

{"title":"Studies of Active Galaxies in Byurakan: Recent Results","authors":"A. Mickaelian, H. Abrahamyan, G. Paronyan, G. Mikayelyan, M. Gyulzadyan","doi":"10.52526/25792776-2019.66.2-173","DOIUrl":"https://doi.org/10.52526/25792776-2019.66.2-173","url":null,"abstract":"We present the recent results of studies on active galaxies (both AGN and Starbursts) by the Extragalactic group of Byurakan Astrophysical Observatory (BAO) Research Department “Astronomical Surveys”. The research has been carried out in 2017-2019 and the results are published in 2018-2019. These studies are characterized by multiwavelength approach to statistical analysis of large amount of data obtained in different wavelengths; from X-ray to radio. Results on HRC/BHRC sample objects (optical identifications of ROSAT X-ray sources), studies of Markarian galaxies in UV and multiwavelength SEDs, abundance and star formation determinations in Mrk galaxies from SDSS spectra, revised optical classification of “LINERs”, study and classification of SDSS spectra for Byurakan-IRAS Galaxies, summary of observations and study of Byurakan-IRAS Galaxies (BIG objects), discovery of new bright ULIRGs from the IRAS PSC/FSC Combined Catalogue and their spectral classification, radio variable sources at 1400 MHz and their optical variability, classification of BZCAT objects having uncertain types (BZU objects), and optical variability of blazars are presented.","PeriodicalId":412578,"journal":{"name":"Communications of the Byurakan Astrophysical Observatory","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125252390","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}

引用次数: 4

Water Ice in AGN and Starbursts AGN和星暴中的水冰

Communications of the Byurakan Astrophysical Observatory Pub Date : 2019-12-01 DOI: 10.52526/25792776-2019.66.2-143

A. Yeghikyan, A. Samsonyan

{"title":"Water Ice in AGN and Starbursts","authors":"A. Yeghikyan, A. Samsonyan","doi":"10.52526/25792776-2019.66.2-143","DOIUrl":"https://doi.org/10.52526/25792776-2019.66.2-143","url":null,"abstract":"Complex chemical species are easier formed in a solid phase, for example in a mixture of ices of water, carbon oxides, methane, ammonia, methanole and other, less abundant molecules. Ultraviolet photons in the range 5 - 13.6 eV and the charged particles with MeV-GeV energies serve as an energy source of reactions. Icy particles containing mentioned substances, can exist only in internal areas of the interstellar molecular clouds protected from influence of external ultraviolet radiation. However cosmic rays are capable to penetrate in clouds and to cause an irradiation of ices by means of secondary ultra-violet photons necessary for initiation of chemical reactions of complexisation. In this work a survivability of ices under harsh conditions of active galaxies is discussed. Preliminary model calculations show that abundances of ices depend not only on ionization parameters of the clouds but also on the shape of incident radiation that is on presence and level of hard ultraviolet and X-ray radiation. The last circumstance is directly related to the radiation of the accretion disk of galaxies with active nuclei and can be used to classify active galaxies, for example to distinguish starburst galaxies from those with active nuclei.","PeriodicalId":412578,"journal":{"name":"Communications of the Byurakan Astrophysical Observatory","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116320662","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}

引用次数: 0

The Origin of Non-Thermal Emission from FSRQs FSRQs非热辐射的来源

Communications of the Byurakan Astrophysical Observatory Pub Date : 2019-09-01 DOI: 10.52526/25792776-2019.66.1-94

S. Gasparyan

{"title":"The Origin of Non-Thermal Emission from FSRQs","authors":"S. Gasparyan","doi":"10.52526/25792776-2019.66.1-94","DOIUrl":"https://doi.org/10.52526/25792776-2019.66.1-94","url":null,"abstract":"The observations of astrophysical sources in a large frequency range (from radio to very high energy gamma-ray bands) provide complete information on the non-thermal processes taking place in different objects. Here, the origin of broadband emission from the jets of at-spectrum radio quasars are discussed. For the current study the blazars detected above 100 GeV: PKS 1441+25, 3C 279, PKS 1222+216, PKS 1510-089, as well as CTA 102, which was in flaring state in optcal/UV, X-ray and high energy gamma-ray bands, are selected. The publicly available data of Fermi LAT, Swift UVOT/XRT, Nustar telescopes have been analyzed, which enables to identify the prominent flaring and quiescent states for those sources, as well as, study the spectral properties, constrain the size and location of the emitting region.\u0000The multiwavelength emission spectra of those sources, in different states, are modeled, which is crucial for understanding the particle acceleration and emission processes in their jets. For this purpose, a new code that can derive the model free parameters which statistically better describe the observed data is used. It derives the best-fit parameters and their uncertainties through Markov Chain Monte Carlo sampling of the likelihood distributions. By means of the detailed theoretical modeling of acquired data, it was possible to derive or at least constrain some crucial parameters such as the magnetic field, jet energetic, electron energy density etc.","PeriodicalId":412578,"journal":{"name":"Communications of the Byurakan Astrophysical Observatory","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130066265","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}

引用次数: 0

The role of dipolar magnetic field of AGN in the morphology and evolution of extragalactic radio sources AGN的偶极磁场在河外射电源的形态和演化中的作用

Communications of the Byurakan Astrophysical Observatory Pub Date : 2019-09-01 DOI: 10.52526/25792776-2019.66.1-8

R. Andreasyan

引用次数: 1

Distribution of Elements Inside Stars 恒星内部元素的分布

Communications of the Byurakan Astrophysical Observatory Pub Date : 2019-09-01 DOI: 10.52526/25792776-2019.66.1-52

G. Alecian

引用次数: 0

Integrable systems connected with black holes 与黑洞相连的可积系统

Communications of the Byurakan Astrophysical Observatory Pub Date : 2019-08-04 DOI: 10.52526/25792776-2019.66.1-89

H. Demirchian

{"title":"Integrable systems connected with black holes","authors":"H. Demirchian","doi":"10.52526/25792776-2019.66.1-89","DOIUrl":"https://doi.org/10.52526/25792776-2019.66.1-89","url":null,"abstract":"We studied some important questions in general relativity and mathematical physics mainly related to the two most important solutions of the theory of relativity - gravitational waves and black holes. In particular, the work is related to astrophysical shock waves, gravitational waves, black holes, integrable systems associated with them as well as their quantum equivalents. We studied the effects of null shells on geodesic congruences and suggested a general covariant definition of the gravitational memory effect. Thus, we studied observable effects that astrophysical shock waves can have on test particles after cataclysmic astrophysical events. We studied the geodesics of massive particles in Near Horizon Extremal Myers-Perry (NHEMP) black hole geometries. This is the space-time in the vicinity of the horizon of higher dimensional rotating black holes. Thus, this work can have applications for studying accretions of black holes. The system is also important in mathematical physics as it describes integrable (in special cases superintegrable) system, where the constants of motion are fully studied. On the other hand, the quantum counterparts of this and other integrable systems are studied as well and a new technique is suggested for geometrization of these systems.","PeriodicalId":412578,"journal":{"name":"Communications of the Byurakan Astrophysical Observatory","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124987343","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}

引用次数: 1

TUIMP: The Universe In My Pocket. Free astronomy booklets in all languages 《我口袋里的宇宙》所有语言的免费天文学小册子

Communications of the Byurakan Astrophysical Observatory Pub Date : 2018-06-01 DOI: 10.52526/25792776-2019.66.1-66

G. Stasińska

引用次数: 1