Communications of the Byurakan Astrophysical Observatory (ComBAO)
Volume 65, Issue 1, Sep 2018
Revised optical classification of “LINERs” 1.4 MB
H. V. Abrahamyan, A. M. Mickaelian, G. A. Mikayelyan, G. M. Paronyan
Abstract. This work is dedicated to reclassification of LINERs. For our investigation we use the catalogue Véron-Cetty&Véron 13th edition. In this catalogue 926 LINERs are included. Cross-correlation of these sources with SDSS DR14 gives 176 objects which have spectra in SDSS. Having medium-resolution spectra from SDSS we have done reclassification of these sources. As a result,54% of these sources have changed their classification.
Discovery of new bright ULIRGs from the IRAS PSC/FSC Combined Catalogue 1.1 MB
G. A. Mikayelyan, A. M. Mickaelian, H. V. Abrahamyan, G. M. Paronyan
Abstract. High-luminosity IR galaxies (LIRGs, ULIRGs, and HLIRGs) are important for studies related to star-formation processes in the early Universe, as their luminosity allows to detect them at large distances. High IR indicates active star-formation and often starburst processes, which is typical to HII (starburst, SB) and AGN. An interesting question is whether the starburst triggers AGN or vice versa or there is no direct impact. Considering that very often such objects manifest double and multiple structure, it is also interesting to investigate the interrelationship between the SB, nuclear activity and interactions or merging. We have analyzed the IRAS PSC/FSC Combined Catalogue for search for new bright ULIRGs. By means of the SDSS DR14 data, namely redshifts for those objects having spectroscopy, we have calculated the IR luminosities and have found 114 very high-luminosity IR galaxies; 107 ULIRGs and 7 HLIRGs. Among them, 48 new ULIRGs and 7 new HLIRGs have been discovered. These objects have been studied by SDSS color-color, luminosity-redshift and other diagrams. Further studies will include the content of the sample for activity types and other available data.
Color-color diagrams in near infrared: (J-H)/(H-K). II. 0.8 MB
A. L. Gyulbudaghian, N. Baloian, I. A. Sanchez
Abstract. In the paper the color-color diagrams (J-H)/(H-K) for all stars with visible magnitudes B < 11m (for which in the existing catalogs the magnitudes of J, H, K, and also their spectral types and luminosity classes are given) are presented. In the preceding paper the data for luminosity classes I, Ia, Ib, II and III were given. In this paper the data on luminosity classes IV (sub giants) and V (main sequence stars) are given. Among the diagrams of luminosity classes the most interesting are the diagrams for GII and GIV stars, each of these diagrams have two centers of concentrations. For stars of spectral class M the minimal amount of stars is at luminosity class IV, the maximal –at class III, which is not so for other spectral classes: for other classes the maximal amount is at class V. There is a tendency (seen in all diagrams)of increasing of the values of J-H and H-K along the sequence O-B-A-F-G-K-M.
Numerical calculation of zeros and weights for Gaussian quadrature: Legendre polynomials 0.6 MB
H. A. Harutyunian, H. A. Poghosyan
Abstract. The roots of the Legendre polynomials and corresponding weights necessary for Gaussian quadrature of integrals are calculated numerically. A package of program created for high accuracy calculations is used for the machine computing. The numerical procedure used for determination of the Legendre polynomials’ roots and corresponding weights is described. We also bring here some results of numerical calculations as an illustration.
Astrochemistry as the basics of Astrobiology: from simplest molecules to bioindicators on exoplanets surfaces 2.1 MB
Abstract. The problem of the origin of Life is discussed from the astrophysical point of view. Most biologists and geologists up to the present time believe that Life was originated on the Earth in some initial natural chemical pre-reactors, where a mixture of water, ammonia, methane containing species and some other substances, under the influence of an energy source like, e.g. lightning, turned into quite complex compounds such as amino acids and complex hydrocarbons. In fact, under conditions of the primordial Earth, it is not possible to obtain such pre-biological molecules by not-bio-chemical methods, as discussed in this paper. Instead, an astrophysical view of the problem of the origin of Life on the Earth is proposed and it is recalled that the biological evolution on the Earth was preceded by the chemical evolution of complex chemical compounds, mostly under extraterrestrial conditions, where it is only possible to form optically active amino acids, sugars and heavy hydrocarbons necessary for constructing the first pre-biomolecules. Then, according to a widespread point of view, they were brought to Earth by comets and dust between 4.5 and 3.8 billion years ago. Some part of the matter of comets landed unchanged during grazing collisions. Prebiotic complexes on the surface of the planet participate in the formation of a specific cover with a reflective spectrum (or color index), whose characteristic details can be tried to reveal by observation. The most promising bio-indicators at present are optically active amino acids and their derivatives, however, the existing observational capabilities are insufficient to identify them. More promising as (pre)biomarkers are the heavy hydrocarbons discussed in this article, in particular bitumen and isoprene hydrocarbons.
Review on the astronomical estimators of number of flare stars 0.9 MB
A. A. Akopian
Abstract. Review is devoted to estimators introduced in astronomy by Ambartsumian and his followers that are used to estimating the unknown number of flare stars and other randomly flashing objects (stars with X-ray flares, solar type stars with superflares). Some important astronomical applications of them are presented. The development of these methods in astronomy have proceeded regardless of development of analogous methods of mathematical statistics. Brief history of this development and parallels with similar statistical methods is presented.
The results of the search and study of young stellar objects with Hα emission in the Byurakan Observatory 0.9 MB
E. H. Nikoghosyan
Abstract. One of the main observational properties of young stellar objects in the optical range is the presence of emission lines, in particular Hα (6563 Å). Therefore, detection of Hα emission is the most common spectroscopic means for identification of young stars. The paper presents the results of searching and studying of young stellar objects in several star forming regions carried out on the 2.6 m telescope in Byurakan observatory. The quantitative relationships between objects with different stage of activity are considered. In addition, a statistical analysis of Hα activity and other manifestations of PMS activity (X-ray, IR excess), as well as an evolutionary age of the Hα emitters in several star-forming regions is provided.
On Ancient Astronomy in Armenia 0.8 MB
IAU South West and Central Asian Regional Workshop (20 September, 2018, BAO)
Armenian Astronomy: Recent Activities 0.5 MB
A. Mickaelian, S. Farmanyan
Abstract. An overview of the current activities of the Armenian astronomy, including professional research, University and school education, public outreach and other organizational affairs. We show that present day Armenian astronomy serves as a leader for the regional activities, as well as is among the most advanced and active sciences in Armenia. Moreover, recent achievements during the years 2000-2018 are such that many years efforts since Viktor Ambartsumian’s times were necessary and finally received recognition in various fields. BAO was recognized as National Value, regional astronomical centre, and Markarian Survey was included in UNESCO Memory of the World documentary heritage list. We succeeded to organize a number of important meetings (IAU symposia and colloquium, JENAM, etc.) and establish a series of Byurakan International Summer Schools. We also present the Armenian Astronomical Society’s (ArAS) and IAU South West and Central Asian regional centre’s activities.
Astronomical research and public outreach in Georgia 0.4 MB
Abstract. Interest in astronomy has been significantly increased in Georgia. As a result, the development of astronomical research, education and public outreach are in progress. In Abastumani Astrophysical Observatory - a research institution at Ilia State University - the observational and theoretical studies comprise a wide range of topics in astronomy and adjacent fields: solar system bodies, solar physics, stellar and extragalactic astronomy, theoretical astrophysics, cosmology, atmospheric and near space physics. Georgian scientists are involved in wide international collaboration and participate in a number of networks and projects. Astronomical education at bachelor, master and doctoral levels are held at Ilia University. PhD programs are also offered at other universities. In 2018, under the financial support of the World Bank and Georgian government, the renovation of Abastumani Observatory has been started. International conferences and workshops have been carried out in Georgia. Excursions at the Observatory and public lectures in astronomy throughout the country are carried out. Amateur astronomers organize astronomical events. A private observatory is under construction near Tbilisi. All these puts better perspective for future development of astronomy in Georgia.
Numerical studies of astrophysical objects at Fesenkov Astrophysical Institute 1.2 MB
A. Bibossinov, D. Jurin, C. Omarov
Abstract. Numerical studies of astrophysical objects are a relatively new direction in Fesenkov Astrophysical Institute (FAI) and is mainly represented by the Laboratory of Cosmology, Stellar Dynamics and Computational Astrophysics. The lab seeks to understand the evolution of gravitating systems at various scales – from star clusters to galaxies to large-scale structure of the universe as a whole, and tackles these problems both through analytical methods and through numerical simulations. The particular focus is on numerical simulations of star clusters, especially those found in active galactic nuclei – this is a topic of old-established collaboration with colleagues from Astronomisches Rechen-Institut (Heidelberg) and National Astronomical Observatories of China (Beijing). The prominent example is STARDISK project dedicated to the numerical research of active galactic nuclei as multicomponent systems composed of compact stellar cluster, gaseous accretion disk and a supermassive black hole. It is demonstrated that an accretion disk can noticeably decelerate stars and thus enhance the accretion rate onto the black hole. In 2013 FAI hosted the MODEST-13 International Workshop dedicated to modeling of star clusters. Recently a new project has been approved aimed at construction of triaxial equilibrium N-body systems that can be of great help in various numerical experiments with disk galaxies. There are also long standing plans to perform cosmological simulations of large scale structures to test a new approach to dark matter and energy actively developed at FAI. For numerical calculations, FAI has a small, but growing computer cluster consisting of several high-performance computing servers equipped with computational GPU cards.
Astrophysical Studies in Tajikistan: from Traditional Approach over Modeling to Empirical Properties 1.1 MB
Abstract. New approach developed in the Institute of Astrophysics, Tajikistan Ac. Sci., aimed to determination of the relationships between SS minor bodies is considered. The method consists of the modeling of objects motion in the past or in the future, calculation of the theoretical parameters, identification of the theoretically predicted properties with the observed ones. Usage of the method allowed to recognize extinct cometary nuclei among the near-Earth asteroids and to establish the parent bodies of some known asteroid-meteoroid complexes.
Outreach Activities and Teacher Training Programs in Turkey 1.2 MB
Abstract. In this paper, outreach activities and teacher training programs that are held in Turkey are presented. There are star parties, public nights, summer schools and open house events among public outreach activities in astronomy. More than a decade special courses and concentrated training programs are organized for science teachers, especially. With the inclusion of planetariums and science centers outreach activities have become more productive in the recent years.
Promotion of Science Communication through Regional Office of Astronomy for Development 0.6 MB
S. Farmanyan, A. Mickaelian
Abstract. The present study is proposed to introduce the outreach activities of IAU South West and Central Asia Regional Office of Astronomy for Development (SWCA ROAD) Significant communications gap between scientists and society will be rendered. We will show how to gain new enthusiasts of the Universe by science popularization. We will point out the positive outcome of the science communication such as the rejection of superstitious beliefs, astrology and numerology. We will analyze the basic processes of communication that explain how different publics deal with scientific information and we will apply these insights so as to help improve communication practices in the field of science. Special focus will be given on the science-society relationship and the usage of the persuasive and effective means like science museums, science exhibitions, science festivals, science busking, science cafes and pubs, public lectures, talks and discussions, scientific journalism and scientific tourism. We have implemented some of these in the frame of SWCA ROAD activities, we will share our experience. It is worth mentioning that in most of these initiatives astronomers have taken the leadership as most of the attractive topics in science communication are astronomy and space sciences, extraterrestrials, astrology, cosmic catastrophes, etc. We will suggest science communicators to use entertainments including humor, storytelling and metaphors. Science communication may also be realized by websites and social media platforms. We conclude with future tendencies of science communication and benefits of the scientists and young researchers who are actively involved in science outreach activities.