Communications of the Byurakan Astrophysical Observatory (ComBAO)
Volume 68, Issue 1, June 2021
Byurakan Astrophysical Observatory: 75 years of outstanding achievements 0.7 MB
A. M. Mickaelian
Abstract. The Byurakan Astrophysical Observatory (BAO) is one of the most famous observatories of the Soviet Union and may be of the world. It was founded in 1946 by the outstanding scientist Viktor Ambartsumian (1908-1996) and became the leader of studies on instability phenomena in the Universe. Many discoveries have been carried out at BAO related to stars, star clusters and other systems, nebulae, galaxies and systems of galaxies. BAO has two major instruments; 1m Schmidt and 2.6m classical telescopes. Together with V. Ambartsumian, outstanding scientists Beniamin Markarian, Grigor Gurzadyan, Marat Arakelian and others have worked at BAO. Many important international meetings and schools for young astronomers have been held. Many important people, including State authorities, Nobel Prize Winners and others have visited BAO. BAO has statuses of RA National Value, Regional Astronomical Centre, it has UNESCO Documentary Heritage item, its garden is recognized as Dendrarium, and there is RA National Hero Viktor Ambartsumian's house-museum.
On the kinematic interpretation of cosmological redshifts 0.7 MB
Abstract. We describe what is essentially a correct solution to the kinematic interpretation of cosmological redshifts in standard cosmological model. In the framework of "stretching of space" point of view of the spatially homogeneous and isotropic Robertson-Walker space-time of standard cosmological model, we study so-called "lookforward" history of expanding universe, subject to certain rules, in order to overcome the ambiguity of the parallel transport of source four-velocity along the null geodesic to an observer. We interpret the cosmological redshifts as the accumulation of a series of infinitesimal "relative" spectral shifts along the path of light consequent on recession. The crux of our solution is the kinetic recession velocity of comoving astronomical object, which is always subluminal even for large redshifts of order one or more, so that it does not violate the fundamental physical principle of causality. Our analysis establishes a straightforward kinematic relationship of overall cosmological redshift and kinetic recession velocity, which is utterly distinct from a familiar global Doppler shift formula. A difference of global Doppler velocity and kinetic recession velocity, for redshifts 0.9 ≤ z ≤ 800, is ≥ 0.072c, where a maximum value, 0.187c, is reached at redshifts z = 4.5 - 5.1. A general solution is reduced to a global Doppler shift along the null geodesic. We discuss the implications for the case of a zero-density cosmological model of Milne universe, whereas a correspondence to the more usual special relativity notion of relative speed retains. In Table 1, we are summing up kinetic recession velocities of some typical distant astronomical objects with spectroscopic redshift determinations collected from the literature.
The Time-dependent Problem of the Line Radiation Reflection 0.8 MB
Abstract. We consider the classical time-dependent problem of diffuse reflection of the line-radiation from a semi-infinite absorbing and scattering atmosphere. By the example of the simplest 1D problem it is shown how its solution is constructed in the general case, when both the photon lifetime in the absorbed state and the time of its travel between two consecutive acts of scattering are taken into account. The numerical values of the coefficients in the expansion of the reflection function in the Neumann series are given. The obtained solution is applied to the problem, in which the scattering in both the spectral line and in the continuous spectrum is taken into account.
Unique definition of relative speed along the line of sight of a luminous object in a Riemannian space-time 0.6 MB
Abstract. Extending the geometrical ideas of well-known general kinematic spectral shift rule in a Riemannian space-time, we use a way of separating the spectral shifts into infinitesimal spectral bins and sum over them to give a unique definition of the relative velocity along the line of sight of a luminous object with respect to observer. A general solution, particularly, is reduced to a global Doppler shift along the null geodesic. We discuss the implications for the spatially homogeneous and isotropic Robertson-Walker space-time of standard cosmological model. The resulting kinetic recession velocity of a galaxy is always subluminal even for large redshifts of order one or more, and thus, it does not violate the fundamental physical principle of causality.
The Morphology of the Spiral Galaxies: Encoded Information on the Origin and Evolution Mechanisms 0.2 MB
H. A. Harutyunian
Abstract. Consequences of the interaction between baryonic matter and dark energy carrier is considered for spinning objects. Some morphological features of spiral galaxies are used as fingerprints of formation processes to show that spiral arms of galaxies could be formed through mass ejection from the core of these objects. The Elmegreens’ arm classification allows one to find some opportune features for this end. For the same purpose, the ratio of vertical and radial sizes of some edge-on spiral galaxies found in deep fields and SDSS surveys is used.
Growth and merging phenomena of black holes: observational, computational and theoretical efforts 0.8 MB
Abstract. We briefly review the observable signature and computational efforts of growth and merging phenomena of astrophysical black holes. We examine the meaning, and assess the validity of such properties within theoretical framework of the long-standing phenomenological model of black holes (PMBHs), being a peculiar repercussion of general relativity. We provide a discussion of some key objectives with the analysis aimed at clarifying the current situation of the subject. It is argued that such exotic hypothetical behaviors seem nowhere near true if one applies the PMBH. Refining our conviction that a complete, self-consistent gravitation theory will smear out singularities at huge energies, and give the solution known deep within the BH, we employ the microscopic theory of black hole (MTBH), which has explored the most important novel aspects expected from considerable change of properties of space-time continuum at spontaneous breaking of gravitation gauge symmetry far above nuclear density. It may shed further light upon the growth and merging phenomena of astrophysical BHs.
Tables of physical and morphological properties of nearby extended radio galaxies 0.3 MB
R. R. Andreasyan and H. V. Abrahamyan
Abstract. It is brought the physical and morphological data of 267 nearby radio galaxies identified with elliptical galaxies brighter than 18th magnitude (sample 1) and for 280 extragalactic radio sources with known position angles between the integrated intrinsic radio polarization and radio axes (sample 2).
Condensations Expelled from the Stars, and Pairs of Stars, Connected with Bright Filaments 0.9 MB
A. L. Gyulbudaghian and R. A. Mendezz
Abstract. During several surveys of high-quality film-copies of the ESO B, R, ESO/SRC J, and EJ plates, except other young unstable objects (HH objects, star-forming regions, cometary nebulae) were found also two types of other unstable objects. 1. Bright condensations, connected with stars by bright filaments. 2. Pairs of stars, connected with each other by bright filaments. The objects of first type are mostly seen in infrared, on 2MASS K images. Due to their infrared colours, two of condensations and half of all stars can have thick dust discs.
BAO Plate Archive Project: Recent Results 0.6 MB
G. A. Mikayelyan, G. M. Paronyan, N. M. Azatyan, G. R. Kostandyan, A. L. Samsonyan, H. R. Andreasyan, H. V. Abrahamyan, D. H. Andreasyan, A. G. Suqiasyan, and A. M. Mickaelian
Abstract. We present the recent results of the Byurakan Astrophysical Observatory (BAO) Plate Archive Project that is aimed at digitization, extraction and analysis of archival data and building an electronic database and interactive sky map. BAO Plate Archive consists of some 37,000 photographic plates and films, obtained with 2.6m telescope, 1m and 0.5m Schmidt telescopes and other smaller ones during 1947-1991 and then by digital methods since 1996. Its most important part, the famous Markarian Survey (or the First Byurakan Survey, FBS) 1874 plates were digitized in 2002-2007 and the Digitized FBS (DFBS, www.aras.am/Dfbs/dfbs.html) was created. New science projects have been conducted based on this low-dispersion spectroscopic material. Several other smaller digitization projects have been carried out as well, such as part of the Second Byurakan Survey (SBS) plates, photographic chain plates in Coma, where the blazar ON 231 is located and 2.6m film spectra of FBS Blue Stellar Objects. However, most of the plates and films were not digitized. In 2015, we have started a project on the whole BAO Plate Archive digitization, creation of electronic database and its scientific usage. Armenian Virtual Observatory (ArVO, www.aras.am/Arvo/arvo.htm) database will accommodate all new data. The project lasted 4 years in 2015-2018. Later on, the project was renovated for 2020-2021. The final result will be an Electronic Database and online Interactive Sky map to be used for further research projects.
An Astronomical Attempt to Determine the Temporal Origin of an Episode of the Armenian Epic ”Sasnay Tzrer” 0.7 MB
Abstract. An attempt was made to estimate the time period of the Armenian epic ”Sasnay Tzrer” by astronomical means. An episode in which Tzovinar mentions a bright star as night guide for sending her sons from Mesopotamia to Armenia has been examined from the point of view of astronomy. On basis of the ”khachapasht” (cross worshipers) self-proclamation of representatives of the House of Sasun and wearing the sign of the cross on their right hand, this guiding star is identified with the constellation Cygnus (ancient Armenian Angkh – Vulture), which depicts the outline of a cross in the northern sky. Subsequently, we calculated when Cygnus’ main star, Deneb, was closest to the North Pole. The calculations show that this event took place 17,500 years ago. This time frame was taken as the time of the creation of the above-mentioned episode of the Sasnay Tzrer Epic.
On the simultaneous generation of radio and soft X-ray emission by AXP 4U 0142+61 0.3 MB
Z. N. Osmanov
Abstract. In the present paper we study the possibility of a simultaneous generation of radio waves and soft X-rays by means of the quasi-linear diffusion (QLD) in the anomalous pulsar AXP 4U 0142+61. Considering the magnetosphere composed of the so-called beam component and the plasma component respectively, we argue that the frozen-in condition will inevitably lead to the generation of the unstable cyclotron waves. These waves, via the QLD, will in turn influence the particle distribution function, leading to certain values of the pitch angles, thus to an efficient synchrotron mechanism, producing soft X-ray photons. We show that for physically reasonable parameters of magnetospheric plasma, the QLD can provide generation of radio waves in the following interval 40 MHz - 111 MHz connected to soft X-rays for the domain 0.3 keV - 1.4 keV.
Coupling and recoupling of binaries in chaotic three body systems 0.4 MB
T. S. Sachin Venkatesh
Abstract. Three body systems where one of the bodies is ejected without escaping the binary system have previously been studied in various restricted forms. However, none of these studies dwells on the problem in a general setting. Thus, to study this phenomenon qualitatively, we try to expand this problem's scope to unequal mass systems and generalize them by considering various configurations of fixed initial points with precisely calculated initial velocities, some zero velocity models, and some optimized models. We will see the use of terminology similar to the previous studies done in this domain, but incorporate different analytical and evaluation methods.
Whereas an observer has nothing to do with it! 0.2 MB
E. E. Ashursky
Abstract. In this article, the author, as possible, subjects to a comprehensive (though mostly, it's true, critical) analysis the one-sided attempts of a number of current Western astrophysicists to somehow substantiate the well-known Fermi paradox. Is it a joke to say: in own perverted designs, some of them even go so far as to unceremoniously rearrange the cause with the effect! However, so to speak, "for greater pluralism of views", we'll along the way quote many other, much clearer and sapider opinions on this topic | right from the lips of alternatively thinking scholars (and besides - I note - with a world name!). Wherein some of them frankly assess the today stalemate uncertainty as a kind of creative stagnation; second are inclined towards the version of consumerity-driven global theoretical shift; while third directly declare that it is time for representatives of the exact sciences, obviously, to prepare for the change of the old starry paradigm to cardinally updated one. But still, without waiting for the weather by the sea (as well as just for spite the arrogant purse-proud Yankees, who, alas, do not seriously recognize our current potential capabilities, or even past truly grandiose achievements), here we will try independently to resolve some of the most controversial issues.
ANNOTATION of PhD THESIS
Study of the radio and optical properties of Active Galactic Nuclei 1.3 MB
H. V. Abrahamyan
Abstract. The investigation of the physical properties of active galactic nuclei is one of the most important tasks of astronomy. Until now, the properties of AGN have not been fully studied. Therefore, we have studied a number of important properties of AGN. For example, one of the main properties of AGN is the variability. We have studied samples of AGN derived by different methods. For these sources, we have identified some properties of activity for the radio and optical ranges. These properties give us some insight into the active galaxies.