HOMECommunications of the Byurakan Astrophysical Observatory (ComBAO)
Volume 69, Issue 2, December 2022
ORIGINAL PAPERS
Evolution of spectral lines under time-dependent illumination of an absorbing and scattering atmosphere 
0.5 MB
A. Nikoghossian
Pages: 140-150
Abstract. This is a continuation of the author’s research on the temporal variations in the spectral line profiles formed in absorbing and scattering atmospheres illuminated by non-stationary energy sources. The line radiation transfer in an atmosphere of finite optical thickness is considered under assumption of complete frequency redistribution. We treat two types of illumination of the medium: the sources of the form of Dirac δ(t) and Heaviside H(t) unit jump functions. The goal of the work is to identify the dependence of the dynamics of changes in the spectral line profiles on frequency redistribution and the values of various optical parameters such as the optical thickness of the medium and the value of scattering coefficient. It is shown that in some cases this dependence allows to use observational material on dynamics of the burst phenomena to estimate some of these characteristics.
Relative velocity in pseudo-Riemannian spacetime 0.3 MB
G. Ter-Kazarian
Pages: 151-171
Abstract. We give a coordinate independent definition of relative velocity of test particle in pseudo-Riemannian spacetime as measured along the observer’s line-of-sight in general and several instructive cases. In doing this, the test particle is considered as a luminous object, otherwise, if it is not, we assume that a light source is attached to it, which has neither mass nor volume. Then we utilize the general solution of independent definition of relative velocity of a luminous source in generic pseudo-Riemannian spacetime. As a corollary, we discuss the implications for the Minkowski metric, the test particle and observer at rest in an arbitrary stationary metric, the uniform gravitational field, the rotating reference frame, the Schwarzschild metric, the Kerr-type metrics, and the spatially homogeneous and isotropic Robertson-Walker (RW) spacetime of standard cosmological model. In the last case, it leads to cosmological consequence that the resulting, so-called, kinetic recession velocity of an astronomical object is always subluminal even for large redshifts of order one or more, so that it does not violate the fundamental physical principle of causality. We also calculate the measure of carrying away of a galaxy at redshift z by the expansion of space, which proves, in particular, that cosmological expansion of a flat 3D–space is fundamentally different from a kinematics of galaxies moving in a non-expanding flat 3D-space. So, it is impossible to mimic the true cosmological redshift by a Doppler effect caused by motion of galaxies in a non-expanding 3D-space, flat or curved. We also give a reappraisal of the `standard ́ kinematic interpretation of redshifts in RW spacetime as accumulated Doppler-shifts.
On mass-loaded accretion during high mass star formation 0.1 MB
A. G. Yeghikyan, A. L. Samsonyan, N. A. Harutyunyan, N. M. Azatyan, D. H. Andreasyan,
D. S. Baghdasaryan, and E. H. Nikoghosyan
Pages: 172-177
Abstract. Analytical formulae of the dependence of the velocity and density on the radius during spherical accretion with both mass and momentum inputs, as well as the rate of mass inflow are presented. Some features of gas inflow near the star are discussed, and details of mass loading are presented and calculated as caused by hydrodynamical ablation and conductivity. It looks like that in one example velocities of inflow are in the range from 10-20 km/s (free fall) to 40-50 km/s and the densities are in the range from 2·108 (free fall) to 6·106 cm-3 at 1017 cm when mass-loading accretion is taken place during formation of 10M⊙ mass star.
Introduction 0.1 MB
Editorial Board
Pages: 178-178
Astronomical Surveys, Catalogues, Archives, Databases and Virtual Observatories 0.3 MB
A. M. Mickaelian, H. V. Abrahamyan, G. M. Paronyan, G. A. Mikayelyan
Pages: 179-186
Abstract. Astronomical surveys and catalogs are the main sources for the discovery of new objects, both Galactic and extragalactic. Archives and Databases maintain billions of astronomical objects; planets, comets, stars, exoplanets, nebulae, galaxies, and quasars. We will review the current background in astronomy for further all-sky or large-area studies. Modern astronomy is characterized by multiwavelength (MW) studies (from gamma-ray to radio) and Big Data (data acquisition, storage, mining and analysis). Present astronomical databases and archives contain billions of objects observed at various wavelengths, and the vast amount of data on them allows new studies and discoveries. Surveys are the main source also for accumulation of observational data for further analysis, interpretation, and achieving scientific results. We review the main characteristics of astronomical surveys (homogeneity, completeness, sensitivity, etc.), compare photographic and digital eras of astronomical studies (including the development of wide-field observations), and describe the present state of MW surveys. Among others, Fermi-GLAST, INTEGRAL (gamma-ray), ROSAT, Chandra, XMM (X-ray), GALEX (UV), DSS1/2, SDSS, Hubble, Gaia (optical), 2MASS, IRAS, AKARI, WISE, Herschel (IR), NVSS and FIRST (radio) surveys and major astronomical archives and databases will be presented and discussed, as well as surveys and databases for variable and transit objects.
On the Place and Role of Astronomy and Astrophysics in the Emerging New Model of Education 0.2 MB
L. A. Gheonjian
Pages: 187-192
Abstract. Developing digital technologies as an evolutionary leap, we are clearly facing a crisis in traditional education system. We are close, or are already at the bifurcation point of techno-cultural evolution. Systems Theory (Bertalanffy (1968)) and the concept of Purposeful Systems (Ackoff & Emery (2009), Ackoff et al. (2006)) focuses on the design of a new model of education. The main difficulty of education is caused by contradictions between the fuzzy logic (Zadeh (1973)) of the humanities and the clear logic of natural sciences. Lingvistic variables of fuzzy logic, reflecting and classifying the multiplicity of objects and connections, allow fuzzy interpretation of reality. The concepts of number and measure achieve convergence in the identification of objects, in their study and in the creation of new objects of reality. Problems arise in the process of combining these two logics in education. Psychology, responsible for understanding of teaching-learning processes, encounters difficulties in solving these problems. Ethology, studying the social behavior of animals and humans, firmly argue that without solving the problems of education as a form of intelligence development, we become an endangered biological species if the environment we have created will be destroyed. We will return to the primitive, animal form of social behavior, since the form of social organization are transmitted genetically and lie deep in our subconscious (Dolnik (2009), Lorenz (1963, 1971)). The digitalization and standardization of education started replacing part, or all of the intelligence with the ability to use databases of” recipes” for recognizing situations and appropriate behavior. Repetitions of each such recipe creates a fixed set of unconscious behavior (Uznadze (1995)) turning people into state of cybernetic organism. This perspective causes some blurred models of the present and gloomy forecasts and plans of social reconstruction. There is the need to clearly describe the reality in which our biological species exists and to transfer this knowledge into the process of education in the form of intellectual development.
Astronomy and astrophysics have created the most fully formulated model of the Universe, that becomes an essential part of culture and practice. The analysis of the intellectual activity of our civilization identifies astronomers and astrophysicists as a special group of purposeful and advanced carriers of intellect which the great potential for formation of a new model of education. The development of astronomy and astrophysics can be represented as a continuous process of transforming the concepts of fuzzy logic into constructing the model the Universe as observable, measurable and clearly described system. The specificity of the subject of study, the need to constantly develop complex specific technologies for remote research and the need to use the most advanced methods for describing, interpreting and understanding the results, created conditions for specific Cerebral Sorting (Saveliev (2016)) and formation of advanced intellectual, professional and social community.
All significant results in General Psychology have been achieved in cooperation with exact and natural sciences. It is reasonable to offer astronomers and astrophysicists ideas explaining their intellectual activity and consistent with the concepts and ideas of General Psychology. This knowledge may became the part of activity technology and motivation to form a system based on astronomy and astrophysics as a model of cognition and education. Such a model based on General Psychological Theory of Set (Nadirashvili (2007), Uznadze (1995)) is proposed for discussion and use.
On the stability of the 'stable systems' in the presence of dark energy 0.1 MB
H. Harutyunian
Pages: 193-200
Abstract. The influence of dark energy on baryon objects and their system is considered. For such an analysis, the concept is adopted, according to which the entire baryonic Universe interacts with dark energy on all cosmic scales. It is shown that the interaction of baryonic objects with a carrier of dark energy inevitably leads to the injection of energy into the baryonic world with tangible physical consequences. The consequences seem quite dramatic, since the accumulation of energy in the baryonic world changes the virial theorem for all objects and systems, making them more and more unstable. This process of stability loss takes place at all spatial scales, including the micro world, where baryonic matter experiences the dark energy influence. It results decaying of all cosmic objects beginning with atomic nuclei and reaching the clusters of galaxies. Evolution under the influence of dark energy can take place in two different ways depending on the existence of the angular momentum of the body and its value. If the angular momentum is small, the object under the influence of dark energy obtains a more regular shape, otherwise at the equatorial plane would appear a structure consisting of less evolved matter.
Semi-detached double-lined eclipsing binaries with Gaia DR3 data 0.1 MB
O.Yu. Malkov , A.D. Grinenko, and A.M. Sachkov
Pages: 201-206
Abstract. Semi-detached double-lined eclipsing binaries (SD DLEB) play an important role in our understanding of basic properties of interacting binaries. We have collected data on semi-detached systems with available light and radial velocity curve solutions, and have compiled the most comprehensive list of SD DLEB, containing astrophysical and orbital parameters. The goal of this work was to make a cross-identification of the catalogued objects with Gaia DR3 archive. We have supplied our catalogue with data from Gaia DR3 as well as multicolor photometry from SIMBAD, and make a preliminary analysis of the results.
First Byurakan Spectral Survey. Late-Type Stars. Dwarfs 0.2 MB
K. S. Gigoyan , K. K. Gigoyan, A. Sarkissian, G. R. Kostandyan, E. Karapetyan, M. Meftah, N. Azatyan, F. Zamkotsian
Pages: 207-216
Abstract. A total of 18 lists of the First Byurakan Survey of Late-Type Stars (FBS LTS) were published between 1990 and 2016. The stars were found on FBS low-dispersion spectral plates. A systematic search and selection were carried out on a surface of ∼16 000 deg2 on almost the whole area of the FBS. Since 2007, all FBS low-resolution spectral plates have been digitized. The second version of the “Revised And Updated Catalogue of the First Byurakan Survey of Late-Type Stars”, containing data for 1471 M and C (carbon) stars (130 C-type giants, 1105 M – giants, and 236 M dwarfs) was generated. Among the 236 M dwarfs selected, 176 are new discoveries. The Gaia EDR3 G broad-band magnitudes are in the range 11.3 < G < 17.1. New distance information by Bailer-Jones et al. (2021), which is based on the EDR3 parallaxes are used to estimate the G-band absolute magnitudes for M dwarfs. 9 FBS M dwarfs (out of 176 new discovered) lie within 25 pc of the Sun. The object FBS 0909-082 is more distant (r = 780 ̇pc) M dwarf among the sample considered, for which G-band absolute magnitude M(G) = 9.18, M = 0.59 MSun, L = 0.13597 LSun, and Teff = 3844 K. This object can be classified as M1-M2 sub-type dwarf. The nearest object is FBS 0250+167, a M7 subtype dwarf with very high proper motion (5.13 arcsec/yr) and is located at 3.83 pc from the Sun. The TESS estimated masses lie in the range 095 (±0.02) M⊙ ≤ M ≤ 0.7 (± 0.1) M⊙ and Teff in the range 4000K < Teff < 2790K for FBS M dwarfs. Color-absolute magnitude (CaMD) diagrams are constructed for the FBS M dwarfs based on Gaia EDR3 and TESS data.
The stellar content of UCHII regions: the molecular cloud GRSMC045.49+00.05 0.2 MB
N. Azatyan , E. Nikoghosyan, L. Kaper, D. Andreasyan, A. Samsonyan, A. Yeghikyan, D. Baghdasaryan, N. Harutyunyan
Pages: 217-222
Abstract. Ultra-compact HII (UC HII) regions are an important phase in the formation and early evolution of massive stars. The main objectives of this work are to study the stellar content associated with the G045.49+00.04 and G045.14+00.14 star-forming regions located in the GRSMC 45.46+0.05 molecular cloud at a distance of about 8 kpc. Both regions contain a number of UC HII regions. The main objective is to characterize the embedded young stellar objects (YSOs), such as their mass, evolutionary age and age spread, spatial distribution, luminosity function. We used near-, mid-, and far-infrared photometric data to identify and classify the YSOs. Their main parameters were determined by the spectral energy distribution (SED) fitting tool using radiation transfer models. Totally, we identified 2864 YSOs. We also constructed a colour-magnitude diagram to compare the parameters of stellar objects with the results of the radiative transfer models. The density distribution of the identified YSOs showed the presence of dense clusters in the UC HII regions. The parameters of YSOs in the IRAS clusters and non-cluster objects surrounding them show some differences. In general, the YSOs in these clusters have an evolutionary age larger than 106 years with an age spread of a few Myr. The clusters include several high- and intermediate-mass zero-age main sequence stellar objects. The small age spread suggests that the clusters may originate from a single triggering event.
The Precise Individual Masses and Theoretical Stability and Habitability of some Single-lined Spectroscopic Binaries 0.1 MB
B. S. Algnamat, A. A. Abushattal, A. F. Kraishan, M. S. Alnaimat
Pages: 223-230
Abstract. Over the past few decades, some Spectroscopic Binaries (SBs) have been resolved using high-resolution techniques. Astrophysics is interested in this subject because we can obtain the mass of each component. By combining a visual solution with a complimentary one, such as the spectroscopic orbit or Edward method, we can determine the individual masses, semimajor axes, magnitudes, spectral types, radii, and temperatures. These provide the most probable physical parameters for some single-lined spectroscopic binaries. Then We can use these parameters to calculate theoretical the stability and habitability of the system. Additionally, we assume the composite spectrum, the apparent global magnitude, and the parallax (generally the Hipparcos, and recently the Gaia). The next step is to obtain the spectrum for each components. The Edwards method will be used in this case. As soon as we have two spectra foe two single-lined spectroscopic binaries (HIP 754 and HIP 3841), we can determine each mass based on the magnitude difference, m. For selected samples, we calculate the rest of the physical parameters needed to calculate the theoretical stability and habitability.
A planetary resonant effect in Parker stellar dynamo 0.1 MB
D.D. Sokoloff, A.Yu. Serenkova, E.V. Yushkov
Pages: 231-234
Abstract. The effect of periodic pumping on dynamo generation in the simplest Parker model is studied in this work. Pumping is understood in the sense that the periodic parameters oscillations in the dynamo system leads to a change in the rate of the exponential growth of the mean magnetic field. And since the Parker model simultaneously describes its time oscillations as the field grows, this phenomenon is very similar to parametric resonance in the classical model of a harmonic oscillator. With the help of asymptotic analysis and numerical simulation, we demonstrate both pump regions similar to parametric resonance, as well as different amplification regions at high driving force frequencies, and suppression regions at low frequencies, find the gain maximum and investigate the behavior of the critical pump frequency separating the regions of generation and suppression.
The Exoplanets Catalogues and Archives: An Astrostatistical Analysis 0.2 MB
A. A. Abushattal, A. F. Kraishan, O. S. Alshamaseen
Pages: 235-241
Abstract. The discovery of more than 5000 exoplanets based on several methods will improve our understanding of the formation and evolution of the exoplanets. Due to the dramatically increases in the amount of the astronomical data in recent decades. Which can be analyzed statistically to extract scientific information and test astrophysical theories. This information is valuable to figure out if there is a life somewhere else on the universe. This work presents a statistical analysis of all these exoplanets based on three primary data sources: NASA Exoplanet Archive, Open Exoplanet Catalogue, and Exoplanet.eu catalogue. Moreover, several parameters are examined, including mass, radius, discovery method, distance, orbital period, and discovery year. As part of our analysis, we have also clarified and summarized the data in the form of graphs based on astrophysical correlations.
The Physical Parameters, Stability, and Habitability of some Double-lined Spectroscopic Binaries 0.2 MB
H. A. Alameryeen, A. A. Abushattal, A. F. Kraishan
Pages: 242-250
Abstract. Large ground telescopes can now resolve most double-lined binaries optically at some point in their orbit due to the improvement of imaging techniques in recent decades. Using additional information about these systems, such as astrometric parallax, even a single precise visual observation can provide a 3D orbit and the primary physical parameters. Furthermore, both the visual and spectroscopic orbits can be determined. We combine the Edward method with the visual solution and the spectroscopic orbit parameters: period (P), periastron epoch (T), eccentricity (e), semimajor axis (a1,2) and inclination (i), we also know the mass ratio of the system. The developed method allows us to select double-lined spectroscopic systems with recently calculated orbits. We calculate the individual masses, orbital parallax, and other fundamental astrophysical parameters. The purpose of these parameters is to verify the reliability of the data received from space missions and to calculate the stability and habitability, which is the primary goal of this study. Astronomical information can be obtained from binary stars. By observing short period binaries using both spectroscopy and interferometry, we can determine the individual masses and orbital parallaxes of the objects based on their corresponding orbits. Spectroscopic binaries with double-lines are therefore fundamentally important to optically resolve. To determine the required telescope aperture for the resolution of a spectroscopic binary, we developed a specific algorithm. We determined the most probable maximum and minimum separations between each spectroscopic binary based on photometric and spectroscopic information. Thus, we also determined the different physical parameters of each system by using the calibrations we obtained in our study. Based on optically resolved spectroscopic binaries with both spectroscopic and visual orbits, the methodology presented here was successfully tested.
Astroinformatics: The Importance of Mining Astronomical Data in Binary Stars Catalogues 0.1 MB
A. A. Abushattal, A. A. Alrawashdeh, A. F. Kraishan
Pages: 251-255
Abstract. The field of Astroinformatics offers exciting new perspectives on astronomical discovery through the implementation of advanced data mining procedures. Data deluges transform research practices and methodologies across various scientific disciplines, including day-to-day astronomical research. It is essential to use innovative algorithms and methods to process astronomical data and its variety. Descriptive Data Mining was used in this study to clarify the importance and effectiveness of obtaining common data between three binary star catalogs. These catalogues are The Ninth Catalogue of Spectroscopic Binary Orbits (SB9), The Sixth Catalog of Orbits of Visual Binary Stars (6COVBS), and The Fourth Catalog of Interferometry Measurements of Binary Stars (4CIMBS). We collect scattered data from the Ninth Catalog in its latest edition in 2021, which contains astronomical information for approximately 4021 binary systems. Then we search for the orbits of these binary systems in the 6COVBS to calculate the physical and the orbital properties with high accuracy. After that, we use the 4CIMBS to look for new observations of these stars in 66,225 resolved stars in its latest edition 2020 to calculate new orbits. As a result of this research, we have found about 600 standard systems among these catalogues, which are valuable data to calculate many physical properties of such binary stars, starting from individual masses, by the combination of the spectroscopic orbital solution with the visual orbital solutions. Furthermore, calculate the orbital parallax for each system with high accuracy compared with those from space missions such as Gaia and Hipparcos give us a new and essential method to verify the validity of the data from those satellites.
Substructures in the Isolated Galaxy Clusters 0.2 MB
E.A. Panko, S. Yemelianov, A. Sirginava, Z. Pysarevskyi
Pages: 256-264
Abstract. The isolated clusters are special objects for understanding the ways of forming observed large-scale distributions of matter. One can consider the isolated clusters as objects evolving without any external influence. We present the results of the analysis of the $2D$ distribution of galaxies in 31 isolated galaxy clusters with redshifts $z<0.15$ and the distance to the nearest neighbor less than 60h-1 Mpc. We defined the morphological types of these clusters accordingly to advance Panko’s classification scheme using the ``Cluster Cartography'' set. The main part of these clusters belongs to the open O-type clusters without any signs of a complex structure. However, we detected the presence of the inner regular substructures for 10 clusters. They are linear substructures, X- and Y-type crosses, and compact short chains. All substructures were detected on a statistically significant level. The detected substructures have special orientations of galaxies, which note to their 3D type. Practically all studied galaxy clusters are young.
Magnetic Field in some Selected Directions of the Galaxy: Sagittarius Spiral Arm 0.2 MB
R. R. Andreasyan, G. M. Paronyan, A. G. Sukiasyan
Pages: 265-269
Abstract. Faraday rotation data on 180 pulsars are used in a detail study of the magnetic field in the direction of galactic longitude 40° < l < 70°, including the Sagittarius spiral arm region. The highly regular magnetic field in northern hemisphere of galaxy is directed to the Sun, when the magnetic field of southern hemisphere is directed from the Sun. We propose that the Sagittarius spiral arm lies mainly to the north of the Galactic plane, while the magnetic field with opposite direction below this plane is the field of the halo of the southern hemisphere of the Galaxy.
Comparison of [CII] 158μm line widths to luminosities 0.1 MB
A.L. Samsonyan
Pages: 270-273
Abstract. A comparison of [CII]158 μm emission line widths to different luminosities is presented to decide if any luminosity relates to velocity dispersion. [CII]158 μm emission lines are observed with Herschel PACS for 379 galaxies and the archival data for [CII] line widths are taken from http://cassis.sirtf.com/herschel/. Emission line widths are compared to [CII] luminosities, to near-infrared 1.6 μm luminosities and to infrared 22μm luminosities. H magnitudes are taken from 2MASS catalogue, and 22 μm fluxes from the WISE catalogue.
Biermann Battery and Magnetic Fields of Accretion Discs 0.1 MB
R. R. Andreasyan, I. K. Marchevsky, V. E. Martynova, E. A. Mikhailov
Pages: 274-279
Abstract. Magnetic fields should be studied to understand different processes in accretion discs, such as transition of angular momentum which is closely connected with them. There are different ways to describe the growth of magnetic fields of cosmic objects. One of them is based on Biermann battery mechanism which previously has been used to study the origin of magnetic fields in galaxies. It is based on different masses and same absolute values of charges of protons and electrons, which move across the disc. They interact with rotating medium, get azimuthal velocity and produce circular currents that are associated with the magnetic fields in the disc. Such magnetic field influences the motion of the charged particles that created it, and we should take into account the feedback. Mathematical description of this mechanism leads us to the Fredholm-type integral equation of the 2nd kind. In the presented work it is solved numerically using Galerkin methods. Here we give the solutions of different cases.
Failure of the hypothesis of accelerated expansion of the universe 0.1 MB
A. P. Mahtessian, G. S. Karapetian , M. A. Hovhannisyan, L. A. Mahtessian
Pages: 280-286
Abstract. Our estimates of the cosmological parameters within the ΛCDM model and the model with zero cosmological constant are very different from other studies. The purpose of this report is to draw attention to the difference between our approach and the approaches of other authors and to evaluate the correctness of these approaches.
Multiwavelength Space Astronomy 0.4 MB
A. M. Mickaelian, G. A. Mikayelyan, H. V. Abrahamyan, G. M. Paronyan
Pages: 287-294
Abstract. Because the Earth’s atmosphere is not transparent for the most of the electromagnetic waves, Space Astronomy was born in 1960s to complement ground-based observations and to provide us with multiwavelength data from gamma-ray to radio. Most Space observatories work in gamma-ray, X-ray, UV and IR, as well as there are also optical and other Space telescopes. We will review the most important Space telescopes: their important technical parameters, scientific results and discoveries. Among them there are (by increasing wavelengths) Fermi, Swift, INTEGRAL, ROSAT, Chandra, XMM, GALEX, Hubble, Gaia, James Webb, Herschel, WISE, Spitzer, IRAS and many others. These telescopes make the Space Astronomy truly multiwavelength and the combination with ground-based data allows us to have better understanding of the Universe and phenomena going on in its all varieties.
Youth project Space-π using small spacecraft for research of near-Earth space and remote sensing of the earth 0.2 MB
S.B. Makarov, S.V. Zavjalov, S.V. Volvenko, A.K. Aharonyan, V.H. Avetisyan
Pages: 295-298
Abstract. This work is devoted to the implementation of the scientific and educational project "Space-π" for the development and production of small spacecraft on the domestic digital platform in order to implement schoolchildren's projects. A very important part of this work is that a lot of school groups take part in it, not only from St. Petersburg, but from all over Russia in general, and in the future from other countries. They have the opportunity to participate via the Internet both in the processing of information and in the process of how the satellite is manufactured.
Detectors for space electronics based on the quantum dots and wells 0.1 MB
R.V. Ustimenko, M.Ya. Vinnichenko , H.A. Sarkisyan, D.B. Hayrapetyan, E.M. Kazaryan
Pages: 299-301
Abstract. One of the promising areas of research applicable in astrophysics is the study of the properties of quantum dots (QDs) and quantum wells (QWs) in the IR region of the spectrum. The IR region of the spectrum contains a huge amount of astronomical information. Devices based on GaAs/AlGaAs QWs and Ge/Si QDs can serve as detectors and sources of IR radiation. In the current work, the photoluminescence, absorption, and transmission spectra of these nanoheterostructures were obtained in the near, mid, and far IR ranges using Fourier spectroscopy. Thus, the studied optical properties of QWs and QDs make it possible to use these structures in astrophysics as sources and detectors of IR radiation.
Robotising Existing Astronomical Observatories 0.1 MB
G. Tuparev, H. R. Andreasyan, T. M. Jackson
Pages: 302-307
Abstract. Astronomical observatories can be operated either manually or remotely, but both of these options currently have many disadvantages. Manual observatories require real-time staffing by on-site astronomers and technicians, and observation time is often not used optimally. Remote observatories, on the other hand, often make it cumbersome or near-impossible to modify any observing schedules already fed into the system, making reacting to important events like gamma-ray bursts unrealistic. In addition, it is generally expected that the cheapest way to upgrade an ageing observatory is to simply build a new one, but this is not always the case. For many relatively modern observatories, it is possible to convert to a fully robotic mode of operation. In these proceedings, we describe a few straightforward ways to robotise an existing observatory and how to connect it to a network of other robotic observatories. We also discuss the use of inexpensive device controllers, the importance of emergency shut-down procedures, the introduction of local and network schedulers, and the implementation of fully automated observation planning. We finally also describe hardware and software solutions, including an example of how this is currently being applied.
New concept of ground based-space radio interferometer and modern technologies application for deployment simulation of precise petal space reflector 0.4 MB
V.I. Bujakas, M.D. Glotov
Pages: 308-314
Abstract. Radio interferometers make it possible to achieve high resolution of astronomical observations due to the large base of the measuring instrument. The ground-space radio telescope RadioAstron holds the record for angular resolution among radio interferometers, its maximum base was about 340 000. km. The project turned out to be very successful. The new concept is based on the experience of the RadioAstron project and proposes the use of several orbiting radio telescopes that work together in the cm and mm spectral regions. This will further increase the base of the radio interferometer and expand the viewing angle at each current moment of time. Modern technical means make it possible to launch into orbit several identical mirrors operating in the short-wavelength region of the spectrum with an effective area no worse than the effective area of the RadioAstron antenna at a wavelength of 1.35 cm. Thus, the project can be quite budgetary. Now 3D modeling and 3D printing technologies make it possible to speed up and simplify the development of physical models. The manufacture of complex parts used to take days of work. Now we can use 3D printing to make different parts in a matter of hours. In the physical model of a new petal mirror project, we used FDM and LCD printing technologies. The paper discusses examples of manufacturing petal mirror physical model components, limitations and features of these technologies.
Application of radio wave reflections from meteor showers falling into the near-Earth space for organizing communications in the subpolar regions of the Earth 0.1 MB
S.V. Zavjalov, S.B. Makarov, I. Lavrenyuk, A.K. Aharonyan, V.H. Avetisyan
Pages: 315-317
Abstract. In this article we consider the possibilities of using organization of meteor-burst communication system in the subpolar regions of the Earth. Orthogonal frequency-division multiplexing (OFDM) signals as a general form of multi-frequency signals with amplitude limitation were applied. Optimal values of Peak-to-average power ratio (PAPR) reduction were found.
A Modern Space Situational Awareness System 0.1 MB
T. M. Jackson, H. Holland, G. Tuparev, M. Steinbatz, W. Promper, D. Weinzinger, E. Doeberl
Pages: 318-323
Abstract. We, Tuparev AstroTech in partnership with Astro Syteme Austria, present a next-generation Space Situational Awareness (SSA) system currently being created for the tracking and characterisation of satellites and space debris in the age of big-data astronomy. Our SSA system will be based on the image processing of white-light images to detect streaks produced by satellites and space debris. These images will be obtained by a network of 20-30 custom and in-house built SSA observatory stations, which will be made operational worldwide over the coming decade. The system will use machine learning algorithms to choose the optimal part of the sky to observe at any given moment, analyse the incoming data on-site and in real-time, and deliver various standardised data packages and science-quality images to be stored on a bespoke central archive capable of storing petabytes of data. With this system, we aim to cover a greater geographical and celestial area than any previous SSA system, to create a scalable system that is both fast and efficient, and to enable access to orders of magnitude more storage capacity and information than any other system currently available, commercial or governmental.
The 'Observation Technologies' in Ancient Armenia 1.2 MB
H. Malkhasyan
Pages: 324-339
Abstract. The paper provides some general information on the recent studies of the “Zorats Qarer” megalithic monument, in particular, some “observational instruments” and the possible observational methodology. Several types of “observational tools” are described, namely “observational platforms” that have their own “guiding stones”, stones with holes and the so-called “angular stones”. Observational “stone tools” of the “mixed type” (multifunctional) were also found in the monument. Recent studies have also shown that the observations were made in 3 main positions: standing, sitting (“on the seating platform”) and kneeling. With the help of the mentioned instruments, apart from the sunrise and sunset of the solstices and equinoxes, the heliacal rising and setting of bright stars, as well as their acronycal rising and cosmical setting were observed in the monument as well. In addition to the mentioned phenomena, apparent appearance and disappearance of stars at the points above the horizon were observed. The observers were also interested in the transitions of the stars in their upper and lower (for circumpolar stars) culmination points. The mentioned “technologies” were mainly used between the 9th and 3rd millennia BC.
Optical properties of variable radio sources from NVSS and FIRST 0.1 MB
H. V. Abrahamyan, A. M. Mickaelian, G. M. Paronyan, G. A. Mikayelyan
Pages: 340-342
Abstract. We have carried out a number of studies to reveal radio properties of active galaxies, namely AGN and Starbursts. A major work was related to the cross-correlation of NVSS and FIRST radio catalogues and revelation of variable radio sources. Most probably, most of them are extragalactic ones; AGN and Starbursts. We have carried out spectroscopic classification of 6301 of these objects and revealed many Seyferts, LINERs and Starbursts. We have also studied radio properties of VCV-13 AGN, Markarian galaxies and Blazars. One of the aims of our studies is to establish the radio/opt flux ratio limit between normal galaxies detected in radio and radio loud active galaxies. The ultimate goal of these studies is to combine results obtained from radio studies and derived radio properties of active galaxies with gamma-ray, X-ray, UV, optical, IR and submm/mm to have the overall multiwavelength understanding on these objects.
New late-type stars found in the BAO Plate Archive 0.1 MB
G. R. Kostandyan , H. V. Abrahamyan, G. A Mikayelyan, G. M Paronyan
Pages: 343-344
Abstract. The BAO Plate Archive low-resolution spectral plate centered α = +04h; δ = +240 is analyzed to find new late-type stars. 25 new late-type stars have been detected. We have performed cross-correlations with GAIA DR3, USNO-B1.0, 2MASS, AllWISE, IRAS PSC/FSC, AKARI and SDSS. For new detected objects, we present luminosity classes estimated from Gaia DR3 and 2MASS photometry and available proper motions. The majority of the objects are red giants.
Detailed investigation of quasar’s 1055+01 0.3 MB
L. A. Mahtessian, M. A. Hovhannisyan, R. A. Karapetyan, L. A. Amiraghyan, M. L. Grigoryan, A. P. Mahtessian
Pages: 345-350
Abstract. QSO 1055+01 studies show that this extended quasar is a very, powerful, active and variable extragalactic source, with many compact sources around. We shown that the distribution of extragalactic sources around is homogenous with high density.
PhD THESES RELATED ARTICLES
Search and study of young infrared stellar clusters 0.4 MB
N. M. Azatyan
Pages: 351-360
Abstract. The “bricks” of the Galactic disc are giant molecular clouds, which are birthplaces of stellar population. Therefore, there is a genetic connection between young stellar objects (YSOs) and their surrounding Interstellar Medium (ISM). The thesis is devoted to a search for young stellar clusters in the vicinity of IRAS sources and a detailed study of three selected star-forming regions: IRAS 05137+3919, 05168+3634, and 19110+1045, which includes determining the parameters of the ISM based on far-infrared data, the identification and classification of YSOs using color-color and color-magnitude diagrams, the modeling of stellar parameters, and the construction and interpretation of the luminosity functions. It is likely that the three young stellar clusters were formed under different scenarios. The age spread of the IRAS 05137+3919 and 05168+3634 regions is much larger, and, therefore, we concluded that the stellar population is formed as a result of independent condensations. The age spread of the IRAS clusters’ members in the third region, which is a pair of ultra-compact HII regions (UCHIIs), namely G45.12+0.13 and G45.07+0.13, is small. The small age spread suggests that the clusters may originate from a single triggering event. Moreover, high-mass YSOs were obtained only in the G45.07+0.13 and G45.12+0.13 UCHII regions where the ISM initial density was higher and the star formation proceeded relatively quickly.