Communications of the Byurakan Astrophysical Observatory (ComBAO)
Volume 67, Issue 1, June 2020
Effect of Continuum Scattering on Early-type Supergiants Spectra 0.2 MB
A. G. Nikoghossian
Abstract. The effect of radiation scattering in continuum on the frequency distribution of the observed flux in atmospheres of supergiants of the late B and A spectral classes is treated. Thomson scattering on free electrons, which is important for hydrodynamic balance and wind dynamics in extended atmospheres of these stars, is considered as a specific scattering mechanism in the continuum. It is shown how stars of the same bolometric luminosity and with equal radii can belong to different spectral classes. The dependence of the continuum shortwave drift on the density of rarefied plasma has been established. The role of Thomson scattering in different domains of the hydrogen spectrum is revealed.
On the Thermal Regime and Density in the Star-Forming Regions 0.3 MB
H. A. Harutyunyan, E. H. Nikoghosyan, N. M. Azatyan
Abstract. We developed an automatic code to determine some physical parameters describing the radiation of a simple one-temperature black body model and implemented it to calculating the temperatures and masses of molecular clouds in several star formation regions, using the observed IR emission fluxes for the chosen sources. Calculations show that the used commonly simpliﬁcations need to study in more detail for estimating the accuracy of computing results.
Spectral observations of Flare stars TZ Ari and Ross 867 0.3 MB
G. R. Kostandyan, N. D. Melikian , R. Sh. Natsvlishvili, and G. M. Paronyan
Abstract. The results of spectral observations of flare stars TZ Ari and Ross 867B are presented. Observations have been carried out by the 2.6m telescope of Byurakan Astrophysical Observatory in 1999, 2001 and 2018. The spectral cameras "ByuFOSC" and "SCORPIO" were used during the observations. A strong change of emission lines detected on TZ Ari in 2018, while at the same time the brightness changes of the star in all measured spectral ranges are within the framework of measurement errors. Slight variations of brightness and EWHα are detected in quiescent state of star during the observations in 1999. A strong flare of Ross 867B were observed, with a duration of more than 20min. In this case if EWHα shows strong change, when its maximum value corresponds to the photometric maximum of are, at the same time EWHα shows decrease, similar to that, observed earlier during the flares of stars EV Lac, HU Del, CM Dra and WX UMa.
Continuum Scattering and Formation of Emission Lines 0.2 MB
A. G. Nikoghossian
Abstract. The effect of radiation scattering in continuum on the spectral lines formation is treated. Compared to the early works in this direction, the conditions of emission lines appearance in the atmosphere with the temperature gradient with depth is discussed in detail. For simplicity's sake, the coherent scattering in the spectral line frequencies is adopted. By the example of atmospheres of supergiant stars of type A and adjacent classes, it is shown which lines and in what parts of the spectrum can be observed in the emission.
The observation of Angegh-Vulture (Cygnus) constellation in Armenia 32 000 years ago 0.4 MB
H. A. Malkhasyan
Abstract. The "Karahunge Observatory" or "Zorats Karer" megalithic monument-complex has been little studied and till today the opinions of different scholars on the age of its construction and significance vary widely. In this article, using astronomical and geometric methods, we have tried to show that this ancient astronomical observational complex could have been built only 32300 years ago by the Angegh-Vulture (Cygnus) constellation model, when the declination of the Sadr star corresponded to the local latitude. It has also been attempted to substantiate the direct link between the constellation and the structure in several respects, in particular, it has been shown that 7800 years ago, some changes were made to the structure, the opening of some stone holes, and the observations of some of the stars of the Angegh-Vulture (Cygnus) constellation. At the same time, however, the original layout-composition of the complex and its contents have been preserved.
The irreplaceable role of ubiquitous cosmic rays in the space chemistry: from the origin of complex species in interstellar molecular clouds to the ozone depletion in the atmospheres of Earth-like planets 0.4 MB
A. G. Yeghikyan
Abstract. A review is given of low-energy cosmic rays (1 MeV-10 GeV), which play an important role in the physics and chemistry of interstellar medium of our Galaxy. According to the generally accepted theory of star formation, cosmic rays penetrate into molecular clouds and ionize the dense gaseous medium of star formation centers besides due to a process of ambipolar diffusion they establish a star formation time scale of about 100-1000 thousand years. The source of cosmic rays in the Galaxy are supernovae remnants where diffusion acceleration at the shock front accelerates particles up to energies of 1015 eV. Being the main source of ionization in the inner regions of molecular clouds, cosmic rays play a fundamental role in the global chemistry of clouds, triggering the entire chain of ion-molecular reactions that make it possible to obtain basic molecules. The review also noted the importance of cosmic rays in atmospheric chemistry: playing a significant role in the formation of nitric oxide, especially with an increase in the flux, they cause a decrease in the concentration of ozone in the atmosphere with all climatic consequences.
Concept of scanning imaging device for optical telescopes 0.2 MB
Abstract. We propose an approach of a focal plane imaging device for a telescope, which is based on spatially-scanned solitary photodetector, and can be used as an alternative to matrix detectors (CMOS or CCD). This approach allows to set efficient sensor size, pixel resolution, sensitivity and recording time on customer demand. Technical feasibility of up to 200 pixel/mm (5000 ppi) spatial resolution for focal field of up to astronomical photographic plate size, with the detection noise-equivalent power of 3 x 1015 W⁄√(Hz ) and the measurement time of ≈ 1 minute per megapixel is justified.
Studies of Seyfert galaxies in Fesenkov Astrophysical Institute 0.3 MB
E. Denissyuk. R. Valiullin, Ch. Omarov, S. Shomshekova, M. Krugov, and B. Omar
Abstract. This article provides an overview of the main research results of a large group of Seyfert galaxies, carried out at Fesenkov Astrophysical Institute (FAI) over the past 50 years. Spectral observations have been performed since 1970. At an early stage, a three cascade image-tube (UM-92) was used as a radiation receiver. In the 1990s, the equipment was modernized, and at present, the modern CCD cameras are used as radiation detectors at the output of spectrographs.
The results of observations were used to determine the absolute fluxes of the emission lines and to study their profiles. Several additional emission features were detected on the wings of the broad emission lines Hα in the spectra of two galaxies NGC 4151 and Ark 120. These features are emitted by compact ionized objects, rotating in the field of Central Body (CB).
Photometric observations of Seyfert galaxies have been carried out at FAI since 2010. Light curves of more than 20 Seyfert galaxies have been obtained. In particular, the light curves of the galaxy NGC 4151, obtained last years, shows that an active stage of its nucleus took place in 2015-2016, when the brightness increased by 0m.5 in the V filter, and by almost 2m in the R filter. Then, in 2018-2019 there was a rather sharp decline of brightness, and B V R magnitudes returned to their minimal values.
PROCEEDINGS OF IAU SOUTH WEST AND CENTRAL ASIAN 3rd REGIONAL ASTRONOMICAL WORKSHOP
(11-13 September 2019, Byurakan, Armenia)
IAU South-West and Central Asian Regional Office of Astronomy for Development 0.2 MB
A. M. Mickaelian, S. V. Farmanyan, and G. A. Mikayelyan
Abstract. The International Astronomical Union (IAU) announced its Strategic Plan on Astronomy for Development in 2009, during the International Year of Astronomy (IYA). One of its main components was the creation of the Office of Astronomy for Development (OAD) and corresponding Regional Offices (ROADs) for implementation and coordination of its aims. The OAD was created in Cape Town, South Africa and later on ROADs were created in 11 regions. Since 2015, Armenia hosts one of them, IAU South West Asian (SWA), later renamed to South West and Central Asian (SWCA) ROAD. At present, already 6 countries have officially joined (Armenia, Georgia, Iran, Kazakhstan, Tajikistan, and Turkey), but the Office serves for a rather broad region, from Eastern Europe to Central Asia. Armenia's geographical location and its historical role in astronomy (both for well-known archaeoastronomical heritage and the presence of the famous Byurakan Astrophysical Observatory (BAO) founded by Viktor Ambartsumian in 1946) serve as a link between Europe and Eastern Partnership countries, Middle East and Asia in general. We run activities in 3 directions, Task Forces (TF): TF1 Universities and Research, TF2 Children and Schools and TF3 Public Outreach. We present our projects and all other accomplishments and discuss the role of our ROAD in maintaining contacts and development of astronomy in the region, as well as contacts between Europe and the Eastern Partnership countries. Most up-to-date information about the IAU SWCA ROAD is available on its webpage at http://iau-swa-road.aras.am/eng/index.php.
Astronomy in Armenia: Recent Activities 0.4 MB
A. M. Mickaelian, S. V. Farmanyan, and G. A. Mikayelyan
Abstract. A report on the activities and achievements of the Armenian Astronomical Society (ArAS) and the Armenian astronomy in general during the last years is given. ArAS membership, ArAS electronic newsletters (ArASNews), ArAS webpage, Annual Meetings, Annual Prize for Young Astronomers (Yervant Terzian Prize) and other awards, international relations, participation in international organizations, Byurakan International Summer Schools (BISS), regional and local schools, Byurakan science camps, astronomical Olympiads and other events, other matters related to astronomical education, astronomical heritage, amateur astronomy, astronomy outreach and ArAS further projects are described and discussed.
Under the Armenian sky-for development and interchange of experiences 0.3 MB
Abstract. The cooperation between two partners: Polish Association Under the common sky and Byurakan Astrophysical Observatory (BAO) was run in 2018/2019. The project based on its leading idea, experience, methodology and knowledge. The Association's fundamental aim is popularization of the cutting-edge knowledge about the Universe as well as teaching skills using modern technology like Stellarium program and telescopes. The future of the project in Armenia depends on schools, teachers and students. They have all the necessary knowledge, skills, equipment and help from the Association as well as BAO to continue their work.
"AYAS": From Aerospace Club to Aerospace Society 1.1 MB
A. E. Grigoryan
Abstract. The history of educational activity and linking the education with research in the aerospace-related areas in Armenia is presented – all the way from the creation of an extra-curricular study group for school students dubbed the "AYAS" Aerospace Club to the foundation of the "AYAS" Aerospace Society.
The State of Astronomy Education in Iran: Challenges and Solutions 0.3 MB
Abstract. Astronomy has a long history in Iran. Our ancestors were pioneered in astronomy and from ancient years was an excelled country in the construction and use of astronomical buildings. Today, there are more than 200 local astronomical societies and centers in the country that the amateur astronomy community has played a significant and influential role in the education and promotion of astronomy to the general public since 2000. A greater part of astronomy education was provided by amateur astronomers through outreaching events, observing nights, and education and outreach projects. Another part of it has been disseminated by science journalists who are amateur astronomers and astronomer teachers in the media and newspapers. Considering the enormous potential that has existed in the growth and development of Iranians in the field of astronomy, in the meantime, challenges such as the specific cultural and social constraints for women's activities, lack of sufficient knowledge of the teachers as well as the training required for them, the lack of a standard curriculum for teaching astronomy and network of astronomy teachers, and also economic barriers, have caused socio-economic development and education through Astronomy to grow less in Iran. This survey suggests challenges for teaching astronomy in general.
IAU100 Activities and Recent Developments in Turkish Astronomy 0.7 MB
Abstract. In this paper, astronomy activities in Turkey in the year of 2019 are summarized. Especially, public outreach activities and teacher training programs in the framework of IAU 100 celebrations are given. Current status of the Eastern Anatolia Observatory and Turkish Space Agency are also summarized. Finally, recently established working group on the legislation for the light pollution is introduced.
BAO Outreach Activities and Scientific Journalism in Armenia 0.3 MB
M. A. Asryan, S. V. Farmanyan, and A. M. Mickaelian
Abstract. The paper gives an overview of BAO Outreach Activities and Scientific Journalism in Armenia. We emphasize the role of scientific journalism in raising awareness among public on the topics of astronomy and science in general.
Scientific Tourism, Astronomical Tourism and Possible Solutions of Scientific Tourism 0.2 MB
R. E. Minasyan and N. Nalbandyan
Abstract. The article discusses the ways and prospects of the development of scientific, in particular astronomical, tourism in Armenia.
The Possible Potentials of Astrotourism in Caucasus 0.3 MB
Mohammad Javad Torabi
Abstract. Astrotourism is not a new topic, but it is certainly a title that has been in the forefront of tourism and astronomy for less than two decades. For nearly half a century, observatories and science centers have been opening their doors to the public on special occasions, such as Astronomy Day. However, for less than a decade, astrotourism has been the constant presence of tourists alongside professional astronomers, especially on weekends. They have made it possible by following all the principles. Until the early 1990s, one of the most important countries in the world to host the world's largest astronomical observatories was the Soviet Union. The Caucasus region in the former Soviet Union hosted very important observatories due to its high altitudes, pure nature, and very low amount of light pollution and, of course, the proper weather in warm seasons. Byurakan in Armenia, Abastumani in Georgia, Shamakhi in Azerbaijan, and BTA-6 in Russia are the four main collections left from that period. Fortunately, nearly two decades after the independence of the countries in the region, the restoration and updating of these observatories have been on the agenda. One of the helping arms to accelerate the revival of these observatories is to take advantage of the potential of astrotourism; especially with the location of these three countries near Iran, which has one of the largest astronomy enthusiast communities in the region.
Armenian Astro Tourism Map 0.5 MB
A. M. Mickaelian, S. V. Farmanyan, and G. A. Mikayelyan
Abstract. Armenia is a country with rich history, as well as high-level science. It is rich in scientific, particularly in astronomical sites, among which archaeological sites related to science, medieval universities, modern scientific institutions and science related museums can be mentioned. Examples of archaeological sites are ancient observatories, petroglyphs (rock art) of astronomical nature, as well as intangible heritage, such as Armenian calendars and chronology tightly related to the astronomical knowledge. Modern observatories and astronomical institutions having tools or laboratories which can be presented in terms of tourism, are considered as astronomical tourism sites as well. Space museum is astronomy and space science related museum. Despite the fact that Astronomical (Astro) Tourism is a new direction, it has great perspectives, and Armenia has a great potential in this field. It is very important to introduce Armenia from this aspect. In this paper we present major astronomical tourism centers of Armenia and the whole picture as a map.
Astro Tourism sites in Georgia 0.2 MB
Abstract. The main astro site in Georgia is the Abastumani Astrophysical Observatory. The history of astronomy in Georgia begins no later than IX century. During the Middle Ages, there were at least four observatories in Georgia, including the Arab Observatory in Tbilisi (Narikala – a fortress). This observatory operated between IX-XIV centuries. Two other observatories functioned in monasteries in eastern part and one - in western part of the country. All these places are active touristic sites in Georgia.
National Sky Fest in Turkey 0.4 MB
Süleyman Fişek and Sinan Aliş
Abstract. In this paper, TÜBÌTAK National Sky Fest which is held annually in Turkey is presented. In 2019, approximately 1000 people attended to the sky fest. This event has been organized since 1998 with an approximate participants of 400 each year. There are several activities in the festival which span the three days both in daytime and in night programs. TÜBÌTAK is planning to organize the event internationally for 2020.