Oknyansky V.L., Winkler H., Tsygankov S.S., Lipunov V.M., Gorbovskoy E.S., van Wyk F., Buckley D.A.H., Tyurina N.V. «Discovery of more changing look events in NGC 1566» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 32, с. 75-78 (2019)

https://doi.org/10.18524/1810-4215.2019.32.182514

Shepelev V.A., Melnik V.N., Vashchishin R.V. «Preliminary results of interferometric observations of the quiet Sun at the frequencies 8–32 MHz» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 31, с. 159-162 (2018)

https://doi.org/10.18524/1810-4215.2018.31.144687

Sidorchuk M.A., Vasilenko N.M., Ulyanov O.M., Konovalenko O.O., Mukha D.V., Abramenkov E.A., Sidorchuk K.M., Miasoied A.I. «50 years of research in continuum at the UTR-2 radio telescope» Радиофизика и радиоастрономия (Украина), 26, № 4, с. 287-313 (2021)

Purpose: The results of research in continuum decameter-wave radio emission of the Galaxy background, ionized hydrogen regions, supernova remnants, extragalactic discrete sources, extended galaxies, galactic clusters, extragalactic background are given. The aim of this work is reviewing the results achieved for over 50-years of the UTR-2 radiotelescope research of our Galaxy and its population, as well as extragalactic radio sources in the continuum radio emission spectrum at extremely low frequencies for the ground based observations. Design/methodology/approach: The review, analysis, collection of archival data in various publications related to the subjectof this work. Findings: The basic results of studying the ionized hydrogen regions, supernova remnants, Galaxy background emission and its large-scale structure are given, and the maps of these sources are obtained. The catalog of extragalactic discrete radio sources of the most Northern sky part and the cosmological conclusions based on its analysis are described; the estimate of the isotropic extragalactic background brightness temperature is obtained; for the first time, the observational results for the Andromeda galaxy and two galactic clusters Coma and A2255 are given briefly. Conclusions: All the results presented here emphasize the uniqueness and importance of research in the decameter wavelength range, and the large area, flexibility of structure, continuous improvement make the UTR-2 radio telescope an indispensable tool for solving the most important tasks of modern radio astronomy, despite its respectable age. For example, only in the range of 10 to 30 MHz the ionized part of the most common element in the universe, the hydrogen, becomes optically thick and begins to absorb the synchrotron emission on the line of sight, which allows rather easy separation of thermal and non-thermal components of radioemission. This property allows to determine the ionized hydrogen regions’ electron temperature and the electron concentration on the line of sight independently in studying the hydrogen emission regions. When studying the supernova remnants, we can determine the ionized matter location by their spectrum drops – before, inside or behind the remnant. Based on the HB3 supernova remnant radio imagies, an assumption was made on the existence of an ionized hydrogen relic shell aroundit, being caused by the initial ultraviolet flash of a supernova. For the first time, the maps of the Northern sky large-scale structure in the declination range from –15 to +85° at extremely low frequencies 10, 12.6, 14.7, 16.7, 20 and 25 MHz for the ground-based observations are published, which, besides their own scientific value, may allow to correct the UTR-2 radio telescope imaging results. Using the full-resolution UTR-2 maps and the developed method of multifrequency T–T diagrams, it was possible to separate the background radiation into galactic and extragalactic components and construct the spectrum of the latter. From the analysis of the most complete decameter wavelength range catalog of discrete sources, it follows that there is a gap in the redshift spatial distribution for all classes of extragalactic sources. The existence of an ionized hydrogen ring in the Andromeda Nebula disk has been suggested. It is shown that the main partof the galaxy clusters decameter-wave emission comes from haloes and relics.

Vasilenko N.M., Sidorchuk M.A. «UTR-2 low frequency continuum survey of the northhen sky. Part II» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 32, с. 110-113 (2019)

https://doi.org/10.18524/1810-4215.2019.32.182536

Khramtsov V., Dobrycheva D.V., Vasylenko M.Yu., Akhmetov V.S. «Deep learning for morphological classification of galaxies from SDSS» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 32, с. 21-23 (2019)

https://doi.org/10.18524/1810-4215.2019.32.182092

Vasylenko M.Yu., Dobrycheva D.V., Vavilova I.B., Melnyk O.V., Elyiv A.A. «Verification of machine learning methods for binary morphological classification of galaxies from SDSS» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 32, с. 46-51 (2019)

https://doi.org/10.18524/1810-4215.2019.32.182538

Stepkin S.V., Konovalenko O.O., Vasylkivskyi Y.V., Mukha D.V. «Interstellar medium and decameter radio spectroscopy» Радиофизика и радиоастрономия (Украина), 26, № 4, с. 314-325 (2021)

Purpose: The analytical review of the main results of research in the new direction of the low-frequency radio astronomy, the interstellar medium radio spectroscopy at decameter waves, which had led to astrophysical discovery, recording of the radio recombination lines in absorption for highly excited states of interstellar carbon atoms (more than 600). Design/methodology/approach: The UTR-2 world-largest broadband radio telescope of decameter waves optimally connected with the digital correlation spectrum analyzers has been used. Continuous modernization of antenna system and devices allowed increasing the analysis band from 100 kHz to 24 MHz and a number of channels from 32 to 8192. The radio telescope and receiving equipment with appropriate software allowed to have a long efficient integration time enough for a large line series simultaneously with high resolution, noise immunity and relative sensitivity. Findings: A new type of interstellar spectral lines has been discovered and studied, the interstellar carbon radio recombination lines in absorption for the record high excited atoms with principal quantum numbers greater than 1000. The line parameters (intensity, shape, width, radial velocity) and their relation ship with the interstellar medium physical parameters have been determined. The temperature of line forming regions is about 100 K, the electron concentration up to 0.1 cm^–3 and the size of a line forming region is about 10 pc. For the first time, radio recombination lines were observed in absorption. They have significant broadening and are amplified by the dielectronic-like recombination mechanism and are also the lowest frequency lines in atomic spectroscopy. Conclusions: The detected low-frequency carbon radio recombination lines and their observations have become a new highly effective tool for the cold partially ionized interstellar plasma diagnostics. Using them allows obtaining the information which is not available with the other astrophysical methods. For almost half a century of their research, a large amount of hardware-methodical and astrophysical results have been obtained including a record number of Galaxy objects, where there levant lines have been recorded. The domestic achievements have stimulated many theoretical and experimental studies in other countries, but the scientific achievements of Ukrainian scientists prove the best prospects for further development of this very important area of astronomical science.

Khlamov S.V., Savanevych V.E., Briukhovetskyi O.V., Dikov E.N., Vavilova I.B. «Development and improvements of computational methods implemented to the Colitec software» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 31, с. 211-215 (2018)

https://doi.org/10.18524/1810-4215.2018.31.144076

Vavilova I.B., Babyk Iu.V. «New approach for analysis of the x-ray data in cores of galaxy clusters: binning on the concentration rings, contour binning, and wavelet transforms» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 31, с. 239-246 (2018)

https://doi.org/10.18524/1810-4215.2018.31.146678

Vasylenko M.Yu., Dobrycheva D.V., Vavilova I.B., Melnyk O.V., Elyiv A.A. «Verification of machine learning methods for binary morphological classification of galaxies from SDSS» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 32, с. 46-51 (2019)

https://doi.org/10.18524/1810-4215.2019.32.182538

Vdovichenko S ., Kovtyukh V.V., Keir L.E. «LIthium-rich classical Cepheid V1033 Cyg: evolutionary status» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 32, с. 83-86 (2019)

https://doi.org/10.18524/1810-4215.2019.32.182232

Velichko A.B., Fedorov P.N. «Kinematics of the milky way from velocities of young red clump giants using the PMA and GAIA DR2 data» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 31, с. 123-127 (2018)

https://doi.org/10.18524/1810-4215.2018.31.144742

Velichko S.F., Andreev M.V. «Photometry of comet с/2009 p1 (Garradd) before and after perihelion» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 31, с. 196-198 (2018)

https://doi.org/10.18524/1810-4215.2018.31.144748

Vidmachenko A.P., Steklov A.F. «Material of cometary nuclei and asteroids can be studied in the Earth's orbit» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 32, с. 176-177 (2019)

https://doi.org/10.18524/1810-4215.2019.32.181911

Fathi M., Villanueva J.R. «The role of elliptic integrals in calculating the gravitational lensing of a charged Weyl black hole surrounded by plasma» Вестник Камчатской региональной ассоциации "Учебно-научный центр" (КРАУНЦ). Серия: Физико-математические науки, 36, № 3, с. 165-188 (2021)

We mainly aim at highlighting the importance of (hyper-)elliptic integrals in the study of gravitational effects caused by strongly gravitating systems. For this, we study the application of elliptic integrals in calculating the light deflection as it passes a plasmic medium, surrounding a charged Weyl black hole. To proceed with this, we consider two specific algebraic ansatzes for the plasmic refractive index, and we characterize the photon sphere for each of the cases. This will be used further to calculate the angular diameter of the corresponding black hole shadow. We show that the complexity of the refractive index expressions, can result in substantially different types of dependencies of the light behavior on the spacetime parameters.

Voitsekhovskiy V.V., Tugay A., Tkachuk V.V., Shevchenko S.Yu. «X-ray emission of ICRF sources» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 31, с. 47-51 (2018)

https://doi.org/10.18524/1810-4215.2018.31.144692

Voitsekhovskiy V.V., Tugay A.V. «Simulation of large-scale structure of universe by gaussian random fields» Публикации Одесской астрономической обсерватории (Odessa Astronomical Publications, Украина), 31, с. 52-55 (2018)

https://doi.org/10.18524/1810-4215.2018.31.144752