Search academic texts

Information × Registration Number 0220U102396, 0117U004968 , R & D reports Title The method of Vector Spherical Harmonics for kinematic investigations of our Galaxy based on space and ground data. popup.stage_title Head Ahmetov Volodymir S., Кандидат фізико-математичних наук Registration Date 12-03-2020 Organization V.N. Karazin Kharkiv National University popup.description2  Object of the research is stellar populations of the Galaxy and extragalactic objects. Method of the research is observational data processing, mathematical methods of statistics, generalization and comparative data analysis, the least square method, filtering and approximating data. The results are present in 14 publications (8 abstracts, 6 articles) as well as 7 oral talks at 5 different international conferences. The aim of the third stage of the project is to derive the kinematic parameters of the Galaxy from the data of the GaiaDR2 and PMA catalogs based on modern physical models as well as the method of the stellar velocity field decomposition onto Vector Spherical Harmonics (VSH). To analyze the kinematic parameters of the Galaxy, Main Sequence (MS) stars were selected and binned by colour. For these stars the dependence on colour is that on the stellar age as well. As a result, all stars with distances up to 1 kpc were divided into subsamples by colour, and kinematic parameters were derived for each subsample both within the framework of the Ogorodnikov-Milne model and with the use of VSH. Significant beyond-the-model harmonics were obtained with the use of VSH. To establish their physical meaning simulations of the stellar velocity field as well as a detailed study of the kinematic parameters of the Galaxy separately in the galactic hemispheres were required. For the latter, Zone VSH (ZVSH) were applied to allow the use of VSH for catalogues with partial coverage of the sky. The t211 and s310 beyond-the-model harmonics have been found to be related to the vertical gradient of the galactic linear rotational velocity. The results of the study formed the basis of the prepared PhD thesis. Product Description popup.authors Akhmetov Volodymyr S Velychko Hanna B Dmytrenko Artem M Khlamov Serhii V Khramtsov Vladyslav P popup.nrat_date 2020-04-01 Close