Globular clusters in the central region of the Milky Way galaxy. II. Frequency analysis of orbits built from Gaia ED3 data

Abstract

This work represents the second stage of research aimed at studying the influence of the bar on the orbital dynamics of globular clusters (Bajkova, Smirnov, and Bobylev, 2023). The orbits of 45 globular clusters in the central galactic region with a radius of 3.5 kpc have been analyzed by spectral dynamics methods in order to identify objects captured by the bar. Since the parameters of the bar of the Milky Way are known with a very large uncertainty, orbits were constructed and their frequency analysis was carried out with varying the mass, length and angular velocity of rotation of the bar in a wide range of values with a fairly dense grid. The orbits were integrated 2.5 billion years backward. As a result, globular clusters supporting the bar were identified for each set of bar parameters. To form the 6D phase space required for orbit integration, we used the most accurate astrometric data from the Gaia satellite (Vasiliev and Baumgardt, 2021), as well as new refined average distances to globular clusters (Baumgardt and Vasiliev, 2021).