AN ADVANCED APPROACH TO THE DEFINITION OF THE “MILKY WAY GALAXIES-ANALOGUES”

Abstract

Our Galaxy — the Milky Way — has certain features of the structure and evolution. The morphological, photometric, kinematic, and chemodynamical properties are usually considered in search for the Milky Way galaxies-analogues (MWAs). The discovery of MWA galaxies with a larger number of simultaneous selection parameters, as well as more stringent constraints on a given parameter, yields a sample of MWA galaxies with properties closer to the true properties of the Milky Way. So, in general, such MW parameters as the morphological type, luminosity, color indices, structural parameters (size, bar, bulge, thin and thick disks, inner ring, halo), bulge- to-total ratio, stellar mass, star formation rate, metallicity, and rotation velocity were used in various combinations for comparison with other galaxies. However, the offset of some MW features in the multi-parameter space of MWAs features should be significant. The paper aims to give a brief overview of the problematics and to present our approach for studying Milky Way and MWAs match- ing characteristics (this project is supported by the National Research Fund of Ukraine). We propose to enlarge as much as possible the number of Milky Way features and compile various samples of MWAs in our co-moving cosmological volume for their further optimization. Such features can include 3D-kinematics of star’s movement in certain regions, low oxygen content on the periphery, low nuclear activity, and the lack of significant merging over the past 10 Gyrs (isolation criterion). This approach will make it possible to widely formulate the necessary and sufficient conditions for the detection of MWA galaxies as well as to reveal other MW multiwave- length features