Investigation of the Galactic Bar based on Photometry and Stellar Proper Motions

Abstract

A new method for selecting stars in the Galactic bar based on 2MASS infrared photometry in combination with stellar proper motions from the Kharkiv XPM catalogue has been implemented. In accordance with this method, red clump and red giant branch stars are preselected on the color -- magnitude diagram and their photometric distances are calculated. Since the stellar proper motions are indicators of a larger velocity dispersion toward the bar and the spiral arms compared to the stars with circular orbits, applying the constraints on the proper motions of the preselected stars that take into account the Galactic rotation has allowed the background stars to be eliminated. Based on a joint analysis of the velocities of the selected stars and their distribution on the Galactic plane, we have confidently identified the segment of the Galactic bar nearest to the Sun with an orientation of 20${}^{\circ }$--25${}^{\circ }$ with respect to the Galactic center -- Sun direction and a semimajor axis of no more than 3 kpc.

14 pages, 7 figures

References in corpus (6)

• Modelling the Galactic bar using OGLE-II Red Clump Giant Stars
• The Long Bar in the Milky Way. Corroboration of an old hypothesis
• Galactic Rotation Curve and Spiral Density Wave Parameters from 73 Masers
• Kinematics of the outer pseudorings and the spiral structure of the Galaxy
• Red Giant Clump in the Tycho-2 Catalogue
• The Red Giant Branch in the Tycho-2 Catalogue

Cited by in corpus (7)

• Evolution of the Milky Way with radial motions of stars and gas I. The solar neighborhood and the thin and thick disk
• Proper motions and kinematics of selected bulge globular clusters
• Different studies of the global pitch angle of the Milky Way's spiral arms
• Combined dynamical effects of the bar and spiral arms in a Galaxy model. Application to the solar neighbourhood
• The structure of the Milky Way based on unWISE 3.4$\mu$m integrated photometry
• Hercules and Wolf 630 Stellar Streams and Galactic Bar Kinematics
• Three-dimensional decomposition of galaxies with bulge and long bar