Proper motions for HST observations in three off-axis bulge fields
Year: 2014
Type: preprint
Abstract: Received; accepted Aims. This is the second in a series of papers that attempt to unveil the kinematic structure of the Galactic bulge through studying radial velocities and proper motions. We report here ∼ 15000 new proper motions for three low foreground-extinction off-axis fields of the Galactic bulge. Methods. Proper motions were derived from a combination of Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) and Advanced Camera for Surveys (ACS) images taken 8 and 9 years apart, and they reach accuracies better than 0.9 mas yr−1 for more than ∼ 10000 objects with magnitudes F814W ≤ 24. Results. The proper motion distributions in these fields are similar to those of Galactic minor axis bulge fields. We observe the rotation of main sequence stars below the turn-off within the Galactic bulge, as in the minor axis fields. Conclusions. Our stellar proper motions measurements show a significant bulge rotation for fields as far from the galactic plane as b ' −8◦. Key words. Galaxy:bulge – Galaxy: kinematics and dynamics – Galaxy: stellar content – Methods: data analysis 1.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3099748242