Proper motions for HST observations in three off-axis bulge fields

Abstract

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 ACS observations taken 9 and 10 years apart, and they reach accuracies better than 0.9 mas/yr 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.

14 pages, 14 figures, published in Astronomy & Astrophysics

References in corpus (8)

• Stellar Proper Motions in the Galactic Bulge from deep HST ACS/WFC Photometry
• Modelling the Galactic bar using OGLE-II Red Clump Giant Stars
• The Bulge Radial Velocity Assay (BRAVA): I. Techniques and a Rotation Curve
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• Transverse kinematics of the Galactic bar-bulge from VVV and Gaia
• Proper motions in the VVV Survey: Results for more than 15 million stars across NGC 6544
• Kinematic data rebuild the Nuclear star cluster as the most metal rich region of the Galaxy
• Mapping the tilt of the Milky Way bulge velocity ellipsoids with ARGOS and $Gaia$ DR2