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.
Cite
@article{arxiv.1403.2533,
title = {Proper motions for HST observations in three off-axis bulge fields},
author = {Mario Soto and Hugo Zeballos and Konrad Kuijken and R. Michael Rich and Andrea Kunder and Tri Astraatmadja},
journal= {arXiv preprint arXiv:1403.2533},
year = {2015}
}
Comments
14 pages, 14 figures, published in Astronomy & Astrophysics