High-Precision Radial Velocities for Faint Giants: Radial Velocities of Extreme Halo Systems and the Mass of the Galaxy
Abstract
Radial velocities of stars in the distant halo globular clusters Palomar 4, 14, and 15 are presented. These MMT echellette data are combined with the MMT data for additional remote cluster giants, along with new and old data for other halo objects, for a compendium of velocities for 16 remote systems (R greater than 50 kpc). From these, the mass of the Galaxy is reassessed, to obtain M(G) = 5 + or - 2 x 10 to the 11th solar masses, if velocities are distributed isotropically. The quoted uncertainty in this estimate merely reflects the few remaining ambiguous velocities. The orbital characteristics are apparently now the largest potential source of error in the mass determination; in particular, the exclusion of radial orbits increases the mass estimate considerably.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1986
- DOI:
- 10.1086/184634
- Bibcode:
- 1986ApJ...302L..45O
- Keywords:
-
- Galactic Structure;
- Globular Clusters;
- Milky Way Galaxy;
- Radial Velocity;
- Astrometry;
- Halos;
- Mass To Light Ratios;
- Astrophysics;
- CLUSTERS: GLOBULAR;
- GALAXIES: MILKY WAY