The masses of globular clusters. II. Velocity dispersions and mass-to-light ratios.
Abstract
Dynamical masses have been determined for 10 southern globular clusters. High-dispersion coude spectra of the integrated light were used to determine the velocity dispersion at the centers of these clusters. The observed velocity dispersions (line-of-sight) range from 7.5 to 18.9 km/s. A method using Fourier techniques for accurately determining the velocity dispersion from integrated light spectra is described. The velocity dispersions were incorporated into King's (1966) self-consistent globular cluster models to determine the cluster masses. The required length scales were determined from comparison of King's (1966) theoretical surface density distributions with surface brightness and star distributions. The masses of these concentrated clusters range from 170,000 solar masses to 1.1 million solar masses. Absolute integrated magnitudes were combined with the mass estimates to give M/L values that range from 0.9 to 2.9, with a mean of 1.6.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1976
- DOI:
- 10.1086/154152
- Bibcode:
- 1976ApJ...204...73I
- Keywords:
-
- Globular Clusters;
- Mass To Light Ratios;
- Stellar Mass;
- Stellar Motions;
- Stellar Spectra;
- Velocity Measurement;
- Astronomical Models;
- Power Spectra;
- Radial Velocity;
- Star Distribution;
- Stellar Luminosity;
- Astrophysics