Globular Cluster Mass Functions
Abstract
Deep imaging data in the I bandpass for three globular clusters were used to construct their luminosity and mass functions. These new data for Omega Cen, M5, and NGC 6752, together with existing data for M13, NGC 6397, and M71 were then employed to investigate any symptomatics of the cluster mass function slopes and their evolution. A related question also considered was the relation between the currently observed and the IMF slopes. While definitive answers regarding the evolution of globular cluster mass function slopes are not yet possible, mainly due to the small existing sample of observed mass functions extending down to low masses (M below 0.2 solar masses) and to restrictions in the theoretical modeling, certain trends are becoming apparent. In particular, it does appear that cluster evolution of stars has been important in modifying the cluster mass function slopes for at least two and possibly three of the clusters studied. A very important and quite robust result is that some (and perhaps all) clusters probably have very steep IMFs with the slope likely exceeding 2.5 (Salpeter value 1.3). This result suggests that low mass Population II stars may be an important component of the mass budget of the halo if the spheroid's mass function is similar to that seen in globular clusters.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1991
- DOI:
- 10.1086/170637
- Bibcode:
- 1991ApJ...381..147R
- Keywords:
-
- Globular Clusters;
- Stellar Luminosity;
- Stellar Mass;
- Brown Dwarf Stars;
- Dark Matter;
- Milky Way Galaxy;
- Astrophysics;
- CLUSTERS: GLOBULAR;
- LUMINOSITY FUNCTION;
- STARS: LOW-MASS