Core velocity dispersion and mass-to-light ratio of the old Magellanicglobular cluster NGC 1835.
Abstract
The projected velocity dispersion in the core of the old Large Magellanic Cloud globular cluster NGC 1835 is deduced from integrated light spectra obtained at the European Southern Observatory (ESO) with CASPEC, the Cassegrain ESO Echelle Spectrograph mounted on the ESO 3.6-m telescope at La Silla, Chile. A numerical cross-correlation technique gives a projected velocity dispersion σ_p_(core) = 10.1 + 0.2 km s^-1^. Multimass anisotropic King-Michie dynamical models are applied to the observational constraints given by the surface brightness profile and the above central projected velocity dispersion. Depending on the model, the values obtained for the total mass of the cluster range from 0.70 to 1.55 10^6^ M_sun_, with a mean total mass <M_tot_> = 1.0 +/- 0.3 10^6^ M_sun_, corresponding to a global mass-to-light ratio <M/L_V_> = 3.4 +/- 1.0 (M/L_V_). The present study shows that when the same kind of dynamical models (King-Michie) constrained by the same kind of observations (surface brightness profile and central value of the projected velocity dispersion) are applied to an old rich Magellanic globular cluster, viz., NGC 1835, the results seem similar to those obtained in the case of galactic globular clusters. Consequently, the rich old globular clusters in the Magellanic clouds could be quite similar (in mass and M/L_V_) to the rich globular clusters in the Galaxy.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1990
- Bibcode:
- 1990A&A...239..142D
- Keywords:
-
- Globular Clusters;
- Magellanic Clouds;
- Mass To Light Ratios;
- Velocity Distribution;
- Astronomical Models;
- Astronomical Observatories;
- Astronomical Photometry;
- Charge Coupled Devices;
- Stellar Evolution;
- clusters: globular;
- galaxies: Magellanic clouds;
- data analysis;
- Astrophysics