Finding out the velocity anisotropy parameter for some globular clusters: the case of stationary model

Abstract

The problem of determination of the velocity anisotropy parameter (A) from star density profiles in globular clusters is considered. The calculations are performed for following clusters: M3, M12, M13, M15, M55, M56, Palomar 3, Palomar 14, NGC5139 (Omega Centauri) and NGC6535. We found that for most clusters is A=0. For M56 the parameter is calculated at limiting magnitudes B=21.5 and B=19.0 and we found A=0.8 and A=0.3 respectively. For Omega Centauri the anisotropy parameter is determined in three separate regions and we found: A=0 for central region, A=0.1 for middle region and A=0.3 for halo.