Internal Kinematics of Stellar Populations in the Globular Cluster NGC 6266

Globular clusters are mainly composed of two groups of stars known as first and second populations. Several formation scenarios have been proposed to explain their origin, but none fully satisfy the observational data. According to many of these scenarios, second population stars originated from material ejected into the interstellar medium by more massive first-population stars. Other theories suggest that globular clusters consist of a single generation of stars, and the second population acquired its particular chemical composition due to exotic physical phenomena that occurred in the proto-globular cluster. Dynamical simulations that assume multiple populations as the result of a sequence of distinct episodes of star formation predict different kinematic signatures for first and second population stars. In this thesis, I extended these studies to the Galactic globular cluster NGC 6266. First, I performed state-of-the-art photometry to obtain both the photometric and astrometric catalogs for this cluster. After correcting the photometric catalog for differential reddening, I produced the first chromosome map for NGC 6266, successfully distinguishing between first and second population stars in both the red giant branch and the main sequence. Finally, I developed a Markov Chain Monte Carlo approach to estimate the intrinsic velocity dispersion of the radial and tangential components of stars in each population as a function of their distance from the cluster center. The results of this work reveal no significant differences in the kinematic behavior of the two populations within 2.5 arcminutes from the cluster center, a region extending to twice the half-light radius of the cluster. The explanation for these observations, lies in the dynamical evolution of the cluster, since two-body relaxation may have erased any initial kinematic differences between the populations. For a cluster like NGC 6266, the half-mass relaxation timescale is significant compared to its age, making this process a likely contributor to the observed uniformity. Understanding the implications of two-body relaxation is therefore essential for assessing the impact of dynamical age on the cluster’s kinematics.