G. Andreuzzi, V. Testa, G. Marconi, G. Alcaino, F. Alvarado, R. Buonanno
Published 2002-10-02Version 1
We present VLT (FORS1) photometry of the lower main sequence (MS) of the Galactic Globular Cluster (GGC) NGC 6397, for stars located in 2 fields extending from a region near the cluster center out to ~ 10'. The obtained CMD shows a narrow MS extending down to V ~ 27 (figure c), much deeper than any previous ground based study and comparable with previous HST photometry (Cool et al. 1996). The comparison between observed MS Luminosity Functions (LFs) derived for 2 annuli at different radial distance from the center of the cluster shows a clear-cut correlation between their slope before reaching the turn-over, and the radial position of the observed fields inside the cluster area: the LFs become flatter with decreasing radius, a trend that is consistent with the interpretation of NGC 6397 as a dynamically relaxed system.
Comments: 2 pages, 1 figure, uses newpasp.sty, to be published in ``New Horizons in Globular Cluster Astronomy'', ASP Conference Series, 2002; Eds.: G. Piotto, G. Meylan, G. Djorgowski and M. Riello
The Lower Main Sequence and the Orbital Period Distribution of Cataclysmic Variable Stars
Tidal Tails Around 20 Galactic Globular Cluster: Observational Evidence for Gravitational Disk/Bulge Shocking
Relative Frequencies of Blue Stragglers in Galactic Globular Clusters: Constraints for the Formation Mechanisms
