Probing Mass Segregation in NGC 6397

TL;DR

This paper investigates mass segregation in the globular cluster NGC 6397 through photometric analysis, revealing that mass segregation is significant within 1 arcminute but not beyond.

Contribution

It provides a detailed photometric and deprojected model analysis of mass segregation in NGC 6397, highlighting the radial extent of mass segregation in the cluster.

Findings

Mass segregation is evident within 1 arcminute of the cluster center.

The total number of stars in NGC 6397 is estimated at approximately 193,000.

Mass segregation is not observed outside the central 1 arcminute.

Abstract

In this study, we present a detailed study of mass segregation in the globular clister NGC 6397. First, we carry out a photometric analysis of projected ESO-VLT data (between 1 and 10 arcmin from the cluster centre), presenting the luminosity function corrected by completeness. The luminosity function shows a higher density of bright stars near the central region of the data, with respect to the outer region. We calculate a deprojected model (covering the whole cluster) estimating a total number of stars of 193000 +- 19000. The shapes of the surface brightness and density-number profiles versus the radial coordinate r (instead of the projected coordinate R) lead to a decreasing luminosity for an average star, and thus of mass, up to 1 arcmin, quantifying the mass segregation. The deprojected model does not show evidence of mass segregation outside this region.