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Preliminary results from VLT (FORS1) photometry of NGC 6397

G. Andreuzzi·V. Testa·G. Marconi·G. Alcaino·F. Alvarado·R. Buonanno
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Abstract

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.

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G. Andreuzzi, V. Testa, G. Marconi, G. Alcaino, F. Alvarado, R. Buonanno. 2002-10-02. Preliminary results from VLT (FORS1) photometry of NGC 6397. https://arxiv.org/abs/astro-ph/0210070

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