The mass function of NGC 288

Abstract

We present NICMOS NIC3 observations of the Galactic globular cluster NGC 288, taken South - East at 2.4 times the cluster's half-light radius in the J and H bands. We have detected the cluster main sequence down to J =~ 25 and H =~ 24. The corresponding luminosity function covers the range 3 < M_H < 9 and peaks at M_H =~ 6.8. The theoretical tracks of Baraffe et al. (1997) at [Fe/H] = -1.3 give a mass function which is best fitted by a log-normal distribution with characteristic mass of m_c = 0.42 M_sun and a standard deviation sigma = 0.35. This result is fully consistent with the global mass function derived by Paresce & De Marchi (2000) for a sample of 12 globular clusters with very different dynamical histories, thus confirming that near the cluster's half-light radius the mass function at appears ``undistorted'' by evaporation or tidal interactions with the Galaxy and should then reflect the initial mass function.