ESO, Garching bei Muenchen, Germany
PUC, Casilla 306, 22 Santiago, Chile
|Accepted by||Astronomy & Astrophysics|
U- and V-band photometry has been measured for all the candidates and the luminosity function, spanning -10.1 < MV < -4.9 and -9.3 < MU < -3.3, constructed. These are the deepest globular cluster luminosity functions in an elliptical galaxy determined so far. The Kolmogorov-Smirnov statistics show that the difference between the globular cluster luminosity functions of NGC 5128 and the MW is not larger than the difference between the ones of M31 and the MW. The (U-V)O color histogram shows a bimodal distribution.
For 23 globular clusters I obtained K-band images with SOFI at the NTT in La Silla. Their positions in the (U-V) vs. (V-K) color-color diagram indicate that they are indeed old globular clusters. Assuming that the globular clusters in NGC 5128 span a similar age range as the ones in the Milky Way and adopting a linear fit between the metallicity and (U-V)O color, the metal-rich clusters peak at [Fe/H]=-0.6 dex and the metal-poor ones peak at [Fe/H]=-1.7 dex.