New g′ r′ i′ z′ photometry of the NGC 5128 globular cluster system

Abstract

We present new photometry for 323 of the globular clusters in NGC 5128 (Centaurus A), measured for the first time in the g′ r′ i′ z′ filter system. The color indices are calibrated directly to standard stars in the g′ r′ i′ z′ system and are used to establish the fiducial mean colors for the blue and red (low and high metallicity) globular cluster sequences. We also use spectroscopically measured abundances to establish the conversion between the most metallicity-sensitive colors ((g′ - r′)0, (g′ - i′)0) and metallicity, [Fe/H]. © 2010. The American Astronomical Society. All rights reserved.