The globular cluster system of NGC 1399

Abstract

Profile-fitting photometry of objects of stellar appearance in B and V CCD frames of the Fornax cluster cD galaxy NGC 1399, as well as in background frames awsay from the galaxy, have been performed. The radial surface density profile of the NGC 1399 globular cluster system (GCS) obeys a power law between 0.5 and 3 arcmin, with a slope of -1.5 + or - 0.2. The radial profile of the GCS is a good match to the halo light over this limited range in radius. The globular clusters are bluer than the halo light near the center of NGC 1399, and there is evidence for a radial color gradient in the NGC 1399 CGS. There is no evidence for such a gradient in the halo light. The globular cluster luminosity functions (GCLFs) in B and V are consistent with being Gaussian in shape. A turnover in the GCLF at V about 23.8 or B about 24.6 is inferred. NGC 1399 has a GCS of specific frequency S = 16 + or - 4; S is only moderately sensitive to the adopted distance scale and assumed dispersion of the GCLF. 90 refs.