| Abstract | We present CCD photometry in B and V for the globular cluster system (GCS) of NGC 1399, the central cD galaxy in the Fornax cluster. We confirm that NGC 1399 has an extremely populous GCS with a specific frequency of S~16. The radial surface density profile of the GCS matches that of the halo light well, from 0.5-3 arcmin, confirming earlier photographic results. As for other giant ellipticals (gEs), the globular clusters are bluer than the halo light at a given radius. Interestingly, there is evidence for a radial (B - V) color gradient in the NGC 1399 GCS; similar gradients have recently been detected in the "normal" Virgo ellipticals NGC 4472 and 4649. The globular cluster luminosity function (GCLF) of NGC 1399 is consistent with being Gaussian in shape, with a value of the dispersion σ~1.5 being slightly preferred. From nonlinear least-squares fits, we derive a turnover in the GCLF at V~23.8 or B~24.6, but completeness corrections at this point are at the 50% level. Using the NGC 1399 and the composite Virgo GCLFs, we derive a relative Virgo-Fornax distance modulus of δ(m - M)_Virgo-Fornax_ = 0.11 + 0.14, in good agreement with several recent determinations. By matching the apparent turnover of the GCLF to the absolute turnover defined by the Milky Way, we infer a distance modulus of (m - M)_0_ = 31.3 + 0.2 for NGC 1399, also in good agreement with other recent results from similar studies. Recent globular cluster data imply that gEs may form in more than one way, but they also raise new puzzles. The differences in the spatial and metallicity structures of the globular cluster and halo systems of different gEs are currently not easy to place into a self-consistent picture. |
