Globular cluster luminosity functions and the Hubble constant from WFPC2 imaging: The dominant group elliptical NGC 5846

The Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) has several advantages over ground-based observations for the study of globular cluster luminosity functions (GCLFs) and distance determination. Here we present WFPC2 data on the globular clusters associated with NGC 5846. This giant elliptical is the dominant galaxy in a small, compact group located similar to 13 Mpc beyond the Virgo cluster. We have detected over 1200 globular clusters in three (central, north, and south) separate pointings. The luminosity functions in each of these pointings are statistically the same, indicating that the mean luminosity (mass) does not vary between similar to 3 and 30 kpc from the galaxy center. This suggests that dynamical friction and bulge shocking destruction processes are insignificant. We have fit a Gaussian and t(5) profile to the GCLF (of the combined pointings) and find that it is well represented by a turnover magnitude of m(V)(0)=25.05+/-0.10 and a dispersion of sigma=1.34+/-0.06. Our 50% incompleteness level is similar to 1 mag fainter than the turnover. After applying a metallicity correction to the ''universal'' GCLF turnover magnitude, we derive a distance modulus of (m-M)=32.32+/-0.23. For a group velocity V-CMB=1883+/-28 km s(-1), the Hubble constant is H-0=65+/-8 km s(-1) Mpc(-1). (C) 1996 American Astronomical Society.