Ho Measurement from VLT Deep I-band Surface Brightness Fluctuations in NGC 564 and NGC 7619

Abstract

We have measured the Hubble constant Ho in NGC 564 at cz ~ 5800 km/s and in NGC 7619 at cz ~ 3700 km/s with deep I-band Surface Brightness Fluctuation distance measurements at the ESO Very Large Telescope (VLT). We obtain Ho = 70 +/- 7 +/- 6 km/s/Mpc for NGC 564 and Ho = 68 +/- 6 +/- 6 km/s/Mpc for NGC 7619. The actual SBF sample used for the measurement of Ho in the Hubble Space Telescope Key Project on the Extragalactic Distance Scale (Freedman et al. 2001) amounts to six galaxies. When we combine the measurements from this work with our previous VLT I-band SBF distance measurement in IC 4296 (Mei et al. 2000), we obtain : Ho = 68 +/- 5 +/- 6 km/s/Mpc. When we add the Freedman et al. (2001) SBF sample, we obtain Ho = 71 +/- 4 +/- 6 km/s/Mpc.