A First Comparison of the Surface Brightness Fluctuation Survey Distances with the Galaxy Density Field: Implications...

We compare the peculiar velocities measured in the surface brightness fluctuation survey of galaxy distances with the predictions from the density fields of the IRAS 1.2 Jy flux-limited redshift survey and the optical redshift survey (ORS) to derive simultaneous constraints on the Hubble constant H0 and the density parameter beta=Omega0.6&solm0;b, where b is the linear bias. We find that betaI=0.42+0.10-0.06 and betaO=0.26+/-0.08 for the IRAS and ORS comparisons, respectively, and that H0=74+/-4 km s-1 Mpc (with an additional 9% uncertainty due to the Cepheids themselves). The match between predicted and observed peculiar velocities is good for these values of H0 and beta, and although there is covariance between the two parameters, our results clearly point toward low-density cosmologies. Thus, the unresolved discrepancy between the "velocity-velocity" and "density-density" measurements of beta continues.