Hubble flows in the pisces-perseus region from the Giovanelli-Haynes galaxy sample

An analysis has been made of the Hubble flow for galaxies in the Pisces-Perseus supercluster region using the Tully-Fisher (TF) relation in the B band, applied to the sample of Giovanelli & Haynes. The number of galaxies, the depth, and the completeness of this sample offer an advantage over previous observations used in determination of the Hubble constant beyond the Virgo Cluster. Photographic surface photometry was carried out on 155 galaxies to correct for the scale error and establish the zero point of the Zwicky magnitudes, which is used in the present analysis. A large data set which contains 1119 galaxies allows us to examine various statistical errors caused by the dispersion of TF relations, observational selection effects, and an inhomogeneous spatial distribution of galaxies. We found that full control over the Malmquist bias is essential in deriving the result. The recession of galaxies is described well by a universal Hubble constant for all galaxies up to a redshift of 10,000-15,000 km s^-1, with the exception of those located within 2000 km s^-1, for which the sample is clearly affected by an inflow. The global value of the Hubble constant is 78.5_-9.1^+10.3- km s^-1Mpc^-1 with respect to the cosmic microwave background (CMB) rest frame or 83.2_-9.6^+10-9 km s^-1 Mpc^-1with respect to the Local Group centroid. In particular, for the Pisces-Perseus supercluster the Hubble constant is found to be 79.9_9-5^+10.6 and 86.8_-10.1^+11.5 km s^-1 Mpc^-1, respectively. Full consistency was found with the H-band Tully-Fisher analysis of Aaronson and coworkers for their galaxy sample, and the difference between their value of H_o and ours is shown to arise from the Malmquist bias. An extensive study was also made for the sources of errors. It is found that the Hubble constant derived from the Pisces-Perseus sample differs from that from the Coma Cluster; H_o(P-P)/H_o(Coma) = 0.81_-01.10^+0.12 in the CMB rest frame. From our error analysis we conclude that this discrepancy is significant. This indicates that either the Tully-Fisher relation is not universal or the difference in recession velocity is real, all galaxies up to ≥ 10,000 km s^-1 moving toward the Virgo Cluster relative to the Coma galaxies or the Hubble flow being slightly anisotropic.