A distance scale from the infrared magnitude/H I velocity-width relations. V - Distance moduli to 10 galaxy clusters, and positive detection of bulk supercluster motion toward the microwave anisotropy

Abstract

The authors use the relation between infrared magnitudes and 21 cm velocity widths to derive relative distance moduli to 10 nearby galaxy clusters. The sample ranges in redshift from Pegasus at V ≡ 4000 km s-1 up to Hercules at V ≡ 11,000 km s-1. Several selection biases in the data set are identified and discussed. The final cluster Hubble ratios exhibit considerable scatter, signifying the presence of an unaccounted for Local Group streaming motion. Formal solution leads to a velocity in close agreement with the 3K dipole anisotropy, which can now be understood to arise from two principal components - Local Group motion within the Supercluster, and bulk motion of the Supercluster itself. Both components are ≡300 km s-1 in size. The expansion rate is discussed and it is stated that the best current evidence favors a large value for the Hubble constant, H0 ≡ 90 km s-1Mpc-1.