The Correlation between Galaxy H I Line Widths and K′ Luminosities

The relationship between galaxy luminosities and rotation rates is studied with total luminosities in the K′ band. Extinction problems are essentially eliminated at this band centered at 2.1 μm. A template luminosity-line width relation is derived based on 65 galaxies drawn from two magnitude-limited cluster samples. The zero point is determined using four galaxies with accurately known distances. The calibration is applied to give the distance to the Pisces Cluster (59 Mpc) at a redshift in the cosmic microwave background frame of 4771 km s-1. The resultant value of the Hubble constant is 81 km s-1Mpc-1. The largest sources of uncertainty are the small number of zero-point calibrators at this time at K′ and the present application to only one cluster.