THE DISTANCES TO 5 TYPE-II SUPERNOVAE USING THE EXPANDING PHOTOSPHERE METHOD, AND THE VALUE OF HO

Abstract

We have used observations gathered at CTIO to measure distances by the expanding photosphere method (EPM) to five Type II supernovae. These supernovae lie at redshifts from cz = 1100 km s-1 to cz - 5500 km s-1, and increase to 18 the number of distances; measured using EPM. We compare distances derived to 11 Type II supernovae with distances to their host galaxies measured using the Tully-Fisher method. We find that the Tully-Fisher distances average 11% +/- 7% smaller. The comparison shows no significant evidence of any large distance-dependent bias in the Tully-Fisher distances. We employ the sample of EPM distances from 4.5 Mpc to 180 Mpc to derive a value for the Hubble constant. We find H-0 = 73 +/- 6(statistical) +/- 7(systematic) km s-1 Mpc-1.