title: Tests of the long and short extragalactic distance scales.
abstract: Distances on the short and long scales of 12 nearby galaxies, one group, and three clusters are compared with recent estimates by independent methods and researchers. All comparisons show a close agreement [within 0.3 magnitude (mag) in the distance modulus (DM)] between the short-scale moduli and the new estimates by others at all distances from the Large Magellanic Cloud [Delta (distance) = 0.05 megaparsec (Mpc); 1 pc = 3.09 x 10(16) m] to the Coma cluster (Delta = 83 Mpc). The mean systematic difference (short - others) is only -0.04 mag with no evidence for a significant Malmquist bias in the short scale. The long scale differs systematically from all the others by about +0.25 mag within the Local Group (DM < 26) and by +1.1 outside (26 < DM < 35). Accidental errors are also much larger in the long-scale moduli (0.5 mag) than in the other two scales (0.1 mag). The mean value of the Hubble expansion ratio for the test objects is <H> = 86 +/- 1 km.sec-1. Mpc-1.
authors.affiliation: Department of Astronomy, University of Texas, Austin, TX 78712, USA.
authors.forename: G
authors.initials: G
authors.lastname: de Vaucouleurs