R. Brent Tully, Helene M. Courtois
In order to measure distances with minimal systematics using the correlation
between galaxy luminosities and rotation rates it is necessary to adhere to a
strict and tested recipe. We now derive a measure of rotation from a new
characterization of the width of a neutral Hydrogen line profile. Additionally,
new photometry and zero point calibration data are available. Particularly the
introduction of a new linewidth parameter necessitates the reconstruction and
absolute calibration of the luminosity-linewidth template. The slope of the new
template is set by 267 galaxies in 13 clusters. The zero point is set by 36
galaxies with Cepheid or Tip of the Red Giant Branch distances. Tentatively, we
determine H0 = 75 km s-1 Mpc-1. Distances determined using the
luminosity-linewidth calibration will contribute to the distance compendium
Cosmicflows-2.
View original:
http://arxiv.org/abs/1202.3191
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