Helene Courtois (Universite of Lyon)

Cosmic Flows - Helene Courtois Colloquium

ATNF Marsfield Lecture Theatre

Abstract

The goal of the “Cosmic Flows” program is to obtain the densest and deepest possible coverage of galaxy distances and, hence, of line-of-sight peculiar velocities. We want to improve the local determination of the Hubble Constant and measure departures from the cosmic expansion that presumably can be attributed to the distribution of matter. We are giving consideration to 7-10 different methods for deriving distances. One of these relies on the correlation between galaxy luminosities and rotation rates, so called Tully-Fisher relation. We have acquired from our own observations and from digital archives, and re-measured more than 16,000 HI spectra, for about 12,500 spiral galaxies in the local universe. I will present the dynamic maps that are currently drawn from this data.

Those cosmic flows lead to a better understanding of the density and distribution of Luminous Matter, Dark Matter, and eventually to the local Dark Energy density.