November 6, 1997 CfA Colloquium


Title: The Hubble Space Telescope Key Project to Measure H_o

Speaker: Wendy Freedman, Carnegie

Abstract: A summary report will be given for the Hubble Space Telescope Key Project on the Extragalactic Distance Scale, reviewing the aims of the Key Project and progress to date. The Key Project aims to provide a value of the Hubble constant (H0) accurate to 10% by providing a set of HST-measured Cepheid distances for the calibration of a number of secondary distance indicators, including type Ia supernovae, theTully-Fisher relation, type II supernovae, the surface-brightness-fluctuation (SBF) method, and the planetary nebula luminosity function (PNLF).

Rather than concentrate on one particular method, the goal of the Key Project is to undertake a comparison and calibration of several different methods so that cross-checks on both the absolute zero pointas well as relative distances, and therefore ultimately on H_o, can beobtained. Studies are ongoing to reduce and test for additional potential systematic errors.

Reference for students: Click here for paper.