Daniel Kelson — Page 2

arXiv1999

The Hubble Constant from the HST Key Project on the Extragalactic Distance Scale

The final efforts of the HST Key Project on the Extragalactic Distance Scale are presented. Four distance indicators, the Surface Brightness Fluctuation method, the Fundamental Plane for early-type galaxies, the Tully-Fisher relation and the Type Ia Supernovae, are calibrated using Cepheid distances to galaxies within 25 Mpc. The calibration is then applied to distant samples reaching cz~10000 km/s and (in the case of SNIa) beyond. By combining the constraints imposed on the Hubble constant by the four distance indicators, we obtain H0 = 71+/-6 km/s/Mpc.

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arXiv1999

The Hubble Space Telescope Extragalactic Distance Scale Key Project XXIII. The Discovery of Cepheids In NGC 3319

The distance to NGC 3319 has been determined from Cepheid variable stars as part of the Hubble Space Telescope Key Project on the Extragalactic Distance Scale. Thirteen and four epochs of observations, using filters F555W (V) and F814W (I) respectively, were made with the Wide Field Planetary Camera 2. Thirty-three Cepheid variables between periods of 8 and 47 days were discovered. Adopting a Large Magellanic Cloud distance modulus of 18.50 +- 0.10 mag and extinction of E(V-I)=0.13 mag, a true reddening-corrected distance modulus (based on an analysis employing the ALLFRAME software package) of 30.78 +- 0.14 (random) +- 0.10 (systematic) mag and the extinction of E(V-I) = 0.06 mag were determined for NGC 3319. This galaxy is the last galaxy observed for the HST H0 Key Project.

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