AAS 202nd Meeting, May 2003
Session 54 Cosmology Runs Through It
Oral, Thursday, May 29, 2003, 10:00-11:30am, 103/104

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[54.03] A New High-Redshift SN Ia Dataset that Addresses Extinction Questions in Cosmology Measurements

R. Knop (Vanderbilt University), Supernova Cosmology Project Collaboration

The Supernova Cosmology Project (SCP) has presented data on a new set of high-redshift Type Ia supernovae with precise enough color measurements that E(B-V) host galaxy extinction corrections may be applied without any need to resort to prior assumptions on the E(B-V) distribution. Earlier results did not have precise enough color measurements to directly apply E(B-V) corrections; instead, they either used a prior on the E(B-V) distribution which greatly reduced the effective error bars, or argued that there was no evidence of a mean difference in extinction between low and high sets redshift supernovae. Based on SCP data which measure lightcurves and colors with the Hubble Space Telescope, cosmological results with assumption-free extinction corrections individually applied show no systematic offset from results without direct extinction corrections. Additionally, with updated K-corrections and intrinsic colors, there are no systematic color differences (red or blue) between low and high redshift supernovae.

This work is supported by the U.S. Dept. of Energy, Office of Science, under contract DE-AC03-76SF00098.

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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.