AAS 197, January 2001
Session 119. The Cosmic Distance Scale
Oral, Thursday, January 11, 2001, 10:30am-12:00noon, San Diego

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[119.04] Resolving Systematic Errors in The Extragalactic Distance Scale

L.M. Macri (Harvard-Smithsonian CfA)

I will present the results of my Ph.D. Thesis, which has dealt with two widely used extragalactic distance indicators: Cepheids and the Tully-Fisher Relation.

My work on Cepheids includes the analysis of HST/NICMOS observations of these variables in galaxies ranging from the Local Group to the Fornax Cluster, to investigate the validity of using a standard Galactic extinction law when correcting the V- and I-band magnitudes of Cepheids in other galaxies. Results indicate that a standard extinction law is indeed appropriate.

My work on the Tully-Fisher relation includes a photometric study of its calibrators to provide a self-consistent set of magnitudes at optical and near-infrared wavelengths. The optical data has been used by the HST Key Project on the Extragalactic Distance Scale to determine the value of the Hubble constant via the I-band Tully-Fisher relation. The IR data has been obtained more recently, and should resolve an existing discrepancy in the value of the Hubble constant determined from the H-band Tully-Fisher relation.

If you would like more information about this abstract, please follow the link to http://cfa-www.harvard.edu/~lmacri. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

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