NOAO > Observing Info > Approved Programs > 2003A-0248
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NOAO > Observing Info > Approved Programs > 2003A-0248 |
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PI: Andrew Dolphin, NOAO, dolphin@noao.edu
Address: KPNO, PO Box 26732, Tucson, AZ 85726, USA
CoI: Abi Saha, NOAO
CoI: Evan Skillman, University of Minnesota
CoI: Frank Thim, NOAO
Title: Cepheids in the Sagittarius Dwarf Irregular Galaxy
Abstract:
Our understanding of the extragalactic distance scale is limited in
large part by uncertainties in the absolute magnitudes of the primary
standard candles -- Cepheids and RR Lyraes. As these calibrations are
largely independent (Cepheid calibrations are tied to the moving cluster
distance to the Pleiades or an assumed LMC distance; RR Lyrae and RGB
tip calibrations are tied to statistical parallax distances to globular
clusters), a comparison between these indicates the degree of accuracy
to which they are known. Dwarf irregular galaxies in the Local Group
provide an ideal testing ground for the distance scales, as they contain
stars of all ages at the same distance. They also provide large numbers
of short-period Cepheids, which are common in low-metallicity star-
forming galaxies and which we have recently demonstrated to be excellent
standard candles. We propose to search for short-period Cepheids in
SagDIG, which is likely the most metal-poor star-forming galaxy in the
Local Group. A comparison between the distance measurements for this
galaxy thus provides an important data point for understanding
metallicity dependencies of the standard candles.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2003A-0248 |
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