The Hubble Space Telescope Extragalactic Distance Scale Key Project. IX. The Discovery of Cepheids in NGC 2090
Illingworth, Garth D.; Huchra, John P.; Kennicutt, Robert C.; Madore, Barry F.; Freedman, Wendy L.; Gibson, Brad K.; Stetson, Peter B.; Ferrarese, Laura; Saha, Abhijit; Graham, John A.; Mould, Jeremy R.; Ford, Holland C.; Hoessel, John G.; Sakai, Shoko; Silbermann, N. A.; Han, Mingsheng; Phelps, Randy L.; Hughes, Shaun M.
United States, Canada, Australia, United Kingdom
Abstract
We report on the discovery of 34 Cepheid variables in NGC 2090, with periods ranging between 5 and 58 days. Apparent V and I period-luminosity relations for Cepheids with P >= 10 days have been constructed, assuming a fiducial distance modulus, μ0, of 18.50 +/- 0.10 mag and a reddening, E(B-V), of 0.10 mag for the Large Magellanic Cloud. Using the ALLFRAME photometry package, an inferred reddening of E(V-I) = 0.09 +/- 0.02 mag (internal error) and a true distance modulus of 30.45 +/- 0.16 (random) +/- 0.16 (systematic) mag for NGC 2090 are found. The corresponding distance is 12.3 +/- 0.9 (random) +/- 0.9 (systematic) Mpc, a value that agrees at the 2.5% level with that derived from an independent analysis using a modified version of the DoPHOT photometry package.
Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, operated by AURA, Inc., under NASA contract No. NAS5-26555.