The HST Key Project on the Extragalactic Distance Scale XVII. The Cepheid Distance to NGC 4725

Brad K. Gibson; Shaun M. G. Hughes; Peter B. Stetson; Wendy L. Freedman; Robert C. Kennicutt, Jr.; Jeremy R. Mould; Fabio Bresolin; Laura Ferrarese; Holland C. Ford; John A. Graham; Mingsheng Han; Paul Harding; John G. Hoessel; John P. Huchra; Garth D. Illingworth; Daniel D. Kelson; Lucas M. Macri; Barry F. Madore; Randy L. Phelps; Charles F. Prosser; Abhijit Saha; Shoko Sakai; Kim M. Sebo; Nancy A. Silbermann; Anne M. Turner

doi:10.1086/306762

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The HST Key Project on the Extragalactic Distance Scale XVII. The Cepheid Distance to NGC 4725

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Abstract

The distance to NGC 4725 has been derived from Cepheid variables, as part of the Hubble Space Telescope Key Project on the Extragalactic Distance Scale. Thirteen F555W (V) and four F814W (I) epochs of cosmic-ray-split Wide Field and Planetary Camera 2 observations were obtained. Twenty Cepheids were discovered, with periods ranging from 12 to 49 days. Adopting a Large Magellanic Cloud distance modulus and extinction of 18.50+/-0.10 mag and E(V-I)=0.13 mag, respectively, a true reddening-corrected distance modulus (based on an analysis employing the ALLFRAME software package) of 30.50 +/- 0.16 (random) +/- 0.17 (systematic) mag was determined for NGC 4725. The corresponding of distance of 12.6 +/- 1.0 (random) +/- 1.0 (systematic) Mpc is in excellent agreement with that found with an independent analysis based upon the DoPHOT photometry package. With a foreground reddening of only E(V-I)=0.02, the inferred intrinsic reddening of this field in NGC 4725, E(V-I)=0.19, makes it one of the most highly-reddened, encountered by the HST Key Project, to date.

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Brad K. Gibson, Shaun M. G. Hughes, Peter B. Stetson, Wendy L. Freedman, Robert C. Kennicutt, Jr., Jeremy R. Mould, Fabio Bresolin, Laura Ferrarese, Holland C. Ford, John A. Graham, Mingsheng Han, Paul Harding, John G. Hoessel, John P. Huchra, Garth D. Illingworth, Daniel D. Kelson, Lucas M. Macri, Barry F. Madore, Randy L. Phelps, Charles F. Prosser, Abhijit Saha, Shoko Sakai, Kim M. Sebo, Nancy A. Silbermann, Anne M. Turner. 1998-10-01. The HST Key Project on the Extragalactic Distance Scale XVII. The Cepheid Distance to NGC 4725. https://doi.org/10.1086/306762

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