The HST Key Project on the Extragalactic Distance Scale: Cepheid Variables in NGC 925

Session 6 -- Cepheid Variables and the Distance Scale
Display presentation, Monday, June 12, 1995, 9:20am - 6:30pm

[6.01] The HST Key Project on the Extragalactic Distance Scale: Cepheid Variables in NGC 925

N.A. Silbermann, B.F. Madore (IPAC/JPL), P. Harding (UA/Steward Obs.), P.B. Stetson (DAO/HIA/NRC), J.A. Graham (DTM/CIW), W.L. Freedman (OCIW), R.C. Kennicutt, A. Turner, F. Bresolin (UA/Steward Obs.), J.R. Mould (MSSSO), L. Ferrarese, H. Ford, A. Saha (JHU/STScI), R.J. Hill, R. Phelps (OCIW), M.S. Han, J.G. Hoessel (U. Wisc.), J.P. Huchra (CfA), S.M. Hughes (RGO), G.D. Illingworth, D. Kelson (Lick/UCSC), S. Sakai (IPAC/JPL)

Results on the search for Cepheid variables in the nearby spiral galaxy NGC 925 are presented. NGC 925, as a member of the NGC 1023 galaxy group, was chosen as a calibrator for several secondary distance indicators such as the Tully-Fisher relation, surface brightness fluctuations, planetary nebulae, and type II supernovae, as part of the HST Key Project on the Extragalactic Distance Scale. V, I, and B exposures of an outer field of NGC 925 were made from August to October 1994 using WFPC-2 on HST. Twelve epochs in V were obtained, as well as a 4 epochs in I and 3 in B for color and reddening determinations. Eighty Cepheids have been discovered in NGC 925. Periods, light and color curves for the variables will be presented, as well as V and I period-luminosity relations. These PL relations will be used to establish the distance and absolute magnitude for this galaxy. A color-magnitude diagram of the region will also be presented.

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