The Discovery of Cepheids and a New Distance to NGC 2841 Using the Hubble Space Telescope

Abstract

We report on the discovery of Cepheids in the spiral galaxy NGC 2841, based on observations made with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. NGC 2841 was observed over 12 epochs using the F555W filter and over five epochs using the F814W filter. Photometry was performed using the DAOPHOT/ALLFRAME package. We discovered a total of 29 variables, including 18 high-quality Cepheids with periods ranging from 15 to 40 days. Period-luminosity relations in the V and I bands, based on the high-quality Cepheids, yield a reddening-corrected distance modulus of 30.74+/-0.23 mag, which corresponds to a distance of 14.1+/-1.5 Mpc. Our distance is based on an assumed LMC distance modulus of μ₀=18.50+/-0.10 mag (D=50+/-2.5 kpc) and a metallicity dependence of the Cepheid P-L relation of γ_VI=-0.2+/-0.2 mag dex^-1. Based on observations with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, operated by AURA, Inc., under NASA contract NAS5-26555.