Journal article

The hubble space telescope key project on the extragalactic distance scale. XIII. The metallicity dependence of the cepheid distance scale1-2

RC Kennicutt, PB Stetson, A Saha, D Kelson, DM Rawson, S Sakai, BF Madore, JR Mould, WL Freedman, F Bresolin, L Ferrarese, H Ford, BK Gibson, JA Graham, M Han, P Harding, JG Hoessel, JP Huchra, SMG Hughes, GD Illingworth Show all

The Astrophysical Journal | Published : 1998

Abstract

Uncertainty in the metal-abundance dependence of the Cepheid variable period-luminosity (PL) relation remains one of the outstanding sources of systematic error in the extragalactic distance scale and in the Hubble constant. To test for such a metallicity dependence, we have used the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST) to observe Cepheids that span a range in oxygen abundance of 0.7 ± 0.15 dex in two fields in the nearby spiral galaxy M101. A differential analysis of the PL relations in V and I in the two fields yields a marginally significant change in the inferred distance modulus on metal abundance, with σ(m-M)0/σ[O/H] = -0.24 ± 0.16 mag dex-1. The tr..

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