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Title: THE METALLICITY DEPENDENCE OF THE CEPHEID P – L RELATION IN M101

The impact of metallicity on the Cepheid period-luminosity (P – L) relation is investigated using Hubble Space Telescope Advanced Camera for Surveys V and I images of M101. Variations in the reddening-free Wesenheit parameter (W), which is employed as a proxy for luminosity, are examined as a function of the radial distance from the center of M101 (and thus metallicity). We determine that there is no dependence of the slope on metallicity. However, the intercept is found to depend on metallicity by γ{sub VI} = –0.33 ± 0.12 mag dex{sup –1} and γ{sub VI} = –0.71 ± 0.17 mag dex{sup –1} using 2σ and 3σ rejection criteria, respectively. Sigma-clipping impacts the derived metallicity dependence, and the 2σ criterion applied likely mitigates blending, particularly in the crowded inner regions of M101. A metallicity-corrected distance for M101 is obtained from 619 Cepheids (μ = 28.96 ± 0.11), a result that agrees with the recently determined SN Ia distance. The metallicity effects described can be bypassed by working at near and mid-infrared wavelengths (e.g., the Carnegie Hubble Program)
Authors:
; ;  [1]
  1. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
Publication Date:
OSTI Identifier:
22270648
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 777; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; CAMERAS; CEPHEIDS; GALAXIES; IMAGES; LUMINOSITY; METALS; RED SHIFT; SUPERNOVAE; TELESCOPES; VARIATIONS