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Title: PROPERTIES OF M31. III. CANDIDATE BEAT CEPHEIDS FROM PS1 PANDROMEDA DATA AND THEIR IMPLICATION ON METALLICITY GRADIENT

We present a sample of M31 beat Cepheids from the Pan-STARRS 1 PAndromeda campaign. By analyzing 3 years of PAndromeda data, we identify 17 beat Cepheids, spreading over a galactocentric distance of 10-16 kpc. Since the relation between the fundamental mode period and the ratio of the fundamental to the first overtone period places a tight constraint on metallicity, we are able to derive the metallicity at the position of the beat Cepheids using the relations from the model of Buchler. Our metallicity estimates show sub-solar values within 15 kpc, similar to the metallicities from H II regions. We then use the metallicity estimates to calculate the metallicity gradient of the M31 disk, which we find to be closer to the metallicity gradient derived from planetary nebula than the metallicity gradient from H II regions.
Authors:
; ; ; ; ; ; ; ;  [1] ; ; ; ; ; ; ; ;  [2] ;  [3]
  1. University Observatory Munich, Scheinerstrasse 1, D-81679 Munich (Germany)
  2. Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)
  3. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
Publication Date:
OSTI Identifier:
22270675
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; CEPHEIDS; DISTANCE; GALAXIES; H2 REGIONS; LIMITING VALUES; METALS; PLANETARY NEBULAE