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The effect of metallicity on Cepheid magnitudes and the distance to M33

The effect of metallicity on Cepheid magnitudes and the distance to M33

Authors :
Peter R. Wood
Victoria Scowcroft
D. Bersier
Jeremy Mould
Source :
Monthly Notices of the Royal Astronomical Society. 396:1287-1296
Publication Year :
2009
Publisher :
Oxford University Press (OUP), 2009.

Abstract

We present the results from a multi‐epoch survey of two regions of M33 using the 3.5 m WIYN telescope. The inner field is located close to the center of the galaxy, with the outer region situated about 5.1 kpc away in the southern spiral arm, allowing us to sample a large metallicity range. We have data for 167 fundamental mode Cepheids in the two regions. The reddening‐free Wesenheit magnitude Wvi period‐luminosity relations were used to establish the distance modulus of each region, with μinner = 24.37±0.02 mag and μouter = 24.54±0.03 mag. The apparent discrepancy between these two results can be explained by the significant metallicity gradient of the galaxy. We determine a value for the metallicity parameter of the Period‐Luminosity relation γ = δ(m−M)0δ log Z = −0.29±0.11 mag dex−1, consistent with previous measurements. This leads to a metallicity corrected distance modulus to M33 of μγ = 24.53±0.11 mag.

Details

ISSN :
13652966 and 00358711
Volume :
396
Database :
OpenAIRE
Journal :
Monthly Notices of the Royal Astronomical Society
Accession number :
edsair.doi...........515eeed3214664d9987a78acdc9de2d0
Full Text :
https://doi.org/10.1111/j.1365-2966.2009.14822.x