M. W. Feast, P. A. Whitelock, J. W. Menzies, N. Matsunaga
Recent estimates of the Cepheid distance modulus of NGC 6822 differ by 0.18
mag. To investigate this we present new multi-epoch JHKs photometry of
classical Cepheids in the central region of NGC 6822 and show that there is a
zero-point difference from earlier work. These data together with optical and
mid-infrared observations from the literature are used to derive estimates of
the distance modulus of NGC 6822. A best value of 23.40 mag is adopted, based
on an LMC distance modulus of 18.50 mag. The standard error of this quantity is
~0.05 mag. We show that to derive consistent moduli from Cepheid observations
at different wavelengths, it is necessary that the fiducial LMC
period-luminosity relations at these wavelengths should refer to the same
subsample of stars. Such a set is provided. A distance modulus based on RR
Lyrae variables agrees with the Cepheid result.
View original:
http://arxiv.org/abs/1201.1987
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