English

A New Cepheid Distance Measurement and Method for NGC 6822

Astrophysics of Galaxies 2015-06-23 v1 Solar and Stellar Astrophysics

Abstract

We present a revised distance to the nearby galaxy NGC6822 using a new multi-band fit to both previously published and new optical, near- and mid-infrared data for Cepheid variables. The new data presented in this study include multi-epoch observations obtained in 3.6\um and 4.5\um with the \emph{Spitzer Space Telescope} taken for the Carnegie Hubble Program. We also present new observations in J, H and \kswith FourStar on the Magellan Baade telescope at Las Campanas Observatory. We determine mean magnitudes and present new period-luminosity relations in V, I, J, H, \ks, IRAC 3.6\um and 4.5\um. In addition to using the multi-band distance moduli to calculate extinction and a true distance, we present a new method for determining an extinction-corrected distance modulus from multi-band data with varying sample sizes. We combine the distance moduli and extinction for individual stars to determine E(BV)=0.35±0.04E(B-V)=0.35\pm0.04 and a true distance modulus μo=23.38±0.02stat±0.04sys\mu_{o}=23.38\pm0.02_{stat}\pm0.04_{sys}.

Keywords

Cite

@article{arxiv.1409.6830,
  title  = {A New Cepheid Distance Measurement and Method for NGC 6822},
  author = {Jeffrey A. Rich and S. E. Persson and Wendy L. Freedman and Barry F. Madore and Andrew J. Monson and Victoria Scowcroft and Mark Seibert},
  journal= {arXiv preprint arXiv:1409.6830},
  year   = {2015}
}

Comments

Accepted for publication in ApJ, 25 pages, 18 figures, 1 table

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