RR Lyrae and short-period variable stars in the dwarf irregular galaxy NGC 6822
Abstract
We report the discovery of a large number of short-period variable stars in the dwarf irregular galaxy NGC6822, based on deep time-series imaging carried out with the ESO Very Large Telescope. In particular, we found a modest population of RR Lyrae stars tracing the presence of an old stellar component in NGC6822. Measurements of the average luminosity of RR Lyrae stars provide a new independent estimate of the distance to this galaxy based on a Pop.II indicator, (m-M)o=23.36 +/-0.17. In addition, our new data show a significant population of small-amplitude, short-period variable stars filling the instability strip starting at luminosities only a few tenths of a magnitude brighter than the RR Lyrae stars.
Cite
@article{arxiv.astro-ph/0304076,
title = {RR Lyrae and short-period variable stars in the dwarf irregular galaxy NGC 6822},
author = {G. Clementini and E. V. Held and L. Baldacci and L. Rizzi},
journal= {arXiv preprint arXiv:astro-ph/0304076},
year = {2009}
}
Comments
14 pages, 3 figures, Ap.J.L., in press, May 10 issue