We present an X-ray analysis of a 4 Gyr old open cluster, M67, using archival
XMM-Newton data. The aim of this study was to find new X-ray members of M67,
and to use the updated member list for studying X-ray variability, and derive
the X-ray luminosity functions (XLFs) of different stellar types and compare
them with other star clusters of similar age. We report the detection of X-ray
emission from 25 members of M67, with membership based primarily on their
proper motion, of which one X-ray source is a new member. Supplementing this
study with previous ROSAT and Chandra studies of M67, and using the most recent
proper motion study by Vereshchagin et al., we have compiled a revised list of
X-ray emitting members of M67 consisting of 43 stars. Sixteen of these are
known RS CVn type binaries having orbital periods < 10 days, and
near-circular orbits, 5 are contact binaries with orbital periods < 6 hours,
5 are yellow and blue stragglers, 2 are Algol-type binaries, and one source is
a cataclysmic variable. Fourteen members do not have any orbital information
and cannot be classified. Fourteen of the X-ray sources detected do not have
any optical counterpart down to a magnitude of V≃22, and their
membership is uncertain. Finally, we report the X-ray luminosity functions of
RS CVn type and other types of stars in M67 and compare them with other open
clusters of intermediate-to-old age.Comment: 13 pages, 8 figures, 5 tables. Accepted for publication in MNRA