Yongbeom Kang, Soo-Chang Rey, Luciana Bianchi, Kyungsook Lee, YoungKwang Kim, Sangmo Tony Sohn
We present a comprehensive catalog of 700 confirmed star clusters in the
field of M31 compiled from three major existing catalogs. We detect 418 and 257
star clusters in Galaxy Evolution Explorer (GALEX) near-ultraviolet (NUV) and
far-ultraviolet (FUV) imaging, respectively. Our final catalog includes
photometry of star clusters in up to 16 passbands ranging from FUV to NIR as
well as ancillary information such as reddening, metallicity, and radial
velocities. In particular, this is the most extensive and updated catalog of UV
integrated photometry for M31 star clusters. Ages and masses of star clusters
are derived by fitting the multi-band photometry with model spectral energy
distribution (SED); UV photometry enables more accurate age estimation of young
clusters. Our catalog includes 182 young clusters with ages less than 1 Gyr.
Our estimated ages and masses of young clusters are in good agreement with
previously determined values in the literature. The mean age and mass of young
clusters are about 300 Myr and 10^4 M_sun, respectively. We found that the
compiled [Fe/H] values of young clusters included in our catalog are
systematically lower (by more than 1 dex) than those from recent high-quality
spectroscopic data and our SED fitting result. We confirm that most of the
young clusters kinematics show systematic rotation around the minor axis and
association with the thin disk of M31. The young clusters distribution exhibits
a distinct peak in the M31 disk around 10 - 12 kpc from the center and follow a
spatial distributions similar to other tracers of disk structure such as OB
stars, UV star-forming regions, and dust. Some young clusters also show
concentration around the ring splitting regions found in the southern part of
the M31 disk and most of them have systematically younger (< 100 Myr) ages.
View original:
http://arxiv.org/abs/1112.2944
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