SCYON Abstract

Received on October 12 2004

NGC 6404 and NGC 6503: two intermediate-age open clusters located toward the Galactic center direction

AuthorsGiovanni Carraro (1,2), Rene Mendez (1), Edgardo Costa (1)
Affiliation1 Universidad de Chile
2 Yale University
Accepted byMonthly Notices of the Royal Astronomical Society
Contactgcarraro@das.uchile.cl
URLastro-ph/0410300
Links

Abstract

We report on VI CCD photometry of two fields centered in the region of the open clusters NGC 6404 and NGC 6583 down to V=22.0. These clusters have never been studied insofar, and we provide for the first time estimates of their fundamental parameters, namely, radial extent, age, distance and reddening. We find that NGC~6404 radius is 2.0 arcmin, as previously proposed, while NGC 6583 radius is 1.0 arcmin, significantly lower than previous estimates.

Both clusters turn out to be of intermediate age (0.5-1.0 Gyr old), and located inside the solar ring, at a Galactocentric distance of about 6.5 kpc. These results make these objects very interesting targets for spectroscopic follow-up to measure their metallicity. In fact they might allow us to enlarge by more than 1 kpc the baseline of the radial abundance gradient in the Galactic disk toward the Galactic Center direction. This baseline is currently rather narrow especially for clusters of this age.