Bibcode
Rosenberg, A.; Aparicio, A.; Saviane, I.; Piotto, G.
Referencia bibliográfica
Astronomy and Astrophysics Supplement, v.145, p.451-465
Fecha de publicación:
9
2000
Número de citas
71
Número de citas referidas
64
Descripción
In this paper we present the second and final part of a large and
photometrically homogeneous CCD color-magnitude diagram (CMD) data base,
comprising 52 nearby Galactic globular clusters (GGC) imaged in the V
and I bands. The catalog has been collected using only two telescopes
(one for each hemisphere). The observed clusters represent 75% of the
known Galactic globulars with (m-M)_V<= 16.15 mag, cover most of the
globular cluster metallicity range (-2.2 <= [Fe/H]<= -0.4), and
span Galactocentric distances from ~ 1.2 to ~ 18.5 kpc. In particular,
here we present the CMDs for the 13 GGCs observed in the Northern
hemisphere. The remaining 39 Southern hemisphere clusters of the catalog
have been presented in a companion paper (Rosenberg et al.
cite{rosenberg00}). We present the first CCD color magnitude diagram
for NGC 6779 (M 56). All the CMDs extend from at least ~ 2 magnitudes
below the turn-off (i.e. V_lim>=22) to the tip of the red giant
branch. The calibration has been done using a large number of standard
stars, and the absolute calibration is reliable to a ~ 0.02 mag level in
both filters. This catalog, because of its homogeneity, is expected to
represent a useful data base for the measurement of the main absolute
and relative parameters characterizing the CMD of GGCs. Based on
observations made with the 1~m Jacobus Kapteyn Telescope operated on the
island of La Palma by the ING in the Spanish Observatorio del Roque de
Los Muchachos of the Instituto de Astrofìsica de Canarias.