Received on March 4 2005
Luminosity and mass functions of galactic open clusters. II. NGC 4852
|Authors||Giovanni Carraro(1), Gustavo Baume(2), Giampaolo Piotto(3), Rene Mendez(1), Linda Schmidtobreick(4)|
|Affiliation||(1) Universidad de Chile|
(2) Universidad de La Plata
(3) Universitá di Padova
|Accepted by||Astronomy & Astrophysics|
We present wide-field deep UBVI photometry for the previously unstudied open cluster NGC 4852 down to a
limiting magnitude I~24, obtained from observations taken with the Wide Field Imager camera on-board
the MPG/ESO 2.2m telescope at La Silla (ESO, Chile). These data are used to obtain the first estimate of the cluster basic parameters,
to study the cluster spatial extension by means of star counts, and to derive the Luminosity (LF)
and Mass Function (MF). The cluster radius turns out to be 5.0 ± 1.0 arcmin.
The cluster emerges clearly from the field down to V=20 mag. At fainter magnitudes, it is completely confused with the general
Galactic disk field.
The stars inside this region define a young open cluster (200 million years old)1.1 kpc far from the Sun (m-M = 11.60, E(B-V) = 0.45).
The Present Day Mass Functions (PDMF) from the V photometry is one of the most extended in mass
obtained to date, and can be represented as a power-law with a slope alpha = 2.3 ± 0.3 and
(the Salpeter MF in this notation has a slope alpha = 2.35), in the mass range 3.2 <= M/Msun <= 0.6.
Below this mass, the MF cannot be considered as representative of the cluster MF,
as the cluster merges with the field and therefore the MF is the result of the combined effect of
strong irregularities in the stellar background and interaction of the cluster with the dense Galactic field.
The cluster total mass at the limiting magnitude results to be 2570 ± 210 Msun.