| Issue |
A&A
Volume 483, Number 3, June I 2008
|
|
|---|---|---|
| Page(s) | 769 - 781 | |
| Section | Extragalactic astronomy | |
| DOI | https://doi.org/10.1051/0004-6361:20078899 | |
| Published online | 01 April 2008 | |
Evidence for metallicity spreads in three massive M 31 globular clusters *,**
1
GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place Jules Janssen, 92190, Meudon, France e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
2
Instituto de Astronomía, Geofísica e Ciencias Atmosféricas, Universidade de São Paulo, Rua do Matão 1226-Cidade Universitária, 05508-900 São Paulo SP, Brazil
3
Observatoire, Université de Genève, chemin des Maillettes 51, 1290 Sauverny, Switzerland e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
4
Laboratoire d'Astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire, 1290 Sauverny, Switzerland e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
5
University of Florida, Department of Astronomy, Gainesville, FL 32611, USA e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
6
Department of Physics, Engineering Physics, and Astronomy, Queen's University, Kingston, ON K7L 3N6, Canada e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
7
California Institute of Technology, Pasadena, CA 91125, USA e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Received:
22
October
2007
Accepted:
14
March
2008
Abstract
Aims. We quantify the intrinsic width of the red giant branches of three massive globular clusters in M 31 in a search for metallicity spreads within these objects.
Methods. We present HST/ACS observations of three massive clusters in M 31, G78, G213, and G280. A thorough description of the photometry extraction and calibration is presented. After derivation of the color-magnitude diagrams, we quantify the intrinsic width of the red giant branch of each cluster.
Results. This width translates into a metallicity
dispersion that indicates a complex star formation history for this
type of system. For G78, ![Mathematical equation: $ \sigma_{[\rm Fe/H]}=0.86 \pm 0.37 $](/articles/aa/abs/2008/21/aa8899-07/aa8899-07_tex_eq1.png)
;
for G213, 
; and for G280, 
.
We find that the metallicity dispersion of the clusters does not scale with mean metallicity. We also find no trend with the cluster mass.
We discuss some possible formation scenarios that would explain our
results.
Key words: galaxies: evolution / galaxies: Local Group / galaxies: star clusters / Galaxy: globular clusters: general
Tables of individual photometric measurements are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/483/769
Figures 4 and 5 are only available in electronic form at http://www.aanda.org
© ESO, 2008
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