Modeling the Stellar Populations in the Canis Major Over-Density: the Relation Between the Old and Young Populations

Details Modeling the Stellar Populations in the Canis Major Over-Density: the Relation Between the Old and Young Populations Modeling the Stellar Populations in the Canis Major Over-Density: the Relation Between the Old and Young Populations

2007-01-05

arxiv.org/abs/astro-ph/0701140v2

Astrophys.J.662:259-271,2007

Astronomy and Astrophysics

Astrophysics

15 pages, 11 figures, (2 additional figures + some textual changes wrt previous version), accepted for publication in Astrophy

Scientific paper

10.1086/517967

We analyze the stellar populations of the Canis Major stellar over-density, using quantitative color-magnitude diagram (CMD) fitting techniques. The analysis is based on photometry obtained with the Wide Field Imager at the 2.2m telescope at La Silla for several fields near the probable center of the over-density. A modified version of the MATCH software package was applied to fit the observed CMDs, enabling us to constrain the properties of the old and young stellar populations that appear to be present. For the old population we find [Fe/H]~-1.0, a distance of ~7.5 kpc and a line-of-sight depth sigma_los of 1.5+-0.2 kpc and a characteristic age range of 3-6 Gyrs. However, the spread in ages and the possible presence of a ~10 Gyr old population cannot be constrained. The young main-sequence is found to have an age spread; ages must range from a few hundred Myr to 2 Gyr. Because of the degeneracy between distance and metallicity in CMDs the estimates of these parameters are strongly correlated and two scenarios are consistent with the data: if the young stars have a similar metallicity to the old stars, they are equidistant and therefore co-spatial with the old stars; if the young stars have close to solar metallicity they are more distant (~9 kpc). The relatively low metallicity of the old main-sequence favors the interpretation that CMa is the remnant of an accreted dwarf galaxy. Spectroscopic metallicity measurements are needed to determine whether the young main-sequence is co-spatial.

Affiliated with

Also associated with

No associations

Rating

Modeling the Stellar Populations in the Canis Major Over-Density: the Relation Between the Old and Young Populations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Modeling the Stellar Populations in the Canis Major Over-Density: the Relation Between the Old and Young Populations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Modeling the Stellar Populations in the Canis Major Over-Density: the Relation Between the Old and Young Populations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-15838