Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2009-03-03
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
accepted for publication in MNRAS
Scientific paper
We obtained long-slit spectra of high signal-to-noise ratio of the galaxy M32 with the GMOS spectrograph at the GEMINI North telescope. We analysed the integrated spectra by means of full spectral fitting in order to extract the mixture of stellar populations that best represents its composite nature. Three different galactic radii were analysed, from the nuclear region out to 2 arcmin from the centre. This allows us to compare, for the first time, the results of integrated light spectroscopy with those of resolved colour-magnitude diagrams from the literature. As our main result, we propose that an ancient and an intermediate-age population coexist in M32, and that the balance between these two populations change between the nucleus and outside 1 effective radius in the sense that the contribution from the intermediate population is larger at the nuclear region. We retrieve a smaller signal of a young population at all radii whose origin is unclear and may be a contamination from horizontal-branch stars, such as the ones identified by Brown et al. in the nuclear region. We compare our metallicity distribution function for a region 1 to 2 arcmin from the centre to the one obtained with photometric data by Grillmair et al. Both distributions are broad, but our spectroscopically derived distribution has a significant component with $[Z/Z_{\sun}] \leq -1$, which is not found by Grillmair et al.
Cid Fernandes Roberto
Coelho Paula
de Oliveira Mendes Cl.
No associations
LandOfFree
An analysis of the composite stellar population in M32 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 An analysis of the composite stellar population in M32, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An analysis of the composite stellar population in M32 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-652691