EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 448/3 Article
Free access article

Issue A&A
Volume 448, Number 3, March IV 2006
Page(s) 1023 - 1030
Section Galactic structure, stellar clusters and populations
DOI http://dx.doi.org/10.1051/0004-6361:20054299

A&A 448, 1023-1030 (2006)
DOI: 10.1051/0004-6361:20054299

Spectral evolution of star clusters in the Large Magellanic Cloud

I. Blue concentrated clusters in the age range 40-300 Myr
J. F. C. Santos Jr.1, J. J. Clariá2, A. V. Ahumada2, E. Bica3, A. E. Piatti4 and M. C. Parisi2

1  Departamento de Física, ICEx, UFMG, CP 702, 30123-970, Belo Horizonte, MG, Brazil
    e-mail: jsantos@fisica.ufmg.br
2  Observatorio Astronómico, Laprida 854, 5000, Córdoba, Argentina
3  Depto. de Astronomia, UFRGS, CP 15051, 91500-970, Porto Alegre, Brazil
4  Instituto de Astronomía y Física del Espacio, CC 67, Suc. 28, 1428, Buenos Aires, Argentina

(Received 4 October 2005 / Accepted 15 November 2005)

Abstract
Aims.Integrated spectroscopy of a sample of 17 blue concentrated Large Magellanic Cloud (LMC) clusters is presented and its spectral evolution studied. The spectra span the range $\approx$(3600-6800) Å with a resolution of $\approx$14 Å FWHM, being used to determine cluster ages and, in connection with their spatial distribution, to explore the LMC structure and cluster formation history.
Methods.Cluster reddening values were estimated by interpolation, using the available extinction maps. We used two methods to derive cluster ages: (i) template matching, in which line strengths and continuum distribution of the cluster spectra were compared and matched to those of template clusters with known astrophysical properties, and (ii) equivalent width (EW) method, in which new age/metallicity calibrations were used together with diagnostic diagrams involving the sum of EWs of selected spectral lines (K Ca II, G band (CH), Mg I, H$\delta$, H$\gamma$ and H$\beta$).
Results. The derived cluster ages range from 40 Myr ( NGC 2130 and SL 237 ) to 300 Myr ( NGC 1932 and SL 709 ), a good agreement between the results of the two methods being obtained. Combining the present sample with additional ones indicates that cluster deprojected distances from the LMC center are related to age in the sense that inner clusters tend to be younger.
Conclusions.Spectral libraries of star clusters are useful datasets for spectral classifications and extraction of parameter information for target star clusters and galaxies. The present cluster sample complements previous ones, in an effort to gather a spectral library with several clusters per age bin.


Key words: galaxies: star clusters -- Magellanic Clouds -- techniques: spectroscopic

SIMBAD Objects




© ESO 2006


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.