EDP Sciences
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Volume 367, Number 1, February III 2001
Page(s) 33 - 45
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20000417

A&A 367, 33-45 (2001)
DOI: 10.1051/0004-6361:20000417

The 1 to 2.5 $\mathsf{\mu}$ broad band emission of Blue Compact Dwarf Galaxies

V. Doublier1, 2, A. Caulet3 and G. Comte2

1  European Southern Observatory, Alonso de Cordova 3107, Casilla 19, Vitacura, Santiago, Chile
2  Observatoire de Marseille and Institut Gassendi, (CNRS), 2 place Le Verrier, 13248 Marseille Cedex 04, France
3  Calypso Observatory, Kitt Peak Observatory 950 North Cherry avenue, Tuscon, AR 85719, USA

(Received 8 November 1999 / Accepted 29 November 2000 )

We present J, H and K surface photometry of 12 Blue Compact Dwarf Galaxies (BCDGs) selected from the southern sample (Doublier et al. 1999). A systematic excess of light in the K band with respect to the other bands in the visible and the near infrared is observed, indicating, since nebular emission is negligible, that a stellar population of red giants dominates the global flux from the galaxy. Moreover, comparisons of the metallicity-color relations of BCDGs and globular clusters show very little differences, indicating that BCDGs are most probably old, in the cosmological sense, systems. Local colors of the star forming regions show that these regions are indeed very young and possibly coeval across the galaxy when several starburst locations exist. At least 4 BCDGs (UM 465A and B, Haro 14 and Tololo 0610-378) show evidence of the presence of young red supergiant stars. The light distributions in the J, H and K bands are generally consistent with those in the optical, the differences are discussed. We confirm that our optical photometric classification remains valid in the near infrared. Thus, the global light distribution in the galaxy is an intrinsic property of the host galaxy independent of the presence of the starburst.

Key words: galaxies: compact -- dwarf -- fundamental parameters -- stellar content

Offprint request: V. Doublier, vdoublie@eso.org

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