Preprint Logo P36 February

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Astronomy & Astrophysics

POX 186: the ultracompact Blue Compact Dwarf Galaxy reveals its nature+

V. Doublier1,2, D. Kunth3, F. Courbin4,5 and P. Magain4

1 European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago, Chile
2 Observatoire de Marseille and Institut Cassendi, 2 place Le Verrier, F-13004 Marseille, France
3 Institut d'Astrophysique de Paris, 98bis Bld Arago, F-75014 Paris, France
4 Institut d'Astrophysique et de Géophysique - Université de Liège, Avenue de Cointe 5, 4000 Liège, Belgium
5 DAEC-URA 173, Observatoire de Paris, F-92195 Meudon Principal cedex, France

+ Based on observations carried out at NTT in La Silla, operated by the European Southern Observatory, during Director's Discretionary Time.


     High resolution, ground based R and I band observations of the ultra compact dwarf galaxy POX 186 are presented. The data, obtained with the ESO New Technology Telescope (NTT), are analyzed using a new deconvolution algorithm which allows one to resolve the innermost regions of this stellar-like object into three Super-Star Clusters (SSC). Upper limits to both masses (M ~ 105 M) and the physical sizes ( 60pc) of the SSCs are set. In addition, and maybe most importantly, extended light emission underlying the compact star-forming region is clearly detected in both bands. The R-I color rules out nebular H contamination and is consistent with an old stellar population. This casts doubt on the hypothesis that Blue Compact Dwarf Galaxies (BCDG) are young galaxies.

Key Words

Galaxies: compact, dwarf, evolution, formation, photometry, starburst


A complete HTML version is available on the "Image Processing: Deconvolution" Page

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