[en] 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 ~ 10[SUP]5[/SUP] M[SUB]sun[/SUB]) and 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 Halpha contamination and is consistent with an old stellar population. This casts doubt on the hypothesis that Blue Compact Dwarf Galaxies (BCDG) are young galaxies. based on observations carried out at NTT in La Silla, operated by the European Southern Observatory, during Director's Discretionary Time.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Doublier, V.; European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago, Chile ; Observatoire de Marseille and Institut Cassendi, 2 place Le Verrier, 13004 Marseille, France
Kunth, D.; Institut d'Astrophysique de Paris, 98bis Bld Arago, 75014 Paris, France
Courbin, F.; Institut d'Astrophysique, Université de Liège, Avenue de Cointe 5, 4000 Liège, Belgium ; URA 173 CNRS-DAEC, Observatoire de Paris, 92195 Meudon Principal Cédex, France
Magain, Pierre ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Language :
English
Title :
POX 186: the ultracompact blue compact dwarf galaxy reveals its nature
