An Extended Star Formation History in an Ultra-Compact Dwarf
MNRAS 451, 3615–3626 (2015) doi:10.1093/mnras/stv1221 An extended star formation history in an ultra-compact dwarf Mark A. Norris,1‹ Carlos G. Escudero,2,3,4 Favio R. Faifer,2,3,4 Sheila J. Kannappan,5 Juan Carlos Forte4,6 and Remco C. E. van den Bosch1 1Max Planck Institut fur¨ Astronomie, Konigstuhl¨ 17, D-69117 Heidelberg, Germany 2Facultad de Cs. Astronomicas´ y Geof´ısicas, UNLP, Paseo del Bosque S/N, 1900 La Plata, Argentina 3Instituto de Astrof´ısica de La Plata (CCT La Plata – CONICET – UNLP), Paseo del Bosque S/N, 1900 La Plata, Argentina 4Consejo Nacional de Investigaciones Cient´ıficas y Tecnicas,´ Rivadavia 1917, C1033AAJ Ciudad Autonoma´ de Buenos Aires, Argentina 5Department of Physics and Astronomy UNC-Chapel Hill, CB 3255, Phillips Hall, Chapel Hill, NC 27599-3255, USA 6Planetario Galileo Galilei, Secretar´ıa de Cultura, Ciudad Autonoma´ de Buenos Aires, Argentina Accepted 2015 May 29. Received 2015 May 28; in original form 2015 April 2 ABSTRACT Downloaded from There has been significant controversy over the mechanisms responsible for forming compact stellar systems like ultra-compact dwarfs (UCDs), with suggestions that UCDs are simply the high-mass extension of the globular cluster population, or alternatively, the liberated nuclei of galaxies tidally stripped by larger companions. Definitive examples of UCDs formed by either route have been difficult to find, with only a handful of persuasive examples of http://mnras.oxfordjournals.org/ stripped-nucleus-type UCDs being known. In this paper, we present very deep Gemini/GMOS spectroscopic observations of the suspected stripped-nucleus UCD NGC 4546-UCD1 taken in good seeing conditions (<0.7 arcsec).
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