A new population of extended, luminous star clusters in the halo of M31 |
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| Authors: | A P Huxor N R Tanvir M J Irwin R Ibata J L Collett A M N Ferguson T Bridges G F Lewis |
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| Institution: | Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB;Institute of Astronomy, Madingley Road, Cambridge CB3 0HA;Observatoire de Strasbourg, 11, rue de l'Universite, F-67000, Strasbourg, France;Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ;Department of Physics, Queen's University, Kingston, Ontario, Canada K7M 3N6;Institute of Astronomy, School of Physics, A29, University of Sydney, NSW 2006, Australia |
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| Abstract: | We present three new clusters discovered in the halo of M31 which, although having globular-like colours and luminosities, have unusually large half-light radii, ～30 pc. They lie at projected galactocentric distances of ≈15 to ≈35 kpc. These objects begin to fill the gap in parameter space between globular clusters and dwarf spheroidals, and are unlike any clusters found in the Milky Way, or elsewhere to date. Colour–magnitude diagrams, integrated photometric properties and derived King profile fit parameters are given, and we discuss possible origins of these clusters and their relationships to other populations. |
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| Keywords: | galaxies: individual: M31 galaxies: star clusters |
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