Crowther, P.A. and Bibby, J.L. (2009) On the massive star content of the nearby dwarf irregular Wolf-Rayet galaxy IC 4662. Astronomy and Astrophysics. ISSN 0004-6361
Aims. We investigate the massive stellar content of the nearby dwarf irregular Wolf-Rayet galaxy IC 4662, and consider its global star forming properties in the context of other metal-poor galaxies, the SMC, IC 10 and NGC 1569.
Methods. Very Large Telescope/FORS2 imaging and spectroscopy plus archival Hubble Space Telescope/ACS imaging datasets permit us to spatially identify the location, number and probable subtypes of Wolf-Rayet stars within this galaxy. We also investigate suggestions that a significant fraction of the ionizing photons of the two giant H II regions A1 and A2 lie deeply embedded within these regions.
Results. Wolf-Rayet stars are associated with a number of sources within IC 4662-A1 and A2, plus a third compact H II region to the north west of A1 (A1-NW). Several sources appear to be isolated, single (or binary) luminous nitrogen sequence WR stars, while extended sources are clusters whose masses exceed the Orion Nebula Cluster by, at most, a factor of two. IC 4662 lacks optically visible young massive, compact clusters that are common in other nearby dwarf irregular galaxies. A comparison between radio and H-derived ionizing fluxes of A1 and A2 suggests that 30–50% of their total Lyman continuum fluxes lie deeply embedded within these regions.
Conclusions. The star formation surface density of IC 4662 is insufficient for this galaxy to qualify as a starburst galaxy, based upon its photometric radius, R25. If instead, we were to adopt the V
|Copyright, Publisher and Additional Information:||© 2009 EDP Sciences. Reproduced in accordance with the publisher's self-archiving policy|
|Keywords:||galaxies: individual: IC 4662 – stars: Wolf-Rayet – (ISM): HII regions – galaxies: star clusters – galaxies: starburst – galaxies: dwarf|
|Institution:||The University of Sheffield|
|Academic Units:||The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield)|
|Depositing User:||Miss Anthea Tucker|
|Date Deposited:||27 May 2009 16:33|
|Last Modified:||13 Jun 2014 11:46|