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Chimneys in the starburst galaxy M82 |
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| Authors: | K A Wills M P Redman T W B Muxlow A Pedlar |
| Institution: | Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL; University of Manchester, Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield, Cheshire SK11 9DL |
| Abstract: | We present MERLIN and VLA observations at 1.4 and 5 GHz of the diffuse radio emission in the centre of M82. We detect a large expanding shell of ionized gas surrounding the brightest supernova remnant 41.95+57.5 with a diameter of ～100 pc and an expansion velocity of ～100 km s On larger radio scales, we observe four chimney structures extending out to the north ～100–200 pc along the minor axis. One of these features is almost certainly related to the 50-pc-scale blow-out from 41.95+57.5, although this is not the most prominent feature. The other features have also been traced to expulsion of material from the very centre by using an 'unsharp masked' image from 5-GHz VLA B-array observations, with the supernova remnant removed. We interpret these chimney features as the base of the superwind, which implies that the ejection of material into the halo does not occur smoothly over the starburst region. Instead, very localized venting of hot gas is clearly in evidence. |
| Keywords: | ISM: jets and outflows galaxies: individual: M82 galaxies: ISM galaxies: starburst radio continuum: galaxies |