Rapid variability of the compact radio sources in Arp220: Evidence for a population of microblazars?

The two nuclei of the starburst galaxy Arp220 contain multiple compact radio sources previously identified as radio supernovae or supernova remnants. In order to search for an embedded radio AGN, the authors have carried out a programme of VLBI monitoring at 6 cm over three epochs each separated by...

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Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2012-06, Vol.542, p.1-1
Main Authors: Batejat, F, Conway, J E, Rushton, A, Parra, R, Diamond, P J, Lonsdale, C J
Format: Article
Language:English
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Summary:The two nuclei of the starburst galaxy Arp220 contain multiple compact radio sources previously identified as radio supernovae or supernova remnants. In order to search for an embedded radio AGN, the authors have carried out a programme of VLBI monitoring at 6 cm over three epochs each separated by four months. Combining the new data with existing data at 6 cm and 18 cm they are able to characterise source flux density variability on a range of timescales. They detect rapid variability in three sources (W7, W26, and W29). These sources show possible superluminal motion of jet-like features near rapidly varying almost stationary components. These enigmatic sources might be associated with an AGN or a highly beamed microquasar. Other hypotheses include that the apparent variability is intrinsic and is produced by neutron star powered central components within a supernova remnant, by a sequence of several supernovae within super star clusters, or is extrinsic and is produced by Galactic interstellar scintillation of very compact non-varying objects.
ISSN:0004-6361
1432-0746