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S. LaMassa, A. Siemiginowska, T.L. Aldcroft (Harvard-Smithsonian Center for Astrophysics), M. Guainazzi, J. Bechtold, M. Elvis (European Space Astronomy Center of ESA)
Powerful compact radio sources have a similar radio morphology to large scale radio sources (with jets, hot spots and lobes) but on a much smaller scale. An entire compact radio source is usually contained within a host galaxy, typically smaller than <20 kpc. They have been considered the progenitors of large scale radio galaxies, although the evolution of radio sources is not yet fully understood. Recent evidence for repetitive AGN activity observed in X-ray clusters indicate that the growth of the radio source may be intermittent, so we may be observing the newly born sources within the relic of the previous source activity. Compact radio sources can represent these re-born sources if they are observed at the early stage of their evolution. (Note that the alternative explanation of the radio source compactness is related to the confining medium, preventing the source expansion.)
Here we present a sample of compact radio sources, containing both galaxies and quasars, observed with Chandra X-ray Observatory. We study the properties of these galaxies, including a comparison of the X-ray and radio luminosities and X-ray morphologies. We find that the quasars are not absorbed in comparison to galaxies which show significant absorption columns (>1022 cm-2). Intrinsic X-ray luminosities (1041-1044) of the galaxies are similar to the other powerful galaxies, so they are not X-ray weak sources. We observed different types of X-ray morphology: large scale jets in two quasars, a binary source, an X-ray cluster around a quasar and a diffuse emission around a galaxy. At least in one case, where we detect the cluster emission, we determined that the source is young and not confined by the dense medium, thus in agreement with the evolution model explaining the source compactness.
This research is funded in part by NASA contract NAS8-39073. Partial support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number GO-01164X and GO2-3148A issued by the Chandra X-Ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-39073. Partial support was also provided through NASA grants NAG5-13267 NNG04GF98G.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.