| HI absorption in 3C 49 and 3C 268.3. Probing the environment of Compact Steep Spectrum and GHz Peaked Spectrum sources (2006) | |||||||||||||||
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| Astronomy Astrophysics manuscript DOI will inserted hand later February absorption and arXiv astro Oct Probing the environment Compact Steep Spectrum and GHz Peaked Spectrum sources Labiano Vermeulen Barthel O Dea Gallimore Baum and Vries Kapteyn Astronomical Institute Groningen The Netherlands Space Telescope Science Institute Baltimore USA Netherlands Foundation for Research Astronomy Dwingeloo The Netherlands Department Physics Rochester Institute Technology Rochester USA Department Physics Bucknell University Lewisburg USA Center for Imaging Science Rochester Institute Technology Rochester USA Lawrence Livermore National Lab Livermore USA Received date accepted date Abstract present and discuss European VLBI Network UHF band spectral line observations made localise the redshifted absorption known occur the subgalactic sized compact steep spectrum galaxies and have detected absorption towards the western radio lobe and the northern lobe However cannot rule out the presence similar amounts towards the opposite and much fainter lobes The radio lobes with detected absorption are brighter and closer the core than the opposite lobes are depolarized and are associated with optical emission line gas The association between the absorption and the emission line gas supports the hypothesis that the absorption produced the atomic cores the emission line clouds Our results are consistent with picture which compact steep spectrum sources interact with clouds dense gas they propagate th. We present and discuss European VLBI Network UHF band spectral line observations, made to localise the redshifted 21cm HI absorption known to occur in the subgalactic sized compact steep spectrum galaxies 3C 49 and 3C 268.3. We have detected HI absorption towards the western radio lobe of 3C 49 and the northern lobe of 3C 268.3. However, we cannot rule out the presence of similar amounts of HI towards the opposite and much fainter lobes. The radio lobes with detected HI absorption (1) are brighter and closer to the core than the opposite lobes; (2) are depolarized; and (3) are associated with optical emission line gas. The association between the HI absorption and the emission line gas, supports the hypothesis that the HI absorption is produced in the atomic cores of the emission line clouds. Our results are consistent with a picture in which compact steep spectrum sources interact with clouds of dense gas as they propagate through their host galaxy. We suggest that the asymmetries in the radio and optical emission can be due to interaction of a two sided radio source with an asymmetric distribution of dense clouds in their environment.. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This research has made use of NASA’s Astrophysics Data System. The European VLBI Network is a joint facility of European, Chinese, South African and other radio astronomy institutes funded by their national research councils. | |||||||||||||||
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