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The Shroud around the ‘Compact, Symmetric’ Radio Jets in NGC 1052

Published online by Cambridge University Press:  05 March 2013

R. C. Vermeulen
Affiliation:
Netherlands Foundation for Research in Astronomy, PO Box 2, NL–7990 AA Dwingeloo, The Netherlands. rvermeulen@astron.nl
E. Ros
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany. ros@mpifr-bonn.mpg.de, azensus@mpifr-bonn.mpg.de
K. I. Kellermann
Affiliation:
National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA. kkellerm@nrao.edu
M. H. Cohen
Affiliation:
California Institute of Technology, Pasadena, CA 91125, USA. mhc@astro.caltech.edu
J. A. Zensus
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany. ros@mpifr-bonn.mpg.de, azensus@mpifr-bonn.mpg.de National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA. kkellerm@nrao.edu
H. J. van Langevelde
Affiliation:
Joint Institute for VLBI in Europe, PO Box 2, NL–7990 AA Dwingeloo, The Netherlands. langevelde@jive.nl
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Abstract

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This is a paper on young jet material in a frustratingly complex environment.

NGC 1052 has a compact, flat or GHz peaked spectrum radio nucleus consisting of bi-symmetric jets, oriented close to the plane of the sky. Many features on both sides move away at υapp ˜0.26 c (H0 = 65 km s−1 Mpc−1). VLBI at seven frequencies shows a wide range of spectral shapes and brightness temperatures; there is clearly free–free absorption, probably together with synchrotron self-absorption, on both sides of the core. The absorbing structure is likely to be geometrically thick and oriented roughly orthogonal to the jets, but it is patchy.

HI VLBI shows atomic gas in front of the approaching as well as the receding jet. There appear to be three velocity systems, at least two of which are local to the AGN environment. The ‘high velocity system’, 125–200 km s−1 redward of systemic, seems restricted to a shell 1–2 pc away from the core. Closer to the centre, this gas might be largely ionised; it could cause the free–free absorption.

WSRT spectroscopy shows 1667 and 1665 MHz OH absorption over a wide velocity range. OH and HI profile similarity suggests co-location of molecular and atomic ‘high velocity’ gas; the connection to H2O masing gas is unclear. Further, at ‘high velocity’ we detected the OH 1612 MHz satellite line in absorption and the 1720 MHz line in emission, with complementary strengths.

Type
GPS/CSS Workshop
Copyright
Copyright © Astronomical Society of Australia 2003

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