Issue |
A&A
Volume 424, Number 1, September II 2004
|
|
---|---|---|
Page(s) | 91 - 106 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20035749 | |
Published online | 17 August 2004 |
New candidate GHz peaked spectrum and compact steep spectrum sources
1
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Yoshinodai 3-1-1, Sagamihara, Kanagawa 229-8510, Japan e-mail: pge@vsop.isas.jaxa.jp
2
Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, Vic. 3122, Australia e-mail: stingay@astro.swin.edu.au
Received:
26
November
2003
Accepted:
21
May
2004
Data from a recent Australia Telescope Compact Array (ATCA)
program of multi-frequency, multi-epoch
monitoring of 202 active galactic nuclei with declinations
have been
searched for GHz Peaked Spectrum (GPS)
and Compact Steep Spectrum (CSS) radio sources.
Supplementary data at higher and lower frequencies, where available,
have been used to further examine the spectral properties of previously
reported and new candidate GPS and CSS sources.
The ATCA monitoring program has allowed the variability and polarization
properties of sources previously reported as GPS and CSS sources, and
the majority of new GPS and CSS candidates, to be investigated, confirming
that these are useful diagnostics in discriminating genuine
GPS and CSS sources from variable sources that display similar spectra
only temporarily. GPS sources are confirmed to be generally more
compact, and less polarized, than CSS sources,
although CSS sources show evidence for being somewhat
less variable than GPS sources at 1.4 and 2.5 GHz.
In addition, the widths of GPS spectra are examined,
and a significant difference is found in the GPS sample of
Snellen et al. (2000) between sources with
compact double (CD) or compact symmetric object (CSO)
morphologies and sources with
other morphologies, in that CD and CSO sources have generally
narrower spectra. Possible reasons for this difference are considered.
Key words: surveys / galaxies: active / radio continuum: galaxies
© ESO, 2004
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