The Parsec-Scale Morphology of Southern GPS sources
arXiv:1701.01172 · doi:10.1017/pasa.2016.57
Abstract
Multi-frequency, multi-epoch ATCA observations of a sample of AGN resulted in the identification of 9 new candidate Giga-hertz Peaked Spectrum (GPS) sources. Here we present Long Baseline Array observations at 4.8 GHz of the four candidates with no previously published VLBI image, and consider these together with previously published VLBI images of the other five sources. We find core-jet or compact double morphologies dominate, with further observations required to distinguish between these two possibilities for some sources. One of the nine candidates, PKS 1831-711, displays appreciable variability, suggesting its GPS spectrum is more ephemeral in nature. We focus in particular on the apparent relationship between a narrow spectral width and "compact double" parsec-scale morphology, finding further examples, but also exceptions to this trend. An examination of the VLBI morphologies high-redshift (z>3) sub-class of GPS sources suggests that core-jet morphologies predominate in this class.
9 pages, 5 figures
References in corpus (7)
- GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
- CGRaBS: An All-Sky Survey of Gamma-Ray Blazar Candidates
- Science With The Australian Square Kilometre Array Pathfinder
- The VSOP 5 GHz Active Galactic Nucleus Survey: V. Imaging Results for the Remaining 140 sources
- The Spectral Variability of the GHz-Peaked Spectrum Radio Source PKS 1718-649 and a Comparison of Absorption Models
- The multi-frequency parsec-scale structure of PKS 2254-367 (IC 1459): a luminosity-dependent break in morphology for the precursors of radio galaxies?
- Evolution of the pc-scale structure of PKS 1934-638 revisited: first science with the ASKAP and New Zealand telescopes