EVN observations of eleven GHz-Peaked-Spectrum radio sources at 2.3/8.4GHz

Abstract

We present results of EVN observations of eleven GHz-Peaked-Spectrum (GPS) radio sources at 2.3/8.4 GHz. These sources are from the classical ''bright'' GPS source samples with peak flux densities $>$ 0.2 Jy and spectral indices $\alpha <-0.2$ ($S\propto {\nu }^{-\alpha }$) in the optically thick regime of their convex spectra. Most of the target sources did not have VLBI images at the time this project started. The aim of the work is to find Compact Symmetric Object (CSO) candidates from the ''bright'' GPS samples. These CSOs play a key role in understanding the very early stage of the evolution of individual radio galaxies. The reason for investigating GPS source samples is that CSO candidates are more frequently found among this class of radio sources. In fact both classes, GPS and CSO, represent a small fraction of the flux limited and flat-spectrum samples like PR+CJ1 (PR: Pearson-Readhead survey, CJ1: the first Caltech--Jodrell Bank survey) and CJF (the Caltech--Jodrell Bank flat spectrum source survey) with a single digit percentage progressively decreasing with decreasing flux density limit. Our results, with at least 3, but possibly more CSO sources detected among a sample of 11, underline the effectiveness of our approach. The three confirmed CSO sources (1133+432, 1824+271, and 2121$-$014) are characterized by a symmetric pair of resolved components, each with steep spectral indices. Five further sources (0144+209, 0554$-$026, 0904+039, 0914+114 and 2322$-$040) can be considered likely CSO candidates. The remaining three sources (0159+839, 0602+780 and 0802+212) are either of core-jet type or dominated by a single component at both frequencies.

11 pages, 22 figures, accepted by A&A

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• The X-ray view of Giga-Hertz Peaked Spectrum Radio Galaxies
• A Search for Intrinsic HI 21 cm and OH 18 cm Absorption Toward Compact Radio Sources
• Quasi-simultaneous multi-frequency observations of inverted-spectrum GPS candidate sources
• AzTEC 1.1 mm images of 16 radio galaxies at 0.5<z<5.2 and a quasar at z=6.3
• VLBI observations of nineteen GHz-Peaked-Spectrum radio sources at 1.6 GHz
• European VLBI Network observations of fourteen GHz-Peaked-Spectrum radio sources at 5 GHz
• A radio structure resolved at the deca-parsec scale in radio-quiet quasar PDS 456 with an extremely powerful X-ray outflow
• A two-sided but significantly beamed jet in the supercritical accretion quasar IRAS F11119+3257
• uGMRT HI 21-cm absorption observations of two extremely inverted spectrum sources
• Structure, spectra and variability of some GPS radio sources
• VLBI observation of giant radio galaxy J1313+696 at 2.3/8.4 GHz