EVN observations of candidate Compact Symmetric Objects

¹ National Astronomical Observatories, Chinese Academy of Sciences, Urumqi 830011, PR China e-mail: liux@ms.xjb.ac.cn
² Istituto di Radioastronomia del CNR, C.P. 141, 96017 Noto SR, Italy
³ Istituto di Radioastronomia del CNR, via P. Gobetti 101, 40129 Bologna, Italy
⁴ Dipartimento di Astronomia, Alma Mater Studiorum, via Ranzani 1, 40127 Bologna, Italy e-mail: ddallaca@ira.cnr.it
⁵ National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, PR China e-mail: hyzhang@class1.bao.ac.cn

Corresponding author: C. Stanghellini, cstan@ira.cnr.it

Received: 14 September 2001
Accepted: 28 January 2002

Abstract

We present pc-scale images of ten Compact Symmetric Objects (CSO) candidates observed with the European VLBI network (EVN). Five radio sources have been observed at 1.6 GHz, and five more at 2.3/8.4 GHz, the latter subsample with the inclusion in the VLBI array of 3 antennae normally used for geodesy. These objects were selected from existing samples of GHz Peaked Spectrum (GPS) radio sources with the purpose to find and/or confirm the CSO classification. These new VLBI observations allow us to confirm the classification of two CSO candidates, and to find a few new ones. The association of GPS radio galaxies with a CSO morphology is strengthened by our findings, and this result suggests an efficient way to increase the number of known CSOs by means of VLBI observations of compact radio galaxies showing a convex radio spectrum.