Astron. Astrophys. Suppl. Ser. 134, 201-210

VLBI observations of 21 extragalactic radio sources

Search for superluminal sources in the mid-southern hemisphere

X.Y. Hong¹ - T. Venturi² - T.S. Wan¹ - D.R. Jiang¹ - Z.-Q. Shen¹ - X. Liu³ - G. Nicolson⁴ - G. Umana⁵

Send offprint request: T. Venturi (tventuri@ira.bo.cnr.it)

1 - Shanghai Astronomical Observatory, Chinese Academy of Sciences, China
2 - Istituto di Radioastronomia del CNR, Via Gobetti 101, 40129 Bologna, Italy
3 - Urumqi Astronomical Station, Chinese Academy of Sciences, China
4 - Hartebeesthoek Radio Astronomy Observatory, South Africa
5 - Istituto di Radioastronomia del CNR, Noto, Italy

Received March 23; accepted July 28, 1998

Abstract:

We present the results of VLBI observations of 21 extragalactic radio sources carried out with an ad-hoc VLBI array including Shanghai, Urumqi, Noto, and Hartebeesthoek radio telescopes. Eleven sources are imaged, three of them for the first time with VLBI. Correlated flux densities of the remaining ten sources are given. From comparison with data taken at earlier epochs, the apparent superluminal motion is confirmed in four sources (0420-014, 0552+398, 1334-127 and 2345-167) and two more superluminal candidates (1504-166 and 2243-123) are found. The physical parameters of the four superluminal sources are derived.

Key words: radio continuum: galaxies -- galaxies: active -- quasars: general