Astron. Astrophys. Suppl. Ser. 134, 505-521
T. Pursimo1 - K. Nilsson1 - P. Teerikorpi1 - A. Kopylov2 - N. Soboleva3 - Yu. Parijskij2 - Yu. Baryshev4 - O. Verkhodanov2 - A. Temirova3 - O. Zhelenkova2 - W. Goss5 - A. Sillanpää1 - L.O. Takalo1
Send offprint request: T. Pursimo
1 - Tuorla Observatory, FIN-21500 Piikkiö, Finland
2 - Special Astrophysical Observatory, Radio Astronomy Sector, 35147 Niznij Arkhyz, Karachey-Cherkessia, Russia
3 - St. Petersburg Branch of the SAO, Radio Astronomy Laboratory, Pulkovskoe Shosse 65, 196140 St. Petersburg, Russia
4 - Astronomical Institute of St. Petersburg University, 198904 St. Petersburg, Russia
5 - National Radio Astronomical observatory, P.O. Box 0, Socorro, New Mexico 87801, U.S.A.
Received February 27; accepted September 7, 1998
We present direct imaging data of 22 ultra steep spectrum radio sources obtained at (or near) a subarcsecond seeing. The basic sample of 40 double radio sources was selected from the RATAN-600 catalogue. The FRII-structure has been confirmed with VLA and preliminary optical identifications which come from the 6 m-telescope. As the RATAN-600 flux limit at 3.9 GHz ( 10 mJy) is fainter than that of major surveys, the sample may have high-z contents. This is also suggested by the faint magnitudes in the Hubble diagram. The final aim is to create a homogeneous sample of high-z radio galaxies in a well defined strip around the sky, with faint radio limit and subarcsecond morphology down to mR=24.
We could confirm 16 identifications down to 24. Most of the extended objects have multicomponent structures as expected from other surveys of high-redshift radio galaxies. We found five unresolved objects even with a subarcsecond seeing. Of the remaining six objects, three are extremely faint and the other three have such a complex environment that further observations are needed to confirm the optical identification.
Key words: galaxies: active; structure -- radio continuum: galaxies
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