Astron. Astrophys. Suppl. Ser. 134, 505-521

Optical morphology of distant RATAN-600 radio galaxies from subarcsecond resolution NOT images

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

Abstract:

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 ($\approx$ 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 m_R=24.

We could confirm 16 identifications down to $m_{R}\sim$ 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