Investigation of radio sources from the interplanetary scintillation Pushchino Survey ^*

II. Optical identification

¹ Special Astrophysical Observatory of RAS, Nizhnij Arkhyz, Karachaevo-Cherkesia, 369167, Russia
² Isaac Newton Institute of Chile, SAO Branch, Russia
³ Pushchino Radio Astronomy Observatory of the Lebedev Physical Institute of RAS, Pushchino, Moscow region, 142290, Russia
⁴ Isaac Newton Institute of Chile, Pushchino Branch, Russia

Corresponding author: A. I. Kopylov, akop@sao.ru

Received: 15 January 2004
Accepted: 25 February 2004

Abstract

We present the results of optical identification of 248 interplanetary scintillating (IPS) radio sources from the Pushchino Survey (PS) in the area of 0.11 sr with the center at . All 260 counterparts of IPS radio sources from the 7C and FIRST catalogues, which had been found in Paper I, were considered. We used USNO–B1.0 catalogue (limiting magnitude ) for the optical identification and searched the literature to find optical data for fainter objects. Photometric and spectroscopic observations were conducted on the 1 m and 6 m telescopes of SAO RAS. Optical magnitudes or deep limits for 22 objects and redshifts for 26 ones have been obtained. In total, we collected optical data for 116 (68 with redshift) counterparts of the PS radio sources. For the subsample of the PS quasars (41 objects) the redshift distribution was compared to those of several other samples of quasars (BRL, 3CRR, MQS, B3–VLA, 7CRS I–III and PKS 0.25 Jy) which have complete or nearly complete redshift information.