The radio source Z0254+43: z = 4.067

In January 2005 spectral observations of the radio source Z0254+43 were made on the BTA at the Special Astrophysical Observatory (SAO) of the Russian Academy of Sciences (RAN) and its red shift was found to be z=4.057. The BVRI magnitudes were found to be 22.68, 21.19, 19.94, and 19.23, respectively. Photometric observations in December 2005 on the Zeiss-1000 at the SAO revealed no significant variation in the optical emission from this object over that year. We can discuss its variability on an hourly time scale with some caution. The variability of the flux from Z0254+43 was observed from 1990–2005 on the RATAN-600 over a wide range of frequencies. It turns out that the amplitude of the variability is minimal at a frequency of ∼8 GHz. A model for the variability has been constructed which yields an estimate of ∼28° for the orientation of the jet of Z0254+43 to the line of sight. The luminosity of Z0254+43 in the optical range is ∼2·10²⁶ W/Hz and in the radio frequency range, ∼2·1027 W/Hz. __________ Translated from Astrofizika, Vol. 49, No. 2, pp. 209–220 (May 2006).