RCR J090511.74+045536.8 - a candidate for the most distant radio galaxies

Using modern radio, infrared and optical sky surveys, hosts have been found for the vast majority of radio sources detected by the Cold experiment and included in the RATAN Cold Refined (RCR) catalog. In this paper, we present details of the optical identification of one of the objects in the RCR catalog – a double radio source RCR J090511.74+045536.8. Initially, we matched it with the to SDSS J090511.94+045537.6, which we assumed to be a supernova that exploded in the host galaxy of the radio source. This hypothesis had to be abandoned, however, as to its properties the SDSS database indicated that it was an asteroid. Searching for the host galaxy of the radio source in deeper optical surveys allowed us to detect an object fainter than $r\approx 26^m$ at the expected location of the host relative to the radio source lobes. We cannot use the selection criteria for Lyman-Break Galaxies (LBG) due to the faintness of the host, but we can assume that the object can be classified as one of them, since it is detected in the r-filter and brighter in the i-filter, but is absent in other filters. Then its estimated host redshift may be greater than $z\gtrsim 4-5$, making it a candidate for the most distant radio galaxies.