Decametric AGNs: FIRST and NVSS maps and radio spectra

Radio sources from the decametric UTR–2 catalog were cross-identified with other radio catalogs at higher frequencies. We used the CATS database to extract all sources within the UTR beam size ($\sim {40}^{\mathrm{\prime }}$) to find candidate radio identifications. Using the least squares method we fitted the spectrum of each source with one of a set of curves. We extracted NVSS and FIRST radio images for the radio-identified sources, and looked for a possible relation between size and spectral index.