Spectral Indices of the Radio Sources

In this paper, 162 radio sources, including 47 BL Lacs, 21 galaxies and 94 flat spectral radio quasars (FSRQs) are studied.All sources were extracted from the University of Michigan Radio Astronomy Observatory (UMRAO)database observed by the 26-meter Michigan Radio Telescope.Most of the sources were observed at three bands 4.8GHz, 8GHz and 14.5GHz.The average flux densities of the three subclasses are calculated and the weighted average spectral index (α_wei), α_BL=0.08±0.28, α_GAL=-0.91±0.32, α_FSRQ=-0.14±0.4 are obtained.Some radio properties are discussed in this paper, including the spectral index, the relation between the flux and the redshift, the relation between the flux and the spectral index.