The Connection between Radio and Gamma Ray Emission in Fermi/LAT Blazars
  We collect the 2LAC and MOJAVE quasi-simultaneous data to investigate the
radio-gamma connection of blazars. The cross sample contains 166 sources. The
statistic analysis based on this sample confirms positive correlations between
these two bands, but the correlations become weaker as the gamma-ray energy
increases. The statistic results between various parameters show negative
correlations of gamma-ray photon spectral index with gamma-ray loudness for
both FSRQs and BL Lacertae objects, positive correlations of gamma-ray
variability index with the gamma-ray loudness for FSRQs, a negative correlation
of the gamma-ray variability index with the gamma-ray photon spectral index for
FSRQs, and negative correlations of gamma-ray photon spectral index with
gamma-ray luminosity for FSRQs. These results suggest that the gamma-ray
variability may be due to changes inside the gamma-ray emission region like the
injected power, rather than changes in the photon density of the external
radiation fields, and the variability amplitude tends to be larger as the
gamma-rays are closer to the high energy peak of spectral energy distribution.
No correlation of variability index found for BL Lacertae objects implies that
variability behavior may differ below and above the peak energy.
