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We use the complete MOJAVE 1.5 Jy sample of active galactic nuclei (AGN) toexamine the gamma-ray detection statistics of the brightest radio-loud blazarsin the northern sky. We find that 23% of these AGN were not detected above 0.1GeV by the Fermi LAT during the 4-year 3FGL catalog period partly because of aninstrumental selection effect, and partly due to their lower Doppler boostingfactors. Blazars with synchrotron peaks in their spectral energy distributionslocated below $10^{13.4}$ Hz also tend to have high-energy peaks that lie belowthe 0.1 GeV threshold of the LAT, and are thus less likely to be detected byFermi. The non-detected AGN in the 1.5 Jy sample also have significantly lower15 GHz radio modulation indices and apparent jet speeds, indicating that theyhave lower than average Doppler factors. Since the effective amount ofrelativistic Doppler boosting is enhanced in gamma-rays (particularly in thecase of external inverse-Compton scattering), this makes them less likely toappear in the 3FGL catalog. Based on their observed properties, we haveidentified several bright radio-selected blazars that are strong candidates forfuture detection by Fermi.

Why Haven't Many of the Brightest Radio Loud Blazars Been Detected by Fermi ?