A WISE perspective of the blazar hunt in the γ-ray sky

Thanks to the data of the WISE all-sky survey we discovered that the non-thermal infrared emission of blazars, the largest population of associated γ-ray sources, has peculiar spectral properties. Here we provide a summary of all results achieved on the infrared–γ-ray connection. We also show results on the latest statistical analysis of the tight correlation between the mid-infrared colors and the γ-ray spectral index for Fermi blazars, a connection that links both emitted powers and spectral shapes of particles accelerated in blazar jets over ten decades in frequency of the electromagnetic spectrum. Finally, we outline all developments performed in the last decade achieved using the infrared– γ-ray connection to discover hundreds of new blazars within the sample of unidentified γ-ray sources thanks to optical spectroscopic observations.