Abstract
WMAP has produced a catalog of millimeter-wave sources outside the Galactic plane, assumed to be primarily blazars. We compared the WMAP catalog with the third EGRET catalog and the early list of bright sources compiled by the Fermi γ-ray Space Telescope, defining a sample of mm-wave/γ-ray bright objects. We briefly present some results from an exhaustive survey of these objects, using optical and near infrared instrumentation at the 2.1 m telescope of the OAGH Cananea observatory.
