Contemporaneous multiwaveband observations of blazars

The authors have observed a number of blazars at wavebands ranging from radio to γ-ray. They find bright γ-ray emission to be associated with strong synchrotron flares observed at lower frequencies. The X-ray flux and entire radio spectrum of 4C 39.25 have each increased in strength by 30% over a 2-year period, in agreement with the prediction of the bent relativistic jet model