We don't know why the radio core flares. There is
no correlation with the X-ray and optical data. But whatever causes the flare produces a
larger than usual density of high-energy electrons that are channeled down the beam toward
the lobes. The enhanced regions of energy in the beam are shown by the white segments
moving in the beam. This energy is probably contained in electrons moving within 1% of the
speed of light. This burst quickly catches up with the lobes moving at half that
speed. The increased energy spurt from the beam energizes the lobe, which then
increases in radio brightness. The energy spurt moving to the right appears much reduced
in intensity and in speed, but only because it is moving away from us. |