The powerful jet in quasar PKS 0637-752
When the Chandra x-ray satellite was trained on one of its first objects, the Compact Array was performing simultaneous comparison observations. This pair of images shows the quasar PKS0637-752 - a bright distant galaxy in the southern sky. Quasars like this are fairly ``normal'' galaxies which contain an active and massive black hole at its centre: the brightness of the quasar is a result of material falling into the black hole. As well as the bright core of emission around the black hole, these images show a jet of material ejected from the black hole, which undergoes a remarkably sharp turn. The upper panel shows the x-ray image, with radio contours overlaid, whereas the lower panel shows an optical image, again with radio contours overlaid.
The discovery of the x-ray jet is important because the power radiated by the x-ray jet is much greater than that of the radio jet. Any theory of jets must take into account the severe energy requirements imposed by the size and power of the x-ray jet.
ATCA image by J. Lovell; X-ray image by Chandra; optical image by HST.