CasA


The X-ray image of the Cassiopeia A supernova remnant on the left is
the official first light image of the Chandra X-ray Observatory. The
5,000 second image was made with the Advanced CCD Imaging Spectrometer
(ACIS). Two shock waves are visible: a fast outer shock and a slower
inner shock. The inner shock wave is believed to be due to the
collision of the ejecta from the supernova explosion with a
circumstellar shell of material, heating it to a temperature of ten
million degrees.  The outer shock wave is analogous to an awesome
sonic boom resulting from this collision. The bright object near the
center may be the long sought neutron star or black hole that remained
after the explosion that produced Cas A.