Chandra Release - September 17, 2003

Visual Description: Cygnus X-1, XTE J1650-500, GX 339-4

 The image consists of two illustrations up top and two X-ray spectra at bottom to help showcase how astronomers have investigated the gravitational effects and spin of black holes with the Chandra X-ray Observatory.   The colors in the image are predominantly shades of red, orange, blue and black.   The key structures in the illustrations include an accretion disk, shaped like a swirly pancake in red, orange and white, and the black hole's shadow. The accretion disk is a disk of gas and dust that orbits around the black hole, eventually falling into it due to its immense gravitational pull. The black hole's shadow is created by the intense gravity of the black hole, which causes light to bend around it, appearing as a dark area in the center of the image.   As shown in the spectra (a plot of X-ray energy over different wavelengths) , the gravity of a black hole shifts X-rays from iron atoms to lower energies, producing a strongly skewed X-ray signal. One black hole is depicted as not spinning (on the left) with a wider area of black space around the black hole, and a second black hole is depicted as spinning rapidly (on the right), with no blank space around the black hole. One consequence of Einstein's theory of relativity is that spinning black holes drag space with them as they spin, making it possible for particles to orbit nearer to the black hole. A possible explanation for the differences in spin among stellar black holes is that they are born spinning at different rates. Another is that the gas flowing into the black hole spins it up.