` High Energy Astrophysics Picture Of the Week

Chandra spectrum of GRO J1655-40
Credit:NASA/CXC/U.Michigan/J.Miller et al.

How Goes the Flow?

A wild wind blows from the blackest holes. Surprising, since black holes are usually thought of as cosmic vacuum cleaners, swallowing everything in their greedy grasp. But winds blow from these things too, as shown by the X-ray spectra obtained by the High Energy Transmission Grating on the Chandra X-ray Observatory. A portion of the spectrum is shown in blue above, and sharp absorption lines produced by a highly ionized plasma can easily be seen. Comparing the observed spectrum in blue to a model spectrum (in yellow) shows that the lines are systematically shifted to shorter wavelengths. The shift results from the Doppler effect, showing that the ionized gas is approaching the observer. These observations provide crucial evidence for the role of magnetic forces in the black hole accretion process, showing that it's not just gravity alone that guides the flow.

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Each week the HEASARC brings you new, exciting and beautiful images from X-ray and Gamma ray astronomy. Check back each week and be sure to check out the HEAPOW archive!

Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:20:51 EDT