XMM-Newton X-ray image of M87+X-ray filaments
Credit: Marco Iacobelli and ESA

Faster than a Speeding Photon?

The summer is the time for touring and sightseeing. No trip of the local Universe is complete without a stop at the Virgo Cluster and its spectacular radio galaxy M87. M87 is a giant elliptical galaxy notable for the large number of globular clusters which surround it, and also for the six billion solar mass black hole that lies at its center. The release of gravitational energy as matter falls into this black hole powers jets on either side of the black hole's accretion disk. The image above shows the central galaxy and X-ray emitting filaments in an X-ray image taken by the XMM-Newton observatory. Detailed observations by the Hubble Space Telescope show that the jets (which can be resolved by the Chandra X-ray Telescope) appear to be moving at six times the speed of light. Was Einstein, the Universe's ultimate traffic cop, wrong? Not really - the apparently superluminal motion, and the jet asymmetry, are optical illusions produced by the high speed of the jets (which move at near, but slightly below, the speed of light) coupled with the special orientation of our line-of-sight to the direction of motion of the jet. On the other hand, the X-ray filaments seen in the image above are believed to be produced when slow buoyant radio-emitting bubbles of cosmic rays uplift relatively cool X-ray-emitting gas, producing trailing wakes of X-rays behind the radio bubbles.
Published: June 15, 2009

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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:11:21 EDT