From: baalke@zagami.jpl.nasa.gov   
      
   Donald Savage   
   Headquarters, Washington              November 17, 2003   
   (Phone: 202/358-1547)   
      
   Steve Roy   
   Marshall Space Flight Center, Huntsville, Ala.   
   (Phone: 256/544-6535)   
      
   Megan Watzke   
   Chandra X-ray Observatory Center, CFA, Cambridge, Mass.   
   (Phone: 617/496-7998)   
      
   RELEASE: 03-367   
      
   MOST DISTANT X-RAY JET YET DISCOVERED PROVIDES CLUES TO BIG   
   BANG   
      
        The most distant jet ever observed was discovered in an   
   image of a quasar made by NASA's Chandra X-ray Observatory.   
      
   Extending more than 100,000 light-years from the supermassive   
   black hole powering the quasar, the jet of high-energy   
   particles provides astronomers with information about the   
   intensity of the cosmic microwave background radiation 12   
   billion years ago.   
      
   The discovery of this jet was a surprise to the astronomers,   
   according to team members. Astronomers had previously known   
   the distant quasar GB1508+5714 to be a powerful X-ray source,   
   but there had been no indication in previous images of any   
   complex structure or a jet.   
      
   "This jet is especially significant because it allows us to   
   probe the cosmic background radiation 1.4 billion years after   
   the big bang," said Aneta Siemiginowska of the Harvard-   
   Smithsonian Center for Astrophysics in Cambridge, Mass., lead   
   author of a report on this research in the November 20   
   Astrophysical Journal Letters. Prior to this discovery, the   
   most distant confirmed X-ray jet corresponded to a time about   
   3 billion years after the big bang.   
      
   Quasars are thought to be galaxies that harbor an active   
   central supermassive black hole fueled by infalling gas and   
   stars. This accretion process is often observed to be   
   accompanied by the generation of powerful high-energy jets.   
      
   As the electrons in the jet fly away from the quasar at near   
   the speed of light, they move through the sea of cosmic   
   background radiation left over from the hot early phase of the   
   universe.   
      
   When a fast-moving electron collides with one of these   
   background photons, it can boost the photon's energy up into   
   the X-ray band. The X-ray brightness of the jet depends on the   
   power in the electron beam and the intensity of the background   
   radiation.   
      
   "Everyone assumes that the background radiation will change in   
   a predictable way with time, but it is important to have this   
   check on the predictions," said Siemiginowska. "This jet is   
   hopefully just the first in a large sample of these distant   
   objects that can be used to tell us how the intensity of the   
   cosmic microwave background changed over time."   
      
   "In fact, if this interpretation is correct, then discovery of   
   this jet is consistent with our previous prediction that X-ray   
   jets can be detected at arbitrarily large distances!" said   
   team member Dan Schwartz, also of the Harvard-Smithsonian   
   Center for Astrophysics.   
      
   Chandra originally observed GB 1508+5714 with the purpose of   
   studying the X-ray emission from the dust located between the   
   Earth and the far-flung quasar. The jet was found by   
   Siemiginowska and her colleagues when they examined the data   
   once it became available publicly in the Chandra archive.   
      
   This led another astronomer to then carefully look at radio   
   observations of the object. Indeed, archived Very Large Array   
   data confirmed the existence of the jet associated with the   
   quasar GB 1508+5714.  A paper on the radio observations of GB   
   1509+5714 has been accepted by Astrophysical Journal Letters   
   from Teddy Cheung of Brandeis University in Waltham, Mass.   
      
   Another group of astronomers led by Weimen Yuan of the   
   University of Cambridge, United Kingdom, independently   
   reported the discovery of the extended emission in GB   
   1508+5714 in X-rays. In a paper to be published in an upcoming   
   issue of the Monthly Notices of the Royal Astronomical   
   Society, the authors note that significant energy is being   
   deposited in the outer regions of the host galaxy at a very   
   early stage. This energy input could have a profound effect on   
   the evolution of the galaxy by triggering the formation of   
   stars, or inhibiting the growth of the galaxy through   
   accretion of matter from intergalactic space.   
      
   NASA's Marshall Space Flight Center, Huntsville, Ala., manages   
   the Chandra program for the Office of Space Science, NASA   
   Headquarters, Washington. Northrop Grumman of Redondo Beach,   
   Calif., formerly TRW, Inc., was the prime development   
   contractor for the observatory. The Smithsonian Astrophysical   
   Observatory controls science and flight operations from the   
   Chandra X-ray Center in Cambridge, Mass.   
      
   Additional information on these results can be found at:   
   http://chandra.harvard.edu   
   and   
   http://chandra.nasa.gov   
      
      
   -end-   
      
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