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کوازار GB 1428
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[تصویر:  13542003021.jpg]






This composite image shows the most distant X-ray jet ever observed.
X-ray data from NASA's Chandra X-ray Observatory are shown in blue,
radio data from the NSF's Very Large Array are shown in purple and
optical data from NASA's Hubble Space Telescope are shown in yellow. The
jet was produced by a quasar named GB 1428+4217, or GB 1428 for short,
and is located 12.4 billion light years from Earth. Labels for the
quasar and jet can be seen by mousing over the image. The shape of the
jet is very similar in the X-ray and radio data.




Giant black holes at the centers of galaxies can pull in matter at a
rapid rate producing the quasar phenomenon. The energy released as
particles fall toward the black hole generates intense radiation and
powerful beams of high-energy particles that blast away from the black
hole at nearly the speed of light. These particle beams can interact
with magnetic fields or ambient photons to produce jets of radiation.




As the electrons in the jet fly away from the quasar, they move through a
sea of background photons left behind after the Big Bang. When a
fast-moving electron collides with one of these so-called cosmic
microwave background photons, it can boost the photon’s energy into
the X-ray band. Because the quasar is seen when the universe is at an
age of about 1.3 billion years, less than 10% of its current value, the
cosmic background radiation is a thousand times more intense than it is
now. This makes the jet much brighter, and compensates in part for the
dimming due to distance.




While there is another possible source of X-rays for the jet - radiation
from electrons spiraling around magnetic field lines in the jet - the
authors favor the idea that the cosmic background radiation is being
boosted because the jet is so bright.




The researchers think the length of the jet in GB 1428 is at least
230,000 light years, or about twice the diameter of the entire Milky Way
galaxy. This jet is only seen on one side of the quasar in the Chandra
and VLA data. When combined with previously obtained evidence, this
suggests the jet is pointed almost directly toward us. This
configuration would boost the X-ray and radio signals for the observed
jet and diminish those for a jet presumably pointed in the opposite
direction.




This result appeared in the Sept. 1, 2012 issue of The Astrophysical Journal Letters.




Credits: X-ray: NASA/CXC/NRC/C.Cheung et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA




› Read more/access all images


› Chandra's Flickr photoset
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 سپاس شده توسط Hamid Jafary Pooya


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