* Astronomy

3C 273 is a quasar located in the constellation Virgo. It was the first quasar ever to be identified.
The name signifies that it was the 273rd object (ordered by right ascension) of the Third Cambridge Catalogue of Radio Sources (3C), published in 1959. After accurate positions were obtained using lunar occultation on August 5, 1962, by Cyril Hazard at the Parkes Radio Telescope, the radio source was quickly associated with an optical counterpart, an unresolved stellar object.
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Title: Hubble Space Telescope far-ultraviolet imaging of the jet in 3C273: a common emission component from optical to X-rays
Authors: Sebastian Jester (1,2), Klaus Meisenheimer (1), Andre' Martel (3), Eric Perlman (4), Bill Sparks (5) ((1) MPIA Heidelberg, (2) Fermilab Particle Astrophysics Center, (3) JHU, (4) FIT, (5) STScI)

We present far-ultraviolet (UV) observations at 150 nm of the jet of the quasar 3C 273 obtained with the Advanced Camera for Survey's Solar Blind Channel (ACS/SBC) on board the Hubble Space Telescope. While the jet morphology is very similar to that in the optical and near-ultraviolet, the spectral energy distributions (SEDs) of the jet's sub-regions show an upturn in nu f_nu at 150 nm compared to 300 nm everywhere in the jet. Moreover, the 150 nm flux is compatible with extrapolating the X-ray power-law down to the ultra-violet region. This constitutes strong support for a common origin of the jet's far-UV and X-ray emission. It implies that even a substantial fraction of the *visible light* in the X-ray brightest parts of the jet arises from the same spectral component as the X-rays, as had been suggested earlier based on Spitzer Space Telescope observations. We argue that the identification of this UV/X-ray component opens up the possibility to establish the synchrotron origin of the X-ray emission by optical polarimetry.

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A new false-coloured image from NASA's Hubble, Chandra, and Spitzer space telescopes shows a giant jet of particles that has been shot out from the vicinity of a type of supermassive black hole called a quasar. The jet is enormous, stretching across more than 100,000 light-years of space -- a size comparable to our own Milky Way galaxy.


Credit nasa

The jet pictured here is streaming out from the first known quasar, called 3C273, discovered in 1963. A kaleidoscope of colours represents the jet's assorted light waves. X-rays, the highest-energy light in the image, are shown at the far left in blue (the black hole itself is well to the left of the image). The X-rays were captured by Chandra. As you move from left to right, the light diminishes in energy, and wavelengths increase in size. Visible light recorded by Hubble is displayed in green, while infrared light caught by Spitzer is red. Areas where visible and infrared light overlap appear yellow.

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-- Edited by Blobrana at 18:35, 2006-07-24

An international team of astronomers led by researchers at Yale has obtained key infrared observations that reveal the nature of quasar particle jets that originate just outside super-massive black holes at the center of galaxies and radiate across the spectrum from radio to X-ray wavelengths; a complementary study of jet X-ray emission led by astronomers at the University of Southampton, reaches the same conclusion.

Both studies involve the jet of the quasar 3C273, famous since its identification in 1963 as the first quasar. It now appears that the most energetic radiation from this jet arises through direct radiation from extremely energetic particles, and not in the way expected by most astronomers based on the previously available data. The two reports, available now online in the Astrophysical Journal, will appear in print in the September 10 issue.

"Quasar jets, although extremely luminous, are so distant as to be relatively faint and difficult to observe. Thanks to the sensitivity of NASA's Great Observatories, we have been able to map the 3C273 jet in infrared, visible light and X-rays. These combined data strongly suggest that ultra-energetic particles in the 3C273 jet are producing their light via synchrotron radiation." - C. Megan Urry, Israel Munson Professor of Physics and Astronomy at Yale, and an author on one study.

Sebastian Jester, now at the University of Southampton, led a complementary study that used the Chandra X-ray Observatory. This team, with collaborators at MIT Kavli Institute for Astrophysics and Space Research and the Smithsonian Astrophysical Observatory (SAO) in Cambridge, MA, and at the Max Planck Institute for Astronomy in Heidelberg, obtained the first detailed study of energy distribution of X-rays from the jet, which also supported the synchrotron theory.
According to the researchers, while the lifetime of the X-ray producing particles is only about 100 years, the data indicate that the visibly brightest part of the jet has a length of about 100,000 light years. Since there would be insufficient time for the particles to shoot out from the black hole at close to the speed of light and then release their energy as radiation as far out as they are seen, the particles have to be accelerated locally, where they produce their emission.

Both teams also used data from the third of NASA's Great Observatories, the Hubble Space Telescope, and the radio telescopes of the Very Large Array (VLA). The three space telescopes and the VLA "see" emission of different wavelengths from celestial objects, and the combined data was essential to reveal the new comprehensive perspective on the jets.

"The new observations show that the flow structure of this jet is more complicated than had been assumed previously. That the present evidence favors the synchrotron model deepens the mystery of how jets produce the ultra-energetic particles that radiate at X-ray wavelengths." - Sebastian Jester

"Our results call for a radical rethink of the physics of relativistic jets that black holes drive. But, we now have a crucial new clue to solving one of the major mysteries in high-energy astrophysics." - Yasunobu Uchiyama.

(see above post)

Source: Yale University