double quasar


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double quasar

The gravitational lens, Q0957+561, where two images of a quasar, at a redshift of 1.41, are created by the gravitational effects of a galaxy at a redshift of 0.36. The two images are separated by 6″, and are observed in the radio, optical, and X-ray wavebands. It was the first bona fide gravitationally-lensed image to be discovered, by Walsh and collaborators in 1979. The spectra of the two images are almost identical, including common absorption lines from intervening matter along the line of sight. A 1.1-year time-of-flight difference has been measured between the two images.
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The Double Quasar's light has been travel- ling for about 9 billion years in its journey towards Earth.
But astronomers say the true nature of a double quasar may shed light on the question.
The double quasar Q2345+007 has intrigued scientists since its 1982 discovery.
But now astronomers using data from three telescopes have examined the double quasar and its surroundings with a sensitivity unmatched by surveys anyplace else in the sky.
Also referred to as the double quasar, the twin quasar was discovered by astronomers Dennis Walsh, Robert F.
The record holder since 1979 was the famous Double Quasar in Ursa Major.
About 80 gravitationally lensed quasars are known, but the record separation of the Double Quasar (6.3 arcseconds) held until last December 18th, when a team led by Naohisa Inada and Masamune Oguri (University of Tokyo) announced finding a quadruple-lensed quasar, SDSS J1004+4112, in Leo Minor.
The object was clearly a double quasar with the same separation and position angle as the radio hot spots.
Since the late 1980s, though, researchers have found about 100 double quasars. And in an announcement made in January at the American Astronomical Society meeting in Seattle, astronomers confirmed that quasars can also come in threes.