Plethora of quasars.Still in its infancy, one of the most ambitious surveys of the heavens ever conducted has already proven its mettle. Observations taken during the first few months of the Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico. The project was named after the Alfred P. , which will ultimately generate a detailed map of one-quarter of the sky, have revealed 12 distant quasars, including the most remote of these brilliant beacons yet discovered. The new record holder has a redshift redshift Displacement of the spectrum of an astronomical object toward longer wavelengths (visible light shifts toward the red end of the spectrum). In 1929 Edwin Hubble reported that distant galaxies had redshifts proportionate to their distances (see of 5.0, a measure of an object's distance from Earth. The newly found quasars all hail from a time when the cosmos was less than a billion years old. Two of the other new finds rank as the second and fourth most distant quasars ever observed. Xiaohui Fan of Princeton University announced the detections Dec. 4 at the Fermi National Accelerator Laboratory Fermi National Accelerator Laboratory (Fermilab), physical science research center located near Batavia, Ill., est. 1968 as the National Accelerator Laboratory, renamed 1974 in honor of Enrico Fermi. It was built on the site of the former village of Weston. in Batavia, Ill. The findings, culled from just 1 percent of the data expected from the planned 5-year survey, prove "we can nail high-redshift quasars," says Sloan researcher Michael S. Turner of Fermilab and the University of Chicago. "At this rate, by the end of the survey we will have almost 1,000 quasars with red-shifts greater than 4.7. Before Sloan, there was only one!" he notes. The survey promises to find the 100,000 brightest quasars, nearly 30 times the current number. As of early December, a radio survey covering the same patch of sky that Sloan is examining in visible light has found 57 previously unknown quasars, Richard L. White of the Space Telescope Science Institute The Space Telescope Science Institute (STScI) is the science operations center for the Hubble Space Telescope (HST; in orbit since 1990) and for the James Webb Space Telescope (JWST; scheduled to be launched in 2013). in Baltimore told SCIENCE NEWS. Known as FIRST (Faint Images of the Radio Sky at Twenty-centimeters), the survey uses the Very Large Array, a bank of telescopes near Socorro, N.M. Early results from the Two-Micron All Sky Survey (2MASS), which examines the sky in near-infrared, have revealed 53 quasars unobserved in visible light, Brant brant or brant goose, common name for a species of wild sea goose. The American brant, Branta bernicla, breeds in the Arctic and winters along the Atlantic coast. O. Nelson of the California Institute of Technology California Institute of Technology, at Pasadena, Calif.; originally for men, became coeducational in 1970; founded 1891 as Throop Polytechnic Institute; called Throop College of Technology, 1913–20. in Pasadena reported this month at a meeting of the American Astronomical Society The American Astronomical Society (AAS, sometimes pronounced "double-A-S") is a US society of professional astronomers and other interested individuals, headquartered in Washington, DC. in Austin, Texas. Infrared light, unlike visible light, easily penetrates dust. The findings thus suggest that many quasars lie hidden behind dust shrouds, Nelson says. |
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