UC Davis Astronomer Helps Find Most Distant Object Ever Observed

The distinctive palette of colors in its light told the scientists that the bright red object they were studying wasn't just another star. Indeed, UC Davis astronomer Bob Becker and others announced today, they were looking at the most distant object human beings have ever identified. It was a quasar -- a brilliant, mysterious object with the mass and energy of an entire galaxy, possibly powered by a black hole -- giving off light that had left home when the universe was a baby, less than a billion years old. This farthest of the quasars, now named SDSS 1044-0125, was indicated by data collected in March by an $80 million, global astronomical collaboration called the Sloan Digital Sky Survey. Using that data, Becker and a handful of other astronomers turned their telescopes last week to a location near the constellation Leo and found the quasar. "This result was a real surprise, since the original Sloan data suggested that it was not a quasar, but rather a very red galaxy," Becker said today. "Discoveries like this one are helping us advance our understanding of the early history of the universe." Large, methodical, high-tech surveys like the Sloan are rapidly pushing back the boundaries of the known universe, and quasar SDSS 1044-0125 may not hold the distance record for long. The old record was held by a galaxy discovered last year by Esther Hu and colleagues at the University of Hawaii and the Institute of Astronomy in Cambridge, England. There are other intriguing objects that might be farther away than the new quasar, but their spectra have not yet been measured. Sky Survey astronomer and Princeton University graduate student Xiaohui Fan spotted the unusual object in data collected by the survey in March. He, Bob Becker, UC Berkeley professor Marc Davis and Space Telescope Science Institute astronomer Richard White used the 10-meter Keck Telescope in Hawaii to investigate further. They measured the object's spectrum, established it as a quasar and confirmed that it was the most distant object yet found. The Keck telescope is jointly operated by the University of California, Caltech, the University of Hawaii and NASA. The newly found quasar has a "redshift" of 5.8. "Since the universe is expanding, distant objects are all speeding away from us. The further away they are, the faster they recede," Becker explained. "The redshift is a measure of that speed, and the higher the redshift, the more distant the object. Since light travels at a finite velocity, looking out to great distances is equivalent to looking back in time." Although they know that SDSS 1044-0125 is the most distant object yet identified, astronomers cannot say exactly how far away it is. To convert redshift to a measure of physical distance requires knowing more than we currently understand about the structure of the universe, including its rate of expansion, still the subject of much controversy. Bob Becker's primary research centers on creating new astronomical surveys with wide-ranging applications. He recently launched a radio survey of the northern galactic pole using the Very Large Array, an assembly of radio telescopes in Socorro, N.M. The survey is called FIRST, for Faint Images of the Radio Sky at Twenty Centimeters. It will cover 10,000 square degrees, or 25 percent of the sky, with unprecedented sensitivity. At UC Davis, the physics department plans to create a cosmology research center. Current faculty members are Becker, Andreas Albrecht (who arrived in August 1998), and Lloyd Knox (who will arrive in January 2001). The group plans two more faculty additions in the next two years. Cosmology is currently being integrated into the undergraduate and graduate physics curriculum, so that both majors and nonmajors will have a chance to learn more about the field. The Sloan Digital Sky Survey (SDSS) is a joint project of the University of Chicago, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Max Planck Institute for Astronomy, Princeton University, the U.S. Naval Observatory and the University of Washington. The survey is based at Apache Point Observatory, 18 miles south of Cloudcroft, N.M., which is operated by the Astrophysical Research Consortium. Funding for the project has been provided by the Alfred P. Sloan Foundation, the SDSS member institutions, the National Aeronautics and Space Administration (NASA), the National Science Foundation and the U.S. Department of Energy.

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