GRB 080607 blew up when the universe was just 2

The NASA-supportedPeters Automated Infrared Imaging Telescope (PAIRITEL) on Mount Hopkins,Ariz., and the Katzman Automatic Imaging Telescope (KAIT) at Lick Observatoryon Mount Hamilton, Calif., observed the burst's afterglow within three minutesof Swift's alert. The spectrum from Keck established that the explosion took place 11.5 billionlight-years away. GRB 080607 blew up when the universe was just 2.2 billionyears old. The molecular cloud in the burst's host galaxy was so dense, less than 1percent of the afterglow's light was able to penetrate it.

"Intrinsically,this afterglow is the second brightest ever seen. That's the only reason wewere able to observe it at all," Prochaska says.Screening from thick molecular clouds provides a natural explanation forso-called "dark bursts," which lack associated afterglows. "We suspect thatprevious events like GRB 080607 were just too faint to be observed," says teammember Yaron Sheffer of the University of Toledo, Ohio. Nearly half of the absorption lines found in the Keck spectrum areunidentified. The team expects that understanding them will provide new dataon the simplest space molecules.Prochaska and Sheffer presented the findings today at the 213th meeting of theAmerican Astronomical Society in Long Beach, Calif. A paper describing theresults will appear in a future issue of Astrophysical Journal Letters.Most gamma-ray bursts occur when massive stars run out of nuclear fuel. As thestar's core collapses into a black hole or neutron star, gas jets punchthrough the star and into space.

Bright afterglows occur as the jets heat gasthat was previously shed by the star. Because a massive star lives only a fewtens of millions of years, it never drifts far from its natal cloud.Swift, launched in November 2004, is managed by NASA's Goddard Space FlightCenter in Greenbelt, Md. It was built and is being operated in collaborationwith Penn State, the Los Alamos National Laboratory, and General Dynamics inthe U.S.; the University of Leicester and Mullard Space Sciences Laboratory inthe United Kingdom; Brera Observatory and the Italian Space Agency in Italy;plus additional partners in Germany and Japan. For related images to this release, please visit: http:// Reddy, 1-301-286-4453, , or Rob Gutro,1-301-286-4044, , both of NASA Goddard Space FlightCenter, Greenbelt, Md.; or Lynn Cominsky of Sonoma State University, RohnertPark, Calif., 1-707-695-7140, . Eastern Standard Time to discuss its fourthquarter 2008 earnings release. To phone into the conference call, parties in the United States should dial1-800-798-2884 and enter the pass code 84275755 after 9:45 a.m. Outside theUnited States, parties should dial 1-617-614-6207 and enter the pass code84275755.