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Universe does a doozie

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By Roger Snodgrass

A robotic telescope on Fenton Hill in the Jemez Mountains west of Los Alamos was the first instrument on Earth to get a look at one of the brightest known explosions in the cosmos March 19.The phenomenon was a major gamma ray burst that had happened 7.5 billion years ago when a massive star collapsed into a black hole. Radiation from the blast had just arrived on earth’s outskirts, tipping off the Swift satellite to swing into position.Los Alamos researchers were already absorbed with an ordinary burst from a half-hour earlier.“Somebody noticed that there was a new e-mail coming in from second burst,” said Dave Palmer, the LANL scientist who developed the software that quickly slews the Swift telescope to locate gamma ray bursts. “We started looking at the second burst and noticed it was unusually bright,” he said.The team started preparing another message for the astronomy community when they got word from the ground telescope people.“They said we can’t get a good position on it because it was saturating their telescopes,” Palmer said.It turned out to be the most luminous gamma-ray burst yet.“The gamma-ray burst reached a peak apparent magnitude of 5.6 while the gamma rays were being emitted,” said astrophysicst Tom Vestrand, who leads Los Alamos National Laboratory’s RAPTOR telescope system that got in on the all-important first minute of the burst.Vestrand was a co-winner last year of the Los Alamos National Laboratory Prize for previous work interpreting the structure of gamma ray blasts, based on a blast witnessed in 2005, 12 billion light-years away.“The Andromeda Galaxy is the most distant object you can see with the naked eye,” said Palmer in a telephone interview this morning. “This would appear that bright, but it’s only a single star 3,000 times as far away.”The lead scientist for the Swift satellite at NASA’s Goddard Space Flight Center Neil Gehrels emphasized how big the event was.“Even by the standards of gamma-ray bursts, this burst was a whopper,” he said in NASA’s announcement on Friday. “It blows away every gamma-ray burst we’ve seen so far.”Palmer offered a preliminary explanation for the phenomenon.“It is likely that the beam that came out of the star was much tighter, much faster and pointed more directly at us than what is normal,” he said.There were five gamma-ray bursts March 19, compared to only two all of December and January. On average there are a couple each week, Palmer said.