Laboratory scientists David Palmer and Ed Fenimore are part of a NASA team that recently detected the most distant gamma-ray burst from the edge of the visible universe. Palmer and Fenimore, of Space Science and Applications (ISR-1) are part of the NASA Swift satellite team.
This powerful burst was detected Sept. 4. It marks the death of a massive star and the birth of a black hole. It comes from an era soon after stars and galaxies first formed, about 500 million to 1 billion years after the Big Bang.
Gamma-ray bursts, first discovered by Los Alamos in the course of nuclear nonproliferation data analysis, occur randomly throughout the universe. They are the most powerful explosions known to mankind, exceeded only by the Big Bang. Swift's Burst Alert Telescope will detect and locate about two bursts a week and relay their positions to the ground in less than 15 seconds.
The component with which Los Alamos is most intimately involved is the Burst Alert Telescope (BAT), hardware built and developed by Goddard Space Flight Center, under the direction of Neal Gehrels. The Los Alamos role was in developing the BAT's onboard scientific software, which "basically tells Swift when to point, and where to point," according to Fenimore.
The onboard "trigger" software scans the data from the BAT and determines when a gamma-ray burst is in progress. The GRBs location information from Swift also will be broadcast to waiting robotic telescopes on the ground. Among them is the Los Alamos RAPTOR telescope, which can point anywhere within 6 seconds and capture the burst while it is still happening.
The critical second piece of the Los Alamos effort is the software to locate the gamma-ray burst so that the satellite knows exactly which direction it should orient its other telescopes. The BAT uses an imaging technique pioneered by Los Alamos called coded-aperture imaging, and most recently used by Los Alamos aboard the High Energy Transient Explorer (HETE) satellite.
"It was David Palmer's software, especially the 'image trigger,' which was able to catch this guy. It is so far away and the universe space-time has expanded so much that the GRB looks like it is on slow motion," said Fenimore. "David's image trigger was especially designed to catch slow moving GRBs."
For more information, see the NASA news release and the Nov. 17, 2004 Daily Newsbulletin.
