For Release: Sept. 9, 1997

Dave Drachlis
Media Services Branch
(256) 544-0034
dave.drachlis@msfc.nasa.gov

RELEASE: 97-231

The latest developments from research efforts to unravel one of the biggest mysteries of the universe -- gamma ray bursts -- will be presented in Huntsville, Ala., Sept. 15-20, at a conference sponsored in part by NASA’s Marshall Space Flight Center.

These perplexing bursts of gamma radiation sweep past Earth on an almost daily basis -- releasing in seconds perhaps as much energy as our Sun will emit in its 10-billion-year life -- but their genesis remains a mystery.

The Fourth Huntsville Gamma-Ray Burst Symposium will bring together world-renowned scientists in the discipline, including the astrophysicist who led the team that first discovered gamma-ray bursts in the late 1960s, Dr. Ray Klebesadel. The symposium, to be held at the Huntsville Hilton, will allow researchers to debate the causes of gamma-ray bursts -- a field developing so rapidly that even the experts find it difficult to keep up with discoveries made almost daily.

"There will be presentations on observations made only in recent weeks. We've even had papers submitted on observations that astronomers expect to make just before the conference," said Dr. Tom Koshut, a Marshall Center astrophysicist on the conference organizing committee. "One special session will be devoted to these last-minute discoveries that are capable of changing how we view gamma-ray bursts."

Since a Los Alamos team headed by Klebesadel serendipitously discovered bursts in the late 1960s, the gamma-ray burst phenomenon has been -- and still is -- one of the most heavily debated topics in astronomy. "Dr. Klebesadel will be able to offer a unique historical perspective on these bursts because he's been involved with them from day one," said Koshut.

One of the debated topics is how bursts are created. The currently favored theory suggests bursts are created by a tremendous explosion, possibly due to merging neutron stars, triggering shock waves that interact with the surrounding matter.

Another hotly debated topic is the origin of gamma-ray bursts, which some astronomers argue "is fairly local, just outside our own galaxy," said Dr. Gerald Fishman, a Marshall astrophysicist and principal investigator of the Burst and Transient Source Experiment. "But most now believe that bursts come from remote parts of the universe, at cosmological distances of billions of light years."

Data from orbiting satellites have shed light on the origin of gamma- ray bursts, but all of the votes are still not in.

"We hope after the latest and greatest gamma-ray burst observations are revealed at the conference, the astronomy community will be closer to solving the mystery," said Fishman.

More information about the Fourth Huntsville Gamma-Ray Burst Symposium, including the workshop agenda, can be found on the World Wide Web at the following URL: http://www.batse.msfc.nasa.gov/information/4hgrbs/

Some of the key presentations to be given at the conference are:

Sept. 16, 9:15 a.m. Latest Results of the Burst and Transient Source Experiment

Dr. Charles Meegan, Marshall Center astrophysicist and co-investigator of the experiment, will present the latest results from the 6 1/2 year duration Burst and Transient Source Experiment, the experiment that positioned the scientific community for the breakthroughs of 1997.

Sept. 16, 4:30 p.m. Late-Breaking Results

This is a special session devoted to the late-breaking results of observations made just prior to the start of the symposium.

Sept. 17, 1:15 p.m. Overview of Recent Detections

Dr. Kevin Hurley, astrophysicist at the University of California, Berkeley, will summarize recent results from searches for counterparts to gamma-ray bursts. Within the last six months, counterpart detection in the X-ray, optical, radio and other wavelength bands has progressed at a pace so fast, that researchers are having difficulty keeping up.

Sept. 18, 9:00 a.m. Optical Counterparts of Bursts

Jan van Paradijs, astrophysicist at the University of Alabama in Huntsville and the University of Amsterdam, will provide results from his groundbreaking detection of the first confirmed optical counterpart to a gamma-ray burst. His optical detection -- involving a number of different experiments and an international collaboration among scientist -- was a major breakthrough in scientific understanding of these events, and showed the scientific community how to obtain optical counterparts to other burst events.

Sept. 18, 11:35 a.m. Radio Counterparts of Bursts

Dr. Dale Frail, astrophysicist at the National Radio Astronomy Observatory in Socorro

N.M., will present a paper on the recent discovery of radio counterparts to gamma-ray bursts. He will address important questions such as what fraction of gamma-ray bursts become radio sources, the conditions under which they become radio sources and the remarkable lifetimes of the radio afterglow.

Other conference sponsors include TRW Space and Electronics Group in Rodondo Beach, Calif., University Space Research Association, in Huntsville and the University of Alabama in Huntsville.

Note to Editors: Media interested in additional information on attending or covering the workshop should call Kelly McFalls of the NASA Marshall Space Flight Center Public Affairs Office at 256/544-3317.

Prepared by: Kelly McFalls