Science News: NASA/Marshall Astronomy
Gamma Ray Bursts To Take Center Stage
at 191st AAS Meeting
December 22, 1997
Perhaps no other area of astronomy has experienced such an explosive revolution in our understanding over the past year as that of gamma-ray bursts. These powerful explosions in space that are detected on a daily basis have been shown conclusively within the past 12 months to come from the most distant reaches of the Universe. Each one releases more energy in 10 seconds than our Sun will emit in its entire 10-billion-year lifetime. On January 7, 1998, Dr. Chryssa Kouveliotou, a USRA scientist at NASA/Marshall, and Sir Martin Rees, Astronomer Royal of Great Britain, will present an invited lecture to the 191st meeting of the American Astronomical Society in Washington DC, to summarize what has been an unparalleled year of discovery in the area of cosmic gamma-ray bursts.Gamma-ray bursts (GRBs) were discovered by accident 30 years ago from data taken by the Vela satellite series. Since then, GRB detectors on US and international spacecraft have amassed a wealth of information on this enigmatic phenomenon. Currently, the Burst And Transient Source Experiment (BATSE), designed, built, and operated by scientists at NASA/Marshall, is the most sensitive GRB experiment. Launched on April 5, 1991, aboard NASA's Compton Gamma-Ray Observatory (CGRO - pictured above after release from the shuttle), BATSE has detected over 2,000 cosmic bursts, more than all other experiments combined.
In early 1996, an Italian-Dutch satellite, BeppoSAX, which is equipped with X-ray Cameras that have a wide field of view, obtained images of an X-ray glow immediately following a GRB. This detection opened a new era in GRB research. These images taken shortly after the burst occurred provided a very precise location in the sky which enabled optical, X-ray and radio telescopes to quickly follow up the emission region and detect the first GRB counterparts in these other wavelengths. Since then, two additional optical counterparts have been found for gamma-ray bursts, the most recent discovery coming only in the third week of December 1997.
During the invited lecture, Dr. Kouveliotou will review the main observational results of the last 7 years obtained with BATSE on the temporal, spectral, and spatial characteristics of GRBs, together with the recent optical, X-ray and radio follow-up results that have made crucial steps towards the solution of the GRB mystery.
Hubble Images of GRB 970228
The Wide-field Planetary Camera Image from Hubble of the burst region in the Visual band. The optical source believed to be the home of the gamma-ray burst is at the center of the photograph.
A Close-Up of the Optical Transient taken not long after the burst shows both a point-like source (the bright emission) plus the extended emission (below and to the right) from what may be the distant host-galaxy.
A later Hubble image taken in September reveals that the optical counterpart to the gamma-ray burst is still visible, indicating to astronomers that these objects are indeed from the most distant parts of the Universe.
|Gamma-Ray Bursts Thought to be from Edge of Universe||January 15, 1997|
|Discovery may be "Smoking Gun" in Gamma Ray Burst Mystery||March 31, 1997|
|Counterpart Discoveries Show Gamma-Ray Bursts ARE Cosmological||June 11, 1997|
|Hubble Confirms Fading Burst Source, and news from the 4th Huntsville Gamma Ray Burst Symposium||September 17, 1997|
|Gamma Ray Bursts are 1 in 100: Mystery tops Discover Magazine's "Top 100" Science Stories for 1997||December 10, 1997|
|BATSE Detects 2000th Cosmic Gamma-Ray Burst||December 15, 1997|
The 191st Meeting of the American Astronomical Society will be held at the Washington Hilton and Towers. The gamma-ray burst invited lecture will begin at 3:40 pm EST, on January 7, in the International Ballroom of the hotel. More information on the meeting can be found at the URL http://www.aas.org/meetings/aas191/program/index.html
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