PRESS RELEASE

The BeppoSAX satellite has given the international scientific community important information for the resolution of one of the greatest misteries of modern astrophysics. For many years astronomers have known of the existence of sudden bursts of gamma rays from an unknown class of celestial sources. These sources appear unexpectedly in any direction in the sky, and last in general only a few seconds, rather like cosmic fireworks. No observation until now has been able to localize simultaneously an emission at other wavelengths, such as optical or radio, eventhough enormous efforts to do so have been performed over the last twenty-five years. For this reason it has not been possible for astronomers to understand the origin of these Gamma-Ray Bursts. The scientific community is divided over their intepretation. Some believe that these phenomena originate inside our own galaxy, in explosions on the surface of neutron stars (extremely dense objects formed in the last stage of the life of massive stars), and others believe instead that the origin is to be found at very large distances in the universe, for instance in galaxies, where two neutron stars may collide or large explosions in their very central regions may occur. BeppoSAX for the first time has detected X-ray emission from the source producing a Gamma-Ray Burst, localizing the source in the sky with an unprecedented precision provoking enormous interest in the international scientific community. In consequence the most important worldwide observatories, during the last few days, have been observing the zone from which the gamma-rays and X-rays have been observed in the hope of discovering the type of astronomical object that produced the burst and thus resolve the mistery of Gamma-Ray Bursts. The BeppoSAX satellite for X-ray astronomy was produced by ASI in collaboration with the Dutch Agency for Space Programs NIVR, and was successfully launched on 30th april 1996.

The gamma ray burst was discovered simultaneously in the data from the Gamma Ray Burst Monitor and Wide Field Cameras onboard by the team of italian/dutch scientists at 05:00 am on Friday 28th february who continually monitor the satellite data at the Scientific Operations Center in Nuova Telespazio, Rome. On the basis of experience gained in january (when a similar gamma-ray burst was observed in the constellation of Serpens by BeppoSAX, and studied in detail 16 hours later, in comparison with the previous record for a X-ray observation of about 18 days) the italian scientists responsible for the gamma-ray burst detector onboard the satellite (E. Costa, CNR, and F. Frontera, University of Ferrara), in conjunction with the Mission Scientist (L. Piro, CNR) and the Mission Director (R. C. Butler, ASI), were able to reschedule the satellite observations and point the BeppoSAX narrow field X-ray telescopes in only 8 hours at the gamma-ray burst source. In consequence a X-ray source never before seen was discovered and localized with an accuracy of one hundreth of a degree. The source is actually in the constellation of Orion.

ASI - Public Relation Office