SPACE.com -- Johannes van Paradijs, Gamma Ray Observer, Dies at 53

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	Johannes van Paradijs, Gamma Ray Observer, Dies at 53 By Greg Clark Staff Writer posted: 09:58 am ET 04 November 1999

vanparadijs

Johannes van Paradijs, the award-winning astrophysicist and gamma ray astronomer who was crucial to pinning down the source of gamma ray bursts, died Tuesday in Amsterdam after an extended illness. He was 53.

Van Paradijs, a professor of astrophysics at the University of Alabama in Huntsville and of astronomy at the University of Amsterdam, divided his time between Alabama and the Netherlands. He had been a major force in gamma ray astronomy for a decade.

In 1998, Van Paradijs shared the American Astronomical Society's Bruno Rossi Prize for his role in finding the first optical counterpart to a gamma ray burst. This counterpart is a simmering cinder called an afterglow that can be detected with optical telescopes from the ground.

Prior to that discovery, which van Paradijs made with the help of two of his graduate students, signs of gamma ray bursts could only be detected from satellites with instruments sensitive to the very high-energy radiation.

This limited what scientists could learn about the tremendous explosions. While the satellites can detect the location of a burst in the sky, there was no way to determine how far away the sources were. Many scientists believed the burst sources to be nearby.

But van Paradijs' discovery of the afterglow allowed astronomers to determine that gamma ray bursts occur billions of light-years away. These explosions, therefore, are the most energetic events ever witnessed.

Van Paradijs published more than 300 scientific papers, including a recent article in the journal Science linking gamma ray bursts and supernovas.

Van Paradijs is survived by his wife, Chryssa Kouveliotou, an astronomer at the University of Alabama, by two children from a previous marriage, and three grandchildren.