GRB jet

In the reigning collapsar model for gamma-ray bursts (GRBs), jets containing small amounts of matter and huge amounts of electromagnetic energy are created when the core of a massive star collapses and produces a black hole. In this computer simulation frame, we see a jet punching through the "surface" of the dying star. Regions of low, medium, and high density are colored blue, red, and yellow, respectively. Click on the image to view a 6 MB movie of the jet propagating through the star and eventually breaking out into space.

Courtesy Weiqun Zhang / Stan Woosley / University of California, Santa Cruz.

Since their discovery in the 1960s, gamma-ray bursts (GRBs) remained a riddle, wrapped in a mystery, inside an enigma. What force of nature could unleash the power of billions of Suns in explosions of high-energy radiation that lasted mere seconds to at most a few minutes?

Over the past few decades, a consensus has slowly emerged as astronomers have armed themselves with better data and computer models. As described in the August 2006 issue of Sky & Telescope (page 30), GRBs that last a few seconds or longer result from the cataclysmic explosions of massive stars. In some of these explosions, some of the energy is channeled into twin jets of electromagnetic radiation and particles that punch through the star. The matter in these jets travels at very close to the speed of light. Outside the star, faster blobs of matter catch up to slower blobs. Calculations indicate that these high-speed collisions can generate the eruptions we see as GRBs.

The movies on this page show some of the processes ultimately responsible for one of Mother Nature's most violent creations.

Wolf-Rayet star blowing up

In this animation produced for NASA, a Wolf-Rayet star blows up as a Type Ic supernova, and produces two jets in the process. The actual GRB is generated within the jets, but far outside the star. A wind blowing off an accretion at the center of the star does most of the work in actually blowing the star to Kingdom Come. Click on the image to view the 9 MB Quicktime animation.

Courtesy NASA / SkyWorks Digital.


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