Models

Since their discovery, there has been considerable speculation concerning the source of gamma ray bursts. It was difficult to test those speculations when we did not even know how far away they were. Now that more quantitative data are becoming available, we can begin to sharpen the discussion.

The data now indicate that gamma ray bursts can produce, in periods as short as seconds, energies that can be at least as large as that of a supernova explosion and maybe 100 times larger. Almost the only way to explain such a rapid release of that amount of energy is from a collapse involving a compact gravitational source. Some popular ideas include

  • The merger of two neutron stars with jet outflow perpendicular to the merger plane.
  • The merger of two black holes or a neutron star and black hole with jet outflow perpendicular to the merger plane. The above animation illustrates a neutron star, black hole merger that produces jet outflow and triggers a series of small gamma ray pulses followed by a very large burst).
  • A hypernova, where it is speculated that a spinning massive star can collapse to a Kerr black hole (a distorted, spinning black hole) and that jet outflow from the region surrounding this collapsed object produces gamma rays.
  • None of these have yet been ruled out by the data. Thus, the source of gamma ray bursts remains one of the most important mysteries in modern cosmology, but there is a sense that we are much closer to solving the mystery today than we were five years ago.