Hubble Detects Fading Fireball Following a Gamma Ray Burst

A U.S. Air Force satellite discovered gamma-ray bursts in the 1960s. Since then astronomers have been trying to decode the mechanism behind these gamma bursts. Latest evidence provided by NASA's Hubble Space Telescope helps solve the cosmic riddle by explaining what powers these short duration bursts.

NASA's Hubble Space Telescope shows that when two small super dense stellar objects merge together, they produce a short duration of gamma ray bursts, according to a press release.  

Gamma ray bursts (GRB) are short duration mysterious flashes with intense high energy radiation that come from random directions in space.

This latest evidence was provided by the detection of a new kind of stellar blast known as Kilonova. Last month, Hubble detected a fading fireball from Kilonova following a short GRB in a galaxy that is 4 billion light years away from Earth.  It was believed that Kilonova is always followed by a short GRB but this is the first time that it has been seen and captured.

Kilonova, which is 1,000 times brighter than a nova and is triggered by the eruption of a white dwarf, is the 'smoking gun' evidence that the merger of two small super dense stellar objects produces a short GRB.  The objects could either be a pair of neutron stars or it could be the merging of the neutron star and a black hole.

"This observation finally solves the mystery of the origin of short gamma ray bursts," said Nial Tanvir of the University of Leicester in the United Kingdom. "Many astronomers, including our group, have already provided a great deal of evidence that long-duration gamma ray bursts (those lasting more than two seconds) are produced by the collapse of extremely massive stars. But we only had weak circumstantial evidence that short bursts were produced by the merger of compact objects. This result now appears to provide definitive proof supporting that scenario."

For decades astrophysicist have said that short GRBs are produced when two super dense neutron stars existing in the binary system spiral together.

The findings were published on Saturday, August 3, in  the journal Nature.