GRB 050509B was a

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milli ...

(GRB) observed by the NASA Swift satellite on May 9, 2005. It was the first short duration GRB for which an accurate positional measurement was made, accurate enough to locate it near to an

elliptical galaxy An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The R ...

lying at a

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...

of 0.225. The significance of this finding is that it lends support to the theory that short bursts are formed during the catastrophic merger of two

neutron star A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white ...

s, or a neutron star and a

black hole A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...

. The

orbital decay Orbital decay is a gradual decrease of the distance between two orbiting bodies at their closest approach (the periapsis) over many orbital periods. These orbiting bodies can be a planet and its satellite, a star and any object orbiting it, or ...

(via gravitational radiation) of stellar binaries consisting of these exotic compact objects is believed to take hundreds of millions of years, hence gamma ray bursts produced this way would be expected to be in old (misleadingly called "early type") galaxies. In contrast, long-duration gamma ray bursts, which are believed to result from the collapse of a single massive star, are expected to be located preferentially in young galaxies.

References

* {{DEFAULTSORT:GRB 050509B 050509B 20050509 May 2005 events Coma Berenices