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Faint gamma-ray bursts do actually exist   Gamma-ray bursts (GRBs) are the most powerful explosions in the Universe. Most GRBs are thought to be triggered by the collision of very massive and compact objects such as neutron stars or black holes, or by the explosion of incredible powerful supernovae – or hypernovae. No one can predict where the next gamma-ray burst will come from, but one or two will erupt every day in the sky. They typically last only a few tens of seconds.
ESA’s Integral gamma-ray observatory detects an average of about 10 GRBs a year. The spacecraft has also confirmed the existence of a new population of faint gamma-ray bursts, located in our cosmic neighbourhood. They are possibly generated the collapse of a massive star that does not present the characteristics of a supernova or hypernova, or by the merger of two white dwarfs (small and dense stars about the size of Earth), or by the merger of a white dwarf with a neutron star or a black hole.  This plot shows the distribution of faint gamma-ray bursts (GRBs), as observed by the IBIS imaging telescope on board ESA’s Integral gamma-ray observatory, in ‘supergalactic coordinates’ (such coordinate system is a spherical system whose equator is aligned with the so-called supergalactic plane, a major structure in the local universe formed by the distribution of near-by clusters of galaxies, out to several hundred megaparsecs; 1 megaparsec corresponds to about 3.26 million light years).
As it can be seen, these faint gamma-ray bursts are mainly distributed along the supergalactic plane. Release date: 3 April 2009 |