Gamma-ray bursts reveal violent phenomena
Astronomers call these explosions gamma-ray bursts. These bursts are so powerful that in just a few seconds they release as much energy as the rest of the Universe put together. HETE-2, a joint mission of the United States, Japan and France, is wholly dedicated to studying these phenomena, which occur when dying stars explode.
For the short time it is visible, a gamma-ray burst gives astronomers a wonderful opportunity to study the formation of black holes, the appearance of the first stars in the Universe and star formation in the most distant galaxies. The jet of material produced by the burst only shines brightly for a few hours, lighting up the entire galaxy before plunging back into darkness.
Hoping and waiting for a shining star
Last year, HETE-2 observations established the link between gamma-ray bursts and supernovae, very short-lived celestial objects produced by exploding stars. They might therefore be signals allowing us to predict the appearance of a supernova.
|A supernova is only detectable a few weeks after its birth, so scientists are glued to their telescopes in expectation to observe any day now the afterglow of the 3 bursts in September. They are hoping at least one of the stars will start shining brightly to unveil its secrets.|| |
The jet of material from the gamma-ray burst of 24 September. The star fades gradually, but will it start shining again? In the days ahead, astronomers will be able to confirm whether gamma-ray bursts signal the appearance of a supernova.
Images taken by George Kosugi with the Japanese Subaru telescope.