Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2001 April 13
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GRB010222: Gamma-Ray Burst, X-Ray Afterglow
Credit: L. Piro (CNR) et al., CXC, NASA

Explanation: A fading afterglow from one of the most powerful explosions in the universe is centred in this false colour image from the spacebased Chandra X-ray Observatory. The cosmic explosion, an enormously bright gamma-ray burst (GRB), originated in a galaxy billions of light-years away and was detected by the BeppoSAX satellite on February 22. GRB010222 was visible for only a few seconds at gamma-ray energies, but its afterglow was followed for days by x-ray, optical, infrared and radio instruments. These Chandra observations of the GRB's x-ray glow hours after the initial explosion suggest an expanding fireball of material moving at near light speed has hit a wall of relatively dense gas. While the true nature of gamma-ray bursters remains unknown, the mounting evidence from GRB afterglows does indicate that the cosmic blasts may be hypernovae -- the death explosions of very massive, short-lived stars embedded in active star forming regions. As the hypernova blasts sweep up dense clouds of material in the crowded star forming regions they may also trigger more star formation.

Tomorrow's picture: First Human Spaceflight

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
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