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.

2004 January 30
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X-Ray Rings Expand from a Gamma Ray Burst
Credit: S. Vaughan, R. Willingale (U. Leicester) et al., XMM, ESA

Explanation: Why do x-ray rings appear to emanate from a gamma-ray burst? The surprising answer has little to do with the explosion itself but rather with light reflected off sheets of dust-laden gas in our own Milky Way Galaxy. GRB 031203 was a tremendous explosion -- a gamma-ray burst that occurred far across the universe with radiation just arriving in our Solar System last December 3. Since GRBs can also emit copious amounts of x-rays, a bright flash of x-rays likely arrived simultaneously with the gamma-radiation. In this case, the x-rays also bounced off two slabs of cosmic dust nearly 3500 light-years distant and created the unusual reflections. The longer path from the GRB, to the dust slab, to the XMM-Newton telescope caused the x-ray light echoes to arrive well after the GRB.

Tomorrow's picture: light-weekend

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