 | |
| Event type | Gamma-ray burst  |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 01m 46.7s |
| Declination | +11° 46′ 53.0″[1] |
| Epoch | J2000 |
| Distance | 8,123,000,000 ly (2.491×109 pc) |
| Redshift | 0.695, 0.695 |
| Total energy output | 5.2×1044 J |
| Other designations | GRB 970228 |
 Related media on Commons | |
GRB 970228[2] was the first gamma-ray burst (GRB) for which an afterglow was observed.[3] It was detected on 28 February 1997 at 02:58 UTC. Since 1993, physicists had predicted GRBs to be followed by a lower-energy afterglow (in wavelengths such as radio waves, x-rays, and even visible light), but until this event, GRBs had only been observed in highly luminous bursts of high-energy gamma rays (the most energetic form of electromagnetic radiation); this resulted in large positional uncertainties which left their nature very unclear.
The burst had multiple peaks in its light curve and lasted approximately 80 seconds. Peculiarities in the light curve of GRB 970228 suggested that a supernova may have occurred as well. The position of the burst coincided with a galaxy about 8.1 billion light-years[4] away (a redshift of z = 0.695), providing early evidence that GRBs occur well beyond the Milky Way; this was proven decisively two months later with a subsequent burst GRB 970508.
- ^ Cite error: The named reference
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- ^ Schilling 2002, p. 101
- ^ Cite error: The named reference
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