What is behind GRB 971214?
May 14, 1998
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May 7, 1998
Dr. David Helfand of Columbia University discusses GRB 971214
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Karen Silver of Bronx, NY, asks:
Given the proximity of the blast to the original Big Bang (give or take two billion years), what does this tell us about the state of the cosmos at the time of the blast?
Dr. David Helfand of Columbia University responds:
Proximity in time, you mean, yes? (Because the Big Bang didn't occur in a given place in space -- in fact, it created space [and time], so proximity in space to the Big Bang is sort of an indefinable concept).
Since we don't yet have a firm idea of what produces these events, it doesn't tell us too much yet, although the idea you suggest -- that the bursts might act as probes of the earliest generations of stars -- is one that has many of us quite excited. The December 14th burst is at a redshift of 3.42 which corresponds to 85% of the way back to the beginning. Just in the past few weeks, astronomers have discovered galaxies that are even older -- the current record holder is 96% of the way back to the origin of the universe. So we aren't too surprised to see events like Dec. 14 if they originate in something related to stars, because we have seen that stars exist at even earlier times. However, our telescopes are easily capable of detecting bursts much fainter than the one on Dec. 14, so if more distant ones exist, we should be able to find them.
Yet another possible model for the bursts is that they result from the violent collapse of a tight cluster of stars which might then form the seed around which the super-massive black holes of a billion Sun masses that we find in the cores of quasars might originate. If this is the case, we would expect there to be many more bursts at early times than today. Once we have measured the distances to a hundred or so bursts, we will be better able to assess their importance in probing the early history of the universe.
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