08-21-2018, 02:44 PM
(This post was last modified: 08-21-2018, 02:47 PM by Avalancheon.)
Finally got an update. After reading this paper, things are more clear to me.
The energy fluence of 100 kilojoules per square meter was chosen based on a probability estimate within a 500 million year period. Piran & co. looked at three different fluence levels, from 10 KJ, to 100 KJ, to 1000 KJ .
The probability of the Earth being hit by a GRB within that time period was 95% for the 10 KJ scenario, 50% for the 100 KJ scenaio, and 4% for the 1000 KJ scenario.
But if you include a 'metallicity bias', the probability goes up significantly. 99.8% for the 10 KJ scenario, 90% for the 100 KJ scenaio, and 25% for the 1000 KJ scenario...
In my humble opinion, though, these estimates are still too optimistic. They all seem to be based on the assumption that the erupting GRB will have a very wide jet (wider than 2 degrees), resulting in a more diffuse spray of gamma rays.
The energy fluence of 100 kilojoules per square meter was chosen based on a probability estimate within a 500 million year period. Piran & co. looked at three different fluence levels, from 10 KJ, to 100 KJ, to 1000 KJ .
The probability of the Earth being hit by a GRB within that time period was 95% for the 10 KJ scenario, 50% for the 100 KJ scenaio, and 4% for the 1000 KJ scenario.
But if you include a 'metallicity bias', the probability goes up significantly. 99.8% for the 10 KJ scenario, 90% for the 100 KJ scenaio, and 25% for the 1000 KJ scenario...
In my humble opinion, though, these estimates are still too optimistic. They all seem to be based on the assumption that the erupting GRB will have a very wide jet (wider than 2 degrees), resulting in a more diffuse spray of gamma rays.