View Full Version : Are all Gamma Ray Bursts Black Hole births?

Tom Mazanec
2015-Jun-20, 01:04 PM
Or can neutron star births create gamma ray bursts too?

2015-Jun-20, 01:37 PM
You ask two questions. The answer to the first one is no, not all GRBs are black hole births.
The answer to the second one is I don't think so. We don't really know the details of what causes all types of Gamma Ray Bursts, but the formation of a new neutron star may not have the magnetic extremes required to be what we are calling any of the categories of Gamma Ray Burst... not that that type of supernova doesn't give off gamma rays, just that it isn't GRB levels of gamma rays. The merging of two neutron stars? yes. The merging of a neutron star and a white dwarf? Maybe. Simple first formation of a neutron star? probably not.

Tom Mazanec
2015-Jun-20, 07:32 PM
What I was getting at is, does number of gamma ray bursts per day (whether directed to/detected by Earth or not) equal number of black holes formed per day?
Also, do we have a handle on what percentage of GRBs are detectable at Earth?

2015-Jun-20, 08:37 PM
To these questions the answers are no and no.

Not every GRB is a black hole forming, though it is possible that the long (but not ultra-long) GRBs are nearly all black holes forming.
As to what fraction of the long GRBs in the observable universe are detectable here at Earth with the Swift and Fermi-LAT detectors, I don't know. It seems likely that there are GRBs too distant to be detected, and also it seems likely that the Pop III stars created black holes, but we haven't been seeing them as GRBs yet.

Tom Mazanec
2015-Jun-20, 09:05 PM
Interesting. I thought Pop III stars were all so massive that they died as Pair Production Supernovae and blew themselves apart without leaving a remnant (except a lot of enriched gas).