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Stefan Rosswog has some ideas about what causes GRB (gammaray bursts)
He and Daniel Price have a recent article in Science journal about it, and they have some stunning movies of two neutronstars spiraling into merge.
I could not find the Science article---the most recent Rosswog---online.
It is an interesting problem the details of what causes GRB and how they actually happen.
also GRB observations are expected to be used to test some non-string QG theories like forms of LQG-DSR. Given the importance of GRB one wants to understand better what makes them
So I will collect some Rosswog links and see what his ideas are
http://arxiv.org/abs/astro-ph/0504368
From Neutron Star Binaries to Gamma-ray bursts
Stefan Rosswog
Proceedings of the 4th Workshop Gamma-Ray Bursts in the Afterglow Era, Rome,18-22 October 2004
Nuovo Cim. 28C (2005) 607-612
"I summarize recent results about how a neutron star binary coalescence can produce short gamma-ray bursts (GRBs). Two possibilities are discussed: the annihilation of neutrino anti-neutrino pairs above the merged remnant and the exponential amplification of magnetic fields in the central object up to values close to equipartition. We find that the neutrino annihilation drives bipolar, relativistic outflows with Lorentz-factors large enough to circumvent the GRB 'compactness problem'. The total energy within these outflows is moderate by GRB-standards (about 10^{48}-10^{49} ergs), but the interaction with the baryonic material blown-off by the neutrinos collimates the outflows into opening angles of typically 0.1 sterad, yielding isotropic energies close to 10^{51} ergs. We further want to stress the plausibility of the central object resisting the immediate collapse to a black hole. In this case the central object will --similar to a proto-neutron star-- be subject to neutrino driven convection that --together with the rapid, differential rotation-- will lead to a drastic amplification of pre-existing magnetic fields. Within fractions of a second, field strengths comparable to equipartition field strength (> 10^{17} G) will be reached. These will produce large torques that will spin-down the object within about 0.2 s, and would thus naturally explain the duration of short GRBs."
A key thing here is the production of magnetic field "comparable" to one stronger than 100 quadrillion gauss.
That is 10 trillion Tesla (1013 T) for us just one Tesla is a very strong field, superconducting magnets used in highenergy particle rings are only a few Tesla
What the recent article has is results of computer SIMULATIONS which calculate and simulate the formation of these very intense magetic fields and in some sense "confirm" that such strong fields are produced.
I gather that the simulations reached fleldstrength of 0.1 trillion Tesla, which I guess is "comparable" although not the figure mentioned in Rosswog's earlier paper
Here is some Science Daily schmoozing about it
http://www.sciencedaily.com/releases/2006/03/060331153110.htm
"Scientists Discover The Universe's Strongest Magnetic Field"
They didn't discover in the sense of observe, they SIMULATED this very strong field, but it is still really interesting I think.
In the schmooze, the field is referred to as "1000 million milllion" or 1015 times stronger than Earth field which is about one gauss. So that would be 1011 Tesla.
So there is a little discrepancy of two orders magnitude! which I need to clear up. But the basic idea is VERY STRONG.
I will get some more Rosswog preprints and see what's in them.
He and Daniel Price have a recent article in Science journal about it, and they have some stunning movies of two neutronstars spiraling into merge.
I could not find the Science article---the most recent Rosswog---online.
It is an interesting problem the details of what causes GRB and how they actually happen.
also GRB observations are expected to be used to test some non-string QG theories like forms of LQG-DSR. Given the importance of GRB one wants to understand better what makes them
So I will collect some Rosswog links and see what his ideas are
http://arxiv.org/abs/astro-ph/0504368
From Neutron Star Binaries to Gamma-ray bursts
Stefan Rosswog
Proceedings of the 4th Workshop Gamma-Ray Bursts in the Afterglow Era, Rome,18-22 October 2004
Nuovo Cim. 28C (2005) 607-612
"I summarize recent results about how a neutron star binary coalescence can produce short gamma-ray bursts (GRBs). Two possibilities are discussed: the annihilation of neutrino anti-neutrino pairs above the merged remnant and the exponential amplification of magnetic fields in the central object up to values close to equipartition. We find that the neutrino annihilation drives bipolar, relativistic outflows with Lorentz-factors large enough to circumvent the GRB 'compactness problem'. The total energy within these outflows is moderate by GRB-standards (about 10^{48}-10^{49} ergs), but the interaction with the baryonic material blown-off by the neutrinos collimates the outflows into opening angles of typically 0.1 sterad, yielding isotropic energies close to 10^{51} ergs. We further want to stress the plausibility of the central object resisting the immediate collapse to a black hole. In this case the central object will --similar to a proto-neutron star-- be subject to neutrino driven convection that --together with the rapid, differential rotation-- will lead to a drastic amplification of pre-existing magnetic fields. Within fractions of a second, field strengths comparable to equipartition field strength (> 10^{17} G) will be reached. These will produce large torques that will spin-down the object within about 0.2 s, and would thus naturally explain the duration of short GRBs."
A key thing here is the production of magnetic field "comparable" to one stronger than 100 quadrillion gauss.
That is 10 trillion Tesla (1013 T) for us just one Tesla is a very strong field, superconducting magnets used in highenergy particle rings are only a few Tesla
What the recent article has is results of computer SIMULATIONS which calculate and simulate the formation of these very intense magetic fields and in some sense "confirm" that such strong fields are produced.
I gather that the simulations reached fleldstrength of 0.1 trillion Tesla, which I guess is "comparable" although not the figure mentioned in Rosswog's earlier paper
Here is some Science Daily schmoozing about it
http://www.sciencedaily.com/releases/2006/03/060331153110.htm
"Scientists Discover The Universe's Strongest Magnetic Field"
They didn't discover in the sense of observe, they SIMULATED this very strong field, but it is still really interesting I think.
In the schmooze, the field is referred to as "1000 million milllion" or 1015 times stronger than Earth field which is about one gauss. So that would be 1011 Tesla.
So there is a little discrepancy of two orders magnitude! which I need to clear up. But the basic idea is VERY STRONG.
I will get some more Rosswog preprints and see what's in them.
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