Re: [math-fun] black hole merger accompanied by gamma ray burst ??!!
APG: I went to a talk at the CMS by Bruce Allen, director of the Max Planck Institute:
http://www.talks.cam.ac.uk/talk/index/64415
He attributed the most probable explanation to the gravitational waves exciting a nearby dust cloud, causing it to resonate gamma rays.
This is consistent with it being several orders of magnitude weaker than the gravitational source.
--so the dust cloud would be about 0.4 light seconds away from the holes to explain the 0.4 second delay gravitons-->photons. As opposed to us at around 1 billion light years distant seeing distance distortions of one part in 10^21. Cloud would be "excited" by the gravity wave altering distances. The distance-altering factors would be of order 10^(-21) * (1 billion years)/(0.4 seconds) = 10^(-4). If you squeeze an atom by 1 part in 10000 it is not going to produce energies anywhere near gamma rays. More like infrared. If you squeezed an atomic nucleus by a factor of 2, then I might believe that'd yield gamma rays. But not 1 part in 10000? If you squeezed a much nearer atomic nucleus, only, say, a light-millisecond away from the holes (100 miles), then you might well be able to get gamma rays. But not with a 0.4 sec delay; they ought to reradiate instantly. So the question is: can squeezing atomic nuclei by 1 part in 10000 cause gamma rays? I doubt it. Nuclei are in an energy min. Small distortions from that min should increase energies by amount QUADRATIC in the distortion. Factor 2=1+1 distortion should yield energies comparable to the nuclear binding energies of order 10 MeV/nucleon or comparable to the proton self-energy of order 1 GeV. So factor 1+1/10000 distortion should provide energies of at most 1 GeV / 10000^2 which is 0.1 eV, which is diddlysquat compared to gamma rays. Or if you viewed it as some probability of converting nucleus to excited state then the probability ought to be of order 1/10000^2, which seems not enough to yield the observed photon luminosity? I mean, only a very tiny part of space is occupied by nuclei, and so only a very tiny fraction of gravity wave could be converted to photon energies in this way, and so, it seems really hard to believe in this whole hypothesis.
another way to see it: if there were enough nuclei for the grav-wave-exciting-nuclei to radiate gammas process to eat enough gravity-wave energy to produce the observed photon pulse -- then there ought to be enough atoms in that same cloud to block those gamma rays from reaching us. Not buying it. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
To explain the 400 millisecond delay, it suffices that the gamma-ray source be anywhere on a prolate ellipsoid with one focus at the black hole, and the other at Earth. The two equal minor axes of the ellipsoid are on the order of the geometric mean of 0.4 and 4 x 10^16, which (handwave, handwave) is around 10^8 light-seconds, or about 3 light-years. It's a very spindly ellipsoid. As Warren points out, we want the gamma-ray source to be as close to the disaster site as possible, and if it were *behind* the site, we could get it to within 0.2 light-seconds. That increases the excitation by a factor of four (is that right?), which isn't enough to overcome Warren's objections. On Sun, Feb 28, 2016 at 3:04 PM, Warren D Smith <warren.wds@gmail.com> wrote:
another way to see it: if there were enough nuclei for the grav-wave-exciting-nuclei to radiate gammas process to eat enough gravity-wave energy to produce the observed photon pulse -- then there ought to be enough atoms in that same cloud to block those gamma rays from reaching us.
Not buying it.
-- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
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