Did a gamma ray burst accompany LIGO's gravity wave detection?

February 19, 2016 by Evan Gough, Universe Today
Did a gamma ray burst accompany LIGO’s gravity wave detection?
An artist's impression of a Gamma Ray Burst. Credit: Stanford.edu

Last week's announcement that Gravitational Waves (GW) have been detected for the first time—as a result of the merger of two black holes—is huge news. But now a Gamma Ray Burst (GRB) originating from the same place, and that arrived at Earth 0.4 seconds after the GW, is making news. Isolated black holes aren't supposed to create GRB's; they need to be near a large amount of matter to do that.

NASA's Fermi telescope detected the GRB, coming from the same point as the GW, a mere 0.4 seconds after the waves arrived. Though we can't be absolutely certain that the two are from the same black hole merger, the Fermi team calculates the of that being a coincidence at only 0.0022%. That's a pretty solid correlation.

So what's going on here? To back up a little, let's look at what we thought was happening when LIGO detected .

Our understanding was that the two black holes orbited each other for a long time. As they did so, their massive gravity would have cleared the area around them of matter. By they time they finished circling each other and merged, they would have been isolated in space. But now that a GRB has been detected, we need some way to account for it. We need more matter to be present.

According to Abraham Loeb, of Harvard University, the missing piece of this puzzle is a massive star—itself the result of a binary star system combining into one—a few hundred times larger than the Sun, that spawned two black holes. A star this size would form a black hole when it exhausted its fuel and collapsed. But why would there be two black holes?

Again, according to Loeb, if the star was rotating at a high enough rate—just below its break up frequency—the star could actually form two collapsing cores in a dumbbell configuration, and hence two black holes. But now these two black holes would not be isolated in space, they would actually be inside a massive star. Or what was left of one. The remnants of the massive star is the missing .

When the joined together, an outflow would be generated, which would produce the GRB. Or else the GRB came "from a jet originating out of the accretion disk of residual debris around the BH remnant," according to Loeb's paper. So why the 0.4 s delay? This is the time it took the GRB to cross the star, relative to the gravitational waves.

It sounds like a nice tidy explanation. But, as Loeb notes, there are some problems with it. The main question is, why was the GRB so weak, or dim? Loeb's paper says that "observed GRB may be just one spike in a longer and weaker transient below the GBM detection threshold."

But was the GRB really weak? Or was it even real? The European Space Agency has their own gamma ray detecting spacecraft, called Integral. Integral was not able to confirm the GRB signal, and according to this paper, the gamma ray signal was not real after all.

Explore further: How did the odd black holes detected by LIGO form – and can we spot them in the sky?

More information: Electromagnetic Counterparts to Black Hole Mergers Detected by LIGO. arxiv.org/abs/1602.04735

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11 comments

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katesisco
2 / 5 (4) Feb 19, 2016
Well, as scientists have discovered with gamma ray bursts from jets, the cause is magnetism.
Protoplasmix
4.3 / 5 (6) Feb 19, 2016
Well, as scientists have discovered with gamma ray bursts from jets, the cause is magnetism.
And the cause of the magnetism is obviously the motion of charged particles, lots and lots of them, all confined to the same path by g r a v i t y , one of the main causes of the jet, since like-charges repel, which (without gravity) would cause the particles to stray off the same path (the path that contributes to the magnetic field which creates and sustains the jet).
Solon
3 / 5 (2) Feb 19, 2016
Once upon a time...
antigoracle
2 / 5 (4) Feb 19, 2016
I believe I'm detecting a retraction.
bschott
2.3 / 5 (6) Feb 19, 2016
I believe I'm detecting a retraction.


As neat as it would be.....

Again, according to Loeb, if the star was rotating at a high enough rate—just below its break up frequency—the star could actually form two collapsing cores in a dumbbell configuration, and hence two black holes. But now these two black holes would not be isolated in space, they would actually be inside a massive star. Or what was left of one. The remnants of the massive star is the missing matter.


The garbage above is more likely the nature of what we have to endure if we keep having to read explanations written by the MS.

Creative though!
Protoplasmix
4.3 / 5 (6) Feb 19, 2016
The garbage above is more likely the nature of what we have to endure if we keep having to read explanations written by the MS.

Creative though!
It's quite creative, and possibly correct, while your explanation, that most of science is wrong, is not only entirely devoid of creative thought, it is intellectually lazy and sorely lacking any intelligent alternative explanations.

Now piss off if you don't want to endure it,
or I shall be forced to be civil with you a - s e c o n d - time.
cantdrive85
1.8 / 5 (5) Feb 19, 2016
And the cause of the magnetism is obviously the motion of charged particles, lots and lots of them, all confined to the same path by g r a v i t y

Yep, the weakest force g r a v i t y somehow overpowers one that is 10^39 stronger. Must be more GR magic. And what is "intellectually lazy" is to spout false "facts" and claim the intellectual high road. Charged particles moving in parallel are short range repulsive, long range attractive, and they tend to follow a helical shape such as this;
https://en.wikipe...x_Nebula

That's not g r a v i t y confining the plasma, EM dominates in plasmas.
Protoplasmix
5 / 5 (6) Feb 19, 2016
Yep, the weakest force g r a v i t y somehow overpowers one that is 10^39 stronger. Must be more GR magic.
Not somehow; gravity is proportional to the amount of mass.

Take the core of the sun for example: the electromagnetic repulsion between two protons is no match for the pressure from the weight of all the mass above it, and about 3.7x10^38 protons are squished together into helium nuclei every second.

The formula for the force of gravity diverges (with increasing mass) while the electromagnetic force of repulsion between two protons [10^39 times stronger than the force of gravitational attraction between them from their individual mass] remains constant. Simple.
cantdrive85
1.6 / 5 (7) Feb 20, 2016
Yep, the weakest force g r a v i t y somehow overpowers one that is 10^39 stronger. Must be more GR magic.
Not somehow; gravity is proportional to the amount of mass.

Take the core of the sun for example: the electromagnetic repulsion between two protons is no match for the pressure from the weight of all the mass above it, and about 3.7x10^38 protons are squished together into helium nuclei every second.

The formula for the force of gravity diverges (with increasing mass) while the electromagnetic force of repulsion between two protons [10^39 times stronger than the force of gravitational attraction between them from their individual mass] remains constant. Simple.

Why don't you show an experiment which supports this conjecture.
morphixnm
3 / 5 (2) Feb 24, 2016
LIGO is said to have localized the origination of the gravity wave to somewhere within a 600 degree area of the southern sky. Tho moon occupies 1/2 degree of sky, so that would be an area the size of 1,200 moons. This cannot be said to be a point that coincides with the location of the gamma ray burst, yet this is being said here and all over the place. Really specious.
mganderson
3 / 5 (2) Mar 12, 2016

This is the type of result you would expect if Gravity is described better by a natural logarithmic solution then by the first order approximation of one that Einstein used.
A natural logarithmic solution is presented in the book "Time Matter and Gravity" by Morris G. Anderson". Also look for the paper "A Method for Predicting Quasar Luminosity Consistent With the NASA/IPAC Extragalactic Database". You can find these documents by searching on the web.

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