Yeah, we talked about this idea for GLAST at some meetings. I think it's still farfetched, but in a short GRB this may be an obvious effect. Good call.

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Phil Plait
The Bad Astronomer
http://www.badastronomy.com
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If you could hypothetically provide an answer, I'd rather you provided the correct answer than the one more acceptable.

Or, are you running for political office?

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Just noticed, by its revival from older times, that there was another Q&A thread on this news: Breakdown of relativity? (also MAGIC delayed photon). Though the questions bespeak of different attitudes, most everyone interested in one will be interested in the other. (Edit: and now they are one, as described below.)

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According to theoretical approaches to tachyons, they should *slow down*, but still remain faster than light, as they *gain* energy:

Tachyons.
http://en.wikipedia.org/wiki/Tachyon#Basic_properties

Then the observations would have more weight if it is found that even higher energy gamma rays travel slower.


Bob Clark

Events energetic enough to create these gamma rays are consuming an awful lot of mass; and in doing so, completely collapse the gravity field associated with the mass converted to energy. That takes time - in the case of our own sun, (if it decided to eat itself), it is reasonable to estimate that the gravity wave peak would occur ~4 minutes after the mass-conversion peak. This is the logic tree that always gets me in trouble, but there you have it: The gamma peak may be closely related to the gravity wave peak.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Hopefully, we can observe more such events to see how the time lag changes (or not) with distance. This has already been suggested by several others.

This very interesting result bears watching. I'm not quite ready to throw GR under the bus, but am looking forward to additional studies.

Ok. The solution to the low energy em first problem.
Nobody has said "Gee I wonder if their model is wrong!!!" Instead its all about new physics..
If an ATM guy had said any of those thing he(or she) would get laughed at with "Wheres your equations".

I have posted this paper before. The author, Petrukhin, A. A. is well published in cosmic ray circles...

Title: Cosmic ray spectrum above 1015 eV (a new approach)
Authors: Petrukhin, A. A.

"A new approach to cosmic ray description based on the model of particle generation and acceleration in plasma pinches and on supposition that a new state of matter appears in cosmic ray interactions above 1015 eV is considered. Consequences for various aspects of cosmic ray physics and some possibilities to check this hypothesis are discussed."

http://adsabs.harvard.edu/abs/2005ICRC....3..137P

A plasma pinch has the required slow rise and slow fall time.

No new physics (even though it is discussed in the preceding paper), quantum foam, dark matter or smashing neutron stars. Relativity is safe even though I think it has problems, and EM/light has a speed limit.
Just like the flux tubes the we see locally, that is where a pinch(reconnection) takes place as Cluster has observed. They just happened to catch the first part. And on a larger scale, like in the DNA nebula......
These signals are characteristic of a compression event. Just like a pulsar is.

Thats it. All you have to do is scale up an existing phenomena.......

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This is direct detection of a plasma pinch accelerating particles. Are you with me on this one. They even say it. They just dont know what to call it....
Can ya feel the glory??? Validation 101...

NASA: major step toward knowing origin of cosmic rays.
"Suzaku spectra of RXJ1713.7 provide independent evidence of rapid acceleration. They show that the hot spots have tangled magnetic fields, which allow particles to bounce back and forth rapidly until they are accelerated to very high energies. Since electrons and protons of a given energy are accelerated at the same high rate, but protons don’t radiate away their energy as electrons do, Uchiyama’s team argues that protons will be accelerated to the higher energies needed to match the energies seen in cosmic rays striking Earth’s atmosphere."
http://www.physorg.com/news111166810.html

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The rate at which light escapes gravitational wells is based upon it's wavelength. Can't recall which, but if I'm not mistaken, it's the lower energies which lag the higher ones.

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If I set the budget, we'd have Ares and more. Unfortunately, I don't set the budget, and Ares is just too expensive and too far out for us to accomplish our goals within the budget we were given.

If we halt the ISS, all versions of Ares, and transport Orion and Altair aboard DIRECTv3's Jupiter family of Shuttle-Derived Launch Vehicles, we just might make it back to the Moon by 2020.

Generally, photons travel at 'c' or so close to it you can't measure the difference, but the gravity well doesn't change the rate of speed. It only affects the wavelength.

Now, in the case we are discussing here, with photons with energies greater than 1 TeV, it is the high energy photons that go a wee bit slower, but not because of a gravity well.

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Forming opinions as we speak

upriver, first, I'm not sure what this Suzaku-based finding has to do with the topic of this thread; would be so kind as to elaborate please?

Second, that UHE cosmic rays may be produced in supernova remnants is very old news. For many decades now researchers have been digging deeper and deeper - which mechanisms? in what combinations? what quantitative models match best? how can new observations best constrain these most favoured models? where else should we look for corroboration?

But maybe I'm misunderstanding some key part of your post? Would you be so kind as to elaborate? What do you think this paper validates (that previously lacked validation)?

Shoot, I thought I was going to get away with this one.

They finally have enough information to formulate a good description.
That description has converged onto a description of a plasma pinch, just with astronomer language instead of already established plasma physicist language.

Again, here is the hypothesis.

Title: Cosmic ray spectrum above 1015 eV (a new approach)
Authors: Petrukhin, A. A.

"A new approach to cosmic ray description based on the model of particle generation and acceleration in plasma pinches and on supposition that a new state of matter appears in cosmic ray interactions above 1015 eV is considered. Consequences for various aspects of cosmic ray physics and some possibilities to check this hypothesis are discussed."
http://adsabs.harvard.edu/abs/2005ICRC....3..137P


Notice that they talk about a "new state of matter". That is not required for the "generation of cosmic rays in plasma pinches" part to work. But that part is very interesting because it would explain some of the results that Sandia Z-machine is getting, and that we are seeing.
Let me post a picture from the lab. This image is of a expanding sonoluminescence bubble.
This bubble is about 2mm in dia. The pressure in the reactor is 1000psi. These shock waves(the black and white striations) my be the strongest ever created by man. This is on a delayed flash triggered by the actual sono flash. We are not sure what is going on inside the bubble.:-)
http://www.brantcallahan.com/images/...000psi%204.jpg
Here is a test reactor after I just set it up.
http://www.brantcallahan.com/images/...al%20table.jpg

But I digress. So this SL process is much like plasma pinch is way because we are compressing a fuel mixture in a bubble to fusion temperatures. And we are trying to achieve a certain convergence ratio over a certain time.
Hence my interest in plasma pinches.

There is the one model, above, that they have either not seen or ignored.

"They show that the hot spots have tangled magnetic fields, which allow particles to bounce back and forth rapidly until they are accelerated to very high energies."

When they show that is not a description of a pinch, I will eat my words.
Also I suspect that cosmic rays are generated as close as the "reconnections" that happen locally.
They will use frozen in magnetic fields. Which are baloney the way they are being used.
These hotspots have x-ray variability of about a year.
That I believe, is also a longer time(/.5) period than a shock wave passing that has enough energy to "heat" the "gas" to x-ray temperatures.

That plasma pinches are a valid phenomena in space generating high energy particles on a large scale as well as a small scale. Even to the point of generating new electrons and protons(maybe neutron decay), and as a mechanism for nucleosynthesis.
This is the only model,(from my limited understanding) that exactly matches the parameters of cosmic ray energy distribution.

Now that there is some establishment(at least in word salad) of what I mean, we could conceivably use this mechanism to explain GRB's and other high energy outbursts. Especially ones that defy the laws of physics.
When you use this other tool, you find that no laws of physics are broken, the only thing you have to do is postulate some sort of charge separation or potential difference between 2 points on a large scale. Like between the galactic center and the rim. The gc is observed to put out massive quantities of protons and electrons.
Milky Way Black Hole May Be a Colossal 'Particle Accelerator'
"This graphic illustrates the idea that the black hole at the center of the Milky Way is like an extremely powerful particle accelerator, revving up protons in the surrounding magnetic plasma and slinging them into lower-energy protons with such energy that high-energy gamma rays result from the collision."
http://www.physorg.com/news91731386.html
(Another pinch description.)

If there is a difference in potential. Then you could have a current flow in a unbalanced plasma(unbalance of electron and proton energies, or species). Even a neutral plasma is a conductor like a wire.
Its not that hard of a leap to make.

I think this(a plasma pinch) is a good answer for the differential in arrival times of different wavelengths, because it preserves current basic physics, and is a real phenomena.

__________________
"Only those who attempt the absurd will achieve the impossible." - M. C. Escher

"Freedom is popular." -Ron Paul

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Everything I need to know I learned through Googling.

I'm still puzzled how the RXJ1713.7-3946 observations, and the Uchiyama et al. paper* relate to the MAGIC observations - is it your idea that plasma pinches are somehow involved in each?

It's worth quoting the abstract of the Uchiyama et al. paper:Note the phrase 'long-standing conjecture'; the 24 references in the paper include one dated 1983 and two 1987; no reference to the Petrukhin conference presentation.

It would seem that Blandford and Eichler's 1987 paper (Particle Acceleration at Astrophysical Shocks - a Theory of Cosmic-Ray Origin) is one of the most widely cited, in terms of presenting how 'tangled magnetic fields' can produce high energy particles. In any case, it's worth presenting the abstract of this 1987 paper here:Perhaps there is a misalignment wrt terms ('plasma pinch' vs 'first order Fermi acceleration at collisionless astrophysical shock fronts'), but perhaps not. AFAIK, there has been at least one paper on plasma pinches as possible sources of cosmic rays, but it did not refer to supernova remnants, and, curiously, did not cite Blandford and Eichler's 1987 paper (so perhaps Trubnikov already accepted that, pace upriver, the two are very different?).

*Extremely fast acceleration of cosmic rays in a supernova remnant

I wish I had access to the Trubnikov paper for comparison. The point I'm trying to make is that its all the same, SNR or not.

All of these observations describe plasma pinch activity. And it doesnt matter where you are, this works over a broad range of scales. It is also known as reconnection.

Largest Magnetic Reconnection Region Ever Observed
http://sci.esa.int/science-e/www/obj...objectid=38577

The term reconnection is a misnomer, and as I have described elsewhere, it is a pinch between 2 filaments in a twisted flux tube.

Only a plasma pinch has the characteristics necessary to generate particles of the energies we are talking about. And it is better than a "rough match". It has the necessary characteristics to produce a delay in emitted energies(saving physics).

I just want to focus on this part here from the abstract of the Uchiyama et al. paper:

So the physical shock waves propagating through plasma. The idea that there is still acceleration going on for some time after the shock has passed bothers me.

The interstellar magnetic field can be amplified(locally with no action from the galactic center!!!???).
At the shock of the SNR by MHD waves generated by cosmic rays.
So what they are saying is that the magnetic field strength is a byproduct of cosmic ray generation.

That it is all mechanically(shock wave) driven instead of electrically(electron intensity) driven.

We both know that magnetic field strength changes because the intensity of the electrons feeding it vary. That is basic physics.

Do you see the error in what they are saying?

Here is their story.
The shock bone is connected to the cosmic ray bone.
The cosmic ray bone is connected to the MHD wave bone.
The MHD wave bone is connected to the magnetic bone.

My version:
The electron flow bone is connected to the magnetic bone.
The magnetic bone is connected to the cosmic ray bone.

See the difference?

Yes, yes, yes, so close. "Indicating amplification" only because the have no way to provide a primary independent source of magnetism(electron flow) or understand about how a pinch works. Again, localized tangled magnetic field comes to mind.
The only way to amplify a magnetic field is increase the electron energy or population.
Electron(proton) acceleration takes place in a pinched flux tube just like suggested by Petrukhin. Easy, breezy, beautiful.
Considering all the places we have seen flux tubes, I would say that a SNR is a good candidate.

Or even the center of our galaxy.
DNA Nebula.
http://www.anthonares.net/2006/03/184.html

Middle top is a huge "flux tube".
Supernova Remnant N 63A.
http://sci.esa.int/science-e-media/img/4e/heic0507a.jpe

So again I'm saying that a plasma pinch works for all these problems. There are different form of pinches, but the basic idea is that you have some electron flow through a flux tube. Then there is a variation in this flow that causes a change in the Biot-Savart forces between the tubes, or an increase in flow which causes a constriction in the flux tube(s), effectively squeezing the plasma, causing an acceleration in particle energies.

__________________
"Only those who attempt the absurd will achieve the impossible." - M. C. Escher

"Freedom is popular." -Ron Paul

I've started a new Q&A thread, What are the (detailed) mechanisms for cosmic ray production, in SNR?, to address your key question.

Let's continue in that thread, and leave this one to the MAGIC GRB observations and interpretations.