Highest energy photons ever recorded coming from Crab Nebula

Crab Nebula
The Crab Nebula. Credit: NASA

A very large team of researchers affiliated with several institutions in China and Japan has measured the highest energy photon ever recorded. In their paper published in the journal Physical Review Letters, the group describes their study of data from the Tibet Air Shower Gamma Collaboration and what they found.

The Tibet Air Shower Gamma Collaboration is an observatory in the Tibetan Plateau and the people that run it. It consists of 600 built on a 65,000-square-meter parcel of land. Its objective is to detect emanating from space. The detectors there observe the debris from photons colliding with particles in the Earth's atmosphere and cosmic rays, which are mostly protons and atomic nuclei. The team members with this new effort were focused on photons that make their way to Earth from far-off places. To measure them, the researchers excluded muon detections, leaving only particles associated with collisions. The researchers were able to calculate the energy of a given photon using data from the particles that it struck.

The researchers report that they found what they believe to be 24 photon-initiated showers, with photon energies above 100 trillion electron volts—one of which registered 450 TeV. These finds represent the first measurements of high energy photons over 100 TeV and the highest ever recorded.

The researchers also used the data from the collaboration to track the paths of the photons, and found they originated in the Crab Nebula, the remains of a supernova that was first observed in 1054 AD. The Crab Nebula is located in the Perseus Arm of the Milky Way, approximately 6,500 light years away.

The research team has been studying high-energy photons that make their way to Earth as part of an effort to understand why they have so much energy. Current theory suggests that the photons get their energy from other high-energy particles via inverse Compton scattering, in which photons absorb the energy of high- when they collide, for example, during supernovae. The photons themselves are believed to have been created by processes involved in the Big Bang.


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More information: M. Amenomori, et al. First detection of photons with energy beyond 100 TeV from an astrophysical source, Physical Review Letters (2019). journals.aps.org/prl/abstract/ … ysRevLett.123.051101 ,

ArXive: 1906.05521v1 [astro-ph.HE]: arxiv.org/abs/1906.05521

Journal information: Physical Review Letters

© 2019 Science X Network

Citation: Highest energy photons ever recorded coming from Crab Nebula (2019, June 26) retrieved 15 September 2019 from https://phys.org/news/2019-06-highest-energy-photons-crab-nebula.html
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Jun 26, 2019
As the Earth's magnetic field is weakening the frequency and severity of cosmic ray impacts will only increase

Jun 26, 2019
Errrr, no, the photons were not "created in the Big Bang."

Do better physorg.

Jun 26, 2019
I believe their viewpoint is Everything was created in the big bang, all scientists are nerds on the inside.
But specifically, these photons are considered to be part of the cosmic microwave background which normally carry very little energy. Then they got smacked by the relativistic jet coming out of the supernova and took on the jet's energy. Those jets travel up past 99.9 the speed of light and contain huge amounts of magnetic and kinetic energy.
It is rather a coincidence the jet is pointing our way, what are the odds?

Jun 27, 2019
"The Tibet Air Shower Gamma Collaboration is an observatory in the Tibetan Plateau and the people that run it." Huh?

Jun 27, 2019
It is rather a coincidence the jet is pointing our way, what are the odds?

With the number of such jets out there the odds that some will be pointed our way is rather large.

(As an aside: you can calculate the odds of any one particular jet pointing our way quite easily if you know the aperture angle of the jet. Just multiply that angle times two - because there are usually two jets coming out of an object at opposite poles - and divide by 720°. Many jets also 'wobble' because the creating object has a precession movement which increases the chance of that jet coming into our view eventually)

450 Trillion eV is enormous. For comparison: 1TeV is about the kinetic energy of a flying mosquito
https://en.wikipe...tronvolt
450 of those. FROM A SINGLE PHOTON...it just boggels the mind.

Jun 27, 2019
@anti, not gonna work. These are people who think 650 mly is only just a little bit further than Jupiter. Cranks can't count.

Jun 28, 2019
It is rather a coincidence the jet is pointing our way, what are the odds?

With the number of such jets out there the odds that some will be pointed our way is rather large.
450 Trillion eV is enormous. For comparison: 1TeV is about the kinetic energy of a flying mosquito
https://en.wikipe...tronvolt
450 of those. FROM A SINGLE PHOTON...it just boggels the mind.


The supernova from 1054 is the most recent observed supernova in the in the Milky Way, they average less than one every thousand years. The number of such events is tiny by human standards,
What are the odds that the only supernova in a thousand years has a jet pointing our way?
I was not after a real number, just noting how statistics do not follow odds for single events.

Jun 28, 2019
What are the odds that the only supernova in a thousand years has a jet pointing our way?


What jets? The x-rays are photons that are accelerated by the supernova shock waves that surround the explosion, the waves essentially go all around (if we average over the necessary asymmetries that allow the waves to be created in the first place).

The inverse scattering is due to the kinetic energy of the shock wave high energy particles the photons scatter off, there is not necessarily anything magnetic involved at all.

On the other hand, according to the article, these supernova sources are rare. I haven't read the paper, but I suspect the nova should be recent and near to create and allow the transport of high energy photons to reach us. Somewhat akin to charged cosmic rays there are damping and scattering effects that push high energy photons to lower energies as they travel.

If ubiquitous background photons are likeliest scattered, as DS say they are generated long after HBB.

Jun 28, 2019
Just out of curiosity, why would anyone think supernova explosions generate jets (like neutron stars of black holes may do)? Is that some "popular science" take on comics depictions of explosions that throw of "jets/rays" to look exciting (but unrealistic)?

Why not simply read up on supernovas and inverse Compton scattering, if this seems to be an interesting subject? A review should not be too hard to google up, if not Wikipedia has good references. Reading/Science 101.

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