Surprising Gamma Rays From Crab Nebula

In summary, astronomers have detected gamma ray emissions from the Crab Pulsar at energies more than 100 gigaelectronvolts. This challenges notions of how these powerful electromagnetic rays are formed and researchers suggest that they may be produced more than 10 stellar radii from the neutron star.
  • #1
Dotini
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http://www.bbc.co.uk/news/science-environment-15203788
Astronomers have spotted gamma ray emissions coming from the Crab Pulsar at far higher energies than expected.

This challenges notions of how these powerful electromagnetic rays - like light, but far more energetic - are formed, researchers suggest in Science.

They found emissions at more than 100 gigaelectronvolts - 100 billion times more energetic than visible light.


http://www.sciencemag.org/content/334/6052/69
Abstract

We report the detection of pulsed gamma rays from the Crab pulsar at energies above 100 giga–electron volts (GeV) with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) array of atmospheric Cherenkov telescopes. The detection cannot be explained on the basis of current pulsar models. The photon spectrum of pulsed emission between 100 mega–electron volts and 400 GeV is described by a broken power law that is statistically preferred over a power law with an exponential cutoff. It is unlikely that the observation can be explained by invoking curvature radiation as the origin of the observed gamma rays above 100 GeV. Our findings require that these gamma rays be produced more than 10 stellar radii from the neutron star.

Respectfully submitted,
Steve
 
Astronomy news on Phys.org
  • #2
The findings reveal that current models of pulsars are, at a minimum, incomplete. Speaking to this fact, The Smithsonian Astrophysical Observatory's Martin Schroedte, who performed most of the analytical work for the study, said :

If you asked theorists a year ago whether we would see gamma-ray pulses this energetic, almost all of them would have said, "No." There's just no theory that can account for what we've found.
The researchers explore several scenarios that could explain the unprecedented observations in a paper published in today's issue of Science, but ultimately conclude that more observations — possibly requiring next-generation observatory equipment — will be necessary before any new pulsar models can be drawn up.

For now, astronomers are left to ruminate on the game-changing results of an experiment that many thought should never have been performed.

"To me it's a real triumph of the experimental approach, not going along with the flow and making assumptions, but just observing to see what there is," said astronomer Rene Ong, spokesperson for the VERITAS gamma ray observatory that was used to detect the Crab Pulsar's radiation.

"And lo and behold, we see something different than what everybody expected."


http://io9.com/nepomuk-otte/

Respectfully submitted,
Steve
 
  • #3
Wow that's a huge amount of energy...
 
  • #4
250px-Crab_Nebula.jpg

Wikipedia said:
the Crab is generally the strongest persistent source in the sky, with measured flux extending to above 10^12 eV.

It may be possible that Type II supernova explosions above 9 solar masses produce baryogenic anti-proton and anti-neutron antimatter residue, as a result of the stellar core shock wave rebounding at near luminous velocity. This could also explain the missing matter and the measured flux, if a matter-antimatter contributing event occurred during the stellar core shock wave rebound.

Reference:
http://en.wikipedia.org/wiki/Crab_Nebula" [Broken]
 
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  • #5
I think that we have an example of *OH MY FREAKING WORD-ism* by popular press. The press loves to make things dramatic and breathlessly interesting.

Dotini said:
The findings reveal that current models of pulsars are, at a minimum, incomplete.


Which is something that we already new. There is a lot we don't understand about the magnetic fields of pulsars.

If you asked theorists a year ago whether we would see gamma-ray pulses this energetic, almost all of them would have said, "No."

I don't think that's true. Since pulsar magnetospheres are not very well understood, it's very hard to say categorically that something can't happen. Having extremely high energy gamma rays is interesting, but it's not totally unexpected.

Here is the original paper

http://arxiv.org/ftp/arxiv/papers/1108/1108.3797.pdf

This is before you to through the *OH MY FREAKING WORD* filter.
 

1. What are gamma rays and why are they surprising from the Crab Nebula?

Gamma rays are high-energy electromagnetic radiation with the shortest wavelengths and highest frequencies in the electromagnetic spectrum. They are surprising from the Crab Nebula because it was previously thought to emit only X-rays and visible light.

2. How were the gamma rays from the Crab Nebula discovered?

The gamma rays from the Crab Nebula were discovered by the Fermi Gamma-ray Space Telescope in 2009. The telescope's Large Area Telescope (LAT) detected a sudden increase in gamma ray emissions from the Crab Nebula, leading to further investigations and discoveries.

3. What causes the gamma ray emissions from the Crab Nebula?

The gamma ray emissions from the Crab Nebula are caused by high-energy particles, such as electrons and positrons, being accelerated to near the speed of light by the nebula's strong magnetic field. These particles then collide with surrounding gas and produce gamma rays.

4. How do the gamma rays from the Crab Nebula affect our understanding of the universe?

The discovery of gamma rays from the Crab Nebula has expanded our understanding of the universe by providing new insights into the mechanisms of particle acceleration and the behavior of magnetic fields in celestial objects. It also helps us better understand the processes that occur in supernova remnants.

5. What future research is being done on the gamma rays from the Crab Nebula?

Future research on the gamma rays from the Crab Nebula includes further observations and analysis from the Fermi Gamma-ray Space Telescope, as well as studies using other high-energy telescopes and ground-based observatories. Scientists are also working to develop new models and theories to better explain the surprising gamma ray emissions from the Crab Nebula.

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