Scientists Discover the Highest Energy Gamma-Rays Ever From a Pulsar (phys.org) 12
Scientists using the H.E.S.S. observatory in Namibia have detected the highest energy gamma rays ever from a dead star called a pulsar. Phys.Org reports: The energy of these gamma rays clocked in at 20 tera-electronvolts, or about 10 trillion times the energy of visible light. This observation is hard to reconcile with the theory of the production of such pulsed gamma rays, as the international team reports in the journal Nature Astronomy. [...] The Vela pulsar, located in the Southern sky in the constellation Vela (sail of the ship), is the brightest pulsar in the radio band of the electromagnetic spectrum and the brightest persistent source of cosmic gamma rays in the giga-electronvolts (GeV) range. It rotates about eleven times per second. However, above a few GeV, its radiation ends abruptly, presumably because the electrons reach the end of the pulsar's magnetosphere and escape from it. But this is not the end of the story: using deep observations with H.E.S.S., a new radiation component at even higher energies has now been discovered, with energies of up to tens of tera-electronvolts (TeV).
"That is about 200 times more energetic than all radiation ever detected before from this object," says co-author Christo Venter from the North-West University in South Africa. This very high-energy component appears at the same phase intervals as the one observed in the GeV range. However, to attain these energies, the electrons might have to travel even farther than the magnetosphere, yet the rotational emission pattern needs to remain intact. "This result challenges our previous knowledge of pulsars and requires a rethinking of how these natural accelerators work," says Arache Djannati-Atai from the Astroparticle & Cosmology (APC) laboratory in France, who led the research. "The traditional scheme according to which particles are accelerated along magnetic field lines within or slightly outside the magnetosphere cannot sufficiently explain our observations. Perhaps we are witnessing the acceleration of particles through the so-called magnetic reconnection process beyond the light cylinder, which still somehow preserves the rotational pattern? But even this scenario faces difficulties to explain how such extreme radiation is produced."
Whatever the explanation, next to its other superlatives, the Vela pulsar now officially holds the record as the pulsar with the highest-energy gamma rays discovered to date. "This discovery opens a new observation window for detection of other pulsars in the tens of teraelectronvolt range with current and upcoming more sensitive gamma-ray telescopes, hence paving the way for a better understanding of the extreme acceleration processes in highly magnetized astrophysical objects," says Djannati-Atai.
"That is about 200 times more energetic than all radiation ever detected before from this object," says co-author Christo Venter from the North-West University in South Africa. This very high-energy component appears at the same phase intervals as the one observed in the GeV range. However, to attain these energies, the electrons might have to travel even farther than the magnetosphere, yet the rotational emission pattern needs to remain intact. "This result challenges our previous knowledge of pulsars and requires a rethinking of how these natural accelerators work," says Arache Djannati-Atai from the Astroparticle & Cosmology (APC) laboratory in France, who led the research. "The traditional scheme according to which particles are accelerated along magnetic field lines within or slightly outside the magnetosphere cannot sufficiently explain our observations. Perhaps we are witnessing the acceleration of particles through the so-called magnetic reconnection process beyond the light cylinder, which still somehow preserves the rotational pattern? But even this scenario faces difficulties to explain how such extreme radiation is produced."
Whatever the explanation, next to its other superlatives, the Vela pulsar now officially holds the record as the pulsar with the highest-energy gamma rays discovered to date. "This discovery opens a new observation window for detection of other pulsars in the tens of teraelectronvolt range with current and upcoming more sensitive gamma-ray telescopes, hence paving the way for a better understanding of the extreme acceleration processes in highly magnetized astrophysical objects," says Djannati-Atai.
It's doof doof music (Score:1)
Whatever the explanation...," says DJ Annati-Atai.
FTFY
Cherenkov Telescope Array Observatory (CTAO) (Score:5, Informative)
In fact there is a multinational, worldwide project, Cherenkov Telescope Array Observatory (CTAO) , to build a new generation of ground-based gamma-ray instrument in the energy range extending from some tens of GeV to about 300 TeV. It has been under construction since 2015 and will be operational in 2022. Here are some links for more information on this:
https://en.wikipedia.org/wiki/... [wikipedia.org]
https://www.cta-observatory.or... [cta-observatory.org]
The Oh-My-God Particle (Score:5, Informative)
Gamma rays are the most energetic variety of particle-waves (aka electromagnetic radiation) known to physics
Sorry but "particle waves" includes every type of particle known and not just EM radiation since all fundamental particles are waves of their respective quantum field and gamma rays are most definitely not the highest energy of these known to physics. The record for photons is 1.4 PeV [wikipedia.org], about 100 times higher in energy than the photons HESS has seen. The IceCube experiment has seen a neutrino at 6.3 PeV, the so-called Glashow resonance energy.
However, the highest energy particle ever observed was the so-called Oh-My-God cosmic ray particle [wikipedia.org] observed in 1991 that had an energy of around 320,000 PeV or 51 J. The particle type was not identified but it was most likely to be proton.
There is currently no well-defined upper limit to these entities. So the observations of the HESS observatory are certainly not unexpected.
Sorry, but this is just a nonsense statement. The fact that there is no upper limit to the energy of a photon has absolutely nothing to do with whether Hess' observation is surprising. What makes it surprising is that nobody expected to see such high-energy photons where they saw them. If you saw your favourite A-list celebrity in your coffee shop one morning I doubt your reaction would be that it's completely unsurprising because you knew they physically existed.
Re: (Score:2)
All well said, and since your post maxed the mods, I'd just clarify that the whole point of this excitement is that it is the highest gamma ray from a Pulsar not overall.
BTW: 320,000 PeV is 320 EeV or even more scary looking 0.32 ZeV - it's almost a half of .22 muzzle escape energy, all the complains about the dangers of LHC kind of look silly in comparison.
Re: (Score:3, Interesting)
2022? Well, the schedule appears to have slipped a bit. Not a criticism, just an observation. Other tidbits from the CTA site...
Bologna, Italy – On 6 September 2023, the Cherenkov Telescope Array Observatory’s (CTAO’s) two governing bodies, the Board of Governmental Representatives (BGR) and the CTAO gGmbH Council, gathered to agree on the significant forthcoming measures to advance the Observatory to its construction phase.
The current legal entity of the CTAO, the CTAO
Aliens are trying to kill us (Score:2)
What we're witnessing is attempts by aliens to slowly wear us down. They accelerate these particles to these high energies then send them downrange. Death by a thousand cuts.
In about 10 billion years they'll have us conquered.
Re: (Score:1)
What we're witnessing is attempts by aliens to slowly wear us down. They accelerate these particles to these high energies then send them downrange. Death by a thousand cuts.
In about 10 billion years they'll have us cooked.
FTFY.
They're slowly boiling us like little pink frogs.
Eventually, all the plastic in the ocean will congeal and we'll be trapped inside an alien take-away container.
The aliens are slowly boring us to death (Score:2)
with Slashdot stories about astrophysical phenomena that don't even matter to nerd Earthlings.
Electric Universe theory FTW? (Score:2)
What if it's a generator?
Just a napkin calculation (Score:2)