Kind of... maybe... there are some interesting problems with various sources.
First, not sure about the process that generates them. Saying "they came from an active galactic nuclei is ok... but how did they get accelerated to such energies?
Part of the problem is that we're not entirely sure what they're made of. Most theories have been working on the "they're protons" assumption, but other approaches with having them be heavier nuclei means that they don't need to travel as fast to have the same amount of energy (which also changes the equation for the GZK limit as that applies to protons).
Thanks this makes sense, My underlying assumption was that a typical star has magnetic acceleration paths which have many orders of magnitude more energy than the LHC (Many intentionally used ambiguously as I have not done the math).
I suppose given the energies involved, we would need to observationally ascertain where in the sky the cosmic rays come from in order to put bounds on how they were made and what they are made of.
Do yo know of any efforts to observe cosmic ray sources or build a cosmic ray telescope?
> ... we would need to observationally ascertain where in the sky the cosmic rays come from in order to put bounds on how they were made and what they are made of.
This is part of the challenge - the map of where they are hint at some hot spots ( https://skyandtelescope.org/astronomy-news/cosmic-rays-hint-... ) but as these are charged particles (not light) the path that they follow isn't necessarily a "draw a straight like back to the source"
> Do yo know of any efforts to observe cosmic ray sources or build a cosmic ray telescope?
We don't directly observe the cosmic rays, but rather the cascade of particles that they make as they crash through the atmosphere.
> But since these high energy particles have an estimated arrival rate of just 1 per km2 per century, the Auger Observatory has created a detection area of 3,000 km2 (1,200 sq mi)—the size of Rhode Island, or Luxembourg—in order to record a large number of these events. It is located in the western Mendoza Province, Argentina, near the Andes.
First, not sure about the process that generates them. Saying "they came from an active galactic nuclei is ok... but how did they get accelerated to such energies?
The next problem is that being so highly energetic, they should be interacting with the cosmic background radiation if they're traveling about 160 mLy which would drain off some energy ( https://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit ) and there are some observations that appear in violation of that limit ( https://en.wikipedia.org/wiki/Oh-My-God_particle )
https://www.quantamagazine.org/cosmic-map-of-ultrahigh-energ... is also interesting to look at (very neat visualization).
Part of the problem is that we're not entirely sure what they're made of. Most theories have been working on the "they're protons" assumption, but other approaches with having them be heavier nuclei means that they don't need to travel as fast to have the same amount of energy (which also changes the equation for the GZK limit as that applies to protons).