snorkack said:
Is there any consensus as to how much of the primary cosmic rays come from supernovae, and of which type, how much from quasars, how much from kilonovae?
No.
It is an active area of investigation, and there are some guesses, but there is nothing approaching a scientific consensus yet.
Wikipedia summarizes what we know so far, and in particular, states:
Supernovae do not produce all cosmic rays, however, and the proportion of cosmic rays that they do produce is a question which cannot be answered without deeper investigation.
citing Jha, Alok (14 February 2013).
"Cosmic ray mystery solved".
The Guardian. London, UK: Guardian News and Media Ltd. Retrieved 21 March 2013.
While Wikipedia's source for this statement is now 12 years old, the basic conclusion still holds true. More recently, a
December 23, 2024 review article stated:
Significant progress has been made over the past decades towards unveiling the sources of the most energetic particles in nature, the ultra-high-energy cosmic rays (UHECRs). Despite these advancements, the exact astrophysical sites capable of accelerating these particles to such extreme energies remain largely unknown. Moreover, the mechanisms by which they achieve these extreme energies are poorly understood.
Similarly,
another recent paper states:
The population of astrophysical sources responsible for accelerating these nuclei remains unidentified, although serious contenders have been identified.
The
basic problem is to a great extent that:
Unlike neutrinos and photons arriving from extra-galactic sources, ultra-high energy cosmic rays (UHECRs) do not trace back to their origins due to propagation effects such as magnetic deflections and energy losses. For ankle energies, UHECRs can propagate for hundreds of megaparsecs with negligible energy losses but the directional information is lost after a few megaparsecs. On the other hand, at the highest energies the directions are kept for larger distances due to the increased rigidity but the interaction rates with the cosmic microwave background strongly suppress the cosmic rays within a few to tens of megaparsecs.
So, basically, the universe is actively hiding this information from us, forcing us to work harder for it.
Photons such as gamma-rays, in principle, should be easier to find sources for, but
this too is challenging, in part, because some gamma-rays have their origins in particles in cosmic rays:
The Galactic gamma-ray flux can be described as the sum of two components: the first is due to the emission from an ensemble of discrete sources, and the second is formed by the photons produced by cosmic rays propagating in interstellar space and interacting with gas or radiation fields. The source component is partially resolved as the contributions from individual sources, but a fraction is unresolved and appears as a diffuse flux. Both the unresolved source flux and the interstellar emission flux encode information of great significance for high energy astrophysics, and therefore the separation of these two contributions is very important. . . . while the flux from unresolved sources is measurable and important, the dominant contribution to the diffuse flux over most of the celestial sphere is interstellar emission.
Give it another 5-10 years and there might be a better answer. Many consortia of astronomers are actively working on the problem with state of art observatories and improved computational capacity to analyze their results. An
arXiv search for the last twelve months reveals 344 papers with the words "cosmic"," ray", and "sources" in their abstracts.
There are papers (such as
this one) that try to bound the proportion of certain kinds of cosmic rays from particular sources. Similarly, there are
papers suggesting statistical methods that can be used to answer the question fully, once there is sufficient data. But right now, we
aren't even entirely sure to what extent some subtypes of cosmic rays are from our own Sun as opposed to more distant and exotic sources.
Of course, I share the frustration that you no doubt have, that comes from being at a moment where were are close to knowing the answer to something, since we finally have the technologies we need to get that answer, yet we are still years away from a definitive answer anyway.
