Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-10-24
J.Phys.G32:1-8,2006
Astronomy and Astrophysics
Astrophysics
8 pages, 3 figures, accepted by J.Phys.G: Nucl.Part.Phys
Scientific paper
10.1088/0954-3899/32/1/001
In view of recent developments attention is directed again at two aspects of the well known 'knee' in the cosmic ray energy spectrum at 3 PeV: the mass of the predominant particles at this energy and their source. It is inevitable in a subject such as this that ideas - and conclusions - evolve. Earlier, we had used a particular acceleration model and the nature of the local ISM to infer that the particles are mainly oxygen nuclei. Initially no specific source was identified. More recently, however, we have specified the Monogem Ring supernova remnant (SNR) as the likely source; this is at just the right distance and age and the energies are reasonable. Concerning the mass composition at the knee, a quantity more difficult to determine, recent direct measurements, which extend to higher energies than hitherto, show a likely flattening in the spectrum above 10^4 GeV/nucleon for He-nuclei, a flattening which, if extrapolated to higher energies, would meet the measured spectrum in the knee region. The other nuclei do not show this feature. He-nuclei in the knee region would also be marginally consistent with KASCADE EAS data, although there are serious problems with EAS mass estimates in that experiment. Concerning the acceleration, recent models applied to the Monogem Ring SNR allow a satisfactory explanation in terms of either oxygen or helium, but with the latter being a distinct possibility and perhaps more likely.
Erlykin Anatoly D.
Wolfendale Arnold W.
No associations
LandOfFree
The nature of the 'knee' in the cosmic ray energy spectrum does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The nature of the 'knee' in the cosmic ray energy spectrum, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The nature of the 'knee' in the cosmic ray energy spectrum will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-522532