Excess GeV radiation and cosmic ray origin

Büsching, I.; Pohl, M.; Schlickeiser, R.

doi:10.1051/0004-6361:20011125

Cited by 25 publications

(24 citation statements)

References 35 publications

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“…Enomoto et al 2002;Reimer & Pohl 2002). The supernova remnant origin would be consistent with the observed GeV excess of diffuse galactic gamma radiation from the inner Galaxy (Büsching et al 2001), although the GeV excess has been found to be present in all directions including galactic latitudes where no supernova remnants are present and the outer Galaxy (Strong et al 2004). This indicates that the origin of the GeV excess is more complex Appendices are only available in electronic form at http://www.aanda.org and is not straightforwardly connected with supernova remnants in the inner Galaxy.…”

Section: Introductionsupporting

confidence: 67%

Confinement and anisotropy of ultrahigh-energy cosmic rays in isotropic plasma wave turbulence

Vukcevic

Schlickeiser

2007

A&A

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Context. The mean free path and anisotropy of galactic cosmic rays is calculated in weak plasma wave turbulence that is isotropically distributed with respect to the ordered uniform magnetic field. Aims. The modifications on the value of the Hillas energy, above which cosmic rays are not confined to the Galaxy, are calculated. The original determination of the Hillas limit has been based on the case of slab turbulence where only parallel propagating plasma waves are allowed. Methods. We use quasilinear cosmic ray Fokker-Planck coefficients to calculate the mean free path and the anisotropy in isotropic plasma wave turbulence. Results. In isotropic plasma wave turbulence the Hillas limit is enhanced by about four orders of magnitude to E c = 2.03 × 10 5 An 1/2 e (L max /10 pc) PeV resulting from the dominating influence of transit-time damping interactions of cosmic rays with obliquely propagating magnetosonic waves. Conclusions. Below the energy E c the cosmic ray mean free path and the anisotropy exhibit the well known E 1/3 energy dependence. At energies higher than E c both transport parameters steepen to a E 3 -dependence. This implies that cosmic rays even with ultrahigh energies of several hundreds of EeV can be rapidly pitch-angle scattered by interstellar plasma turbulence, and are thus confined to the Galaxy.

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Section: Introductionsupporting

confidence: 67%

Confinement and anisotropy of ultrahigh-energy cosmic rays in isotropic plasma wave turbulence

Vukcevic

Schlickeiser

2007

A&A

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“…The local GCR spectrum (and therefore presumably the local composition, confinement time, etc.) may, however, not be typical of the Milky Way as a whole (Buesching et al 2001). There remain some interesting uncertainties in the rate at which GCRs diffuse through the galaxy (Lerche & Schlickeiser 2001), much slower when turbulence is parallel to the magnetic field, which we suppose would encourage the persistence of regional fluctuations.…”

Section: Too Medium?mentioning

confidence: 99%

Astrophysics in 2002

Trimble

Aschwanden

2003

PUBL ASTRON SOC PAC

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ABSTRACT. This has been the Year of the Baryon. Some low temperature ones were seen at high redshift, some high temperature ones were seen at low redshift, and some cooling ones were (probably) reheated. Astronomers saw the back of the Sun (which is also made of baryons), a possible solution to the problem of ejection of material by Type II supernovae (in which neutrinos push out baryons), the production of R Coronae Borealis stars (previously-owned baryons), and perhaps found the missing satellite galaxies (whose failing is that they have no baryons). A few questions were left unanswered for next year, and an attempt is made to discuss these as well.

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“…2? Enomoto et al have used a power-law proton spectrum with high-energy cut-off (s = 2.08, E c 50 TeV) to calculate the γ-ray spectrum. We have used a scaling model for the nucleon-nucleon interactions (Büsching et al 2001) to realistically investigate what proton spectra would have a γ-ray yield in accord with that observed. As a result we find that a lowenergy cut-off must be imposed on the proton spectrum with E 1 100 GeV (for s = 2).…”

Section: Discussionmentioning

confidence: 99%

No evidence yet for hadronic TeV gamma-ray emission from SNR RX J1713.7-3946

Reimer

Pohl

2002

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Abstract. Recent TeV-scale γ-ray observations with the CANGAROO II telescope have led to the claim that the multi-band spectrum of RX J1713.7−3946 cannot be explained as the composite of a synchrotron and an inverse Compton component emitted by a population of relativistic electrons. It was argued that the spectrum of the high-energy emission is a good match to that predicted by pion decay, thus providing observational evidence that protons are accelerated in SNR to at least TeV energies. In this Letter we discuss the multi-band spectrum of RX J1713.7−3946 under the constraint that the GeV-scale emission observed from the closely associated EGRET source 3EG J1714−3857 is either associated with the SNR or an upper limit to the gamma-ray emission of the SNR. We find that the pion-decay model adopted by Enomoto et al. is in conflict with the existing GeV data. We have examined the possibility of a modified proton spectrum to explain the data, and find that we cannot do so within any existing theoretical framework of shock acceleration models.

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Excess GeV radiation and cosmic ray origin

Cited by 25 publications

References 35 publications

Confinement and anisotropy of ultrahigh-energy cosmic rays in isotropic plasma wave turbulence

Confinement and anisotropy of ultrahigh-energy cosmic rays in isotropic plasma wave turbulence

Astrophysics in 2002

No evidence yet for hadronic TeV gamma-ray emission from SNR RX J1713.7-3946

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