The nature of the ‘knee’ in the cosmic ray energy spectrum

Erlykin, A. D.; Wolfendale, A. W.

doi:10.1088/0954-3899/32/1/001

Cited by 19 publications

(3 citation statements)

References 25 publications

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“…Another interpretation was suggested by Erlykin & Wolfendale (2006), Erlykin et al (2011), and Lagutin et al (2008) who assumed that CRs at the knee were produced by a single, recent local SN. Recently Butt (2009) summarized problems (including energies within the knee) of the conception that isolated SNRs are the main accelerators of CRs and discussed alternative scenarios of CR acceleration.…”

Section: Cr Acceleration By Snrs In the Galaxymentioning

confidence: 99%

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

Cheng

Chernyshov

Dogiel

et al. 2012

ApJ

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The Fermi Large Area Telescope has recently discovered two giant gamma-ray bubbles that extend north and south of the Galactic center with diameters and heights of the order of H ∼ 10 kpc. We suggest that the periodic star capture processes by the Galactic supermassive black hole Sgr A * , with a capture rate of τ −1 cap ∼ 3 × 10 −5 yr −1 and an energy release of W ∼ 3 × 10 52 erg per capture, can result in hot plasma injecting into the Galactic halo at a wind velocity of u ∼ 10 8 cm s −1. The periodic injection of hot plasma can produce a series of shocks. Energetic protons in the bubble are re-accelerated when they interact with these shocks. We show that for energy larger than E > 10 15 eV, the acceleration process can be better described by the stochastic second-order Fermi acceleration. We propose that hadronic cosmic rays (CRs) within the "knee" of the observed CR spectrum are produced by Galactic supernova remnants distributed in the Galactic disk. Re-acceleration of these particles in the Fermi Bubble produces CRs beyond the knee. With a mean CR diffusion coefficient in this energy range in the bubble D B ∼ 3 × 10 30 cm 2 s −1 , we can reproduce the spectral index of the spectrum beyond the knee and within it. The conversion efficiency from shock energy of the bubble into CR energy is about 10%. This model provides a natural explanation of the observed CR flux, spectral indices, and matching of spectra at the knee.

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Section: Cr Acceleration By Snrs In the Galaxymentioning

confidence: 99%

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

Cheng

Chernyshov

Dogiel

et al. 2012

ApJ

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“…Although many models have been suggested, the explanation of the origin of knee is still in strong debate due to number of uncertainties in Galactic magnetic field structure and lack of direct detections of primary cosmic rays. The sharpness of the knee energy spectra could in fact indicate the existence of a single source at knee energy level [95]. Thus, our model could serve as an alternative and relatively simple explanation of the knee appearing in the cosmic ray spectra.…”

Section: Cosmicrays From Galactic Center Black Holementioning

confidence: 79%

Fifty Years of Energy Extraction from Rotating Black Hole: Revisiting Magnetic Penrose Process

Tursunov

Dadhich

2019

Universe

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Magnetic Penrose process (MPP) is not only the most exciting and fascinating process mining the rotational energy of black hole but it is also the favored astrophysically viable mechanism for high energy sources and phenomena. It operates in three regimes of efficiency, namely low, moderate and ultra, depending on the magnetization and charging of spinning black holes in astrophysical setting. In this paper, we revisit MPP with a comprehensive discussion of its physics in different regimes, and compare its operation with other competing mechanisms. We show that MPP could in principle foot the bill for powering engine of such phenomena as ultra-high-energy cosmic rays, relativistic jets, fast radio bursts, quasars, AGNs, etc. Further, it also leads to a number of important observable predictions. All this beautifully bears out the promise of a new vista of energy powerhouse heralded by Roger Penrose half a century ago through this process, and it has today risen in its magnetically empowered version of mid 1980s from a purely thought experiment of academic interest to a realistic powering mechanism for various high-energy astrophysical phenomena.

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“…But the ARGO+WFCT finds the spectral break of the light species appears at ∼ 700 TeV [6]. Meanwhile, in the analysis with various experiments, it is found the dominant specie at the knee is likely to be the Helium [7], and measurement from GAMMA attribute the knee to the light species (P and He) [8]. Different from those, the ASγ experiment indicates the knee originates from the nuclei higher than the Helium [9].…”

Section: Introductionmentioning

confidence: 99%

Expectation on probing the origin of the cosmic ray knee with the LHAASO experiment

Jin

Yin

Chen

et al. 2019

Radiat Detect Technol Methods

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The cosmic-ray (CR) knee and the compositions contain abundant information for probing the CR's origin, acceleration and propagation mechanisms, as well as the frontier of the fundamental physics. Realizing that major proposals toward the knee's shape can be divided into two categories: the rigidity-dependent (also Z-dependent) knee and the mass-dependent (also A-dependent) knee, where the former one relates to the acceleration or the propagation mechanisms, and the other one is often associated with the new physics, it is essential to precisely measure the individual compositions. Benefit from the high altitude and hybrid detection methods, the LHAASO experiment has the ability in determining the individual component and brings us an opportunity in discriminating these two models. We test this expected ability of LHAASO from 100 TeV to 10 PeV with 3-year observation. And find the dominant component at the knee is essential to this issue, while much heavier nuclei occupying the knee leads to higher significance. In the analysis, the He-dominant knee under the A-dependent case can be recognized at the significance about 6.6 σ, while the P-dominant knee under the Z-dependent case will be classified with 2 σ significance.

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The nature of the ‘knee’ in the cosmic ray energy spectrum

Cited by 19 publications

References 25 publications

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

Fifty Years of Energy Extraction from Rotating Black Hole: Revisiting Magnetic Penrose Process

Expectation on probing the origin of the cosmic ray knee with the LHAASO experiment

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The nature of the ‘knee’ in the cosmic ray energy spectrum

Cited by 19 publications

References 25 publications

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >1015eV

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >1015eV

Fifty Years of Energy Extraction from Rotating Black Hole: Revisiting Magnetic Penrose Process

Expectation on probing the origin of the cosmic ray knee with the LHAASO experiment

Contact Info

Product

Resources

About

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV

THE FERMI BUBBLE AS A SOURCE OF COSMIC RAYS IN THE ENERGY RANGE >10¹⁵eV