New Universal Cosmic-Ray Knee near a Magnetic Rigidity of 10 TV with the NUCLEON Space Observatory

Atkin, E.; Bulatov, V.; Dorokhov, V.; Gorbunov, I.; Filippov, S.; Grebenyuk, V.; Karmanov, D.; Kovalev, I.; Kudryashov, I.; Kurganov, A.; Merkin, M.; Панов, А. Д.; Podorozhny, D.; Polkov, D.; Porokhovoy, S.; Shumikhin, V.; Tkachenko, A.; Ткачев, Л.; Turundaevskiy, A.; Vasiliev, О.; Voronin, A.

doi:10.1134/s0021364018130015

Cited by 83 publications

(72 citation statements)

References 36 publications

(43 reference statements)

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“…Most recently, the DAMPE observation shows clearly that the proton spectrum further experiences a spectral softening at ∼ 14 TeV [22]. Hints of such spectral features were also found previously by CREAM [23] and NUCLEON measurements [24]. These new observations indicate that the structures of the energy spectra of CRs are more complicated than expected (see e.g., [25,26] for discussions).…”

Section: Introductionsupporting

confidence: 67%

Anisotropies of different mass compositions of cosmic rays

Qiao

Liu

Guo

et al. 2019

J. Cosmol. Astropart. Phys.

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The spectral hardenings of cosmic ray nuclei above ∼ 200 GV followed by softenings around 10 TV, the knee of the all-particle spectrum around PeV energies, as well as the pattern change of the amplitude and phase of the large-scale anisotropies around 100 TeV indicate the complexities of the origin and transportation of Galactic cosmic rays. It has been shown that nearby source(s) are most likely to be the cause of such spectral features of both the spectra and the anisotropies. In this work, we study the anisotropy features of different mass composition (or mass groups) of cosmic rays in this nearby source model. We show that even if the spectral features from the nearby source component is less distinctive compared with the background component from e.g., the population of distant sources, the anisotropy features are more remarkable to be identified. Measurements of the anisotropies of each mass composition (group) of cosmic rays by the space experiments such as DAMPE and HERD and the ground-based experiments such as LHAASO in the near future are expected to be able to critically test this scenario.

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Section: Introductionsupporting

confidence: 67%

Anisotropies of different mass compositions of cosmic rays

Qiao

Liu

Guo

et al. 2019

J. Cosmol. Astropart. Phys.

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“…The existing measurements of helium and other nuclei at E 10 TeV [6,8,9] suggest that the softening is also present for cosmic ray particles heavier than protons, and within the large statistical and systematic errors, the feature is again consistent with having a rigidity dependent shape, common to all particle types. More data are however required to reach a firm conclusion.…”

Section: Discussionmentioning

confidence: 61%

“…The spectral hardening for protons measured by AMS02 is centered at higher rigidity (ρ p 336 +95 −52 GV) in comparison to the PAMELA results, and has a smaller step in spectral index ∆α 0.133 +0.056 −0.037 (with α 1 2.849 +0.006 −0.005 , and α 2 2.716 +0.037 −0.056 ). Measurements of the proton spectrum above 1 TeV have been now obtained by several CR calorimeters: ATIC [5], CREAM [6], CALET [7], NUCLEON [8,9] and DAMPE [10]. The ATIC, CREAM and NUCLEON detectors cover only the energy range E 1 TeV, and therefore do not observe directly the hardening, but only the spectral shape above it.…”

Section: Measurements Of the Cr Proton Spectrummentioning

confidence: 99%

The shape of the cosmic ray proton spectrum

Lipari

Vernetto

2020

Astroparticle Physics

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Recent observations of cosmic ray protons in the energy range 10 2 -10 5 GeV have revealed that the spectrum cannot be described by a simple power law. A hardening of the spectrum around an energy of order few hundred GeV, first observed by the magnetic spectrometers PAMELA and AMS02, has now been confirmed by several calorimeter detectors (ATIC, CREAM, CALET, NUCLEON and DAMPE). These new measurements reach higher energy and indicate that the hardening corresponds to a larger step in spectral index than what estimated by the magnetic spectrometers. Data at still higher energy (by CREAM, NUCLEON and DAMPE) show that the proton spectrum undergoes a marked softening at E ≈ 10 4 GeV. Understanding the origin of these unexpected spectral features is a significant challenge for models of the Galactic cosmic rays. An important open question is whether additional features are present in the proton spectrum between the softening and the "Knee". Extensive Air Shower detectors, using unfolding procedures that require the modeling of cosmic ray showers in the atmosphere, estimated the proton flux below and around the Knee (at E 3 PeV). These results however have large systematic uncertainties and are in poor agreement with each other. The measurement in the PeV energy range, recently presented by IceTop/IceCube, indicates a proton flux higher than extrapolations of the direct measurements calculated assuming a constant slope, and therefore requires the existence of an additional spectral hardening below the Knee. A clarification of this point is very important for an understanding of the origin of the Galactic cosmic rays, and is also essential for a precise calculation of the spectra of atmospheric neutrinos in the energy range (E 10 TeV) where they constitute the foreground for the emerging astrophysical ν signal.

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“…Furthermore, the spectral hardening observed in the spectra of various nuclei [1][2][3][4][5][6][7][8][9][10][11] calls for the extensive attempts to theoretically interpret these unexpected phenomena. The current experimental approaches to direct measurements of the proton spectrum are based on two main classes of instruments, i.e., magnetic spectrometers [5,6] at lower energies where the presence of a spectral breakpoint was observed, and calorimeters [1,4,8,33,34] at higher energies where the spectrum undergoes a hardening. It is of particular interest to determine the onset of spectral hardening and its development in terms of index variation and smoothness parameter (as defined in Ref.…”

mentioning

confidence: 99%

“…In Fig. 4, the CALET spectrum is compared with recent experiments from space (PAMELA [58,59], AMS-02 [6], and NUCLEON [34]) and from the high altitude balloon experiments (BESS-TeV [60], ATIC-2 [1], CREAM-I [4], and CREAM-III [8]). Our spectrum is in good agreement with the very accurate magnetic spectrometer measurements by AMS-02 in the low-energy region, and the spectral behavior is also consistent with measurements from calorimetric instruments in the higher energy region.…”

mentioning

confidence: 99%

Direct Measurement of the Cosmic-Ray Proton Spectrum from 50 GeV to 10 TeV with the Calorimetric Electron Telescope on the International Space Station

Adriani¹,

Akaike²,

Asano³

et al. 2019

Phys. Rev. Lett.

154

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In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate subranges by magnetic spectrometers (BESS-TeV, PAMELA, and AMS-02) and calorimetric instruments (ATIC, CREAM, and NUCLEON). The observed spectrum is consistent with AMS-02 but extends to nearly an order of magnitude higher energy, showing a very smooth transition of the power-law spectral index from −2.81 AE 0.03 (50-500 GeV) neglecting solar modulation effects (or −2.87 AE 0.06 including solar modulation effects in the lower energy region) to −2.56 AE 0.04 (1-10 TeV), thereby confirming the existence of spectral hardening and providing evidence of a deviation from a single power law by more than 3σ.

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New Universal Cosmic-Ray Knee near a Magnetic Rigidity of 10 TV with the NUCLEON Space Observatory

Cited by 83 publications

References 36 publications

Anisotropies of different mass compositions of cosmic rays

Anisotropies of different mass compositions of cosmic rays

The shape of the cosmic ray proton spectrum

Direct Measurement of the Cosmic-Ray Proton Spectrum from 50 GeV to 10 TeV with the Calorimetric Electron Telescope on the International Space Station

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