共查询到20条相似文献,搜索用时 437 毫秒
1.
A. V. Uryson 《JETP Letters》1997,65(10):763-767
The complicated form of the cosmic-ray spectrum recorded in the energy range 1017–1020 eV by giant detector arrays is analyzed. It is shown that the spectrum in the region 1018–1019 eV is apparently identical to the injection spectrum with power-law exponent approximately equal to 3.2–3.3. The flat component
in the region (3.2–5)×1019 eV is due to the braking of extragalactic protons by relict photons. The spectrum apparently has no blackbody cutoff at energies
above 3.2×1019 eV.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 10, 729–733 (25 May 1997) 相似文献
2.
N. N. Kalmykov G. V. Kulikov V. P. Sulakov Yu. A. Fomin 《Moscow University Physics Bulletin》2009,64(5):536-540
Data on muon and electron components of extensive air showers (EAS) (obtained with the EAS MSU array) were used to derive
the primary cosmic ray (PCR) mass composition. It is shown that for energies beyond the knee at energy 3 × 1015 eV the abundance of heavy nuclei increases with energy. But at energies above 1017 eV the abundance of light nuclei starts to grow. The primary cosmic ray spectrum in the range 1015–1018 eV is analyzed. It is shown that at energies above 1017 eV the additional component appears and it differs from the bulk of Galactic cosmic rays generated by shocks in SN remnants. 相似文献
3.
We discuss the GZK horizon of protons and present a method to constrain the injection spectrum of ultrahigh energy cosmic
rays (UHECRs) from supposedly identified extragalactic sources. This method can be applied even when only one or two events
per source are observed and is based on the analysis of the probability for a given source to populate different energy bins,
depending on the actual cosmic ray injection spectral index. In particular, we show that for a typical source density of 4
× 10−5 Mpc−3, a data set of 100 events above 6 × 1019 eV allows one in 97% of all cases to distinguish a source spectrum dN/dE ∝ E
−1.1 from one with E
–2.7 at 95% confidence level.
The article is published in the original. 相似文献
4.
It is shown that a statistically significant anisotropy exists in the arrival directions of cosmic rays with energies ∼1×1017 eV and 4×1018 eV.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 5, 289–292 (10 September 1997) 相似文献
5.
L. G. Dedenko A. V. Glushkov S. P. Knurenko I. T. Makarov M. I. Pravdin I. E. Sleptsov T. M. Roganova G. F. Fedorova 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(3):296-298
The signals from particles of extensive air showers in the energy region of 1017–1020 eV in both the surface and underground scintillation detectors of the Yakutsk array are calculated using the CORSIKA 6.616
and GEANT4 software packages and compared with experimental data. It is shown that a transition from a heavy primary composition
to proton primaries at energies (1–2.6) × 1018 eV and from primary protons again to heavy primaries at energies above 1.3 × 1019 eV might be observed. 相似文献
6.
The differential energy spectrum of cosmic rays that is obtained on the basis of the measurements of Cherenkov radiation from
extensive air showers in an energy range of 1015–1020 eV is compared with the model of the propagation of primary particles in the interstellar medium with fractal properties.
It is found that the shape of the experimental spectrum is in good agreement with the shape of the calculated spectrum of
“all particles” at 1015–1018 eV. The average mass composition of cosmic rays that is calculated on the basis of five components does not contradict the
average mass composition obtained from the experimental data for several parameters in this energy range.
Original Russian Text ? S.P. Knurenko, A.A. Ivanov, A.V. Saburov, 2007, published in Pis’ma v Zhurnal éksperimental’noĭ i
Teoreticheskoĭ Fiziki, 2007, Vol. 86, No. 10, pp. 709–712. 相似文献
7.
A. V. Uryson 《Journal of Experimental and Theoretical Physics》1999,89(4):597-602
Showers with energies E>3.2×1019 eV and E≥1020 eV detected at the AGASA (Akeno, Japan), Haverah Park, and Yakutsk arrays are investigated. The question of how the identification
of sources depends on the error in determining the shower arrival directions is analyzed. Confirmation is obtained for the
conclusion in the author’s earlier work, that the principal sources of shower-driven particles are Seyfert galaxies with red
shifts z≤0.0092, which are weak emitters in the x-ray and radio ranges.
Zh. éksp. Teor. Fiz. 116, 1121–1130 (October 1999) 相似文献
8.
A. A. Ivanov S. P. Knurenko I. E. Sleptsov 《Journal of Experimental and Theoretical Physics》2007,104(6):872-886
We present a method for determining the energy of the primary particle that generates an extensive air shower (EAS) of comic rays based on measuring the total flux of Cherenkov light from the shower. Applying this method to Cherenkov light measurements at the Yakutsk EAS array has allowed us to construct the cosmic ray energy spectrum in the range 1015 ? 3 × 1019 eV. 相似文献
9.
The nonlinear scattering of an ultrashort laser pulse by free electrons is considered. The pulse is described in the “Mexican
hat” wavelet basis. The equation of motion for a charged particle in the field of a plane electromagnetic wave has an exact
solution allowing, together with the instant spectrum approximation, the calculation of the intensity of nonlinear Thomson
scattering for a high-intensity laser pulse. The spectral distribution of scattered radiation for the entire pulse duration
is found by integrating with respect to time. The maximum of the emission spectrum of a free electron calculated in 1019–1021 W/cm2 fields lies in the UV spectral region between 3 and 12 eV. A part of the continuous spectrum achieves high photon energies.
One percent of the scattered energy for the field intensity 1020 W/cm2 is concentrated in the range ħω > 2.7 × 102 eV, for a field intensity of 1021 W/cm2 in the range ħΩ > 7.9 × 102 eV, and for an intensity of 1022 W/cm2 in the range ħΩ > 2.45 × 105 eV. These results allow us to estimate nonlinear scattering as a source of hard X-rays. 相似文献
10.
A. V. Glushkov 《Journal of Experimental and Theoretical Physics》2009,109(5):770-774
The arrival directions of primary cosmic ray particles with energies E
0 ≥ 1019 eV and zenith angles θ ≤ 60° recorded on the Yakutsk array over the period 1974–2009 are analyzed. These events separated
by different time intervals are shown to have different global anisotropies. 相似文献
11.
E. N. Gudkova N. M. Nesterova N. M. Nikolskaya V. P. Pavlyuchenko 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(4):457-459
The primary cosmic ray energy spectrum at energies of 1015 to 5 × 1017 eV is presented using the results from observations by the Tien Shan HADRON array. The spectrum was obtained from the spectrum of showers according to the number of electrons using a new way of determining the parameter of spatial distribution function S of electrons. The energy spectrum can be extended to low energies up to 2 × 1013 eV using data from separate experiments at the former Tien Shan array. Conclusions are drawn regarding changes in the form of the spectrum and its chemical composition at energies over 1016 eV. The spectrum is compared to the results from the TUNKA installation. 相似文献
12.
An experiment to measure energetic neutrons and gamma rays in space was launched in the first Indian scientific satellite,Aryobhata, on April 19, 1975. From this experiment, the first measurements in space of the Earth’s albedo fiux of neutrons of energy
between 20 and 500 MeV have been made; the values obtained for two mean geomagnetic vertical cut-off rigidities of 5.6 and
17.0 GV are (6.3±0.4)×10−2 and (1.4±0.3)×10−2 neutrons cm−2 sec−1 respectively. These measurements confirm that protons arising from cosmic ray albedo neutron decay, can adequately account
for the protons in the inner radiation belt. Observations on gamma rays of energy between 0.2 and 24 MeV have enabled the
determination of the total background gamma ray flux in space as a function of latitude. This in turn has permitted useful
information on the diffuse cosmic gamma rays. We have also observed four events that showed sudden increases in the gamma
ray counting rates between 0.2 and 4.0 MeV. Observational details of these events are given. 相似文献
13.
A. V. Glushkov 《Journal of Experimental and Theoretical Physics》2010,111(1):57-63
The arrival directions of primary cosmic ray particles with energies E
0 ≥ 1017 eV and zenith angles θ ≤ 60° recorded on the Yakutsk array over the period 1974–2009 are analyzed. These events are shown
to have different anisotropies in different energy ranges. 相似文献
14.
A W Wolfendale 《Pramana》1979,12(6):631-651
Cosmic rays were discovered in 1911 but it is only now that some ideas are beginning to emerge as to their origin. This paper
will examine the present evidence concerning the origin question over the whole energy range, from 109 eV to 1020 eV.
At the lowest energies, (109–1010 eV), the new subject of gamma ray astronomy plays a crucial role and a galactic origin is favoured. At higher energies (1012–1017 eV) recent measurements of the anisotropies in arrival directions also suggest a galactic origin, although the evidence is
not as strong.
At the very highest energies it seems likely that some, at least, of the particles come from outside the galaxy although the
non-existence of the cut-off at about 6 × 1019 eV arising from interactions with the cosmological relict radiation provides a paradox. The likely future areas of advance
in this fascinating subject will be indicated.
Based on the B. B. Roy memorial lectures delivered at Calcutta University, February 1–3, 1978. 相似文献
15.
It is shown that the expected dip in the diffuse photon spectrum above the threshold of e
+
e
− pair production, i.e., at energies 1015–1017 eV, may be absent due to the synchrotron radiation by the electron component of the extragalactic ultrahigh-energy cosmic
rays (UHE CRs) in the Galactic magnetic field. The mechanism we propose requires small (<2×10−12 G) extragalactic magnetic fields and a large photon fraction in the UHE CRs. For a typical photon flux expected in top-down
scenarios of UHE CRs, the predicted flux in the region of the dip is close to the existing experimental limit. The sensitivity
of our mechanism to the extragalactic magnetic field may be used to improve existing bounds on the latter by two orders of
magnitude.
Pis’ma Zh. éksp. Teor. Fiz. 70, No. 8, 487–492 (25 October 1999)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
16.
Tadeusz Wibig 《Central European Journal of Physics》2007,5(4):528-538
A new feature in the spectrum of ultra high energy cosmic rays (UHECR) has been announced in the paper by Berezinsky, Gazizov
and Kachelrieβ. The ratio of the solution of the exact transport equation to its solution in the continuous energy loss limit
shows intriguing features which, according to the Authors, are related to the very nature of the energy loss processes of
UHECR: the very sharp second dip predicted at 6.3 × 1019 eV can be used as an energy calibration point and also as the UHECR mass indicator for big future cosmic ray experiments.
In the present paper we would like to advocate that this statement is an overinterpretation. The second dip is a result of an inappropriate approximation used, and thus it cannot help to understand the nature of UHECR in any way.
相似文献
17.
Cosmic rays of the highest energy, above the Greisen-Zatsepin-Kuzmin (GZK) cutoff of the spectrum, may originate in decays
of superheavy long-lived particles. We conjecture that these particles may be produced naturally in the early Universe from
vacuum fluctuations during inflation and may constitute a considerable fraction of cold dark matter. We predict a new cutoff
in the ultrahigh-energy cosmic ray spectrum E
cutoff<m
inflaton≈1013 GeV, the exact position of the cutoff and the shape of the cosmic ray spectrum beyond the GZK cutoff being determined by
the QCD quark/gluon fragmentation. The Pierre Auger Project installation may in principle observe this phenomenon.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 4, 255–259 (25 August 1998) 相似文献
18.
A large stack of lead-emulsion sandwich detector assembly was flown over Hyderabad, India. High energy gamma rays at the float
altitude were unambiguously identified from the cascades they induced, and their energies reliably determined by improved
methods. From an analysis of 163 gamma rays of energy ≳ 30 GeV, it is found that the differential energy spectrum is represented
by the power lawJ
r
(E)= 129·4E
−2·62±0·12 photons m−2 sr−1sec−1 GeV−1 at an effective atmospheric depth of 14·3 g cm−2; this is the first reliable balloon measurement of atmospheric gamma rays in the energy range 40–1000 GeV. After correcting
for the gamma rays radiated by the primary cosmic ray electrons, the production spectrum of gamma rays, resulting from the
collisions of cosmic ray nuclei with air nuclei, at the top of the atmosphere isP
r
(E, 0)=8·2 × 10−4 E2.60±0.09 photons g−1sr−1sec−1 GeV−1. The atmospheric propagation of the electromagnetic component due to the cascade process is also derived from the gamma ray
production spectrum. 相似文献
19.
V. P. Vlasov B. A. Trubnikov S. K. Zhdanov 《Journal of Experimental and Theoretical Physics》1997,84(2):211-220
It is shown that the two bends observed in the cosmic ray energy spectrum can be well approximated by equations derived by
assuming that cosmic rays can be generated and accelerated in plasma pinches.
Zh. éksp. Teor. Fiz. 111, 385–403 (February 1997) 相似文献
20.
E. G. Berezhko L. T. Ksenofontov 《Journal of Experimental and Theoretical Physics》1999,89(3):391-403
The kinetic theory of regular acceleration of cosmic rays in supernova remnants is used to investigate the expected chemical
composition of the rays. It is shown that the shapes of the calculated profiles of the chemical elements making up the cosmic
rays are consistent with experiment wherever the results of measurements are available. The acceleration process is accompanied
by relative enrichment of the cosmic rays with heavy elements. If the analogous property of the mechanism underlying the injection
of superthermal particles into the acceleration regime is taken into account, such enrichment supports the formation of the
required composition of cosmic rays in the energy range up to 1014–1015 eV.
Zh. éksp. Teor. Fiz. 116, 737–759 (September 1999) 相似文献