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  • 1
    Electronic Resource
    Electronic Resource
    Magnetic pair production in Cygnus X-3 and a cut off in the γ -ray spectrum (1984)
    [s.l.] : Nature Publishing Group
    Nature 308 (1984), S. 828-830 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The Cygnus X-3 system consists of a pulsar in close orbit around a companion star. The companion star undergoes mass loss through a dense stellar wind. Such an outflow of gas was invoked to explain the profile of the X-ray modulation5,6. Making use of the observed value of P/P and assuming that the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/308828a0
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  • 2
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    "Women in the Ancient World: The Arethusa Papers" edited by John Peradotto and J. P. Sullivan (Book Review) (1985)
    Chicago : Periodicals Archive Online (PAO)
    Signs. 11:1 (1985:Autumn) 187 
    Details
    ISSN: 0097-9740
    Topics: Sociology
    Notes: BOOK REVIEWS
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:h305-1985-011-01-000020
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  • 3
    Electronic Resource
    Electronic Resource
    Cosmic ray antiprotons and modified closed galaxy model (1981)
    [s.l.] : Nature Publishing Group
    Nature 289 (1981), S. 267-269 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The secondary p spectrum in cosmic rays has been calculated in the past by Gaisser and Maurer4, and Badhwar et al.5 using the extensive accelerator data available for the production of p. However, these calculated spectra differ by more than a factor of two at 10 GeV and by even larger factors at ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/289267a0
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  • 4
    Electronic Resource
    Electronic Resource
    Cosmic-ray electrons and galactic radio emission—a conflict? (1977)
    [s.l.] : Nature Publishing Group
    Nature 265 (1977), S. 424-426 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We will refer first to the spectral shape of the cosmic-ray electrons expected from radio observations. It is found from the latest compilation of the radio intensity, I(v), by A. S. Webster (personal communication) between 10 and 8,000 MHz in the direction of the anticentre, that the spectrum ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/265424a0
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  • 5
    Electronic Resource
    Electronic Resource
    Cosmic Ray Electron Spectrum above 200 GeV (1969)
    [s.l.] : Nature Publishing Group
    Nature 224 (1969), S. 1290-1291 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We have explored the advantages of a pure nuclear emulsion stack in the study of high energy electrons2 by using a horizontal sandwich assembly consisting of an upper block of pure emulsion 1-8 cm thick followed by sixteen alternate layers of 600 µ?? thick emulsion pellicles and lead sheets ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2241290a0
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  • 6
    Electronic Resource
    Electronic Resource
    Relative abundance of antiprotons and antihelium in the primary cosmic radiation (1978)
    [s.l.] : Nature Publishing Group
    Nature 274 (1978), S. 137-139 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We have previously reported on the p/p in the 4.2-12.5 GeV/c range from an earlier (September 1975) balloon flight3. The present instrument, shown in Fig. 1, differs from the previous experiment in one important respect. In the present flight there were three additional position measuring multiwire ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/274137b0
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  • 7
    Electronic Resource
    Electronic Resource
    Gamma-ray astronomy and the study of electrons 〉1013 eV and bursts using an array of γ-ray detectors in space platform (1985)
    Springer
    Astrophysics and space science 112 (1985), S. 145-155 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have discussed the possiblity of employing an array of high-energy γ-ray detectors in space platform in order to achieve higher sensitivity than by using a single detector. It is shown that such a detector system can be utilized for the study of faint galactic and extragalactic sources, and for deep survey of complex regions. The array can also be operated in the γ-ray burst mode to detect bursts. The energy spectrum of bursts can be obtained over a wide range from 0.1 MeV to 50 GeV, and their direction determined accurately. Further, the array can be used for the study of cosmic-ray electrons above 1013 eV, for which there is no other technique exists today to detect them. Detection of ultra-high energy electrons would open up a new dimension in the understanding of cosmic-ray propagation in the solar neighbourhood and of the local distribution of cosmic-ray sources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00668416
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  • 8
    Electronic Resource
    Electronic Resource
    Adiabatic deceleration of secondary antiprotons in the envelopes of supernova exploding in dense clouds (1985)
    Springer
    Astrophysics and space science 110 (1985), S. 337-350 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Antiprotons ( $$\bar p$$ ) in cosmic rays are believed to be secondary particles created by the collisions of cosmic rays with interstellar gas. On the basis of the well-established models of cosmic-ray propagation. the expected flux of $$\bar p$$ in the few hundred MeV region is very small compared to the observed flux. In order to explain the observational data, we have examined the possibility of $$\bar p$$ being produced in supernova (SN) envelopes during the expansion phase and undergoing the consequent adiabatic deceleration. For this purpose, we have considered in our investigation SN explosion in dense clouds withn H=104 cm−3 to 105 cm−3. Because of this dense medium the SN remnant is decelerated within a few thousand years, and a large amount of $$\bar p$$ are produced during this period. We have calculated the $$\bar p$$ spectrum from such sources by taking into account all energy-loss processes, and examined its spectral evolution. It is shown that the $$\bar p$$ data can be well explained by this model, if about 25% of the cosmic-ray nucleons originate from such sources. The required fraction of SN explosions to occur in dense clouds is about 70%. We have also investigated in detail the influence of various energy-loss processes on the spectral evolution. Furthermore, we have examined the possibility of obtaining $$\bar p$$ spectrum with enhanced flux at low energies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00653680
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  • 9
    Electronic Resource
    Electronic Resource
    Secondary production of antiprotons in cosmic radiation (1981)
    Springer
    Astrophysics and space science 76 (1981), S. 87-103 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A reliable representation to the invariant cross-section for the production of antiprotons ( $$\bar P$$ ) in inclusive reactions has been obtained, which fits the data extremely well from threshold to ISR energies. Using this, the production spectrum of $$\bar P$$ by cosmic ray interaction with interstellar gas is calculated and is compared with other existing calculations. The equilibrium spectrum $$\bar P$$ in the Galaxy has been derived from about 100 MeV to a few hundred GeV in kinetic energy using Leaky Box Model for the propagation of cosmic rays, by taking into account all energy loss processes. It is found that $$\bar P$$ /P ratio calculated here is very much smaller than the observed ratio. In view of the fact that this excess of observed $$\bar P$$ /P ratio is much larger than the measured upper limits on the fraction of antimatter in the form of antinuclei, the excess $$\bar P$$ /P ratio has not been attributed to the existence of antimatter. Instead, it is shown that Closed Galaxy Model for the propagation of cosmic rays predicts more antiprotons than observed. Therefore, it is suggested that if cosmic rays contain about 50% new component of local origin, the resulting Closed Galaxy Model explains well the observations. The present calculations also predict too small a flux of $$\bar P$$ below a few hundred MeV to make this energy region ideally suited to look for antiprotons of primordial origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00651245
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  • 10
    Electronic Resource
    Electronic Resource
    An analysis of the longitudinal distribution of gamma rays from SAS-II data (1981)
    Springer
    Astrophysics and space science 79 (1981), S. 419-434 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An analysis of the longitudinal distribution of gamma rays from SAS-II data has been carried out using the available information on the gas distribution in the Galaxy. The overall distribution of cosmic rays in the galactic plane can be represented by an exponential function in galactocentric distance with a scale length of ∼8 kpc upto the solar circle and ∼10 kpc beyond. There is no evidence for a large gradient of the cosmic ray intensity in the outer parts of the Galaxy. The local emissivities of gamma rays in the energy regionsE γ〉100 MeV and 35 MeV〈E γ〈100 MeV are (1.73±0.27)×10−25 photon/(cm3 s nH) and (2.40±0.41)×10−25 photon/(cm3 s nH) respectively. The contribution of π°-decay gamma rays is ∼80% forE γ〉100 MeV and ∼20% at lower energies. The electron spectrum required by this analysis has a power law spectral index of about −2.7 below a few hundred MeV. The observed gas distribution towards the galactic centre would predict a gamma-ray flux larger than observed. It is suggested that the molecular gas in the central region may be in the form of dense coudlets, in which low evergy cosmic rays do not penetrate; in this case the centre should be seen as a strong source only at high energies. An analysis of the radio sky survey map of the Galaxy at 408 MHz shows thatB ⊥ varies with a scale-length of ∼40 kpc; no significance can be attached to the apparent deviation from the equipartition of energy densities between cosmic rays and magnetic field. The derived local emissivity is (1.46±0.28)×10−40 W/((m3 Hz), which corresponds toB ⊥≈5 μG. The surface brightness of radio and gamma-ray emissions in the Galaxy decreases from the centre with scale-lengths ∼6 kpc and ∼7 kpc respectively. No positive correlation can be noticed with either co-rotation radius or pattern speed, when compared with external spiral galaxies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00649438
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