The heliocentric radial gradient in cosmic ray density and the ‘swinson’ sidereal time variation

1973 ◽  
Vol 21 (1) ◽  
pp. 133-143 ◽  
Author(s):  
D.M. Thomson
Keyword(s):  
Time Variation ◽  
Cosmic Ray ◽  
Sidereal Time ◽  
Radial Gradient ◽  
Ray Density

A two-way sidereal anisotropy

1968 ◽  
Vol 46 (10) ◽  
pp. S611-S613 ◽  
Author(s):  
K. Nagashima ◽  
H. Ueno ◽  
S. Mori ◽  
S. Sagisaka
Keyword(s):  
Time Variation ◽  
Cosmic Ray ◽  
Sidereal Time ◽  
Cosmic Ray Intensity ◽  
Data Support ◽  
Ion Chambers ◽  
Using Data ◽  
Sidereal Anisotropy

The sidereal time variation is analyzed using data for the ion chambers at Cheltenham and Christchurch for the period 1938–58 and for the meson and neutron components during the IGY. All the results derived from these three kinds of data support the existence of a two-way sidereal anisotropy, suggested by Jacklyn, which has two maxima of the cosmic-ray intensity in the directions of 8 h and 20 h S.T. (sidereal time).

Time Variation Study and Intensity Measurement for the Nearly Horizontal Cosmic Ray Muon Component

1971 ◽  
Vol 49 (15) ◽  
pp. 2079-2081 ◽  
Author(s):  
R. B. Hicks ◽  
R. W. Flint ◽  
S. Standil
Keyword(s):  
Time Variation ◽  
Cosmic Ray ◽  
Absolute Intensity ◽  
Intensity Measurement ◽  
Statistical Accuracy ◽  
Sidereal Time ◽  
Muon Component ◽  
Narrow Angle ◽  
Time Variations ◽  
East West

A narrow angle cosmic ray particle telescope was operated at Winnipeg, Manitoba for a 2-year period commencing Oct. 16, 1967. The telescope was oriented East–West and was sensitive to muons at zenith angles in the range 86° to 90°. The data were analyzed for solar and sidereal time variations; the results are consistent with zero amplitude within the statistical accuracy of the experiment. An absolute intensity was calculated and is compared with previous measurements.

scholarly journals An estimate of the time variation of the O/H radial gradient from planetary nebulae

2002 ◽  
Vol 397 (2) ◽  
pp. 667-674 ◽  
Author(s):  
W. J. Maciel ◽  
R. D. D. Costa ◽  
M. M. M. Uchida
Keyword(s):  
Time Variation ◽  
Planetary Nebulae ◽  
Radial Gradient

Evidence for Large Scale Cosmic Ray Electron Gradients in the Galaxy

1976 ◽  
Vol 3 (1) ◽  
pp. 1-6 ◽  
Author(s):  
W. R. Webber
Keyword(s):  
Large Scale ◽  
Spiral Structure ◽  
Cosmic Ray ◽  
Point Sources ◽  
Interstellar Matter ◽  
Interstellar Gas ◽  
The Galaxy ◽  
Ray Density ◽  
Γ Rays ◽  
Γ Ray

In recent years observations of γ-ray emission from the disk of the galaxy have provided a new opportunity for research into the structure of the spiral arms of our own galaxy. In Figure 1 we show a map of the structure of the disk of the galaxy as observed for γ-rays of energy > 100 MeV by the SAS-2 satellite (Fichtel et al. 1975). The angular resolution of these measurements is ~ 3°, and besides two point sources at l = 190° and 265° several features related to the spiral structure of the galaxy are evident in the data. Most of these γ-rays are believed to arise from the decay of π° mesons produced by the nuclear interactions of cosmic rays (mostly protons) with the ambient interstellar gas. As a result, the γ-ray fluxes represent a measure of the line of sight integral of the product of the cosmic ray density NCR and the interstellar matter density N1

scholarly journals Gamma rays from violent interstellar events

1989 ◽  
Vol 120 ◽  
pp. 494-499
Author(s):  
J.B.G.M. Bloemen
Keyword(s):  
Gamma Rays ◽  
High Velocity ◽  
Galactic Disk ◽  
Cosmic Ray ◽  
Point Sources ◽  
Prominent Feature ◽  
Hii Region ◽  
Ray Density ◽  
Γ Ray ◽  
High Velocity Clouds

SummaryAs an illustration of what the next generation of γ-ray telescopes may show us, an up-to-date COS-B ‘finding chart’ of potential γ-ray point sources and unexplained extended γ-ray features is presented. The latter, in particular, may be related to energetic phenomena in the interstellar medium, capable of enhancing the local cosmic-ray density. As an example, a prominent feature, extending over at least 10° — 15° almost perpendicular to the Galactic disk, is discussed in some detail, linking it to the giant HII region S54 and Complex C of high-velocity clouds.

The solar semidiurnal variation of cosmic-ray intensity 70 m.w.e. underground

1968 ◽  
Vol 46 (10) ◽  
pp. S839-S843 ◽  
Author(s):  
G. Cini-Castagnoli ◽  
M. A. Dodero ◽  
L. Andreis
Keyword(s):  
Diurnal Variation ◽  
Cosmic Ray ◽  
Fermi Acceleration ◽  
Sidereal Time ◽  
Cosmic Ray Intensity ◽  
Intensity Measurements ◽  
Hourly Data ◽  
Semidiurnal Variation ◽  
Order Of Magnitude ◽  
Different Depths

Cosmic-ray intensity measurements have been carried out during the last year at a depth of 70 m.w.e. in the Monte dei Cappuccini laboratory in Torino, using solid vertical semicubical scintillator telescopes with a total area of 2 m2. Hourly data for 245 days corrected for barometric changes have been analyzed for the solar, apparent sidereal, and antisidereal daily variations whose harmonics are as follows:[Formula: see text]The true sidereal diurnal variation is estimated to have an amplitude of 0.019% with a time of maximum at 1720 h local sidereal time. The solar diurnal variation at different depths underground follows the energy dependence calculated with Axford's theory. The solar semidiurnal variation shows instead a fairly constant value at different μ energies. Its order of magnitude agrees with that expected as a result of Fermi acceleration in collisions of primaries moving in roughly solar and antisolar directions with solar wind inhomogeneities.

The North–South Anisotropy and the Radial Density Gradient of Galactic Cosmic Rays at 1 AU

1995 ◽  
Vol 12 (2) ◽  
pp. 153-158 ◽  
Author(s):  
D. L. Hall ◽  
M. L. Duldig ◽  
J. E. Humble
Keyword(s):  
Cosmic Rays ◽  
Diurnal Variation ◽  
Density Gradient ◽  
Cosmic Ray ◽  
Ecliptic Plane ◽  
Galactic Cosmic Rays ◽  
Radial Density ◽  
Sidereal Time ◽  
Direction Parallel ◽  
The North

AbstractThe radial density gradient (Gr) of Galactic cosmic rays in the ecliptic plane points outward from the Sun. This indicates an increasing density of cosmic ray particles beyond the Earth’s orbit. Due to this gradient and the direction of the Sun’s interplanetary magnetic field (IMF) above and below the IMF wavy neutral sheet, there exists an anisotropic flow of cosmic ray particles approximately perpendicular to the ecliptic plane (i.e. in the direction parallel to BIMF × Gr). This effect is called the north–south anisotropy (ξNS) and manifests as a diurnal variation in sidereal time in the particle intensity recorded by a cosmic ray detector. By analysing the yearly averaged sidereal diurnal variation recorded by five neutron monitors and six muon telescopes from 1957 to 1990, we have deduced probable values of the average rigidity spectrum and magnitude of ξNS. Furthermore, we have used determined yearly amplitudes of ξNS to infer the magnitude of Gr for particles with rigidities in excess of 10 GV.

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