The composition of low energy primaries withZ≥9 in cosmic radiation

Photometric mean track width measurements have been made on 81 primary particles (Z9) stopping in a nuclear emulsion stack exposed at 2.7 g/cm² of residual atmosphere at Fort Churchill, Canada. The standard deviation of the charge determinations amounts to 0.14 units of charge for oxygen and increases to 0.40 units for iron nuclei when 10 mm track is measured. The relative abundances of the nuclei in the charge interval 8Z14 are given for the energy interval 250–400 MeV/nucleon, and comparisons are performed with the results of other measurements. The VH-particles are dominated by iron. The distribution of the VH-particles seems to be consistent with the assumption that the VH-nuclei have in the mean passed through only 1.6±0.5 g/cm² interstellar matter.     

The curvature radiation of cosmic monopoles

It is shown that curvature radiation of magnetic monopole is suppressed in a plasma medium.     

The fluctuation origin of cosmic radiation

We have investigated the origin of cosmic radiation in terms of a sudden injection of particles in time, momentum and space. The appropriate boundary conditions for the various regions through which the particles pass were used. With all of the acceleration within a turbulent region, we find that the observed spectrum is explained by a continuous deceleration in which statistical fluctuations dominate. This is contradictory to the usual assumptions in which fluctuations do not play an important part. We find that the time dependent solution has an exponent of the power law spectrum that varies weakly with the momentum and time. The steady state solution shows the usual constant exponent.This work was supported by the National Aeronautics and Space Administration under Grant NsG-695.     

The dipole anisotropy of the cosmic microwave background radiation

We review the prediction, discovery and precise measurements of CMB Dipole Anisotropy, a field in which Dennis Sciama has provided important initial insight.     

Polarization of the cosmic background radiation and secondary ionization of the cosmic medium

We discuss the properties of the cosmic background polarization as predicted by secondary ionization models, and the prospects for the determination of reheating parameters from forthcoming space experiments.     

A Moon orbiting observatory for the measurement of the elemental and isotopic composition in the primary cosmic radiation

We describe a project for the measurement of elemental composition of the primary cosmic radiation to be performed by a space observatory orbiting around the Moon. The absence of atmosphere and the low intrinsic magnetic field of the Moon give access to the very low energy component of the cosmic radiation, allowing the search for rare events.The quest for antinuclei, the determination of the lunar lepton albedo and the abundance measurement of galactic radioactive clocks (Be¹⁰, C¹⁴, Al²⁶) are the major tasks of the ANTARES apparatus (ANTimatter Assessment RESearch).We report details of the instrument design, the expected performance for single detectors, their capability to accomplish the proposed measurements and the characteristics of the space mission.     

Study of the primary cosmic radiation mass composition near the “knee” from EAS data

A string-decay cascade phenomenological model that conservatively extrapolates accelerator data has been adapted to cosmic ray-air collisions. Monte Carlo simulations of extensive air showers (EAS) initiated by primary protons and nuclei have been performed. The best agreement between the predictions of this model and experimental data on spectra of electron sizes (N_e) for vertical incidence at different altitudes is found for a heavy mass composition of the cosmic rays (above the “knee” energy).     

The statistical properties of cosmic gamma-ray bursts

Recent localizations of cosmic gamma-ray bursts (GBRs) are studied taking into account the estimations of their intensities. The increase of the avergage intensity of GRBs along galactic longitudesl=220–260° andl=40–80° is found. It may be associated with the Orion spiral arm and the central region of the Galaxy. Corresponding enhancement of the number of intense GRBs for directions along the Orion arm is also found. Astrophysical conclusions from this possible galaxy-scale distribution of GRBs are discussed.     

The cosmic microwave background radiation in a non-expanding universe

During the nineteenth century, it was common for physicists to believe in the existence of a material vacuum composed of an incompressible fluid that fills the whole universe. This fluid was called the aether. Its original purpose was to provide an elastic tenuous medium for light propagation through space. Although it is well understood today that no such medium is needed for light propagation, the existence of a cosmic aether medium in space is still possible and its physical properties can be understood on models of cosmology that have nothing to do with Big-Bang cosmology. It is possible that electromagnetic radiation emitted by the cosmic aether medium has already been detected. The low-frequency electromagnetic radiation emitted by the aether is called the cosmic microwave background radiation. The present study outlines a model for an aether medium that explains the genesis of the microwave background radiation in a closed static (nonexpanding) universe. It is shown that the spectrum of the microwave background radiation is a perfect blackbody with a temperature T _rad=2.77 K in harmony with the perfect cosmological principle. It is further shown that the aether medium is opaque at radio and microwave frequencies. This particular feature of the model does not contradict any observations regarding the existence of distant radio galaxies and quasars.     

Lasting recombination and cosmic background radiation spectrum

The thermal decoupling during recombination and the endurance of this process can significantly deform the black-body background radiation spectrum even in the absence of heating sources. Observational data contradicts a flat standard universe but agrees with a low-density model and with a flat matter-antimatter symmetric universe. Evidence is presented against the presumption that matter-antimatter annibilation should necessarily produce large distortions.     

The relative energy spectra of carbon and oxygen nuclei in the primary cosmic radiation

Measurements of the energy spectra of carbon and oxygen nuclei in the primary cosmic radiation over the energy range from 140 MeV/nuc to 30 BeV/nuc are reported. An average C/O ratio of 1.11±0.02 is obtained at the top of the atmosphere. This ratio is found to be constant to within 5% over the entire energy range. The energy spectra of these two nuclei are presented and compared with earlier measurements and with satellite observations at low energies. After correction for propagational effects in 4 g/cm² of interstellar hydrogen the source C/O ratio is found to be 0.9. The astrophysical implications of this C/O ratio are discussed.     

Collisions, cosmic radiation and the colors of the Trojan asteroids

The Trojan asteroids orbit about the Lagrangian points of Jupiter and the residence times about their present location are very long for most of them. If these bodies originated in the outer Solar System, they should be mainly composed of water ice, but, in contrast with comets, all the volatiles close to the surface would have been lost long ago. Irrespective of the rotation period, and hence the surface temperature and ice sublimation rate, a dust layer exists always on the surface. We show that the timescale for resurfacing the entire surface of the Trojan asteroids is similar to that of the flattening of the red spectrum of the new dust by solar-proton irradiation. This, if the cut-off radius of the size distribution of the impacting objects is between 1 mm and 1 m and its slope is −3, for the entire size range. Therefore, the surfaces of most Trojan asteroids should be composed mainly of unirradiated dust.     

Secondary production of antiprotons in cosmic radiation

A reliable representation to the invariant cross-section for the production of antiprotons ( ) in inclusive reactions has been obtained, which fits the data extremely well from threshold to ISR energies. Using this, the production spectrum of by cosmic ray interaction with interstellar gas is calculated and is compared with other existing calculations. The equilibrium spectrum 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 /P ratio calculated here is very much smaller than the observed ratio. In view of the fact that this excess of observed /P ratio is much larger than the measured upper limits on the fraction of antimatter in the form of antinuclei, the excess /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 below a few hundred MeV to make this energy region ideally suited to look for antiprotons of primordial origin.     

Spacecraft measurement of Forbush decreases in the cosmic radiation

The Forbush decrease in the cosmic radiation has been measured by a charged-particle monitor (E _p )> 50 MeV) on board the OGO-6 satellite. For the events of June 7–10, September 27–30, and November 21–December 6, 1969, the Forbush decrease totalled 4.6, 6, and 6% in amplitude, respectively, for the Mt. Washington neutron monitor (P _c = 1.24 GV), and 5.2, 13, and 16%, respectively, for the OGO-6 charged-particle monitor in the polar region (P _c < 0.3 GB). The depression in the OGO-6 charged-particle monitor was larger at higher geomagnetic latitudes than at lower latitudes. However, for the events of June 7–10 and November 21–December 6, 1969, the Forbush decrease totalled 20 and 15% in amplitude respectively for the Pioneer 8 cosmic-ray telescope (P _c > 0.4 GV), which was at the respective distances of 1.08 AU and 1 AU from the Sun. These results indicate that the Forbush decrease has greater effects on lower-energy charged particles, the magnitude of the effect also depending on the location of the detector with respect to the modulating region.The spacecraft data near Earth also showed that, for vertical cut-off rigidities P _c 1.8 GV, the total percentage decrease in the amplitudes of the Forbush decreases can be represented by –mP _c + k, where m and k are each constant for the particular Forbush decrease but which increase with increasing Mt. Washington neutron monitor monthly average rates, an indication of a flattening of the rigidity dependence of Forbush decreases towards maximum solar modulation.     

The anomalous distribution in heliocentric longitude of solar injected cosmic radiation

Concurrent observations of the solar flare of March 12, 1969 by two spacecrafts separated in solar longitude by 38° show that the accessibility at 1 AU to cosmic ray particles is not a simple function of the relative solar longitude. The cosmic ray flux, degree of anisotropy, and rise time all indicate that the favored path for cosmic ray propagation in this event was some 40° to the east of the nominal Archimedes spiral line of force from the flare location. This is interpreted as evidence for either (a) extreme stochastical wandering of the lines of force of the interplanetary magnetic field, or (b) the redistribution of the cosmic rays in coronal magnetic fields prior to escape onto the nominal Archimedes spiral lines of force.Now at CSIRO, G.P.O. Box 124, Port Melbourne, Victoria 3207, Australia.Now at Physical Research Laboratory, Ahmedabad, India.     

Testing isotropy of cosmic microwave background radiation

We introduce new symmetry-based methods to test for isotropy in cosmic microwave background (CMB) radiation. Each angular multipole is factored into unique products of power eigenvectors, related multipoles and singular values that provide two new rotationally invariant measures mode by mode. The power entropy and directional entropy are new tests of randomness that are independent of the usual CMB power. Simulated Galactic plane contamination is readily identified. The ILC– WMAP data maps show seven axes well aligned with one another and the direction Virgo. Parameter free statistics find 12 independent cases of extraordinary axial alignment, low power entropy, or both having 5 per cent probability or lower in an isotropic distribution. Isotropy of the ILC maps is ruled out to confidence levels of better than 99.9 per cent, whether or not coincidences with other puzzles coming from the Virgo axis are included. Our work shows that anisotropy is not confined to the low l region, but extends over a much larger l range.     

Periodic variations of the cosmic radiation—III. The 27-day variation

The relation between the 27-day variation of the cosmic radiation and of the terrestrial horizontal magnetic intensity has been investigated by means of the data recorded from 1957 to 1968. The periods have a correlation of about +0.5. The cosmic radiation is undoubtedly modulated by the Sun. A persistent wave with a periodicity of approximately 27.2 days could be proved from the data of several ion chamber and neutron monitor stations, but not underground (14m w.e.). The frequency of the daily period of the cosmic radiation shows a 27.3 day variation, too. The sum total of the relative sunspot numbers has a period length of 27.4 days. Their connection with the cosmic radiation is discussed.     

UH cosmic rays and solar system material: The elements just beyond iron

The origin of the elements from Cu to As in the UH (ultra-heavy) cosmic rays is investigated and related to current concepts of the nucleosynthesis of solar system material. The charge spectrum of the UH cosmic rays in the interval 29Z60 is studied via a fully developed propagation calculation for source abundances given by solar system material, ther-process, the massive-star core helium-burnings-process, and explosive carbon burning. None of these sources considered individually can explain the cosmic ray observations. However a combination of material produced in ther-process, the core helium-burnings-process and in explosive carbon burning provides a good representation of the experimental data. The cosmic-rayr-process is found to differ from solar systemr-process events by an underproduction of the low-massr-process peaks relative to theA195 peak. The large cosmicray abundance forZ=40–44 may be due to anr-process fission component, but this explanation is by no means certain. Improved cosmic-ray data, especially for Zn–Sr, can provide limits to the various source contributions. The model described here gives a consistent picture for the origin of both the cosmic rays and the solar system elements just beyond iron, and adds additional evidence for the importance of massive stars as a site of nucleosynthesis and the birthplace of the cosmic rays.Enrico Fermi Institute.     

Studies of the correlation between the global radiation,ultraviolet radiation,cosmic radiation,sunspot number and meteorological parameters

The correlation between the ratio of the global irradiation to the extraterrestrial solar radiation (H/H ₀), and the ratio of the ultraviolet solar irradiation to the extraterrestrial solar radiation (H _u /H ₀) on a horizontal surface at Bahrain (=26°), and some terrestrial and solar parameters (the monthly average relative humidity, temperature, relative sunshine duration, cosmic radiation intensity, and sunspot number) have been studied. Moreover, the role of the solar effects and the terrestrial effects on the global and the solar ultraviolet radiation has been studied. A detailed investigation has been carried between the level of the cosmic radiation received at Bahrain and the sunspot number. It was concluded that as the solar activity increases, cosmic radiation and sunspot number play a predominant effect on the correlation of (H/H ₀) and (H _u /H ₀). Furthermore, the correlation between cosmic radiation and sunspot number also increases.