Galactic Radio Emission Research Articles

41. The spherical component of the galactic radio emission

As part of the programme of observations with the large Cambridge radio telescope, a survey of the integrated radio emission has been made using one of the four elements of the interferometer. At a wave-length of 3·7 metres this aerial has beam-widths to half-power points of 2° in right ascension and 15° in declination. The use of a long wave-length makes it possible to obtain accurate measurements of the brightness temperature of the sky in regions away from the galactic plane. It is with the radiation from these regions that this paper is primarily concerned.

Galactic Radio Emission and the Energy Released in Nuclear Collisions of Primary Cosmic-Ray Protons

Galactic Radio Emission and the Energy Released in Nuclear Collisions of Primary Cosmic-Ray Protons

Galactic Radio Emission and the Energy Released in Nuclear Collisions of Primary Cosmic-Ray Protons

Galactic Radio Emission and the Energy Released in Nuclear Collisions of Primary Cosmic-Ray Protons

Radio Emission from Novae and Supernovae

Attempts have been made to observe the radio emission at 3?5 m from two supernovae and ten novae. Kepler's star was the only reasonably certain identification. A comparison with radio observations of other supernova remnants suggests a constant ratio between the present radio emission and the maximum emission of light. It is concluded that for common novae, which are not detectable as radio sources, this ratio must be smaller than for supernovae. The galactic radio emission near the plane of the Milky Way could be largely the integrated emission of supernova remnants but common novae could not contribute appreciably.

The nature of cosmic radio emission and the origin of cosmic rays

This chapter discusses the nature of cosmic radio emission and the origin of the cosmic rays. To formulate the theory of the origin of cosmic radiation, it is necessary to have a certain amount of information related to composition, energy spectrum, and spatial distribution of the cosmic radiation outside the Earth's atmosphere, in the solar system, in the galaxy, and between galaxies. The chapter also presents the theoretical and the mathematical concepts of the magnetic bremsstrahlung nature of cosmic radio emission and the origin of cosmic rays. Cosmic radio waves emitted with a continuous spectrum consist of radiation from discrete sources and of general cosmic radio emission, which varies relatively slowly with the galactic coordinates. The general radiation can, in turn, be resolved into metagalactic and galactic components, and the galactic radio emission may be divided into thermal and nonthermal components. The chapter also explains how the total energy of relativistic electrons in the envelopes of supernovae is of the same magnitude as the energy of the optical radiation produced during the outburst.

The Distribution of the Galactic Radio Emission

The Distribution of the Galactic Radio Emission

CXXVI. The isotropic component of cosmic radio-frequency radiation

Summary Attempts have been made to interpret the observed galactic radio-emission in terms of the integrated radiation from sources having a spatial distribution similar to that of the common optical stars. It is found, however, that such models fail to explain the large intensity observed towards the direction of the galactic poles. The origin of this additional component is discussed and the two most probable explanations seem to be (a) the incidence of an isotropic component from extra-galactic sources, and (b) the existence of a new class of object having a wide spatial distribution relative to the galactic plane. The integrated radiation from normal extra-galactic nebulae is shown to be inadequate to account for the observations. An estimate has been made of the intensity likely to be produced by sources of the type associated with the collision of two galaxies, and it is shown that such sources will increase significantly the emission per unit volume. An independent figure can be derived from data o...

Cosmic Rays as the Source of General Galactic Radio Emission

The galactic radio emission is not a thermal free-free radiation of interstellar gas, as was first believed. The electronic temperature would have to be of the order of 100,000° in contradiction to all spectroscopic evidence which gives values around 10,000°. Stars could be considered as sources only under very artificial assumptions. The observed intensities, which must come from the outermost layers of stellar atmospheres, could not be blackbody radiation and might be understood only in terms of coherent plasma oscillations of extended regions. The formation and maintenance of these oscillations is hardly possible in stellar atmospheres.