scholarly journals On the Relationship Between Recent Measurements of Cosmic Ray Electrons, Nonthermal Radio Emission from the Galaxy, and the Solar Modulation of Cosmic Rays

1968 ◽  
Vol 21 (6) ◽  
pp. 845 ◽  
Author(s):  
WR Webber
Keyword(s):  
Cosmic Rays ◽  
Radio Emission ◽  
Electron Spectrum ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Nonthermal Radio ◽  
The Galaxy ◽  
Nonthermal Radio Emission ◽  
Modulation Parameter ◽  
The Relationship

Utilizing recent measurements of the cosmic ray electron spectrum at the Earth and the effects of solar modulation on this spectrum, possible limits on the local interstellar electron spectrum have been determined. Synchrotron emission from these interstellar electrons is then compared with the local (disk) volume emissivity of nonthermal radio emission as deduced from a study of radio intensity profiles along the galactic equator. The detailed spectrum and magnitude of radio emissivity can be reproduced from the electron spectrum only for very stringent, conditions on the magnitude of the local interstellar magnetic field, and the amount of solar modulation of cosmic rays. Specifically it is found that B -L "'" 7 !-,G, and the residual modulation parameter KR "'" 0�75 GV. If solar modulation effects on the cosmic ray electron component are negligible then an implausibly high local field of "'" 20 !-,G is required.

scholarly journals Radio haloes around galaxies and in clusters

1978 ◽  
Vol 79 ◽  
pp. 161-163
Author(s):  
V. L. Ginzburg
Keyword(s):  
Cosmic Rays ◽  
Radio Emission ◽  
Cosmic Ray ◽  
Relativistic Electrons ◽  
Radio Halo ◽  
Normal Galaxies ◽  
Extended Region ◽  
The Galaxy ◽  
Nuclear Component ◽  
Galactic Sources

The question of whether or not our and other normal galaxies have some sort of halo - an extended region containing, in particular, cosmic rays - has been discussed for no less than 25 years. Such a “cosmic ray halo” (CRH) appears as a radio-halo, although the absence of the latter is not evidence against the presence of CRH. the point is that the relativistic electrons responsible for the radio emission from the radio-halo undergo synchrotron and Compton losses which are practically absent in the case of the cosmic-ray proton-nuclear component. Possibly because the discussion concerning the existence of the radio-halo in the Galaxy has lasted for years it has acquired a particular character. the latter is clearly reflected in the report by Baldwin (1976) who emphasized that: ȜIn this discussion so far I have avoided the use of the phrase Ȝradio-haloȝ. It arouses antagonism in otherwise placid astronomers and many sought to deny its existence …ȝ Such a situation evidently reflects the difficulties that arise in detecting the radio-halo of our own Galaxy when account is taken of other confusing galactic sources as well as of the metagalactic background.

scholarly journals Radial distributions of constituents in M33, the Galaxy, and M51

1985 ◽  
Vol 106 ◽  
pp. 431-434
Author(s):  
Elly M. Berkhuijsen ◽  
Ulrich Klein
Keyword(s):  
Radio Emission ◽  
Blue Light ◽  
Column Density ◽  
Surface Brightness ◽  
Far Infrared ◽  
Abundance Ratio ◽  
Nonthermal Radio ◽  
The Galaxy ◽  
Nonthermal Radio Emission

The radial distributions of the surface brightness or column density of thermal and nonthermal radio emission, far-infrared (FIR) emission, blue light, HI and CO in the Sc galaxies M33 and M51 are compared with the corresponding distributions in the Galaxy. Information on the variation of the absorption at Hα and on the variation of the abundance ratio O/H is also shown.

scholarly journals Search for Nonthermal X-Rays from Supernova Remnant Shells

1998 ◽  
Vol 188 ◽  
pp. 117-120
Author(s):  
R. Petre ◽  
J. Keohane ◽  
U. Hwang ◽  
G. Allen ◽  
E. Gotthelf
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Cosmic Ray ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Nonthermal Radio ◽  
Cosmic Ray Acceleration ◽  
Nonthermal Radio Emission

The suggestion that the shocks of supernova remnants (SNR's) are cosmic ray acceleration sites dates back more than 40 years. While observations of nonthermal radio emission from SNR shells indicate the ubiquity of GeV cosmic ray production, there is still theoretical debate about whether SNR shocks accelerate particles up to the well-known “knee” in the primary cosmic ray spectrum at ~3,000 TeV. Recent X-ray observations of SN1006 and other SNR's may have provided the missing observational link between SNR shocks and high energy cosmic ray acceleration. We discuss these observations and their interpretation, and summarize our ongoing efforts to find evidence from X-ray observations of cosmic ray acceleration in the shells of other SNR's.

scholarly journals Global Dynamics of the Interstellar Gas, Magnetic Field, and Cosmic Rays

1978 ◽  
Vol 77 ◽  
pp. 57-65
Author(s):  
E. H. Levy
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Radio Emission ◽  
Composite System ◽  
Global Dynamics ◽  
Interstellar Gas ◽  
Dynamical Equilibrium ◽  
Nonthermal Radio ◽  
Nonthermal Radio Emission ◽  
Physical Principles

I have been asked to review the physical principles which underlie the dynamical equilibrium and stability of a composite system of gas, magnetic field, and cosmic rays. What is of particular concern here are those aspects which control the distribution of magnetic field and cosmic rays, and thus influence the morphology of galaxies as seen in nonthermal radio emission.

Some Astrophysical Implications of Recent Measurements on the Intensity of Cosmic-Ray Electrons

1968 ◽  
Vol 1 (3) ◽  
pp. 112-113 ◽  
Author(s):  
W.R. Webber
Keyword(s):  
Electron Spectrum ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
List Type ◽  
Secondary Electrons ◽  
The Earth ◽  
Thermal Radio Emission ◽  
The Galaxy ◽  
Electron Intensity ◽  
Spiral Arm

We have extended our recent measurements on the extraterrestrial cosmic ray electron spectrum, this spectrum now being determined over the energy range from ~15 MeV to 6 GeV. The extraterrestrial electron intensity between 15 MeV and 200 MeV can be determined unambiguously by studying the diurnal variation of these particles. We have also measured the effects of the 11-year solar modulation on the electrons, thus enabling the electron spectrum observed near the Earth to be extrapolated to the local region of the spiral arm. It is the purpose of this paper to relate these measurements to: (i) calculations of ‘secondary’ electrons produced by cosmic ray nuclei moving in the Galaxy; and(ii) the observations of non-thermal radio emission from disk components of the Galaxy.

Spectrum of nonthermal radio emission from the galaxy. Observations at frequencies of 200 and 375 MHz

1983 ◽  
Vol 26 (9) ◽  
pp. 769-777
Author(s):  
P. P. Belyaev ◽  
A. F. Tarasov ◽  
Yu. V. Tokarev ◽  
M. A. Yurishchev
Keyword(s):  
Radio Emission ◽  
Nonthermal Radio ◽  
The Galaxy ◽  
Nonthermal Radio Emission
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