Evidence for an Unusual Source of High Radio Brightness Temperature in the Crab Nebula

Nature ◽  
1965 ◽  
Vol 207 (4992) ◽  
pp. 59-60 ◽  
Author(s):  
A. HEWISH ◽  
S. E. OKOYE
Keyword(s):  
Brightness Temperature ◽  
Crab Nebula ◽  
Radio Brightness ◽  
Radio Brightness Temperature ◽  
The Crab Nebula

scholarly journals Radial distributions of some constituents in M31, the galaxy and M33

1979 ◽  
Vol 84 ◽  
pp. 427-427
Author(s):  
Elly M. Berkhuijsen
Keyword(s):  
Brightness Temperature ◽  
Surface Density ◽  
Hii Regions ◽  
Radio Brightness ◽  
The Galaxy ◽  
Radio Brightness Temperature

The Figure shows the distributions perpendicular to the planes of the galaxies of: (a) the surface density of HI, σHI(R), (b) the surface density of HII regions, σHII(R), and (c) the radio brightness temperature, σTB(R). Details may be found in Berkhuijsen (A.A. 57, 9, 1977; Proc. IAU Symp. 77, 1978); here σHI(R) of the Galaxy was taken from Gordon and Burton (Ap. J. 208, 346, 1976) and σTB(R) of M31 has been revised. Distances to the centre are scaled with the Holmberg radius RH (21, 15 and 7.8 kpc for M31, Galaxy, M33).

scholarly journals Radio observations of the lunar atmosphere

1959 ◽  
Vol 9 ◽  
pp. 47-49
Author(s):  
B. Elsmore
Keyword(s):  
Radio Source ◽  
Crab Nebula ◽  
Large Diameter ◽  
Radio Observations ◽  
Radio Brightness ◽  
Lunar Occultation ◽  
Terrestrial Atmosphere ◽  
Accurate Position ◽  
The Crab Nebula

Observations of a lunar occultation of a radio source may provide information concerning both the distribution of radio “brightness” across the source and its accurate position. For sources of which these results are already fairly well known, observations at long wavelengths may be used to derive the density of the lunar atmosphere [1]. During recent years two such occultations have been observed at Cambridge: one, the occultation of IC 443, the large-diameter radio source in the constellation of Gemini, from which the density of the lunar atmosphere was estimated to be less than 10–12 of that of the density of the terrestrial atmosphere [2] and [3]; and two, the occultation of the Crab nebula on 1956 January 24 [4].

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