The Spectrum of the Galactic Radio Emission

Abstract

Absolute measurements of the cosmic background radiation have been made at wave-lengths of 1.7 m and 7.9 m. Scaled aerials were used in conjunction with thermally-calibrated receivers in order to make an accurate determination of the spectrum of the emission. Observations by Baldwin at a wave-length of 3.7 m have been smoothed to provide a comparison at an intermediate frequency. The spectral index, x , defined by $$T_\text A \propto \lambda^x$$ , was found to be 2.37±0.04. There are no significant departures from this value, measured over solid angles of approximately 0.2 steradians, except for regions on the galactic plane within 60° of the galactic centre. The possibility of detecting the extra-galactic component of the integrated emission by means of its spectral index is discussed and upper limits are derived.