Observations on continuum emission from the Sun at 34.5 MHz

Abstract

We have made two-dimensional maps of the weak continuum emission from the Sun at 34.5 MHz during periods of little or no solar burst activity using the large Decameter Wave Radio Telescope at Gauribidanur. The half- power beam widths of the radio telescope are 26' x 40'. These observations showed that the centroid of the radio emission is some- times shifted in position from the center of the Sun by 1.5 to 2.0 R e . The maximum brightness temperatures are found to be of 6 the order of 0.5 x 10 K, and the half power widths of the brightness distributions are I 4 R , . These observations can be explained in terms of thermal emission from coronal regions of enhanced density and temperature located at distances of 1.5 to 2 Re from the center of the Sun.