An Approach to the Minimum Bandwidth of the Solar Decimetric Spikes

Thousands of spikes were observed with very high spectral resolution by the 0.6-1.5 GHz spectrometer of Yunnan Observatory on Jume 24, 2001.The special software is designed to distinguish the spikes and measure the relevant parameters.The distributions of the absolute bandwidth of these spikes are statistically analyzed in detail.76% of the total spikes have the absolute bandwidth of 1.4MHz (the spectral resolution of the instrument), hence the relative bandwidth is down to 0.1 %.This result suggests that the most spikes are due to the electron cyclotron maser mechanism (ECM).