Observation of 17 GHz Radio Emission from X-ray Bright Points

Using observations made with the Nobeyama radio heliograph (NRH) at 17 GHz and the Yohkoh/SXT experiment, we report the first detection of 17 GHz signatures of coronal X-ray bright points (XBP's). This is also the first reported detection of flaring bright points in microwaves. We have detected four BP's at 17 GHz out of eight observed by SXT on July 31, 1992, for which we looked for 17 GHz emission. For one XBP located in a quiet mixed-polarity-region, the peak times at 17 GHz and X-rays are very similar, and both are long lasting -- at least 6 hours in duration. There is a second BP (located near an active region) which is most likely flaring also, but the time profiles in the two spectral domains are not similar. The other two 17 GHz BPs are quiescent with fluctuations superposed upon them. For the quiet region XBP, we believe that the 17 GHz emission is thermal.