Occurrence rate of microflares in an X-ray bright point within an active region

We examine the occurrence rate of microflares (transient brightenings) in a n X-ray bright point (XBP) during the lifetime of the XBP observed with the Yohkoh soft X-ray telescope (SXT). The XBP with a size of similar to 30 " appeared near a preceding spot of NOAA 7270 on 1992 September 1 and disappe ared on 1992 September 4. The XBP produced 92 microflares during the observ ation time of the SXT. We found that the occurrence rate (number of events per hour) did not change much during the lifetime of the XBP, although the magnetic flux of the XBP changed. We also found that the frequency distribu tion of microflares as a function of the soft X-ray peak intensity shows a power law with index 1.7 +/- 0.4, which is consistent with the previously k nown index for flares and microflares based on the data for the whole Sun o r a whole active region, This result suggests that the power-law distributi on of flares holds not only for larger areas but also for smaller areas.