RHESSI Microflare Statistics II. X-ray Imaging, Spectroscopy & Energy Distributions

Abstract

We present X-ray imaging and spectral analysis of all microflares the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observed between March 2002 and March 2007, a total of 25,705 events. These microflares are small flares, from low GOES C Class to below A Class (background subtracted) and are associated with active regions. They were found by searching the 6-12 keV energy range during periods when the full sensitivity of RHESSI's detectors was available (see paper I). Each microflare is automatically analyzed at the peak time of the 6-12 keV emission: the thermal source size is found by forward-fitting the complex visibilities for 4-8 keV, and the spectral parameters (temperature, emission measure, power-law index) are found by forward fitting a thermal plus non-thermal model. The combination of these parameters allows us to present the first statistical analysis of the thermal and non-thermal energy at the peak times of microflares.

17 pages, 21 figs, ApJ

References in corpus (6)

• Temporal aspects and frequency distributions of solar soft X-ray flares
• Energy Distribution of Micro-events in the Quiet Solar Corona
• Size dependence of solar X-ray flare properties
• Microflares and Hot Component in Solar Active Regions
• First limits on the 3-200 keV X-ray spectrum of the quiet Sun using RHESSI
• Micro-events in the active and quiet solar corona

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