Characterization of the RHESSI 3-10 keV spectrum
Abstract
We describe an empirical characterization of the RHESSI X-ray spectrum in the 3-10 keV range, using a sample of flares for which the attenuating shutters remained open. The main spectral features comprise the continuum, which we study in two broad-band ranges (F3: 2.83-5.5 keV, and F8: 7.5-10.17 keV). The lower-energy band F3 normally shows time profiles resembling those of the GOES hard channel, and the F8/F3 ratio exhibits a heating/cooling variation similar to that of the two GOES channels; in addition an impulsive component appears in the F8 channel. In between these bands lies the prominent Fe line complex. We fit the Fe excess emission to a Gaussian, using 2-sec integrations, and find values of sigma on the order of 0.3-0.4 keV for most of the RHESSI detectors. This emission feature embraces the 2-1 transitions for all of the Fe ionization states. The centroid of the Fe line feature varies significantly in energy as the flare evolves; the time variability resembles the F8 continuum more than the F3 continuum. We present statistical results for these properties of the 3-10 keV spectrum, including the systematic variation of Fe feature equivalent width.
- Publication:
-
AAS/Solar Physics Division Meeting #34
- Pub Date:
- May 2003
- Bibcode:
- 2003SPD....34.1806H