On the Photometric Accuracy of RHESSI Imaging and Spectrosocopy

Abstract

We compare the photometric accuracy of spectra and images in flares observed with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI)}spacecraft. We test the accuracy of the photometry by comparing the photon fluxes obtained in different energy ranges from the spectral-fitting software SPEX with those fluxes contained in the images reconstructed with the Clean, MEM, MEM-Vis, Pixon, and Forward-fit algorithms. We quantify also the background fluxes, the fidelity of source geometries, and spatial spectra reconstructed with the five image reconstruction algorithms. We investigate the effects of grid selection, pixel size, field-of-view, and time intervals on the quality of image reconstruction. The detailed parameters and statistics are provided in an accompanying CD-ROM and web page. We find that Forward-fit, Pixon, and Clean have a robust convergence behavior and a photometric accuracy in the order of a few percents, while MEM does not converge optimally for large degrees of freedom (for large field-of-views and/or small pixel sizes), and MEM-Vis suffers in the case of time-variable sources. This comparative study documents the current status of the RHESSI spectral and imaging software, one year after launch.

2 Figures, full version on http://www.lmsal.com/~aschwand/eprints/2003_photo/index.html

Cited by in corpus (14)

• Double Coronal Hard and Soft X-ray Source Observed by RHESSI: Evidence for Magnetic Reconnection and Particle Acceleration in Solar Flares
• Evolution of the Loop-Top Source of Solar Flares--Heating and Cooling Processes
• On the Relationship between the Continuum Enhancement and Hard X-ray Emission in a White-Light Flare
• RHESSI and TRACE observations of multiple flare activity in AR 10656 and associated filament eruption
• Impulsive Phase Coronal Hard X-ray Sources in an X3.9 Class Solar Flare
• Multiwavelength observation of a large-scale flux rope eruption above kinked mini-filament
• Double Coronal X-ray and Microwave Sources Associated With A Magnetic Breakout Solar Eruption
• Statistical study of hard X-ray emitting electrons associated with flare-related coronal jets
• RHESSI images and spectra of two small flares
• Identification of multiple hard X-ray sources in solar flares: A Bayesian analysis of the February 20 2002 event
• RHESSI Observations of Long-Duration Flares With Long-Lasting X-ray Loop-Top Sources
• Plasma dynamics in the flaring loop observed by RHESSI
• RESIK and RHESSI observations of the 20 September 2002 flare
• Energy-Containing Electrons in Solar Flares: Improving Hard X-Ray and EUV Diagnostics