Gamma-Ray Burst Spectroscopy with RHESSI: Scaling the Highest Epeaks
Abstract
We describe our use of the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) as a serendipitous observatory of gamma-ray bursts (GRBs). RHESSI uses nine Germanium detectors to image the Sun at hard X-ray to gamma-ray energies (3 keV - 17 MeV). These detectors are unshielded and therefore frequently receive emission from GRBs occurring within RHESSI's two pi steradian field of view. We discuss Monte Carlo simulations used to calculate RHESSI's uncalibrated off-axis response and detail systematic effects, including radiation damage in the detectors and correlations of fit parameters in the Band function. We combine RHESSI data with publicly available Swift data and present the results of joint spectral fits to several bursts. Accurate knowledge of GRB spectral parameters obtained over a wide energy band is crucial to evaluating and utilizing proposed relationships determining intrinsic burst energetics. RHESSI plays a unique role in extending the high energy spectral coverage well above the Swift upper energy threshold.
- Publication:
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AAS/High Energy Astrophysics Division #9
- Pub Date:
- September 2006
- Bibcode:
- 2006HEAD....9.1305B