RHESSI Spectral Fits of Swift GRBs

TL;DR

This paper demonstrates how combining RHESSI and Swift-BAT data improves the accuracy of Epeak measurements in GRB spectra, addressing challenges in the Swift era.

Contribution

It introduces a joint spectral fitting method using RHESSI and Swift data, showing improved Epeak estimation over previous methods relying solely on BAT data.

Findings

Joint spectral fits for 26 GRBs with RHESSI and Swift-BAT

Bayesian Epeak estimator aligns better with measured results

Improved Epeak estimation accuracy compared to BAT-only methods

Abstract

One of the challenges of the Swift era has been accurately determining Epeak for the prompt GRB emission. RHESSI, which is sensitive from 30 keV to 17 MeV, can extend spectral coverage above the Swift-BAT bandpass. Using the public Swift data, we present results of joint spectral fits for 26 bursts co-observed by RHESSI and Swift-BAT through May 2007. We compare these fits to estimates of Epeak which rely on BAT data alone. A Bayesian Epeak estimator gives better correspondence with our measured results than an estimator relying on correlations with the Swift power law indices.