Bpow - Broken Power Law

Broken Power Law

Introduction

The broken power law component models the non-thermal portion of the spectrum for a selected time interval during a flare. It fits the spectrum above approximately 25keV with a broken power law, normalized to the value of the count flux at 50keV.

Parameters

• a[0] - normalization at epivot
• a[1] - negative power law index below break
• a[2] - break energy (keV)
• a[3] - negative power law index above break

Fitting with Bpow

There are four free parameters that are allowed to vary when using Bpow to fit the non-thermal portion of a spectrum. In practice, a[1], the negative power law index below the break energy is set to -1.5 and fixed.

A broken power law fit to the count flux spectrum (top panel) and the photon flux spectrum (bottom panel)