Vth - Variable Thermal

Vth

Introduction

Vth fits the thermal part of a spectrum. This usually extends from ~20keV to ~25keV. Vth fits this portion of the spectrum with a single Emission Measure and Temperature. In cases where the Fe line is present at ~6.7keV Vth can be used to fit this feature as well.

Parameters

Below is the list of parameters available to the user when fitting with vth

• a[0] em_49, emission measure units of 10^49cm^-3
• a[1] KT, plasma temperature in keV
• a[2] Relative abundance for Fe, Ni, Si, and Ca. S as well at half the deviation from 1 as Fe.
  • Relative to coronal abundance for Chianti
  • Relative to solar abundance for Mewe