Vth abun - Variable Thermal, Separate Abundances

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Vth Separate Abundances

Introduction

Vth - Separate Abundances can be used to model the thermal portion of the photon spectrum (from ~3keV to ~25keV) including lines produced by elements other than Iron and Nickel. This is generally used in used in cases were there is more detail in the data spectrum, for example if a detector has better resolution, such as the XRS detector on MESSENGER, then Vth- Separate Abundances may be a good fit component.

Parameters

vth abun - Optically thin thermal bremsstrahlung radiation function as differential spectrum seen at Earth in units of photon/(cm2 s keV) with separate parameters for relative abundance for Fe/Ni, Ca, S, Si

  • a[0] - Emission measure in units of 1e49 cm^(-3)
  • a[1] - KT, plasma temperature in keV
  • a[2] - Relative abundance for Iron and Nickel
  • a[3] - Relative abundance for Calcium
  • a[4] - Relative abundance for Sulfur
  • a[5] - Relative abundance for Silicon
  • a[6] - Relative abundance for Argon
  • a[7] - Relative abundance for He, C, N, O, F, Ne, Na, Mg, Al, K
    • Relative to coronal abundance for Chianti
    • Relative to solar abundance for Mewe
      • (unless user selects a different abundance table manually)
      • Keyword options: full/continuum/lines Chianti/Mewe

Fitting with Vth - Separate Abundances

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