3.4 Spectral Fitting

Using XSPEC scripts supplied with AE (§5.12), the extracted spectra can be fit with the FIT_SPECTRA stage (§7.18). In the example below, the spectral band specified to be used for fitting is the PI channel range [35-548], corresponding to the approximate energy range of 0.5-8 keV. A thermal model (tbabs_vapec.xcm) is used. The spectrum is not grouped, and the C-statistic is minimized in the fit.

  idl |& tee -a AE_fitting.log
    acis_extract, 'all.srclist', /FIT_SPECTRA, /CSTAT, CHANNEL_RANGE=[35,548], $
                  MODEL_FILENAME='xspec_scripts/thermal/tbabs_vapec.xcm'

We recommend that you consider any warnings produced by AE; use grep to scan for them in the log:

  egrep -i "WARNING|ERROR" AE_fitting.log