Re: Exporting unabsorbed data points

On Tue, Apr 26, 2011 at 00:06 -0400, David P. Huenemoerder wrote:
>     Fabien> But, what I would like to get now is the unabsorbed data fluxes with
>     Fabien> their errors. And I have not been able to figure out how to export
>     Fabien> those ... I guess I have missed something obvious.
[...]
>
> Doesn't flux_corr() provide the "corrected" data (with errors)?  This
> is the isis built-in function, similar to Mike's plot_unfold, in part.
> It creates an array which is the data divided by the integral of
> arf*rmf (that is, the counts divided by counts per constant flux
> model; the instrumental convolution is included).  You can then
> get_data_flux(n), and then scale by the transmission.

While it's straightforward to use flux_corr to derive
flux-corrected data and then to scale that by the transmission,
the interpretation of the result depends on what sort of data
you're looking at.

For CCD data, absorption causes the incident spectrum to vary
rapidly (exponentially) across a detector energy-resolution
element.  In that regime, one cannot avoid the integral
equation that relates the incident spectrum to the detected
counts.

But if you're looking at grating data, then the energy
resolution is no longer an issue and scaling by the
transmission should be ok.

Thanks,
-John
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