> Hmm, this gets me started. I'll try your suggestions for Sherpa. But in the
> meantime I have a couple of further questions regarding what you said about
> pile-up:
>
> [...]
> > Pile-up model in Sherpa is only available for 1D analysis. The
> > modification of PSF by pile-up needs to be folded into your psf image.
>
> I'm a bit lost here: how do you propose I modify my PSF file for pile-up?
> Also it seems to me that doing things this way would force one into assuming
> that all sources have exactly the same fraction of piled-up pohtons. This
> isn't the case in my data: there are four sources affected by pile-up, with
> fluxes (and presumably piled-up fractions) that vary by about a factor 4.
>
Sorry, I do not propose any specific modification. Pile-up is a hard problem to
solve and I do not have a solution. The PSF will be modified due to pile-up
depending on the input flux and the incident spectrum of the source. So in
theory any attempt to model pile-up should be done in 3D. As far as I know such
models do not exist.
Aneta
__________________________________________________________________________
Aneta Siemiginowska Chandra X-Ray Center (CXC)
asiemiginowska@cfa.harvard.edu Harvard-Smithsonian
Center for Astrophysics
Phone:(617)-495-7243 60 Garden St. MS-4
FAX: (617)-495-7356 Cambridge, MA 02138
__________________________________________________________________________
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