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XRT HRI

The HRI model is an analytic fit to the in-flight response, performed by MPE/GSFC/SAO. The functional form is,

  PSF = A1*EXP(-0.5*(R/S1)**2) + A2*EXP(-0.5*(R/S2)**2) + A3*EXP(-R/S3)

where the radial distance R from the psf centre is in arcseconds. The constants A and S have values,

     A1 = 0.9638       S1 = 2.1858"
     A2 = 0.1798       S2 = 4.0419"
     A3 = 0.001168     S3 = 31.69"

This model provides a reasonable description of the psf out to radii of 100", but does not model the azimuthal asymmetry present within R12". The model will be updated when this effect can be parameterised.

This model does not vary with position in the field of view.

Next: RESPFILE option Up: Instrument psfs Prev: XRT PSPC