Pile-up model for dispersed spectra

The observation of a bright X-ray source by the Chandra X-ray Observatory's High Energy Transmission Grating Spectrometer (HETGS) can be compromised by photon pile-up in the CCD leading to false absorption features in the observed spectrum. A method for removing the effects of pile-up in a dispersed grating spectrum is presented. The effectiveness of the technique is demonstrated through its application to the HETGS observation of 4U 1636-53, a bright X-ray binary system.