XMM-Newton Science Analysis System


esensmap (esensmap-3.13) [xmmsas_20190531_1155-18.0.0]

Description

This task creates a sensitivity map giving point source detection upper limits (vignetting corrected source count rate corresponding to the likelihood of detection as specified in the parameter file) for each image pixel. The task may either be called for individual energy bands or combinations of energy bands and instruments. The upper limits are derived by assuming Poissonian count statistics in each 3 $\times$ 3 pixel detection cell, using the exposure and background values read from the input images. It is assumed that 30% of the PSF fall into the detection cell. Likelihoods are calculated as function of raw source and background counts via the incomplete gamma function as described for eboxdetect. This simple upper limit calculation is meant as a reference point for a more detailed assessment of the sensitivity of the detection process to be determined through Monte Carlo simulations.

In the case of multiple input energy bands the upper limits are expressed in units of counts per seconds for the combined band (i.e. they refer to the detection sensitivity which would be achieved by adding up the photons observed in the individual bands). Pixels outside of the detection mask used by the eboxdetect detection task as well as pixels with zero exposure time are assigned a sensitivity value of -1.0. This also holds for pixels where - due to a failure of the esplinemap backgound task - zero or negative values occure in the input background maps.