Two statistics can be used to compare the data with this model - the Cash C-statistic or a gaussian correlation statistic. The evaluation of both these statistics results in a detection significance in sigma. The equivalent probability of a one tailed normal distribution gives the probability of the detection being spurious (over the whole sky).
PSS can be run in 4 different modes, SEARCH - Search the input image for detections above a significance level specified by the user. PARAM - Test the value of source parameters at one or more points. UPLIM - As PARAM mode, but find upper limits at a specified level of confidence. UPMAP - Map the upper limit flux in a specified area. The mode is controlled by the hidden parameter MODE. For modes other than SEARCH, the value must either be specified on the command line or be given in reply to the prompt forced by the PROMPT keyword.
PARAM and UPLIM modes require input of source positions. See the topic "Source_Lists" above.