X-ray Source Detection Using the Wavelet Transform

We present a new method that uses the Mexican Hat wavelet transform in a particularly simple manner to detect X-ray sources. We use an iterative approach to correlate data with the Mexican Hat function and to cleanse suspected sources from the data. This allows us to estimate the background and specify a threshold for source detection in the correlation map of the original (uncleansed) data. This method is valid in the Gaussian limit of high background counts and assumes that the background does not vary over the instrument eld-of-view. Application of this method to simulated data of the ROSAT PSPC show it to detect X-ray sources more sensitively than a method in which we calculate S=N, and its use with ROSAT PSPC data of the Pleiades Cluster results in the detection of 30 X-ray sources not detected with the S=N method.