Localization of GRBs by Bayesian Analysis of Data from the HETE WXM

We describe a new method of transient point source localization for coded-aperture X-ray detectors that we have applied to data from the HETE Wide-Field X-Ray Monitor (WXM). The method is based upon the calculation of the likelihood function and its interpretation as a probability density for the transient source location by an application of Bayes' Theorem. The method gives a point estimate of the source location by finding the maximum of this probability density, and credible regions for the source location by choosing suitable contours of constant probability density. We describe the application of this method to data from the WXM, and give examples of GRB localizations which illustrate the results that can be obtained using this method.