The CFA BATSE IMAGE SEARCH (CBIS) as used for a Galactic plane survey

The CFA BATSE IMAGE SEARCH (CBIS) system allows automated analysis of large sets of BATSE images. CBIS is being used to conduct a deep survey of the Galactic plane to search for faint transients (∼100 mCrab) in the archival data [2]. Furthermore, together with the earth occultation technique [3], CBIS is now applied to a real time imaging survey of the plane to discover new transients and monitor known sources. The CBIS processing is made of two sequential steps: First, the images are scanned to search for excesses. Second, the positions of all these excesses are cross-correlated to produce a list of candidate sources. In this paper, we will detail the algorithms of the scanner and the cross-correlator.