Back to Volume
Paper: Cheating Poisson: A Biased Method for Detecting Faint Sources in All-Sky Survey Data
Volume: 77, Astronomical Data Analysis Software and Systems IV
Page: 327
Authors: Lewis, J. W.
Abstract: One approach to compiling a catalog of point sources from all-sky survey data is to apply a source detection algorithm to the entire data set and include in the catalog any location whose significance exceeds some minimum value. The detection threshold is generally chosen to keep the expected number of spurious detections below some more-or-less arbitrary figure; in low signal-to-noise ratio data, such as the Extreme Ultraviolet Explorer (EUVE) survey skymaps, even a small change in the detection threshold can result in an explosion of spurious detections, destroying the usefulness of the catalog. This result does not, however, imply that real sources below the limiting catalog threshold cannot be reliably detected. If one has some prior knowledge of where the real sources are likely to be found, it is possible to ``cheat Poisson'' and include these sub-threshold sources without introducing significant numbers of spurious detections. This paper describes the theoretical and practical aspects of the biased search technique as applied to EUVE all-sky survey skymaps.
Back to Volume