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Paper: A Method for Visualizing Time Variability in X-Ray Images
Volume: 77, Astronomical Data Analysis Software and Systems IV
Page: 117
Authors: Giommi, P.; White, N. E.; Angelini, L.
Abstract: We present a new method for visualizing flux variations in X-ray images. Starting from event list files, images are created where the pixel intensity is proportional to the probability that a strong variation in flux (approximately a factor 2 or more) occurred during the observation. The method is based on the Kolmogorov-Smirnov test and is not sensitive to data interruptions due to temporary loss of telemetry, earth occultations etc. Since only strong variations can be detected this approach is also insensitive to most spurious events induced by satellite pointing instability. This method has been implemented within the XIMAGE package and was used during a systematic analysis of all publicly available ROSAT PSPC images. The results of this analysis were used to construct the WGA catalog of X-ray sources. In this paper we describe the method and give some specific examples. The results presented here make use of the ROSAT PSPC data obtained from the ROSAT public archive accessible via the ESIS or the HEASARC systems.
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