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Paper: Optimization of Aperture Photometry in the Chandra Source Catalog
Volume: 523, Astronomical Data Analysis Software and Systems XXVIII
Page: 155
Authors: Allen, C.; Miller, J. B.; Primini, F. A.
Abstract: The Chandra Source Catalog has identified over 315,000 unique sources, across 10,382 observations. The aperture photometry system was created to characterize energy and photon fluxes for these observed sources by fitting a point-spread function matrix and observed counts to calculate actual intensities. To support overlapping point-spread functions of adjacent sources, multiple sources are fitted simultaneously. Sources are fitted per observation, across all observations to create master properties, and across subsets of similar observations, using a Bayesian blocking algorithm applied to the per-observation aperture photometry results.
Populating the catalog, aperture photometry is run a great many times - approximately 2.9 million times on the current detection list. As such, optimization in the dimensions of both time and memory is crucial. Herein we will discuss the challenges and decisions made as we moved from requirements analysis, prototyping, and development into production.
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