Edge detection gives Chandra a sharper view of cluster astrophysics

The Chandra Source Catalog (CSC) is a general purpose virtual X-ray astrophysics facility that provides access to a carefully selected set of generally useful quantities for individual X-ray sources, and is designed to satisfy the needs of a broadbased group of scientists, including those who may be less familiar with astronomical data analysis in the X-ray regime. The first release of the CSC includes information about 94,676 distinct X-ray sources detected in a subset of public ACIS imaging observations from roughly the first eight years of the Chandra mission. This release of the catalog includes point and compact sources with observed spatial extents 30 . The catalog (1) provides access to the best estimates of the X-ray source properties for detected sources, with good scientific fidelity, and directly supports scientific analysis using the individual source data; (2) facilitates analysis of a wide range of statistical properties for classes of X-ray sources; and (3) provides efficient access to calibrated observational data and ancillary data products for individual X-ray sources, so that users can perform detailed further analysis using existing tools. The catalog includes real X-ray sources detected with flux estimates that are at least 3 times their estimated 1 uncertainties in at least one energy band, while maintaining the number of spurious sources at an acceptable level. For each source, the CSC provides commonly tabulated quantities, including source position, extent, multi-band fluxes, hardness ratios, and variability statistics, derived from the observations in which the source is detected. In addition to these traditional catalog elements, for each X-ray source the CSC includes an extensive set of file-based data products that can be manipulated interactively, including source images, event lists, light curves, and spectra from each observation in which a source is detected. This work is supported by NASA contract NAS8-03060 (CXC). Acknowledgements. Support for the development of the Chandra Source Catalog is provided by the National Aeronautics and Space Administration through the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics and Space Administration under contract NAS8-03060. a urce atalog Ian N. Evans,1 Francis A. Primin ,1 Kenny J. Glotfelty,1 Craig S. Anderson,1 Nina R. Bonaventura,1 Judy C. hen,1 John E. Davis,2 Stephen M. Doe,1 Janet D. Evans,1 Giuseppina Fabbiano,1 Elizabeth Galle,1 Daniel G. Gibbs II,1 John D. Grie ,1 Roger M. Hain,1 Diane M. Hall,3 Pet r N. Harbo,1 Xiangqun (Hel n) He,1 John C. Houck,2 Margarita Karovska,1 Vinay L. Kashyap,1 Jennifer Lauer,1 Michael L. McCollough,1 Jonathan C. McDowell,1 Joseph B. Miller,1 Arik W. Mitschang,1 Douglas L. Morgan,1 Amy E. Mossman,1 Joy S. Nichols,1 Michael A. Nowak,2 David A. Plum er,1 Brian L. Refsdal,1 Arnold H. Rots,1 Aneta Siemiginowska,1 Beth A. Sundheim,1 Michael S. Tib etts,1 David W. Van Stone,1 Sherry L. Winkelman,1 and Pan goula Zografou1 1Smithsonian Astrophysical Observatory, 2MIT Kavli Institute for Astrophysics and Space Res arch, 3North op Grumman I formation Systems