Optimal Merging of Point Sources Extracted from Spitzer Space Telescope Data in Multiple Infrared Passbands Versus Simple General Source Association
For collating point-source flux measurements derived from multiple infrared passbands of Spitzer-Space-Telescope data -- e.g., channels 1-4 of the Infrared Array Camera (IRAC) and channels 1-3 of the Multiband Imaging Photometer for Spitzer (MIPS) -- it is best to use the `bandmerge' software developed at the Spitzer Science Center rather than the relatively simple method of general source association (GSA). The former method uses both source positions and positional uncertainties to form a chi-squared statistic that can be thresholded for optimal matching, while the latter method finds nearest neighbors across bands that fall within a user-specified radius of the primary source. Our assertion is supported by our study of completeness (C) vs. reliability (R) for the two methods, which involved MIPS-24/IRAC-1 matches in the SWIRE Chandra Deep Field South. Both methods can achieve C = 98%, but with R=92.7% for GSA vs. R=97.4% for bandmerge. With almost a factor of three lower in unreliability (1-R), bandmerge is the clear winner of this comparison.
Astronomical Data Analysis Software and Systems XVII
- Pub Date:
- August 2008