SMC-Last: Building the Point Source Catalog from Spitzer’s Last Survey of the Small Magellanic Cloud

We are extracting a catalog of point sources from Spitzer’s final two mapping epochs of the Small Magellanic Cloud (SMC). These 2017-2018 maps duplicate the footprint from the SAGE-SMC program in 2008 and were obtained at 3.6 and 4.5 µm using the Infrared Array Camera (IRAC). The new and previous epochs provide a nearly 10-year baseline of observations of the SMC. We are using SExtractor Version 2.12.4 to extract point sources at all levels of processing starting with the basic calibrated data (BCD) to the final processed maps. This approach provides consistency checks and maximizes the number of reliable sources from these final epochs. We are not using prior catalogs as inputs for the extractor in order to search for moving objects (e.g., foreground brown dwarfs) and transient phenomena. This presentation focuses on two test fields: one sparsely populated with only point sources and a second, more crowded field centered on NGC 346, which also includes nebulosity. This work is supported by NASA Award 80NSSC19K0585.