A Search for Faint Sources of Infrared Excess in the SEIP Catalog

The Spitzer Enhanced Imaging Products catalog (SEIP) contains over 42 million sources, many of which were serendipitously imaged as a part of other projects and so have never been individually examined. The SEIP also contains the largest sample of sources detected at 24 microns fainter than 8th magnitude. Finding an excess of infrared radiation in a source's spectral energy distribution can indicate the presence of dust, which is often an indicator of an interesting evolutionary phase. So the SEIP provides a unique opportunity to find IR excess objects at 24 microns that would not have been detected in other surveys. This study built upon the work of three previous studies of infrared excess sources found in the SEIP, finding fainter objects than those surveys had been able to identify. After using the SEIP to identify sources with infrared excess at 24 microns with a signal to noise ratio greater than five, the sources were crossmatched with the Gaia database, excluding any sources without distance measurements, thereby also excluding extragalactic sources. Additionally we chose to concentrate on identifying sources outside of the Galactic plane. Of the 19,540 sources with Gaia distances, the final selection included 831 sources. The sources were then inspected visually to ensure that the fluxes of the identified sources were free from contamination by nearby objects. Finally, this dataset was cross checked with SIMBAD (Set of Identifications, Measurements, and Bibliography for Astronomical Data) to eliminate known sources of infrared excess. This catalog of new visually-vetted sources with infrared excess will provide a rich opportunity for further study by current and future infrared telescopes.