The unWISE Catalog analyzes the unWISE coadds of the WISE images to detect two billion sources over the entire sky at 3.4 and 4.6 microns. The WISE point spread function has a full-width at half-maximum of about 6'', which coupled with the large number of sources means that many sources significantly overlap with others. To accurately model the photometry of these blended sources, we use the crowdsource (available on GitHub) analysis pipeline to simultaneously determine the positions and fluxes of all sources in the unWISE coadds. The greater depth of the unWISE coadds relative to those from the first year of the survey, combined with the crowdsource crowded-field modeling, allow the unWISE catalog to detect roughly three times as many sources as were detected in the AllWISE catalog.
The full data set is publicly available. The imaging can be conveniently browsed and inspected via the Legacy Survey viewer. The unWISE coadd images are also available. The unWISE Catalog is documented and served here.