The Second and Third Data Releases from the UKIRT Hemisphere Survey

This paper describes the second and third data releases (DR2 and DR3, respectively) from the ongoing United Kingdom Infrared Telescope Hemisphere Survey (UHS). DR2 is primarily comprised of the K-band portion of the UHS survey, and was released to the public on 2023 June 1. DR3 mainly includes the H-band portion of the survey, with a public release scheduled for September 2025. The H- and K-band data releases complement the previous J-band data release (DR1) from 2018. The survey covers approximately 12,700 square degrees between declinations of 0° and +60° and achieves median 5σ point source sensitivities of 19.0 mag and 18.0 mag (Vega) for H and K, respectively. The data releases include images and source catalogs, which include ∼581 million H-band detections and ∼461 million K-band detections. DR2 and DR3 also include merged catalogs, created by combining J- and K-band detections (DR2) and J-, H-, and K-band detections (DR3). The DR2 merged catalog has a total of ∼513 million sources, while the DR3 merged catalog contains ∼560 million sources.