The Wide-Field Near Infrared Data: Optimal Photometry in Crowded Fields

We present JHK infrared data from the UK Infrared Telescope for a subset of the regions of the MYStIX (Massive Young Star-Forming Complex Study in Infrared and X-ray) survey. Some of the data were obtained specifically for the MYStIX project, and some as part of the UKIRT Infrared Deep Sky Survey’s Galactic Plane Survey. In most of these fields crowding is a significant issue for aperture photometry, and so we have re-extracted the photometry from the processed images using an optimal extraction technique, and we describe how we adapt the optimal technique to mitigate the effects of crowding.