A digital photometric survey of the magellanic clouds: First results from one million stars

We present the first results from, and a complete description of, our ongoing UBVI digital photometric survey of the Magellanic Clouds. In particular, we discuss the photometric quality and automated reduction of a CCD survey (magnitude limits, completeness, and astrometric accuracy) that covers the central 8° × 8° of the Large Magellanic Cloud (LMC) and 4° × 4° of the Small Magellanic Cloud (SMC). We discuss photometry of over 1 million stars from the initial survey observations (an area northwest of the LMC bar covering ∼2° × 1.5°) and present a deep stellar cluster catalog that contains about 45% more clusters than previously identified within this region. Of the 68 clusters found, only 12 are also identified as concentrations of "old," red clump stars. Furthermore, only three clusters are identified solely on the basis of a concentration of red clump stars, rather than as a concentration of luminous (V<21) main sequence stars. Extrapolating from the current data, we expect to obtain B and V photometry for 25 million stars, and U and I photometry for 10 and 20 million stars, respectively, over the entire survey area.