The optical gravitational lensing experiment, BVI maps of dense stellar regions. I. The Small Magellanic Cloud

We present three color, BVI maps of the Small Magellanic Cloud. The maps contain precise photometric and astrometric data for about 2.2 million stars from the central regions of the SMC bar covering approximate to 2.4 square degrees on the sky. Mean brightness of stars is derived from observations collected in the course of the OGLE-II microlensing search from about 130, 30 and 15 measurements in the I, V and B-bands, respectively. Accuracy of the zero points of photometry is about 0.01 mag, and astrometry 0.15 arcsec (with possible systematic error up to 0.7 arcsec). Color-magnitude diagrams of observed fields are also presented. The maps of the SMC are the first from the series of similar maps covering other OGLE fields: LMC, Galactic bulge and Galactic disk. The data are very well suited for many projects, particularly for the SMC which has been neglected photometrically for years. Because of potentially great impact on many astrophysical fields we decided to make the SMC data available to the astronomical community from the OGLE Internet archive.