STAR-FORMATION IN THE LARGE MAGELLANIC CLOUD .3. A STUDY OF THE REGIONS LMC-30, LMC-45 AND LMC-61

In this paper we present the BV-CCD photometry of three stellar fields of the Large Magellanic Cloud (LMC). They are taken at the center of V-charts of the Hedge & Wright (1967) catalog after which they are nam ed. The fields under examination are LMC-30 (2 degrees North-West of t he Bar), LMC-45 (2 degrees North of the Bar) and LMC-61 (3 degrees Nor th-East of the Bar). Their color-magnitude diagrams (CMD) and luminosi ty functions (LF) are studied using the R-method of Bertelli et al. (1 992) with the aim of reconstructing the past history of star formation in these regions. We find that the bulk of star formation took place at different epochs in the three regions: about 2 Gyr ago in LMC-30, a bout 2.5 Gyr ago in LMC-45, and about 4 Gyr ago in LMC-61. These resul ts are combined with those obtained by Bertelli et al. (1992) and Vall enari et al. (1995) for other areas of the LMC and a preliminary carto graphy of the star formation history across the LMC is attempted.