The Star Formation Histories of Two Northern LMC Fields

Abstract

Ground-based UBV photometry of two fields in the northern disk of the LMC are presented. A distance modulus of (m-M)_0 = 18.41 +/- 0.04 and an extinction of A_V = 0.30 +/- 0.05 has been calculated for these fields. The measurable star formation history of the LMC began no more than 12 Gyr ago with a strong star forming episode with [Fe/H] = -1.63 +/- 0.10 that accounted for approximately half (by mass) of the LMC's total star formation in the first 3 Gyr. The data does not give accurate star formation rates during intermediate ages, but there appears to have been a recent increase in the star formation rate in these fields, beginning approximately 2.5 Gyr ago, with the current metallicity in the region being [Fe/H] = -0.38 +/- 0.10. The two fields have had very similar star formation rates until 200 Myr ago, at which point one shows a large increase.