Star Formation History in two fields of the Small Magellanic Cloud Bar
  The Bar is the most productive region of the Small Magellanic Cloud in terms
of star formation but also the least studied one. In this paper we investigate
the star formation history of two fields located in the SW and in the NE
portion of the Bar using two independent and well tested procedures applied to
the color-magnitude diagrams of their stellar populations resolved by means of
deep HST photometry. We find that the Bar experienced a negligible star
formation activity in the first few Gyr, followed by a dramatic enhancement
from 6 to 4 Gyr ago and a nearly constant activity since then. The two examined
fields differ both in the rate of star formation and in the ratio of recent
over past activity, but share the very low level of initial activity and its
sudden increase around 5 Gyr ago. The striking similarity between the timing of
the enhancement and the timing of the major episode in the Large Magellanic
Cloud is suggestive of a close encounter triggering star formation.
