Population I Cepheids and star formation history of the Large Magellanic
  Cloud
  In this paper we study the Cepheids distribution in the Large Magellanic
Cloud (LMC) as a function of their ages using data from the OGLE III
photometric catalogue. To determine age of the Pop I Cepheids, we derived a
period-age (PA) relationship using the Cepheids found in the LMC star clusters.
We find two peaks in the period distribution at logP =0.49+/-0.01 and logP
=0.28+/-0.01 days which correspond to fundamental and first overtone pulsation
modes, respectively. Ages of the Cepheids are used to understand star formation
scenario in the LMC in last 30-600 Myr. The age distribution of the LMC
Cepheids is found to have a peak at log(Age)=8.2+/-0.1. This suggests that
major star formation event took place at about 125-200 Myr ago which may have
been triggered by a close encounter between the SMC and the LMC. Cepheids are
found to be asymmetrically distributed throughout the LMC and many of them lie
in clumpy structures along the bar. The frequency distribution of Cepheids
suggests that most of the clumps are located to the eastern side of the LMC
optical center.
