Mapping the star formation history of Mrk86: II. Stellar populations and   global interpretation
  In this paper, continuation of Gil de Paz et al. (Paper I), we derive the main properties of the stellar populations in the Blue Compact Dwarf galaxy Mrk86. Ages, stellar masses, metallicites and burst strengths have been obtained using the combination of Monte Carlo simulations, a maximum likelihood estimator and Cluster and Principal Component Analysis. The three stellar populations detected show well defined properties. We have studied the underlying stellar population, which shows an age between 5-13 Gyr and no significant color gradients. The intermediate aged (30 Myr old) central starburst show a very low dust extinction with high burst strength and high stellar mass content (9 10^6 M_sun). Finally, the properties of 46 low-metallicity star-forming regions were also studied. The properties derived suggest that the most recent star-forming activity in Mrk86 was triggered by the evolution of a superbubble originated at the central starburst by the energy deposition of stellar winds and supernova explosions. Finally, different mechanisms for the star formation triggering in this massive central starburst are studied, including the merging with a low mass companion and the interaction with UGC4278. 
A. Gil de Paz, J. Zamorano, J. Gallego (1) ((1) Dept. Astrofisica,   UCM)