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Astron. Astrophys. 361, 465-479 (2000)

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5. Summary and conclusions

The main conclusions derived from this work are summarized hereafter.

  • The Blue Compact Dwarf galaxy Mrk 86 is constituted by three well defined stellar populations. An evolved (5-13 Gyr old) stellar component characterized by an exponential light profile, no significant color gradients and low metallicity. A massive ([FORMULA]9[FORMULA]106 [FORMULA]) central starburst, about 30 Myr old, with very low dust content and high burst strength ([FORMULA]20 per cent). And, finally, a young stellar population distributed in, at least, 46 star-forming regions. These star-forming regions are characterized by very low metallicities, burst strengths and stellar masses.

  • The distribution of the star-forming regions properties suggest that their star formation triggering is related with a large-scale mechanism. Following the models of Silich & Tenorio-Tagle (1998), we propose that the growth of a superbubble produced by the energy deposition at the galaxy central starburst led to the formation of a dense toroid of ISM mass. Then, the high gas surface densities reached produced the activation of the current star-forming activity.

  • Finally, we studied the possible triggering mechanisms for the activation of the star formation in the galaxy central starburst. Since both candidates for a distant encounter, NGC 2537A and UGC 4278, seem to be background galaxies, the merging with a low mass companion seems the most feasible explanation for this central starburst activation.

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© European Southern Observatory (ESO) 2000

Online publication: October 2, 2000