Abstract
We present a stellar population study of three HII galaxies (Mrk 36, UM 408,
and UM 461) based on the analysis of new ground-based high resolution
near-infrared J, H and Kp broad-band and Br narrow-band images obtained with
Gemini/NIRI. We identify and determine relative ages and masses of the
elementary star clusters and/or star cluster complexes of the starburst regions
in each of these galaxies by comparing the colors with evolutionary synthesis
models that include the contribution of stellar continuum, nebular continuum
and emission lines. We found that the current star cluster formation efficiency
in our sample of low luminosity HII galaxies is ~10%. Therefore, most of the
recent star formation is not in massive clusters. Our findings seem to indicate
that the star formation mode in our sample of galaxies is clumpy, and that
these complexes are formed by a few massive star clusters with masses > 10^4
Mo. The age distribution of these star cluster complexes shows that the current
burst started recently and likely simultaneously over short time scales in
their host galaxies, triggered by some internal mechanism. Finally, the
fraction of the total cluster mass with respect to the low surface brightness
(or host galaxy) mass, considering our complete range in ages, is less than 1%.
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