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Session 81 - Dwarf Galaxies.
Display session, Friday, January 09
Exhibit Hall,
We have obtained high spatial and spectral resolution HI synthesis images of 5 blue compact dwarf galaxies in order to investigate the regulatory role of gas density on their star formation activity. These high sensitivity, high spatial resolution maps (5\arcsec or \sim400 pc at the typical distance of this sample) provide new insights into the gas distribution and kinematics of these intrinsically compact systems. As seen in other dwarf galaxies, the HI gas extends well beyond the stellar distribution. Further, a strong correlation is found between local peaks in the HI surface density and sites of active star formation. Analysis of the HI velocity fields indicates that these systems are not simple, smoothly rotating disk galaxies, but all appear to have a significant rotational component. These observations indicate that high spatial resolution is feasible, and indeed necessary, for HI synthesis studies of gas--rich blue compact dwarf galaxies. In the future, additional high sensitivity, high resolution observations of other systems will provide a powerful probe to investigate possible metallicity effects on the empirical star formation threshold.
