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Session 43 -- HII Regions and Star Formation in Spirals

Display presentation, Thursday, January 13, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[43.04] H II Regions in Interacting Galaxies

We present a census of H II regions in 50 pairs of interacting galaxies, carried out on CCD and ISIT narrow-band images from Kitt Peak, Lowell, and La Palma. Objects were identified objectively using peak finding at multiple Gaussian smoothing levels to allow for the fact that the larger H II regions are marginally resolved, and measured using aperture photometry. We consider statistics of the space distribution, radial distribution, and luminosity functions. Preliminary analysis shows that the enhancement in star formation is strongest not only in the nuclear regions, but in preferred annuli as well. Interactions can produce significant asymmetries in the star-formation distribution. Some interacting galaxies show flatter luminosity functions for H II regions than seen in normal galaxies, either through an excess of very luminous star-forming complexes or a change in their clumping properties. We compare the statistics of both the location and luminosity of H II regions in interacting systems to results on isolated spirals.

This work was supported by the NSF through REU grant AST-9300413 and EPSCoR grant EHR-9108761.

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