H$\alpha$ and IRAS Properties of Hot Spot Galaxies
Session 31 -- Star-Forming Galaxies
Display presentation, Tuesday, 9:30-6:30, Heller Lounge Room

## [31.07] H$\alpha$ and IRAS Properties of Hot Spot Galaxies

A. C. Phillips (University of California, Santa Cruz)

H$\alpha$ luminosities of a small sample of barred hot spot'' galaxies are compared to IRAS properties. Several correlations are found, in particular between the strength of circumnuclear H$\alpha$ emission and the 25-$\mu$m enhancement, confirming the hypothesis of Hawarden et al. (1986, {MNRAS,} 221, 41P) that the excess warm'' IRAS flux in barred spirals is due to vigorous circumnuclear star formation. A simple two-component model fit to the data indicates that both Lyman-continuum and H$\alpha$ absorption are much higher in the hot spot regions than in disk HII regions. Circumnuclear star formation rates derived from corrected H$\alpha$ luminosities are an order of magnitude greater than those derived assuming properties similar to disk HII regions, and if such rates are sustained by bar-driven gas inflow imply rapid evolution of the central regions of these galaxies.