THE FAR-INFRARED H-ALPHA CORRELATION OF EXTREME IRAS GALAXIES

Using IRAS infrared data and H-alpha CCD data for a sample of 38 far-infrared selected starburst galaxies with far-infrared luminosities ranging from 10(9) to 5 10(11) L., we find that the far-infrared and H-alpha luminosities are correlated. The average value of log(L(FIR)/L(H-alpha)0) equals 1.9 +/- 0.1. The H-alpha luminosities have been corrected for reddening using H-alpha/H-beta line ratios. The relation between the far-infrared and uncorrected H-alpha luminosities of optically selected normal galaxies and far-infrared selected starburst galaxies indicates that the dust absorption in H-alpha increases smoothly with increasing luminosities. Application of a simple starburst model to the L(FIR)/L(H-alpha)0 correlation indicates that in a starburst stars are formed up to masses of 60 M.. Star formation rates derived for these starburst galaxies range from 0.3 to 300 M.yr-1. Estimates of the available gas masses indicate that these star formation rates can be sustained for at least 10(8) yr.