Brackett line spectroscopy of bursts of star formation in the nuclei of galaxies

Abstract

Br-alpha and Br-gamma lines with 7.2 arcsec spatial and 350 km/s spectral resolution have been observed in seven infrared-bright galaxies, and the measurements are used to derive the Lyman continuum flux and the luminosity resulting from young stars. By analyzing the possible range of uncertainties in various parameters of the derivations, it is shown that several of the galaxies appear to have quite extreme conditions, with OB populations that are probably more massive and, in some cases, much younger than seen locally.