STATISTICS AND PROPERTIES OF H-II REGIONS IN A SAMPLE OF GRAND DESIGNGALAXIES .1. LUMINOSITY FUNCTIONS

We present new high quality continuum-subtracted Her images of the gra nd-design galaxies NGC 157, NGC 3631, NGC 6764 and NGC 6951. We have d etermined the positions, angular sizes, and fluxes of their individual HII regions, and describe statistical properties of the HII region sa mples. We construct luminosity functions for all the HII regions in th e disc and separately for arm and interarm zones for each galaxy. The slopes of the luminosity functions for the complete sample agree well with values published for other spiral galaxies of comparable morpholo gical type. For three galaxies we determined the slopes of the luminos ity functions for the spiral arm and interarm zones separately. We fin d that for NGC 157, NGC 3631, and NGC 6951 these slopes are equal with in the errors of determination. We compare our results to those found from earlier work, specifically for M51 and NGC 6814, and discuss impl ications for massive star forming processes.