Massive star formation in the central regions of spiral galaxies

International audienceContext: . The morphology of massive star formation in the central regions of galaxies is an important tracer of the dynamical processes that govern the evolution of disk, bulge, and nuclear activity. Aims. We present optical imaging of the central regions of a sample of 73 spiral galaxies in the Halpha line and in optical broad bands, and derive information on the morphology of massive star formation. Methods. We obtained images with the William Herschel Telescope, mostly at a spatial resolution of below one second of arc. For most galaxies, no Halpha imaging is available in the literature. We outline the observing and data reduction procedures, list basic properties, and present the I-band and continuum-subtracted Halpha images. We classify the morphology of the nuclear and circumnuclear Halpha emission and explore trends with host galaxy parameters. Results. We confirm that late-type galaxies have a patchy circumnuclear appearance in Halpha, and that nuclear rings occur primarily in spiral types Sa-Sbc. We identify a number of previously unknown nuclear rings, and confirm that nuclear rings are predominantly hosted by barred galaxies. Conclusions. Other than in stimulating nuclear rings, bars do not influence the relative strength of the nuclear Halpha peak, nor the circumnuclear Halpha morphology. Even considering that our selection criteria led to an over-abundance of galaxies with close massive companions, we do not find any significant influence of the presence or absence of a close companion on the relative strength of the nuclear Halpha peak, nor on the Halpha morphology around the nucleus