Massive star formation in the central regions of spiral galaxies
Publication date: 14 March 2006
Authors: Knapen, J.H., et al.
Journal: Astronomy & Astrophysics
Context: 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 H-a line and in optical broad bands, and derive information on the morphology of massive star formation.
Methods:We obtained images with theWilliam Herschel Telescope, mostly at a spatial resolution of below one second of arc. For most galaxies, no H-a 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 H-a images. We classify the morphology of the nuclear and circumnuclear H-a emission and explore trends with host galaxy parameters.
Results: We confirm that late-type galaxies have a patchy circumnuclear appearance in H-a, 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 H-a peak, nor the circumnuclear H-a 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 H-a peak, nor on the H-a morphology around the nucleus.Link to publication