Bibcode
Knapen, J. H.
Referencia bibliográfica
Astronomy and Astrophysics, v.429, p.141-151 (2005)
Fecha de publicación:
1
2005
Revista
Número de citas
100
Número de citas referidas
73
Descripción
From Hα images of a carefully selected sample of 57 relatively
large, Northern spiral galaxies with low inclination, we study the
distribution of the Hα emission in the circumnuclear and nuclear
regions. At a resolution of around 100 parsec, we find that the nuclear
Hα emission in the sample galaxies is often peaked, and
significantly more often so among AGN host galaxies. The circumnuclear
Hα emission, within a radius of two kpc, is often patchy in
late-type, and absent or in the form of a nuclear ring in early-type
galaxies. There is no clear correlation of nuclear or circumnuclear
Hα morphology with the presence or absence of a bar in the host
galaxy, except for the nuclear rings which occur in barred hosts. The
presence or absence of close bright companion galaxies does not affect
the circumnuclear Hα morphology, but their presence does correlate
with a higher fraction of nuclear Hα peaks. Nuclear rings occur in
at least 21% (±5%) of spiral galaxies, and occur predominantly in
galaxies also hosting an AGN. Only two of our 12 nuclear rings occur in
a galaxy which is neither an AGN nor a starburst host. We confirm that
weaker bars host larger nuclear rings. The implications of these results
on our understanding of the occurrence and morphology of massive star
formation, as well as non-stellar activity, in the central regions of
galaxies are discussed.