Bibcode
Diaz, Angeles I.; Terlevich, Elena; Vilchez, Jose M.; Pagel, Bernard E. J.; Edmunds, Michael G.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society (ISSN 0035-8711), vol. 253, Nov. 15, 1991, p. 245-255. Research supported by CAICYT.
Advertised on:
11
1991
Citations
142
Refereed citations
125
Description
Spectrophotometric observations in the optical and near-infrared of six
giant H II regions in the high metallicity spiral galaxy M51 are
presented. Five of the regions are located in the spiral arms, and the
sixth one is very close to the nucleus. These observations and the
application of adequate photo-ionization models allow the determination
of the functional parameters of the regions: ionization parameter,
effective temperature of the ionizing radiation, and metallicity. The
results of this work confirm previously found trends of decreasing
ionization parameter and radiation hardness with increasing metallicity.
N/O and S/O ratios are in general higher and lower than solar,
respectively. The first trend is expected from the viewpoint of stellar
nucleosynthesis and chemical evolution theories. However, the existence
of a lower S/O ratio in regions of high metallicity, if confirmed as
real, needs to be accounted for.