Issue |
A&A
Volume 441, Number 3, October III 2005
|
|
---|---|---|
Page(s) | 981 - 997 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20053369 | |
Published online | 23 September 2005 |
A VLT study of metal-rich extragalactic H II regions
I. Observations and empirical abundances
1
Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu 96822, USA e-mail: bresolin@ifa.hawaii.edu
2
Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland e-mail: daniel.schaerer@obs.unige.ch
3
Laboratoire Astrophysique de Toulouse-Tarbes (UMR 5572), Observatoire Midi-Pyrénées, 14 avenue E. Belin, 31400 Toulouse, France
4
Instituto de Astrofísica de Andalucía (CSIC), Apdo. 3004, 18080 Granada, Spain e-mail: rosa@iaa.es
5
LUTH, Observatoire de Paris-Meudon, 5 place Jules Jansen, 92195 Meudon, France e-mail: grazyna.stasinska@obspm.fr
Received:
5
May
2005
Accepted:
3
June
2005
We have obtained spectroscopic observations from 3600 Åto
9200 Åwith FORS at the Very Large Telescope for approximately 70
H iiregions located in the spiral galaxies NGC 1232, NGC 1365,
NGC 2903, NGC 2997 and NGC 5236. These data are part of a project to
measure the chemical abundances and characterize the massive
stellar content of metal-rich extragalactic H iiregions. In this
paper we describe our dataset, and present emission line fluxes for the
whole sample. In 32 H iiregions we measure at least one of the
following auroral lines: [S ii]4072, [N ii]
5755, [S iii]
6312 and
[O ii]
7325. From these we derive electron temperatures, as well as
oxygen, nitrogen and sulphur abundances, using classical empirical
methods (both so-called “Te-based methods” and “strong line methods”).
Under the assumption that the temperature does not introduce severe
biases, we find that the most metal-rich nebulae with detected auroral
lines are found at 12 + log(O/H)
8.9, i.e. about 60%
larger than the adopted solar value. However, classical abundance determinations
in metal-rich H iiregions may be severely biased and must be tested
with realistic photoionization models. The spectroscopic observations
presented in this paper will serve as a homogeneous and high-quality
database for such purposes.
Key words: galaxies: abundances / galaxies: ISM / galaxies: stellar content
© ESO, 2005
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