Bibcode
García-Rojas, J.; Esteban, C.; Peimbert, M.; Costado, M. T.; Rodríguez, M.; Peimbert, A.; Ruiz, M. T.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 368, Issue 1, pp. 253-279.
Advertised on:
5
2006
Citations
104
Refereed citations
86
Description
We present deep echelle spectrophotometry of the Galactic HII regions
M16, M20 and NGC 3603. The data have been taken with the Very Large
Telescope Ultraviolet-Visual Echelle Spectrograph in the 3100-10400
Å range. We have detected more than 200 emission lines in each
region. Physical conditions have been derived using different continuum
and line intensity ratios. We have derived He+,
C++ and O++ abundances from pure recombination
lines as well as collisionally excited lines (CELs) for a large number
of ions of different elements. We have obtained consistent estimations
of the temperature fluctuation parameter, t2, using different
methods. We also report the detection of deuterium Balmer lines up to
Dδ (M16) and to Dγ (M20) in the blue wings of the hydrogen
lines, which excitation mechanism seems to be continuum fluorescence.
The temperature fluctuation paradigm agrees with the results obtained
from optical CELs, and the more uncertain ones from far-infrared
fine-structure CELs in NGC 3603, although, more observations covering
the same volume of the nebula are necessary to obtain solid conclusions.