Bibcode
Mesa-Delgado, A.; Núñez-Díaz, M.; Esteban, C.; López-Martín, L.; García-Rojas, J.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 417, Issue 1, pp. 420-433.
Fecha de publicación:
10
2011
Número de citas
21
Número de citas referidas
20
Descripción
We present integral field spectroscopy of two selected zones in the
Orion nebula obtained with the Potsdam Multi-Aperture Spectrophotometer,
covering the optical spectral range from 3500 to 7200 Å and with a
spatial resolution of 1 arcsec. The observed zones are located on the
prominent Bright bar and on the brightest area at the north-east of the
Orion south cloud, both containing remarkable ionization fronts. We
obtain maps of emission-line fluxes and ratios, electron density and
temperatures, and chemical abundances. We study the ionization structure
and morphology of both fields, whose ionization fronts show different
inclination angles with respect to the plane of the sky. We find that
the maps of electron density, O+/H+ and O/H ratios
show a rather similar structure. We interpret this as produced by the
strong dependence on density of the [O II] lines used to derive the
O+ abundance, and that our nominal values of electron density
- derived from the [S II] line ratio - may be slightly higher than the
appropriate value for the O+ zone. We measure the faint
recombination lines of O II in the field at the north-east of the Orion
south cloud, allowing us to explore the so-called abundance discrepancy
problem. We find a rather constant abundance discrepancy across the
field and a mean value similar to that determined in other areas of the
Orion nebula, indicating that the particular physical conditions of this
ionization front do not contribute to this discrepancy. Based on
observations collected at the Centro Astronómico Hispano
Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck
Institut für Astronomie and the Instituto de Astrofísica de
Andalucía (CSIC).
Proyectos relacionados
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