1999ApJ...511..686A -
Astrophys. J., 511, 686-708 (1999/February-1)
Physical conditions in the Seyfert galaxy NGC 2992.
ALLEN M.G., DOPITA M.A., TSVETANOV Z.I. and SUTHERLAND R.S.
Abstract (from CDS):
This paper presents long-slit spectral maps of the bicone-shaped extended narrow-line region (ENLR) in the Seyfert galaxy NGC 2992. We investigate the physical properties of the ENLR via emission-line diagnostics and compare the observations to shock and photoionization models for the excitation mechanism of the gas. The line ratios vary as a function of position in the ENLR, and the loci of the observed points on line ratio diagrams are shown to be most consistent with shock+precursor model grids. We consider the energetics of a nuclear ionizing source for the ENLR and perform the q-test in which the rate of ionizing photons from the nucleus is inferred from measurements of the density and ionization parameter. The q-test is shown to be invalid in the case of NGC 2992 because of the limitations of the [S II] λ6717/λ6731 density diagnostic. The excitation of the gas is shown to be broadly consistent with the kinematics, with higher [N II] λ6583/Hα present in the more dynamically active region. We also show that the pressure associated with the X-ray-emitting plasma may provide a large fraction of the pressure required to power the ENLR via shocks.
Abstract Copyright:
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Journal keyword(s):
Galaxies: Active - Galaxies: Individual: NGC Number: NGC 2992 - Galaxies: Seyfert
CDS comments:
p.689 : Standard * W485A not identified, Wolf 485A?
Simbad objects:
4
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