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Full-Text Articles in Physics

The Narrow-Line Region In The Seyfert 2 Galaxy Ngc 3393, Andrew J. Cooke, J. A. Baldwin, Gary J. Ferland, Hagai Netzer, Andrew S. Wilson Aug 2000

The Narrow-Line Region In The Seyfert 2 Galaxy Ngc 3393, Andrew J. Cooke, J. A. Baldwin, Gary J. Ferland, Hagai Netzer, Andrew S. Wilson

Physics and Astronomy Faculty Publications

The narrow-line region (NLR) of the Seyfert 2 galaxy NGC 3393 is dominated by a symmetric structure which appears as S-shaped arms in Hubble Space Telescope (HST) images. These arms, which occupy the central few arcseconds of the nucleus, border a linear, triple-lobed radio source. We use HST imaging and spectra, ground-based optical images, long-slit spectra, Fabry-Perot imaging spectroscopy, and VLA radio data to perform a detailed investigation of the kinematics and ionization of the line-emitting gas in NGC 3393 and of its relationship with the relativistic gas responsible for the radio emission. The excitation map [O III] …


A Look At What Is (And Isn't) Known About Quasar Broad Line Regions And How Narrow-Line Seyfert 1s Fit In, C. Martin Gaskell Jun 2000

A Look At What Is (And Isn't) Known About Quasar Broad Line Regions And How Narrow-Line Seyfert 1s Fit In, C. Martin Gaskell

Department of Physics and Astronomy: Faculty Publications

The evidence is reviewed that the Broad Line Region (BLR) probably has two distinct components located at about the same distance from the central black hole. One component, BLR II, is optically-thick, low-ionization emission at least some of which arises from a disc and the other, BLR I, is probably optically-thin emission from a more spherically symmetric halo or atmosphere. The high Fe II/Hβ ratios seen in Narrow-Line Seyfert 1 galaxies (NLS1s) are not due to strong Fe II emission, as is commonly thought, but to unusually weak Balmer emission, probably caused by higher densities. NLS1s probably differ from non-NLS1s …