Book contents
- Frontmatter
- Contents
- Index of Participants
- Preface
- I Evidence and Implications of Anisotropy in AGN
- Evidence for Anisotropy and Unification
- Any Evidence against Unified Schemes?
- Spectropolarimetry of Cygnus A
- Spectropolarimetery of the Ultraluminous Infrared Galaxy IRAS 110548–1131
- Are there Dusty Tori in Seyfert 2 Galaxies?
- Imaging Spectrophotometry of Extended-Emission Seyfert Galaxies
- Spectroscopy of the Extended Emission Line Regions in NGC 4388
- Evidence and Implications of Anisotropy in Seyfert Galaxies
- Collimated Radiation in NGC 4151
- A Dust Ring around the Nucleus of NGC 4151
- Evolution of Narrow Line Clouds
- Star Formation in NGC 5953
- Stellar Activity in the Seyfert Nucleus of NGC 1808
- Direct Evidence for Anisotropy: Radio Maps and their Relation to Optical Morphology
- The Radio-Optical Connection in AGN
- Knots in Extragalactic Radio Jets
- Radio Emission and the Nature of Compact Objects in AGN
- The Radio Properties of Hidden Seyfert 1's: Implications for Unified Models
- Anisotropic Optical Continuum Emission in Radio Quasars
- The UV Component in Distant Radio Galaxies
- A Connection between BL Lacertæ Objects and Flat-Spectrum Radio Quasars?
- The Difference between BL Lacs and QSOs
- The Evolutionary Unified Scheme and the θ-z Plane
- II Luminosity Functions and Continuum Energy Distributions
- III The Broad Line Region: Variability and Structure
- IV X-rays and Accretion Disks
- V Beams, Jets and Blazars
- VI Concluding Talk
Spectroscopy of the Extended Emission Line Regions in NGC 4388
from I - Evidence and Implications of Anisotropy in AGN
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- Index of Participants
- Preface
- I Evidence and Implications of Anisotropy in AGN
- Evidence for Anisotropy and Unification
- Any Evidence against Unified Schemes?
- Spectropolarimetry of Cygnus A
- Spectropolarimetery of the Ultraluminous Infrared Galaxy IRAS 110548–1131
- Are there Dusty Tori in Seyfert 2 Galaxies?
- Imaging Spectrophotometry of Extended-Emission Seyfert Galaxies
- Spectroscopy of the Extended Emission Line Regions in NGC 4388
- Evidence and Implications of Anisotropy in Seyfert Galaxies
- Collimated Radiation in NGC 4151
- A Dust Ring around the Nucleus of NGC 4151
- Evolution of Narrow Line Clouds
- Star Formation in NGC 5953
- Stellar Activity in the Seyfert Nucleus of NGC 1808
- Direct Evidence for Anisotropy: Radio Maps and their Relation to Optical Morphology
- The Radio-Optical Connection in AGN
- Knots in Extragalactic Radio Jets
- Radio Emission and the Nature of Compact Objects in AGN
- The Radio Properties of Hidden Seyfert 1's: Implications for Unified Models
- Anisotropic Optical Continuum Emission in Radio Quasars
- The UV Component in Distant Radio Galaxies
- A Connection between BL Lacertæ Objects and Flat-Spectrum Radio Quasars?
- The Difference between BL Lacs and QSOs
- The Evolutionary Unified Scheme and the θ-z Plane
- II Luminosity Functions and Continuum Energy Distributions
- III The Broad Line Region: Variability and Structure
- IV X-rays and Accretion Disks
- V Beams, Jets and Blazars
- VI Concluding Talk
Summary
Abstract
We present and discuss the results of long-slit spectroscopic observations of the extended emission line regions (EELR) in NGC4388, a Seyfert 2 galaxy in which extended, off-nuclear broad Hα emission (FWZI ≈ 4000 km s−1) has been reported (Shields & Filippenko 1988). These features have been interpreted as scattered radiation from a Seyfert 1 nucleus that is obscured along our line of sight. Our spectroscopic observations cover a large fraction of the inner part of the EELR, including some of the positions where the presence of broad lines has been claimed. Broad wings in the Hα + [NII] λλ6548, 6583 complex are also present in our data but they can be explained by the superposition of several narrow components. However, we cannot, at present, exclude the possibility that an intrinsically broad component to Hα exists at some locations. The implications of our results for unified models of Seyfert galaxies are briefly discussed.
Introduction
NGC4388 is a high-inclination Seyfert 2 galaxy with bright EELR (Colina et al. 1987, Pogge 1988, Corbin et al. 1988). Radio observations reveal a double-peaked source close to the apparent optical nucleus and more extended emission aligned roughly perpendicular to the galaxy disk (Stone et al. 1988, Hummel & Saikia 1991). The axis of the cone-like, high-excitation gas is almost perpendicular to the galaxy disk and close to that of the extended radio emission (Pogge 1988, Corbin et al. 1988), suggesting that the EELR are photoionized by nuclear radiation which escapes preferentially along and around the radio axis.
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- The Nature of Compact Objects in Active Galactic NucleiProceedings of the 33rd Herstmonceux Conference, held in Cambridge, July 6-22, 1992, pp. 40 - 43Publisher: Cambridge University PressPrint publication year: 1994