Book contents
- Frontmatter
- Contents
- Index of Participants
- Preface
- I Evidence and Implications of Anisotropy in AGN
- II Luminosity Functions and Continuum Energy Distributions
- III The Broad Line Region: Variability and Structure
- Emission Line and Continuum Variability in Active Galactic Nuclei
- Results of the LAG Monitoring Campaign
- A Relation Between the Profiles and Intensities of Broad Emission Lines
- Broad Line Profile Variability in NGC 4593
- Deconvolution of Variable Seyfert 1 Profiles
- Ultra-violet Variability of AGN
- Broad-Line Variations in NGC 5548
- NGC 4593: A Low Luminosity Compact Seyfert 1 Nucleus
- UV Continuum Origin and BLR Structure in F-9
- UV Emission Line Intensities and Variability: a Self Consistent Model for Broad-Line Emitting Gas in NGC 3783
- Non-Linear Anisotropic BLR Models
- Anisotropic Line Emission from Extended BLR's
- Active Galactic Nuclei and Nuclear Starbursts
- Rapidly Evolving Compact SNRs and the Nature of the Lag in AGNs
- Supernova Explosions in QSOs? - II
- High Metallicities in QSOs
- The Chemical Evolution of QSOs
- Non-Linearity of Ly α Response in Variable AGNs
- Implications of Broad Line Profile Diversity among AGN
- Emission Line Studies of AGN
- A Search for Velocity Shifts in QSO Broad Lines
- Broad Line Region Structure from Profile Shapes
- IV X-rays and Accretion Disks
- V Beams, Jets and Blazars
- VI Concluding Talk
NGC 4593: A Low Luminosity Compact Seyfert 1 Nucleus
from III - The Broad Line Region: Variability and Structure
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- Index of Participants
- Preface
- I Evidence and Implications of Anisotropy in AGN
- II Luminosity Functions and Continuum Energy Distributions
- III The Broad Line Region: Variability and Structure
- Emission Line and Continuum Variability in Active Galactic Nuclei
- Results of the LAG Monitoring Campaign
- A Relation Between the Profiles and Intensities of Broad Emission Lines
- Broad Line Profile Variability in NGC 4593
- Deconvolution of Variable Seyfert 1 Profiles
- Ultra-violet Variability of AGN
- Broad-Line Variations in NGC 5548
- NGC 4593: A Low Luminosity Compact Seyfert 1 Nucleus
- UV Continuum Origin and BLR Structure in F-9
- UV Emission Line Intensities and Variability: a Self Consistent Model for Broad-Line Emitting Gas in NGC 3783
- Non-Linear Anisotropic BLR Models
- Anisotropic Line Emission from Extended BLR's
- Active Galactic Nuclei and Nuclear Starbursts
- Rapidly Evolving Compact SNRs and the Nature of the Lag in AGNs
- Supernova Explosions in QSOs? - II
- High Metallicities in QSOs
- The Chemical Evolution of QSOs
- Non-Linearity of Ly α Response in Variable AGNs
- Implications of Broad Line Profile Diversity among AGN
- Emission Line Studies of AGN
- A Search for Velocity Shifts in QSO Broad Lines
- Broad Line Region Structure from Profile Shapes
- IV X-rays and Accretion Disks
- V Beams, Jets and Blazars
- VI Concluding Talk
Summary
Abstract
We present the results of a monitoring campaign of the low luminosity Seyfert 1 NGC 4593, at X-ray, ultraviolet, optical and near IR frequencies. The rapid and large amplitude fluctuations detected set interesting upper limits to the sizes of the various emitting regions. We investigate the properties of the nuclear energy distribution, its pattern of variability and the relationship between the emission processes at different frequencies. We also study the variations of the broad emission lines in relation to those of the continuum. The implications of our data are discussed. It is found that they are consistent with a very hot accretion disk illuminated by the hard X-ray source.
Observations
Repeated observations of the nucleus of NGC 4593 have been performed from the near IR to X-rays. Though the temporal density of our observations is poor, they have the advantage of a wide wavelength coverage. Besides, NGC 4593 turned out to be highly variable at all frequencies.
Results and implications
The strong and rapid variations detected in all wavebands imply that the continuum source is unusually compact: ≤ 1.1 lt-hr in the hard X-rays, ≤ 3 lt-hrs in the soft X-rays, 70 lt-hrs at 1450 Å, and 37 lt-days at 2.5 microns. The latter corresponds roughly to the dust evaporation radius (∼ 33 lt-d, Barvainis, 1987) in such a low luminosity source. Such an IR behaviour is reminiscent to that of Fairall 9, a more luminous Seyfert 1, (Clavel et al., 1989).
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- Information
- The Nature of Compact Objects in Active Galactic NucleiProceedings of the 33rd Herstmonceux Conference, held in Cambridge, July 6-22, 1992, pp. 194 - 196Publisher: Cambridge University PressPrint publication year: 1994