Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XV. Long-Term Optical Monitoring of NGC 5548
arXiv:astro-ph/9808236 · doi:10.1086/306604
Abstract
We present the results of three years of ground-based observations of the Seyfert 1 galaxy NGC 5548, which combined with previously reported data, yield optical continuum and broad-line H-beta light curves for a total of eight years. The light curves consist of over 800 points, with a typical spacing of a few days between observations. During this eight-year period, the nuclear continuum has varied by more than a factor of seven, and the H-beta emission line has varied by a factor of nearly six. The H-beta emission line responds to continuum variations with a time delay or lag of 10-20 days, the precise value varying somewhat from year to year. We find some indications that the lag varies with continuum flux in the sense that the lag is larger when the source is brighter.
29 pages, 6 figures. Accepted for publication in ApJ (1999 Jan 10)
References in corpus (4)
- On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei
- Optical Continuum and Emission-Line Variability of Seyfert 1 Galaxies
- Reverberation Mapping and the Physics of Active Galactic Nuclei
- Evidence for a Physically Compact Narrow-Line Region in the Seyfert 1 Galaxy NGC 5548
Cited by in corpus (59)
- Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
- Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei: I. Comparing the Photoionization and Reverberation Techniques
- Determining Central Black Hole Masses in Distant Active Galaxies
- Simultaneous X-ray/optical/UV snapshots of active galactic nuclei from XMM-Newton: spectral energy distributions for the reverberation mapped sample
- Keplerian Motion of Broad-Line Region Gas as Evidence for Supermassive Black Holes in Active Galactic Nuclei
- Evidence for Supermassive Black Holes in Active Galactic Nuclei from Emission-Line Reverberation
- Broad Emission Line Regions in AGN: the Link with the Accretion Power
- What the Optical Recombination Lines Can Tell Us About the Broad Line Regions of Active Galactic Nuclei
- X-Ray and Optical Variability in NGC 4051 and the Nature of Narrow-Line Seyfert 1 Galaxies
- On the Reliability of Cross Correlation Function Lag Determinations in Active Galactic Nuclei
- Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A Thirteen-Year Study of Spectral Variability in NGC 5548
- Toward a Self Consistent Model of the Ionized Absorber in NGC 3783
- Systematic Uncertainties in Black Hole Masses Determined from Single Epoch Spectra
- The effect of radiation pressure on emission line profiles and black hole mass determination in active galactic nuclei
- Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-Line Analysis for NGC 5548
- Variability in active galactic nuclei: confrontation of models with observations
- The Size of the Narrow-Line Emitting Region in the Seyfert 1 Galaxy NGC 5548 from Emission-Line Variability
- Optical--to--X-ray emission in low-absorption AGN: Results from the Swift-BAT 9 month catalogue
- Locally Optimally-Emitting Clouds and the Variable Broad Emission Line Spectrum of NGC 5548
- The Sloan Digital Sky Survey Reverberation Mapping Project: Estimating Masses of Black Holes in Quasars with Single-Epoch Spectroscopy
- Spectral Optical Monitoring of the Narrow Line Seyfert 1 galaxy Ark 564
- Evidence for periodicity in 43 year-long monitoring of NGC 5548
- Modeling Variable Emission Lines in AGNs: Method and Application to NGC 5548
- Reverberation Mapping of the Broad-line Region in NGC 5548: Evidence for Radiation Pressure?
- Profile variability of the H-alpha and H-beta broad emission lines in NGC5548
- Constraints for the accretion disk evaporation rate in AGN from the existence of the Broad Line Region
- Intermediate resolution H-beta spectroscopy and photometric monitoring of 3C 390.3 I. Further evidence of a nuclear accretion disk
- Quasar Parallax: a Method for Determining Direct Geometrical Distances to Quasars
- Optical Variability of Narrow-Line Seyfert 1 Galaxies
- Simulations of the OzDES AGN Reverberation Mapping Project
- A parallax distance to 3C 273 through spectroastrometry and reverberation mapping
- Time Dilation and Quasar Variability
- Photoionized HBeta Emission in NGC 5548: It Breathes!
- Timescale of variation and the size of the accretion disc in active galactic nuclei
- Variability of Fe II Emission Features in the Seyfert 1 Galaxy NGC 5548
- Super- and sub-Eddington accreting massive black holes: A comparison of slim and thin accretion discs through study of the spectral energy distribution
- Iron line reverberation mapping with Constellation-X
- Naked active galactic nuclei
- Determination of the Central Mass in Active Galactic Nuclei Using Cross-Correlation Lags and Velocity Dispersions
- Monitoring of the optical and 2.5-11.7 micron spectrum and mid-IR imaging of the Seyfert 1 galaxy Mrk279 with ISO
- Quasar Rain: the Broad Emission Line Region as Condensations in the Warm Accretion Disk Wind
- Astronomical Distance Determination in the Space Age. Secondary distance indicators
- Test of the Formation mechanism of the Broad Line Region in Active Galactic Nuclei
- Supermassive Black Hole and Broad-line Region in NGC~5548: Results from Five-season Reverberation Mapping
- Oscillatory patterns in the light curves of 5 long-term monitored type 1 AGN
- Emission Signatures from Sub-parsec Binary Supermassive Black Holes II: Effect of Accretion Disk Wind on Broad Emission Lines
- Far Ultraviolet Spectroscopic Explorer Observations of the Seyfert 1.5 Galaxy NGC 5548 in a Low State
- Colour changes in quasar light curves
- Active Galactic Nuclei with Ultra-fast Outflows Monitoring Project: The Broad-line Region of Mrk 79 as a Disk Wind
- The Formation of Broad Line Clouds in the Accretion Shocks of Active Galactic Nuclei
- Spectral optical monitoring of a double-peaked emission line AGN Arp 102B: I. Variability of spectral lines and continuum
- Long term variability of the Broad Emission Line profiles in AGN
- Anomalous Broad-Line Region Responses to Continuum Variability in Active Galactic Nuclei. I. H Variability
- Correlation between Line Width and Line Flux of Double-Peaked Broad Halpha of 3C390.3
- A Spectroscopic and Photometric Study of Short-Timescale Variability in NGC5548
- Broadband spectral and temporal study of Ton 599 during the brightest January 2023 flare
- X-ray and Multiwavelength Insights into the Inner Structure of High-Luminosity Disc-Like Emitters
- A novel approach to study the variability of NGC 5548
- A New Model for the Width of the Broad Emission Lines in AGN: The Role of the Accretion Rate