Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 5: Variability of the ultraviolet continuum and emission lines of NGC 3783

Reichert, G. A.; Rodriquez-Pascual, P. M.; Alloin, D.; Clavel, J.; Crenshaw, D. M.; Kriss, G. A.; Krolik, Julian H.; Malkan, M. A.; Netzer, H.; Peterson, B. M.; Wamsteker, W.; Altamore, A.; Altiéri, B.; Anderson, K. S. J.; Blackwell, John; Boisson, C.; Brosch, Noah; Carone, T. E.; Dietrich, M.; England, Martin N.; Evans, I. N.; Filippenko, A. V.; Gaskell, C. M.; Goad, M. R.; Gondhalekar, P. M.; Horne, K.; Kazanas, D.; Kollatschny, W.; Koratkar, Anuradha; Korista, K. T.; MacAlpine, G. M.; Maoz, Dan; Mazeh, T.; McCollum, B.; Miller, H. R.; Oliveira, C. Mendes de; O’Brien, P. T.; Pastoriza, M. G.; Pelat, D.; Pérez, E.; Perola, G. C.; Pogge, Richard W.; Ptak, R.; Recondo, Carmen; Rodriguez‐Espinoza, J. M.; Rosenblatt, E. I.; Sadun, A. C.; Santos-Lleo, M.; Shields, J. C.; Shrader, C. R.; Shull, J. M.; Simkin, S. M.; Sitko, M. L.; Snijders, M. A. J.; Sparke, L. S.; Stirpe, G. M.; Stoner, R.; Storchi‐Bergmann, Thaisa; Sun, Wei‐Hsin; Wang, T.; Welsh, William F.; White, R. J.; Winge, Cláudia; Zheng, Wei

doi:10.1086/174007

Cited by 121 publications

(101 citation statements)

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“…The results of that work have been published by Reichert et al (1994), Stirpe et al (1994), and Alloin et al (1995). Compared to the consortium's earlier study of another Seyfert galaxy, NGC 5548 (see Clavel et al 1991;Peterson et al 1991;Dietrich et al 1993), the emission-line time lags were relatively uncertain, too poorly constrained in fact to reveal any possible virial relationship between line width and time lag.…”

Section: Introductionmentioning

confidence: 76%

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The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783

Onken

Peterson

2002

ApJ

141

144

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Improved analysis of ultraviolet and optical monitoring data on the Seyfert 1 galaxy NGC 3783 provides evidence for the existence of a supermassive, ð8:7 AE 1:1Þ Â 10 6 M , black hole in this galaxy. By using recalibrated spectra from the International Ultraviolet Explorer satellite and ground-based optical data, as well as refined techniques of reverberation mapping analysis, we have reduced the statistical uncertainties in the response of the emission lines to variations in the ionizing continuum. The different time lags in the emissionline responses indicate a stratification in the ionization structure of the broad-line region and are consistent with the virial relationship suggested by the analysis of similar active galaxies.

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Section: Introductionmentioning

confidence: 76%

“…The first interval (of 45 epochs) had an average spacing of 4.0 days, while the final 24 epochs observed the AGN with an average spacing of 2.0 days. A more complete description of the UV observing program is provided by Reichert et al (1994).…”

Section: Uv Datamentioning

confidence: 99%

The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783

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Peterson

2002

ApJ

141

144

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“…However, whereas C iv reverberation studies of a handful of objects are consistent with expectations from Hb (Peterson et al 2005), a clear indication of reverberation has not yet been found for Mg ii. Although the line has been seen to vary in both flux and width (e.g., Clavel et al 1991;Dietrich & Kollatschny 1995;Metzroth et al 2006;Woo 2008), only weak Mg ii reverberation signals have been seen (Reichert et al 1994). Thus, the mass relation for Mg ii relies on the correlation of single-epoch estimates with Hb masses and the argument that Mg ii and Hb have similar ionization potentials (McLure & Dunlop 2004).…”

Section: Methods Of Analysismentioning

confidence: 99%

An Improved Method for Using Mg ii to Estimate Black Hole Masses in Active Galactic Nuclei

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Kollmeier

2008

ApJ

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We present a method for obtaining accurate black hole (BH) mass estimates from the Mg ii emission line in active galactic nuclei (AGNs). Employing the large database of AGN measurements from the Sloan Digital Sky Survey (SDSS) presented by Shen et al., we find that AGNs in the redshift range 0.3-0.9, for which a given object can have both Hb and Mg ii line widths measured, display a modest but correctable discrepancy in Mg ii-based masses that correlates with the Eddington ratio. We use the SDSS database to estimate the probability distribution of the true (i.e., Hb-based) mass given a measured Mg ii line width. These probability distributions are then applied to the SDSS measurements from Shen et al. across the entire Mg ii-accessible redshift range (0.3-2.2). We find that accounting for this residual correlation generally increases the dispersion of Eddington ratios by a small factor (∼0.09 dex for the redshift and luminosity bins we consider). We continue to find that the intrinsic distribution of Eddington ratios for luminous AGNs is extremely narrow, 0.3-0.4 dex, as demonstrated by Kollmeier et al. Using the method we describe, Mg ii emission lines can be used with confidence to obtain BH mass estimates.

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“…However, wavelengths shorter than ∼3200Å are inaccessible from the ground, so the rest-frame optical continuum is often used as a proxy for the ionizing source in low-redshift AGNs. Although the far-UV and optical continua have been shown to vary almost simultaneously in some cases (e.g., Clavel et al 1991;Reichert et al 1994;Korista et al 1995;Wanders et al 1997), more recent high-cadence studies have found that the optical continuum can lag the UV continuum by up to a few days (Collier et al 1998;Sergeev et al 2005;McHardy et al 2014;Shappee et al 2014;Edelson et al 2015;Fausnaugh et al 2016). This can significantly affect the measured broadline lag if the BLR has a characteristic radius on the order of light-days.…”

Section: Introductionmentioning

confidence: 99%

Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548

Pei¹,

Fausnaugh²,

Barth³

et al. 2017

ApJ

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We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He II λ4686 broad emission-line light curves lag that of the 5100Å optical continuum by , respectively. The Hβ lag relative to the 1158Å ultraviolet continuum light curve measured by the Hubble Space Telescope is ∼50% longer than that measured against the optical continuum, and the lag difference is consistent with the observed lag between the optical and ultraviolet continua. This suggests that the characteristic radius of the broad-line region is ∼50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for Hβ and found a complex velocity-lag structure with shorter lags in the line wings, indicative of a broadline region dominated by Keplerian motion. The responses of both the Hβ and He II emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C IV, Lyα, He II (+O III]), and Si IV(+O IV]) during the same monitoring period. Finally, given the optical luminosity of NGC 5548 during our campaign, the measured Hβ lag is a factor of five shorter than the expected value implied by the R BLR -L AGN relation based on the past behavior of NGC 5548.

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Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. 5: Variability of the ultraviolet continuum and emission lines of NGC 3783

Cited by 121 publications

References 1 publication

The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783

The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783

An Improved Method for Using Mg ii to Estimate Black Hole Masses in Active Galactic Nuclei

Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548

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