- Authors:
-
- Bentz, Misty C. ;
- Denney, Kelly D. ;
- Cackett, Edward M. ;
- Dietrich, Matthias ;
- Fogel, Jeffrey K. J. ;
- Ghosh, Himel ;
- Horne, Keith D. ;
- Kuehn, Charles ;
- Minezaki, Takeo ;
- Onken, Christopher A. ;
- Peterson, Bradley M. ;
- Pogge, Richard W. ;
- Pronik, Vladimir I. ;
- Richstone, Douglas O. ;
- Sergeev, Sergey G. ;
-
Vestergaard, Marianne
;
Close
0000-0001-9191-9837
Dark Cosmology Centre, Niels Bohr Institute, Faculty of Science, Københavns Universitet - Walker, Matthew G. ;
- Yoshii, Yuzuru
- Subtitle:
- Implications for the Broad-Line Region
- DOI:
- 10.1086/516724
- Abstract:
- We describe results from a new ground-based monitoring campaign on NGC 5548, the best studied reverberation-mapped AGN. We find that it was in the lowest luminosity state yet recorded during a monitoring program, namely L(5100) = 4.7 x 10^42 ergs s^-1. We determine a rest-frame time lag between flux variations in the continuum and the Hbeta line of 6.3 (+2.6/-2.3) days. Combining our measurements with those of previous campaigns, we determine a weighted black hole mass of M_BH = 6.54 (+0.26/-0.25) x 10^7 M_sun based on all broad emission lines with suitable variability data. We confirm the previously-discovered virial relationship between the time lag of emission lines relative to the continuum and the width of the emission lines in NGC 5548, which is the expected signature of a gravity-dominated broad-line region. Using this lowest luminosity state, we extend the range of the relationship between the luminosity and the time lag in NGC 5548 and measure a slope that is consistent with alpha = 0.5, the naive expectation for the broad line region for an assumed form of r ~ L^alpha. This value is also consistent with the slope recently determined by Bentz et al. for the population of reverberation-mapped AGNs as a whole.
- Type:
- Journal article
- Language:
- English
- Published in:
- Astrophysical Journal, 2007, Vol 662, Issue 1
- Keywords:
- astro-ph
- Main Research Area:
- Science/technology
- Publication Status:
- Published
- Review type:
- Peer Review
- Submission year:
- 2007
- Scientific Level:
- Scientific
- ID:
- 231992344
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