Williams, PR;
Pancoast, A;
Treu, T;
Brewer, BJ;
Peterson, BM;
Barth, AJ;
Malkan, MA;
... Ma, Z; + view all
(2020)
Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548.
The Astrophysical Journal
, 902
(1)
, Article 74. 10.3847/1538-4357/abbad7.
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Abstract
=We present geometric and dynamical modeling of the broad line region (BLR) for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The data set includes photometric and spectroscopic monitoring in the optical and ultraviolet, covering the Hβ, C iv, and Ly broad emission lines. We find an extended disk-like Hβ BLR with a mixture of near-circular and outflowing gas trajectories, while the C iv and Ly BLRs are much less extended and resemble shell-like structures. There is clear radial structure in the BLR, with C iv and Ly emission arising at smaller radii than the Hβ emission. Using the three lines, we make three independent black hole mass measurements, all of which are consistent. Combining these results gives a joint inference of log_{10}(M_{BH}/M_{sun}) = 7.64^{+0.21}_{-0.18}. We examine the effect of using the V band instead of the UV continuum light curve on the results and find a size difference that is consistent with the measured UV-optical time lag, but the other structural and kinematic parameters remain unchanged, suggesting that the V band is a suitable proxy for the ionizing continuum when exploring the BLR structure and kinematics. Finally, we compare the Hβ results to similar models of data obtained in 2008 when the active galactic nucleus was at a lower luminosity state. We find that the size of the emitting region increased during this time period, but the geometry and black hole mass remained unchanged, which confirms that the BLR kinematics suitably gauge the gravitational field of the central black hole.
| Type: | Article |
|---|---|
| Title: | Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4357/abbad7 |
| Publisher version: | https://doi.org/10.3847/1538-4357/abbad7 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher's terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10113454 |
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