Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548

Authors

P. R. Williams, University of California, Los Angeles
A. Pancoast, Harvard-Smithsonian Center for Astrophysics
T. Treu, University of California, Los Angeles
B. J. Brewer, The University of Auckland
B. M. Peterson, The Ohio State University
A. J. Barth, University of California, Irvine
M. A. Malkan, University of California, Los Angeles
G. De Rosa, Space Telescope Science Institute
Keith Horne, University of St Andrews
G. A. Kriss, Space Telescope Science Institute
N. Arav, Virginia Polytechnic Institute and State University
M. C. Bentz, Georgia State University
E. M. Cackett, Wayne State University
E. Dalla Bontà, Università degli Studi di Padova
M. Dehghanian, University of Kentucky
C. Done, Durham University
G. J. Ferland, University of Kentucky
C. J. Grier, The Ohio State University
J. Kaastra, SRON Netherlands Institute for Space Research
E. Kara, MIT Kavli Institute for Astrophysics and Space Research
C. S. Kochanek, The Ohio State University
S. Mathur, The Ohio State University
M. Mehdipour, SRON Netherlands Institute for Space Research
R. W. Pogge, The Ohio State University
D. Proga, University of Nevada, Las Vegas
M. Vestergaard, The University of Arizona
T. Waters, University of Nevada, Las Vegas
S. M. Adams, The Ohio State University
M. D. Anderson, Georgia State University
P. Arévalo, Universidad de Valparaiso
T. G. Beatty, The Ohio State University
V. N. Bennert, Cal Poly San Luis Obispo
A. Bigley, University of California, Berkeley

Document Type

Article

Publication Date

10-10-2020

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 . 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.

Publication Source (Journal or Book title)

Astrophysical Journal

Recommended Citation

Williams, P., Pancoast, A., Treu, T., Brewer, B., Peterson, B., Barth, A., Malkan, M., Rosa, G., Horne, K., Kriss, G., Arav, N., Bentz, M., Cackett, E., Bontà, E., Dehghanian, M., Done, C., Ferland, G., Grier, C., Kaastra, J., Kara, E., Kochanek, C., Mathur, S., Mehdipour, M., Pogge, R., Proga, D., Vestergaard, M., Waters, T., Adams, S., Anderson, M., Arévalo, P., Beatty, T., Bennert, V., & Bigley, A. (2020). Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548. Astrophysical Journal, 902 (1) https://doi.org/10.3847/1538-4357/abbad7