Space Telescope and Optical Reverberation Mapping Project. IX. Velocity-Delay Maps for Broad Emission Lines in NGC 5548
Abstract
We report velocity-delay maps for prominent broad emission lines, Ly_alpha, CIV, HeII and H_beta, in the spectrum of NGC5548. The emission-line responses inhabit the interior of a virial envelope. The velocity-delay maps reveal stratified ionization structure. The HeII response inside 5-10 light-days has a broad single-peaked velocity profile. The Ly_alpha, CIV, and H_beta responses peak inside 10 light-days, extend outside 20 light-days, and exhibit a velocity profile with two peaks separated by 5000 km/s in the 10 to 20 light-day delay range. The velocity-delay maps show that the M-shaped lag vs velocity structure found in previous cross-correlation analysis is the signature of a Keplerian disk with a well-defined outer edge at R=20 light-days. The outer wings of the M arise from the virial envelope, and the U-shaped interior of the M is the lower half of an ellipse in the velocity-delay plane. The far-side response is weaker than that from the near side, so that we see clearly the lower half, but only faintly the upper half, of the velocity--delay ellipse. The delay tau=(R/c)(1-sin(i))=5 light-days at line center is from the near edge of the inclined ring, giving the inclination i=45 deg. A black hole mass of M=7x10^7 Msun is consistent with the velocity-delay structure. A barber-pole pattern with stripes moving from red to blue across the CIV and possibly Ly_alpha line profiles suggests the presence of azimuthal structure rotating around the far side of the broad-line region and may be the signature of precession or orbital motion of structures in the inner disk. Further HST observations of NGC 5548 over a multi-year timespan but with a cadence of perhaps 10 days rather than 1 day could help to clarify the nature of this new AGN phenomenon.
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Cite
@article{arxiv.2003.01448,
title = {Space Telescope and Optical Reverberation Mapping Project. IX. Velocity-Delay Maps for Broad Emission Lines in NGC 5548},
author = {Keith Horne and G. De Rosa and B. M. Peterson and A. J. Barth and J. Ely and M. M. Fausnaugh and G. A. Kriss and L. Pei and S. M. Adams and M. D. Anderson and P. Arevalo and T G. Beatty and V. N. Bennert and M. C. Bentz and A. Bigley and S. Bisogni and G. A. Borman and T. A. Boroson and M. C. Bottorff and W. N. Brandt and A. A. Breeveld and M. Brotherton and J. E. Brown and J. S. Brown and E. M. Cackett and G. Canalizo and M. T. Carini and K. I. Clubb and J. M. Comerford and E. M. Corsini and D. M. Crenshaw and S. Croft and K. V. Croxall and E. Dalla Bonta and A. J. Deason and M. Dehghanian and A. De Lorenzo-Caceres and K. D. Denney and M. Dietrich and C. Done and R. Edelson and N. V. Efimova and M. Eracleous and P. A. Evans and G. J. Ferland and A. V. Filippenko and K. Flatland and O. D. Fox and E. Gardner and E. L. Gates and N. Gehrels and S. Geier and J. M. Gelbord and M. R. Goad and L. Gonzalez and V. Gorjian and J. E. Greene and C. J. Grier and D. Grupe and A. Gupta and P. B. Hall and C. B. Henderson and S. Hicks and E. Holmbeck and T. W. -S. Holoien and T. Hutchison and M. Im and J. J. Jensen and C. A. Johnson and M. D. Joner and J. Jones and J. Kaastra and S. Kaspi and P. L. Kelly and J. A. Kennea and M. Kim and S. Kim and S. C. Kim and A. King and S. A. Klimanov and C. S. Kochanek and K. T. Korista and Y. Krongold and M. W. Lau and J. C. Lee and D. C. Leonard and Miao Li and P. Lira and C. Lochhaas and Zhiyuan Ma and F. MacInnis and M. A. Malkan and E. R. Manne-Nicholas and S. Mathur and J. C. Mauerhan and R. McGurk and I. M. Mc Hardy and C. Montuori and L. Morelli and A. Mosquera and D. Mudd and F. Mueller-Sanchez and S. V. Nazarov and H. Netzer and R. P. Norris and J. A. Nousek and M. L. Nguyen and P. Ochner and D. N. Okhmat and A. Pancoast and I. Papadakis and J. R. Parks and M. T. Penny and A. Pizzella and R. W. Pogge and R. Poleski and J. -U. Pott and D. Proga and S. E. Rafter and H. -W. Rix and J. Runnoe and D. A. Saylor and J. S. Schimoia and K. Schnuelle and B. Scott and S. G. Sergeev and B. J. Shappee and I. Shivvers and M. Siegel and G. V. Simonian and A. Siviero and A. Skielboe and G. Somers and M. Spencer and D. Starkey and D. J. Stevens and M. A. Strauss and H. -I. Sung and J. Tayar and K. G. Teems and N. Tejos and T. Treu and C. S. Turner and P. Uttley and J . Van Saders and M. Vestergaard and L. Vican and S. Villanueva and C. Villforth and Y. Weiss and J. -H. Woo and H. Yan and S. Young and H. Yuk and N. L. Zakamska and W. Zheng and W. Zhu and Y. Zu},
journal= {arXiv preprint arXiv:2003.01448},
year = {2021}
}
Comments
19 pages, 9 figures, ApJ in press