Continuum Reverberation Mapping of the Accretion Disks in Two Seyfert 1 Galaxies

M.~M. Fausnaugh, D.~A. Starkey, Keith Horne, C.~S. Kochanek, B.~M. Peterson, M.~C. Bentz, K.~D. Denney, C.~J. Grier, D. Grupe, R.~W. Pogge, G. De Rosa, S.~M. Adams, A.~J. Barth, Thomas G. Beatty, A. Bhattacharjee, G.~A. Borman, T.~A. Boroson, M.~C. Bottorff, Jacob E. Brown, Jonathan S. BrownM.~S. Brotherton, C.~T. Coker, S.~M. Crawford, K.~V. Croxall, Sarah Eftekharzadeh, Michael Eracleous, M.~D. Joner, C.~B. Henderson, T.~W. -S. Holoien, T. Hutchison, Shai Kaspi, S. Kim, Anthea L. King, Miao Li, Cassandra Lochhaas, Zhiyuan Ma, F. MacInnis, E.~R. Manne-Nicholas, M. Mason, Carmen Montuori, Ana Mosquera, Dale Mudd, R. Musso, S.~V. Nazarov, M.~L. Nguyen, D.~N. Okhmat, Christopher A. Onken, B. Ou- Yang, A. Pancoast, L. Pei, Matthew T. Penny, Radoslaw Poleski, Stephen Rafter, E. Romero- Colmenero, Jessie Runnoe, David J. Sand, Jaderson S. Schimoia, S.~G. Sergeev, B.~J. Shappee, Gregory V. Simonian, Garrett Somers, M. Spencer, Daniel J. Stevens, Jamie Tayar, T. Treu, Stefano Valenti, J. Van Saders, Jr. Villanueva S., C. Villforth, Yaniv Weiss, H. Winkler, W. Zhu

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We present optical continuum lags for two Seyfert 1 galaxies, MCG+08-11-011 and NGC 2617, using monitoring data from a reverberation mapping campaign carried out in 2014. Our light curves span the ugriz filters over four months, with median cadences of 1.0 and 0.6 days for MCG+08-11-011 and NGC 2617, respectively, combined with roughly daily X-ray and near-UV data from Swift for NGC 2617. We find lags consistent with geometrically thin accretion-disk models that predict a lag-wavelength relation of τ ∝ λ 4/3. However, the observed lags are larger than predictions based on standard thin-disk theory by factors of 3.3 for MCG+08-11-011 and 2.3 for NGC 2617. These differences can be explained if the mass accretion rates are larger than inferred from the optical luminosity by a factor of 4.3 in MCG+08-11-011 and a factor of 1.3 in NGC 2617, although uncertainty in the SMBH masses determines the significance of this result. While the X-ray variability in NGC 2617 precedes the UV/optical variability, the long (2.6 day) lag is problematic for coronal reprocessing models.
Original languageEnglish
Article number107
Number of pages1
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 16 Feb 2018


  • accretion, accretion disks, galaxies: individual: MCG+08-11-011, NGC 2617, galaxies: Seyfert, Astrophysics - Astrophysics of Galaxies

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    Fausnaugh, M. M., Starkey, D. A., Horne, K., Kochanek, C. S., Peterson, B. M., Bentz, M. C., Denney, K. D., Grier, C. J., Grupe, D., Pogge, R. W., De Rosa, G., Adams, S. M., Barth, A. J., Beatty, T. G., Bhattacharjee, A., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brown, J. E., ... Zhu, W. (2018). Continuum Reverberation Mapping of the Accretion Disks in Two Seyfert 1 Galaxies. Astrophysical Journal, 854(2), [107].