Continuum reverberation mapping of the accretion disks in two Seyfert 1 galaxies
Abstract
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.
Citation
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 , Brown , J S , Brotherton , M S , Coker , C T , Crawford , S M , Croxall , K V , Eftekharzadeh , S , Eracleous , M , Joner , M D , Henderson , C B , Holoien , T W -S , Hutchison , T , Kaspi , S , Kim , S , King , A L , Li , M , Lochhaas , C , Ma , Z , MacInnis , F , Manne-Nicholas , E R , Mason , M , Montuori , C , Mosquera , A , Mudd , D , Musso , R , Nazarov , S V , Nguyen , M L , Okhmat , D N , Onken , C , Ou-Yang , B , Pancoast , A , Pei , L , Penny , M T , Poleski , R , Rafter , S , Romero-Colmenero , E , Runnoe , J , Sand , D J , Schimoia , J S , Sergeev , S G , Shappee , B J , Simonian , G V , Somers , G , Spencer , M , Stevens , D J , Tayar , J , Treu , T , Valenti , S , Van Saders , J , Villanueva Jr , S , Villforth , C , Weiss , Y , Winkler , H & Zhu , W 2018 , ' Continuum reverberation mapping of the accretion disks in two Seyfert 1 galaxies ' , Astrophysical Journal , vol. 854 , no. 2 , 107 . https://doi.org/10.3847/1538-4357/aaaa2b
Publication
Astrophysical Journal
Status
Peer reviewed
ISSN
0004-637XType
Journal article
Description
K.H.acknowledges support from STFC grant ST/M001296/1.Collections
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