Reverberation Mapping Of The Kepler Field AGN Ka1858+4850

Date
2014-11
Authors
Pei, Liuyi
Barth, Aaron J.
Aldering, Greg S.
Briley, Michael M.
Carroll, Carla J.
Carson, Daniel J.
Cenko, S. Bradley
Clubb, Kelsey I.
Cohen, Daniel P.
Cucchiara, Antonino
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Abstract

KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3 m telescope from 2012 February to November, and obtained complementary V-band images from five other ground-based telescopes. We measured the H beta light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method and found rest-frame lags of tau(CCF) = 13.53(+2.03)(-2.32) days and tau(JAVELIN) = 13.15(+1.08)(-1.00) days. The H beta rms line profile has a width of sigma line = 770 +/- 49 km s(-1). Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M-BH = 8.06(+1.59)(-1.72) x 10(6) M circle dot for the mass of the central black hole and an Eddington ratio of L/L-Edd approximate to 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei.

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Citation
Pei, Liuyi, Aaron J. Barth, Greg S. Aldering, Michael M. Briley, Carla J. Carroll, Daniel J. Carson, S. Bradley Cenko et al. "Reverberation Mapping of the KEPLER Field AGN KA1858+ 4850." The Astrophysical Journal, Vol. 795, No. 1 (Nov., 2014): 38.