http://arxiv.org/abs/1806.08360
We present accretion-disk structure measurements from continuum lags in the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Lags are measured using the \texttt{JAVELIN} software from the first-year SDSS-RM $g$ and $i$ photometry, resulting in well-defined lags for 95 quasars, 33 of which have lag SNR $>$ 2$\sigma$. We also estimate lags using the \texttt{ICCF} software and find consistent results, though with larger uncertainties. Accretion-disk structure is fit using a Markov Chain Monte Carlo approach, parameterizing the measured continuum lags as a function of disk size normalization, wavelength, black hole mass, and luminosity. In contrast with previous observations, our best-fit disk sizes and color profiles are consistent with the (Shakura \& Sunyaev 1973) analytic solution. We also find that more massive quasars have larger accretion disks, similarly consistent with the analytic accretion-disk model. The continuum lag fits have a large excess dispersion, indicating that our measured lag errors are underestimated and/or our best-fit model may be missing the effects of orientation, spin, and/or radiative efficiency. We demonstrate that fitting disk parameters using only the highest-SNR lag measurements biases best-fit disk sizes to be larger than the disk sizes recovered using a Bayesian approach on the full sample of well-defined lags. This work represents a significant advance in continuum reverberation mapping, providing a large number of accretion-disk size and structure measurements for quasars spanning a broad range of redshift, mass and luminosity.
Y. Homayouni, J. Trump, C. Grier, et. al.
Mon, 25 Jun 18
32/54
Comments: 18 pages and 17 figures. Complete version of table 1 and full figure set (similar to figure 4) are provided through this http URL this http URL
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