r-band LCs of a doubly imaged lensed SDSS quasar

We analyze variability in 15-season optical lightcurves from the doubly imaged lensed quasar SDSS J165043.44+425149.3, comprising five seasons of monitoring data from the Maidanak Observatory (277 nights in total, including the two seasons of data previously presented in Vuissoz+ 2007A&A...464..845V), five seasons of overlapping data from the Mercator telescope (269 nights), and 12 seasons of monitoring data from the US Naval Observatory, Flagstaff Station at lower cadence (80 nights).

We update the 2007 time-delay measurement for SDSS_J165043.44+425149.3 with these new data, finding a time delay of {Delta}t_AB_=-55.1_-3.7_^+4.0^days, with image A leading image B. We analyze the microlensing variability in these lightcurves using a Bayesian Monte Carlo technique to yield measurements of the size of the accretion disk at {lambda}_rest_=2420{AA}, finding a half-light radius of log(r1/2/cm)=16.19_-0.58_^+0.38^ assuming a 60{deg} inclination angle.