A New Microlensing Event in the Doubly Imaged Quasar Q 0957+561
Kochanek, C. S.; Harris, Hugh C.; Fadely, Ross; Hainline, Laura J.; Morgan, Christopher W.; Beach, Joseph N.; Tilleman, Trudy; Falco, Emilio E.; Le, Truong X.
United States
Abstract
We present evidence for ultraviolet/optical microlensing in the gravitationally lensed quasar Q 0957+561. We combine new measurements from our optical monitoring campaign at the United States Naval Observatory, Flagstaff, with measurements from the literature and find that the time-delay-corrected r-band flux ratio mA - mB has increased by ~0.1 mag over a period of five years beginning in the fall of 2005. We apply our Monte Carlo microlensing analysis procedure to the composite light curves, obtaining a measurement of the optical accretion disk size, log {(rs /cm)[cos (i)/0.5]1/2} = 16.2 ± 0.5, that is consistent with the quasar accretion disk size-black hole mass relation.