A New Microlensing Event in the Doubly-Imaged Quasar Q0957+561
Abstract
We present evidence for ultraviolet/optical microlensing in the gravitationally lensed quasar Q0957+561. We combine new measurements from our optical monitoring campaign at the United States Naval Observatory, Flagstaff (USNO) with measurements from the literature and find that the time-delay-corrected r-band flux ratio mA - mB has increased by ~0.1 magnitudes 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+0.5-0.6, that is consistent with the quasar accretion disk size - black hole mass relation.
0