Time Delay and Accretion Disk Size Measurements in the Lensed Quasar SBS 0909+532 from Multiwavelength Microlensing Analysis
Abstract
We present three complete seasons and two half-seasons of Sloan Digital Sky Survey (SDSS) r-band photometry of the gravitationally lensed quasar SBS 0909+532 from the U.S. Naval Observatory, as well as two seasons each of SDSS g-band and r-band monitoring from the Liverpool Robotic Telescope. Using Monte Carlo simulations to simultaneously measure the system's time delay and model the r-band microlensing variability, we confirm and significantly refine the precision of the system's time delay to \Delta t_{AB} = 50^{+2}_{-4}\,{days}, where the stated uncertainties represent the bounds of the formal 1σ confidence interval. There may be a conflict between the time delay measurement and a lens consisting of a single galaxy. While models based on the Hubble Space Telescope astrometry and a relatively compact stellar distribution can reproduce the observed delay, the models have somewhat less dark matter than we would typically expect. We also carry out a joint analysis of the microlensing variability in the r and g bands to constrain the size of the quasar's continuum source at these wavelengths, obtaining log {(r s, r /cm)[cos i/0.5]1/2} = 15.3 ± 0.3 and log {(r s, g /cm)[cos i/0.5]1/2} = 14.8 ± 0.9, respectively. Our current results do not formally constrain the temperature profile of the accretion disk but are consistent with the expectations of standard thin disk theory.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2013
- DOI:
- 10.1088/0004-637X/774/1/69
- arXiv:
- arXiv:1307.3254
- Bibcode:
- 2013ApJ...774...69H
- Keywords:
-
- accretion;
- accretion disks;
- gravitational lensing: micro;
- gravitational lensing: strong;
- quasars: individual: SBS 0909+532;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 10 pages, 5 figures, 3 tables, accepted for publication in ApJ