The Effect of a Time-Varying Accretion Disk Size on Quasar Microlensing Light Curves

Abstract

Microlensing perturbations to the magnification of gravitationally lensed quasar images are dependent on the angular size of the quasar. If quasar variability at visible wavelengths is caused by a change in the area of the accretion disk, it will affect the microlensing magnification. We derive the expected signal, assuming that the luminosity scales with some power of the disk area, and estimate its amplitude using simulations. We discuss the prospects for detecting the effect in real-world data and for using it to estimate the logarithmic slope of the luminosity's dependence on disk area. Such an estimate would provide a direct test of the standard thin accretion disk model. We tried fitting six seasons of the light curves of the lensed quasar HE 0435-1223 including this effect as a modification to the Kochanek et al. (2006) approach to estimating time delays. We find a dramatic improvement in the goodness of fit and relatively plausible parameters, but a robust estimate will require a full numerical calculation in order to correctly model the strong correlations between the structure of the microlensing magnification patterns and the magnitude of the effect. We also comment briefly on the effect of this phenomenon for the stability of time delay estimates.

6 pages, 5 figures. Modified slightly to match published version

References in corpus (26)

• On the variation of the Initial Mass Function
• Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations?
• The Quasar Accretion Disk Size -- Black Hole Mass Relation
• The Quasar Accretion Disk Size - Black Hole Mass Relation
• Quantifying Quasar Variability As Part of a General Approach To Classifying Continuously Varying Sources
• A Robust Determination of the Time Delay in 0957+561A,B and a Measurement of the Global Value of Hubble's Constant
• Quantitative Interpretation of Quasar Microlensing Light Curves
• The Sizes of the X-ray and Optical Emission Regions of RXJ1131-1231
• X-Ray and Optical Flux Ratio Anomalies in Quadruply Lensed Quasars: I. Zooming in on Quasar Emission Regions
• X-ray Microlensing in RXJ1131-1231 and HE1104-1805
• The Time Delays of Gravitational Lens HE0435-1223: An Early-Type Galaxy With a Rising Rotation Curve
• Size is Everything: Universal Features of Quasar Microlensing with Extended Sources
• The Spatial Structure of An Accretion Disk
• Microlensing variability in the gravitationally lensed quasar QSO 2237+0305 = the Einstein Cross. II. Energy profile of the accretion disk
• A microlensing study of the accretion disc in the quasar MG 0414+0534
• Gravitational Microlensing
• Microlensing Evidence That A Type 1 Quasar Is Viewed Face On
• The accretion disc in the quasar SDSS J0924+0219
• The Dark-Matter Fraction in the Elliptical Galaxy Lensing the Quasar PG1115+080
• The Transverse Peculiar Velocity of the Q2237+0305 Lens Galaxy and the Mean Mass of Its Stars
• Microlensing of Relativistic Knots in the Quasar HE1104-1805
• Detection of chromatic microlensing in Q 2237+0305 A
• Microlensing of an extended source by a power-law mass distribution
• Signatures of Accretion Disks in Quasar Microlensing
• Integral field spectroscopy of four lensed quasars: analysis of their neighborhood and evidence for microlensing
• Measuring the Size of Quasar Broad-Line Clouds Through Time Delay Light-Curve Anomalies of Gravitational Lenses

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• The Microlensing Properties of a Sample of 87 Lensed Quasars
• COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses IX. Time delays, lens dynamics and baryonic fraction in HE 0435-1223
• Substructure in the lens HE 0435-1223
• Accretion onto Stars in the Disks of Active Galactic Nuclei
• A Study of Gravitational Lens Chromaticity using Ground-based Narrow Band Photometry
• The Structure of HE 1104-1805 from Infrared to X-Ray
• I. Flux and color variations of the quadruply imaged quasar HE 0435-1223
• On the UV/optical variation in NGC 5548: new evidence against the reprocessing diagram
• Gravitational microlensing of AGN dusty tori
• Evidence for a milliparsec-separation Supermassive Binary Black Hole with quasar microlensing
• A 5.5-year robotic optical monitoring of Q0957+561: substructure in a non-local cD galaxy