Signatures of Accretion Disks in Quasar Microlensing

Abstract

We propose that relative variability on short time-scales of the multiple images of a lensed quasar, after removal of the time delay, may be caused by hot spots or other moving structures in the accretion disk crossing microlens caustics caused by stellar mass objects in the lensing galaxy. Such variability has been reported in the two images of 0957+561. The short durations would be due to the high rotation speed of the disk (v/c ~ 0.1), rather than planetary mass objects in the slowly moving (v/c ~ 0.001) lens. This interpretation could be confirmed by finding periodicity, or correlations of the spectral and flux variations due to the Doppler effect in the disk. We also propose another signature of stationary accretion disks (with no intrinsic variability): the gradient of the magnification over the accretion disk should cause a relative color change between the images whose sign and amplitude are correlated with the time derivative of the flux difference between the images. Other color terms induced by the radial variation of disk colors are of second order in the magnification gradient. The methods proposed here can be used first to verify that accretion disks near supermassive black holes are the source of the continuum radiation from quasars, and then to study them.

11 pages plus 1 postscript figure

Cited by in corpus (25)

• Gravitational Lensing in Astronomy
• Quasar Accretion Disks Are Strongly Inhomogeneous
• Size is Everything: Universal Features of Quasar Microlensing with Extended Sources
• Effects of gravitational-wave recoil on the dynamics and growth of supermassive black holes
• Microlensing Makes Lensed Quasar Time Delays Significantly Time Variable
• Double-peaked Narrow-Line Signatures of Dual Supermassive Black Holes in Galaxy Merger Simulations
• Analysis of Time Delays in the Gravitational Lens PG1115+080
• Imaging a Quasar Accretion Disk with Microlensing
• Microlensing of Relativistic Knots in the Quasar HE1104-1805
• Time delay measurement of the lensed quasar HE1104-1805
• Microlensing of an Elliptical Source by a Point Mass
• A Rapid Microlensing Event in the Q0957+561 A,B Gravitational Lens System
• The optical variability of Supermassive Black Hole Binary Candidate PG1302-102: Periodicity and perturbation in the light curve
• BVRI photometry of QSO 0957+561A, B: Observations, new reduction method and time delay
• Observations Supporting the Existence of an Intrinsic Magnetic Moment Inside the Central Compact Object Within the Quasar Q0957+561
• The Effect of a Time-Varying Accretion Disk Size on Quasar Microlensing Light Curves
• Measuring the Size of Quasar Broad-Line Clouds Through Time Delay Light-Curve Anomalies of Gravitational Lenses
• Microlensing of a Ring Model for Quasar Structure
• Short-timescale Fluctuations in the Difference Light Curves of QSO 0957+561A,B: Microlensing or Noise?
• Q2237+0305 source structure and dimensions from light curves simulation
• Evidence for a milliparsec-separation Supermassive Binary Black Hole with quasar microlensing
• Resolving the Structure at the Heart of BAL Quasars Through Microlensing Induced Polarisation Variability
• Probing the Mass Fraction of MACHOs in Extragalactic Halos
• The Mass Function of Primordial Rogue Planet MACHOs in quasar nanolensing
• Microlensing Black Hole Shadows