Gamma-Ray Variability Induced by Microlensing on Intermediate Size Structures in Lensed Blazars

Abstract

Changes of the magnification ratio of images in a lensed blazar, caused by microlensing on individual stars, have been proposed as a probe of the size and velocity of the emission region in the lensed source. We study whether similar changes in the magnification ratio can be caused by the microlensing on the intermediate size structures in the lensing galaxy, namely stellar clusters and giant molecular clouds. Our numerical simulations show that changes in the magnification ratio of two images with similar time scales (as seen in QSO B0218+357) can be obtained for relativistically-moving emission regions with sizes up to 0.01 pc in the case of microlensing on clumps in giant molecular clouds.

Keywords

• gravitational lensing: micro
• galaxies: active
• globular clusters: general
• open clusters and associations: general
• ISM: clouds