Micro-images of macro-lensed objects
Name
1082845248-MIT.pdf
Description
Full printable version
Size
7.62 MB
Format
Adobe PDF
Checksum (MD5)
9a89081c02656f916d3e33cb3daf1c3d
Author(s)
Weisenbach, Luke
Advisor(s)
Paul L. Schechter.
Date Issued
2018
Publisher
Massachusetts Institute of Technology
Abstract
The study of gravitational micro-lensing at high optical depth has only rarely involved the close examination of the individual actual micro-images that arise as a result of the phenomenon. We discuss methods that refine on previous work done in the search for micro-images, which have been largely ignored in favor of other methods to study micro-lensing. With the help of magnification maps generated by Herr Prof. Dr. Joachim Wambsganss, we ran simulations that track positions and magnifications of micro-minima as functions of source position. We discuss the breakdown of a commonly used approximation for magnifications near fold caustics. Our results show that the approximation is noticeably broken at a caustic strength-scaled distance of 0.1. The relevance of this breakdown to work done by other authors is briefly examined. We then then discuss a few new results for the statistics of micro-images, deriving a formula for the mean micro-minimum magnification. We present a method for exactly calculating the caustic networks of micro-lensed systems, and calculate probability distributions for the caustic strength for two sets of parameters of interest. We present the creation of videos of the micro-lensing affect for pedagogical purposes. Finally, we briefly examine micro-lensing near macro-caustics and study the motion of micro-images as a point source crosses a macro-caustic.
Description
Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 79-80).
Subjects
Physics.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
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