GRAVITATIONAL LENS DISCOVERY AND INVESTIGATION USING OPTICAL AND INFRA-RED SURVEYS.

Abstract

This thesis presents a new method, that combines multi-wavelength optical and infrared surveys to detect gravitational lensed candidates. This method takes advantage of a newly discovered property of gravitational lenses, whereby the separation between the two images decreases from optical to infrared wavelengths. The method was initially tested on simulated gravitational lenses, which indicates that the method is complete for image separations greater than 1 arcsecond, and flux ratios less than 6. However, at higher flux ratios, the method was found to be sensitive to gravitational lenses with large separations. The survey began with 24 896 quasars from the United Kingdom Infrared Telescope Deep Sky Survey (UKIDSS), which was reduced to 461 sources that displayed gravitational lens morphologies within a radius of 3 arcseconds. From the 461 sources, 90 sources with image separations greater than 1 arcsecond and flux ratios less than 15 were selected as possible gravitational lenses with our method. This list of 90 gravitational lens candidates are expected to be observed with the Keck telescope at a later date. Comparisons with known lensing rates from previous gravitational lens surveys, our survey is expected to detect 12-30 new gravitational lenses.

Date of Award	31 Dec 2010
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Neal Jackson (Supervisor)