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Weak lensing flexion as a probe of galaxy cluster substructure

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dc.contributor.advisor Marshall W. Bautz and Enectali Figueroa-Feliciano. en_US Cain, Benjamin Martin en_US
dc.contributor.other Massachusetts Institute of Technology. Dept. of Physics. en_US 2012-01-30T17:07:26Z 2012-01-30T17:07:26Z 2011 en_US 2011 en_US
dc.description Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2011. en_US
dc.description Cataloged from PDF version of thesis. en_US
dc.description Includes bibliographical references (p. 129-133). en_US
dc.description.abstract Measuring galaxy cluster total masses and the amount of dark matter substructure within galaxy cluster haloes is a fundamental probe of the ACDM model of structure formation, as well as the interactions between baryonic and non-baryonic matter. In this thesis I approach the topic of cluster mass structure in two ways. With a combination of optical imaging, spectroscopy, and X-ray observations I determine that the cluster RCS043938-2904.7, while apparently anomalous initially due to its high optical richness and low X-ray surface brightness, is in fact an association of structures along the line of sight. Accounting for this structure brings the observed cluster properties into agreement with known scaling relations. I also present a novel method for measuring weak gravitational lensing flexion to inform mass measurements on small scales. While previously published methods for measuring flexion focus on measuring derived properties of the lensed images, such as shapelet coefficients or surface brightness moments, my method fits a fully mass-sheet-invariant parametrized Analytic Image Model (AIM) to the each galaxy image. This simple parametric model traces the distortion of lensed image isophotes. I tested the AIM method using simulated data images with realistic noise and a variety of input image properties, and I show that it successfully reproduces the input lensing fields. I also apply the AIM method for flexion measurement to Hubble Space Telescope observations of Abell 1689, and detect mass structure in that cluster using only flexion measured with the AIM method. en_US
dc.description.statementofresponsibility by Benjamin Martin Cain. en_US
dc.format.extent 133 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri en_US
dc.subject Physics. en_US
dc.title Weak lensing flexion as a probe of galaxy cluster substructure en_US
dc.type Thesis en_US Ph.D. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Physics. en_US
dc.identifier.oclc 774026583 en_US

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