As an alternative to dark matter, Modified Newtonian Dynamics (MOND) can
explain dynamical measurements of galaxies on small scales. It is, however, unclear
whether MOND still works for galaxies on the large scale. In this study, we use galaxy-
galaxy (g-g) weak lensing measurements to examine MOND in the outer regions of
galaxies. First, we study the amplitude of the weak gravitational lensing signal
as a function of stellar mass around relatively isolated galaxies. We find that our
measurements are inconsistent with the predictions from MOND. Second, we examine
whether MOND can produce an anisotropic lensing signal as observed in the real data.
Starting with a mass distribution of an extremely high ellipticity, we find it is very
hard for MOND to reproduce the observed extensive anisotropic lensing signal from
only the visible mass. Because the g-g lensing is measured at radii of up to hundreds
of kiloparsecs, these two tests indicate that MOND does not work in outer regions of
galaxies. Our study casts serious doubt on the notation that MOND can convincingly
prove itself as a viable alternative to dark matter.
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/1036 |
| Date | 30 July 2008 |
| Creators | Tian, Lanlan |
| Contributors | Hoekstra, Henk |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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