Testing the Hypothesis of Modified Dynamics with Low Surface Brightness Galaxies and Other Evidence

The rotation curves of low surface brightness galaxies provide a unique data set with which to test alternative theories of gravitation over a large dynamic range in size, mass, surface density, and acceleration. Many clearly fail, including any in which the mass discrepancy appears at a particular length-scale. One hypothesis, MOND [Milgrom 1983, ApJ, 270, 371], is consistent with the data. Indeed, it accurately predicts the observed behavior. We find no evidence on any scale which clearly contradicts MOND, and a good deal which supports it. Subject headings: cosmology: dark matter — galaxies: formation — galaxies: halos — galaxies: kinematics and dynamics — galaxies: structure — gravitation When you have eliminated the impossible, whatever remains, however improbable, must be the truth. — Sherlock Holmes Present Address: Physics and Astronmy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 Present Address: Astrophysics Groups, School of Physics, University of Melbourne, Parkville, Victoria 3052, Australia