http://arxiv.org/abs/2103.05003
Galaxies are the basic structural element of the universe; galaxy formation theory seeks to explain how these structures came to be. I trace some of the foundational ideas in galaxy formation, with emphasis on the need for non-baryonic cold dark matter. Many elements of early theory did not survive contact with observations of low surface brightness galaxies, leading to the need for auxiliary hypotheses like feedback. The failure points often trace to the surprising predictive successes of an alternative to dark matter, the Modified Newtonian Dynamics (MOND). While dark matter models are flexible in accommodating observations, they do not provide the predictive capacity of MOND. If the universe is made of cold dark matter, why does MOND get any predictions right?
S. McGaugh
Wed, 10 Mar 21
36/56
Comments: 29 pages (plus 20 pages of references), 8 figures. Invited review for a conference on Dark Matter and Modified Gravity, part of the project `LHC and Gravity’. Includes an introduction accessible to a broad audience and some historical narrative leading to more advanced material