Putting MOND to the Test

Wednesday, 27 August 2014 9 a.m. — 10 a.m. MST

AURA Lecture Hall

NOIRLab South Colloquia
GRAEME CANDLISH (Astronomy Postdoc from Universidad de Concepción and Gemini South Visiting Astronomer)

The LCDM standard cosmological model is strongly supported by multiple lines of evidence, particularly from observations at large scales such as the CMB and large scale structure. There are some indications, however, of problems at smaller scales. An alternative to the CDM approach is to modify the gravitational force, as exemplified by the MOdified Newtonian Dynamics (MOND) idea. While evidence suggests MOND cannot account for dynamics at all scales without dark matter, it has been successful at galactic scales. Due to the complexity of the theory, however, most tests of MOND have extended no further than using a simple scaling relation to determine rotation curves or velocity dispersions. Therefore, to test the concept more thoroughly we require numerical simulations. In this talk I will discuss the development and testing of a new N-body solver, using two distinct formulations of MOND, that is incorporated into the RAMSES code. I will briefly summarise the theory of MOND, and how it is implemented in the code. I will then demonstrate the effectiveness of the code in various test cases: an isolated star cluster, two orbiting clusters, and an exponential galactic disk. Finally I will discuss several future applications of the code to test the MOND idea, including a first step in estimating the behaviour of MOND galactic disks in ram-pressure stripping and ring galaxy dynamics.