A Fully Self-Consistent Constraint on the Mass of M31 and the Local Group
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Authors
Foreman-MacKey, Daniel
Date
2010-08-27T17:26:36Z
Type
thesis
Language
eng
Keyword
Physics , Galaxy Astrophysics
Alternative Title
Abstract
We present the first fully self-consistent, axisymmetric, dynamical model of the Andromeda galaxy (M31). We constrain the physical parameters of the model with datasets on all radial scales: the bulge projected velocity dispersion, rotation curve, surface brightness profile, and the kinematics of globular clusters and satellite galaxies. Combining these highly heterogeneous datasets into a single self-consistent analysis is natural in the framework of Bayesian inference. Using a geometric argument, we also infer the three-dimensional velocity of M31 relative to the Milky Way. From this orbit, we constrain the total mass of the Local Group by the ``timing argument''. We find that the virial mass of M31 is $M_\mathrm{M31,vir} = 5.0^{+2.2}_{-1.7} \times 10^{12} \, M_\odot$ and the mass of the Local Group is $M_\mathrm{LG} = 8.8^{+8.0}_{-4.2} \times 10^{12} \, M_\odot$. We conclude that the large uncertainties in our results are due primarily to the small sample size at large radii and that either a significantly larger sample or unjustifiably informative priors are necessary to improve the constraint.
Description
Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2010-08-27 08:32:52.823
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This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.