Milky Way potentials in CDM and MOND. Is the Large Magellanic Cloud on a bound orbit?
Abstract
We compute the Milky Way potential in different cold dark matter (CDM) based models, and compare these with the modified Newtonian dynamics (MOND) framework. We calculate the axis ratio of the potential in various models, and find that isopotentials are less spherical in MOND than in CDM potentials. As an application of these models, we predict the escape velocity as a function of the position in the Galaxy. This could be useful in comparing with future data from planned or already-underway kinematic surveys (RAVE, SDSS, SEGUE, SIM, GAIA or the hypervelocity stars survey). In addition, the predicted escape velocity is compared with the recently measured high proper motion velocity of the Large Magellanic Cloud (LMC). To bind the LMC to the Galaxy in a MOND model, while still being compatible with the RAVE-measured local escape speed at the Sun's position, we show that an external field modulus of less than is needed.
Cite
@article{arxiv.0803.0977,
title = {Milky Way potentials in CDM and MOND. Is the Large Magellanic Cloud on a bound orbit?},
author = {Xufen Wu and Benoit Famaey and Gianfranco Gentile and Hagai Perets and HongSheng Zhao},
journal= {arXiv preprint arXiv:0803.0977},
year = {2009}
}
Comments
Accepted for publication in MNRAS, 13 pages, 7 figures, 3 tables