Testing formation mechanisms of the Milky Way's thick disc with RAVE
Abstract
We study the eccentricity distribution of a thick disc sample of stars observed in the Radial Velocity Experiment (RAVE) and compare it to that expected in four simulations of thick disc formation in the literature (accretion of satellites, heating of a primordial thin disc during a merger, radial migration, and gas-rich mergers), as compiled by Sales et al. (2009). We find that the distribution of our sample is peaked at low eccentricities and falls off smoothly and rather steeply to high eccentricities. This distribution is fairly robust to changes in distances, thin disc contamination, and the particular thick disc sample used. Our results are inconsistent with what is expected for the pure accretion simulation, since we find that the dynamics of local thick disc stars implies that the majority must have formed "in situ". Of the remaining models explored, the eccentricity distribution of our stars appears to be most consistent with the gas-rich merger case.
Keywords
Cite
@article{arxiv.1009.2052,
title = {Testing formation mechanisms of the Milky Way's thick disc with RAVE},
author = {Michelle Wilson and Amina Helmi and H. L. Morrison and M. A. Breddels and O. Bienayme and J. Binney and J. Bland-Hawthorn and R. Campbell and K. C. Freeman and J. P. Fulbright and B. K. Gibson and G. Gilmore and E. K. Grebel and U. Munari and J. F. Navarro and Q. A. Parker and W. Reid and G. Seabroke and A. Siebert and A. Siviero and M. Steinmetz and M. E. K. Williams and R. F. G. Wyse and T. Zwitter},
journal= {arXiv preprint arXiv:1009.2052},
year = {2015}
}
Comments
8 pages, 7 figures, submitted to MNRAS