Kinematic Evidence for an Old Stellar Halo in the Large Magellanic Cloud
Astrophysics
2009-11-10 v1
Abstract
The oldest and most metal-poor Milky Way stars form a kinematically hot halo, which motivates the two major formation scenarios for our galaxy: extended hierarchical accretion and rapid collapse. RR Lyrae stars are excellent tracers of old and metal-poor populations. We measure the kinematics of 43 RR Lyrae stars in the inner regions of the nearby Large Magellanic Cloud (LMC) galaxy. The velocity dispersion, \sigma_{true}=53\pm10 km/s, indicates that a kinematically hot metal-poor old halo also exists in the LMC. This suggests that our galaxy and smaller late-type galaxies like the LMC have similar early formation histories.
Cite
@article{arxiv.astro-ph/0309351,
title = {Kinematic Evidence for an Old Stellar Halo in the Large Magellanic Cloud},
author = {Dante Minniti and Jura Borissova and Marina Rejkuba and David R. Alves and Kem H. Cook and Kenneth C. Freeman},
journal= {arXiv preprint arXiv:astro-ph/0309351},
year = {2009}
}
Comments
8 pages, 2 figures; to be published in Science on Sept. 12, 2003