Kinematic evidence for an old stellar halo in the Large Magellanic Cloud.

نویسندگان

  • Dante Minniti
  • Jura Borissova
  • Marina Rejkuba
  • David R Alves
  • Kem H Cook
  • Kenneth C Freeman
چکیده

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 measured the kinematics of 43 RR Lyrae stars in the inner regions of the nearby Large Magellanic Cloud (LMC) galaxy. The velocity dispersion equals 53 +/- 10 kilometers per second, which indicates that a kinematically hot metal-poor old halo also exists in the LMC. This result suggests that our galaxy and smaller late-type galaxies such as the LMC have similar early formation histories.

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عنوان ژورنال:
  • Science

دوره 301 5639  شماره 

صفحات  -

تاریخ انتشار 2003