SIMBAD references

2012ApJ...747L..37M - Astrophys. J., 747, L37 (2012/March-2)

Exploring halo substructure with giant stars: substructure in the local halo as seen in the grid giant star survey including extended tidal debris from ω Centauri.

MAJEWSKI S.R., NIDEVER D.L., SMITH V.V., DAMKE G.J., KUNKEL W.E., PATTERSON R.J., BIZYAEV D. and GARCIA PEREZ A.E.

Abstract (from CDS):

We present the latitude-normalized radial velocity (vb) distribution of 3318 subsolar metallicity, V ≲ 13.5 stars from the Grid Giant Star Survey (GGSS) in southern hemisphere fields. The sample includes giants mostly within ∼5 kpc from the Galactic disks and halo. The nearby halo is found to (1) exhibit significant kinematical substructure, and (2) be prominently represented by several velocity coherent structures, including a very retrograde "cloud" of stars at l ∼ 285° and extended, retrograde "streams" visible as relatively tight l-vbsequences. One sequence in the fourth Galactic quadrant lies within the l-vb space expected to contain tidal debris from the "star cluster" ω Centauri. Not only does ω Cen lie precisely in this l-vbsequence, but the positions and vb of member stars match those of N-body simulations of tidally disrupting dwarf galaxies on orbits ending with ω Cen's current position and space motion. But the ultimate proof that we have very likely found extended parts of the ω Cen tidal stream comes from echelle spectroscopy of a subsample of the stars that reveals a very particular chemical abundance signature known to occur only in ω Cen. The newly discovered ω Cen debris accounts for almost all fourth Galactic quadrant retrograde stars in the southern GGSS, which suggests ω Cen %%%% Already done %%%% is a dominant contributor of retrograde giant stars in the inner Galaxy.

Abstract Copyright:

Journal keyword(s): galaxies: individual: ω Centauri - galaxies: interactions - galaxies: kinematics and dynamics - Galaxy: structure

Simbad objects: 17

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