SIMBAD references

2011ApJ...732L..36D - Astrophys. J., 732, L36 (2011/May-2)

Separating the conjoined red clump in the galactic bulge: kinematics and abundances.

DE PROPRIS R., RICH R.M., KUNDER A., JOHNSON C.I., KOCH A., BROUGH S., CONSELICE C.J., GUNAWARDHANA M., PALAMARA D., PIMBBLET K. and WIJESINGHE D.

Abstract (from CDS):

We have used the AAOMEGA spectrograph to obtain R ∼ 1500 spectra of 714 stars that are members of two red clumps in the Plaut Window Galactic bulge field (l, b) = (0°, - 8°). We discern no difference between the clump populations based on radial velocities or abundances measured from the Mgb index. The velocity dispersion has a strong trend with Mgb-index metallicity, in the sense of a declining velocity dispersion at higher metallicity. We also find a strong trend in mean radial velocity with abundance. Our red clump sample shows distinctly different kinematics for stars with [Fe/H] ←1, which may plausibly be attributable to a minority classical bulge or inner halo population. The transition between the two groups is smooth. The chemo-dynamical properties of our sample are reminiscent of those of the Milky Way globular cluster system. If correct, this argues for no bulge/halo dichotomy and a relatively rapid star formation history. Large surveys of the composition and kinematics of the bulge clump and red giant branch are needed to further define these trends.

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Journal keyword(s): Galaxy: bulge - Galaxy: formation - Galaxy: halo

Simbad objects: 4

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