Kinematics and composition of the Galactic bulge: Recent progress

R. Michael Rich, Christian Howard, David B. Reitzel, Hongsheng Zhao, Roberto De Propris

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

We present recent results from a Keck study of the composition of the Galactic bulge, as well as results from the bulge Bulge Radial Velocity Assay (BRAVA). Culminating a 10 year investigation, Fulbright, McWilliam, & Rich (2006, 2007) solved the problem of deriving the iron abundance in the Galactic bulge, and find enhanced alpha element abundances, consistent with the earlier work of McWilliam & Rich (1994). We also report on a radial velocity survey of 2MASS-selected M giant stars in the Galactic bulge, observed with the CTIO 4m Hydra multi-object spectrograph. This program is to test dynamical models of the bulge and to search for and map any dynamically cold substructure in the Galactic bulge. We show initial results on fields at 10 < l < + 10 and b = 4. We construct a longitude-velocity plot for the bulge stars and the model data, and find that contrary to previous studies, the bulge does not rotate as a solid body; from 5 < l < + 5 the rotation curve has a slope of 100 km s1 and flattens considerably at greater l and reaches a maximum rotation of 45 km s1 (heliocentric) or ~ 70 km s1 (Galactocentric). This rotation is slower than that predicted by the dynamical model of Zhao (1996).

Original languageEnglish
Pages (from-to)333-338
Number of pages6
JournalProceedings of the International Astronomical Union
Volume3
Issue numberS245
DOIs
Publication statusPublished - 1 Jul 2007

Keywords

  • Galaxies: bulges
  • Galaxy: abundances
  • Galaxy: bulge
  • Galaxy: formation
  • Galaxy: kinematics and dynamics

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