Colloquium

The Galactic Bulge

I will give a brief introduction to galactic bulges, and then describe a spectroscopic survey of 28,000 bulge stars (the ARGOS survey) which we have recently completed. Our data support the view that the Galactic bulge did not form from mergers but through the bar-forming and bar-buckling instability of the early disk. The bulge is not a single homogeneous stellar population. It shows several well-defined metallicity components with different spatial and dynamical properties. These components reflect the components of the early disk, which are now trapped within the bulge structure. From N-body models, we can evaluate how the disk instability maps the components of the early disk into the bulge.

Followed by wine and cheese in Pupin 1402.

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