Abstract
I will give a brief overview of galactic bulges and then discuss in more detail what is known about the bulge of our Galaxy. The Milky Way has a small boxy/peanut-shaped bulge which we believe formed via instabilities of the disk rather than through mergers. The bulge of the Milky Way therefore appears to be a dynamical product of the early Galactic disk, without significant contamination from mergers with other galaxies. The instabilities are believed to have occurred about 2 Gyr after the inner stellar disk was formed. The bulge therefore contains a relatively clean sample of the early disk as it was about 8 Gyr ago, trapped dynamically within the boxy bulge structure. The various components of the early disk (young thin disk, older thin disk, thick disk) are visible as substructure in the stellar metallicity distribution function and kinematics of the bulge stars.
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Acknowledgements
I am grateful to Lia Athanassoula, Ortwin Gerhard, John Kormendy, Inma Martinez-Valpuesta and Melissa Ness for many discussions about bulges. My best wishes to David Block and Bruce Elmegreen on this notable occasion.
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Freeman, K. (2015). The Galactic Bulge. In: Freeman, K., Elmegreen, B., Block, D., Woolway, M. (eds) Lessons from the Local Group. Springer, Cham. https://doi.org/10.1007/978-3-319-10614-4_3
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DOI: https://doi.org/10.1007/978-3-319-10614-4_3
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