Precision Measurements in the Milky Way Galaxy in the age of Large Scale Surveys, A resonant heating model for the X- or peanut-shaped Galactic bulge

Alice Quillen

October 24, 2013

–

Abstract: Using deep photometric surveys, Nataf, McWilliam and Zoccali, have recently discovered that the Milky Way’s bulge is X- or peanut-shaped. X- or peanut shape bulge formation in disk galaxies is often attributed to bar buckling. However, orbits in the bulge can have vertical oscillations resonant with the Galctic bar. I will explore and test a second order vertical resonance heating model for the feature that implies that the stellar orbits contributing to it are confined to a narrow region in action/angle space. The X- or peanut shaped feature in our Galaxy gives a second example of a precision measurement of the structure of the Galaxy that has been made possible by recent large scale Galactic surveys.