We present a detailed comparison of the Milky Way ( MW ) globular cluster ( GC ) kinematics with the 25 Milky Way-mass cosmological simulations from the E-MOSAICS project .
While the MW falls within the kinematic distribution of GCs spanned by the simulations , the relative kinematics of its metal-rich ( [ Fe / H ] > -1.2 ) versus metal-poor ( [ Fe / H ] < -1.2 ) , and inner ( r < 8 \mbox { ~ { } kpc } ) versus outer ( r > 8 \mbox { ~ { } kpc } ) populations are atypical for its mass .
To understand the origins of these features , we perform a comprehensive statistical analysis of the simulations , and find 18 correlations describing the assembly of L ^ { * } galaxies and their dark matter haloes based on their GC population kinematics .
The correlations arise because the orbital distributions of accreted and in-situ GCs depend on the masses and accretion redshifts of accreted satellites , driven by the combined effects of dynamical fraction , tidal stripping , and dynamical heating .
Because the kinematics of in-situ/accreted GCs are broadly traced by the metal-rich/metal-poor and inner/outer populations , the observed GC kinematics are a sensitive probe of galaxy assembly .
We predict that relative to the population of L ^ { * } galaxies , the MW assembled its dark matter and stellar mass rapidly through a combination of in-situ star formation , more than a dozen low-mass mergers , and 1.4 \pm 1.2 early ( z = 3.1 \pm 1.3 ) major merger .
The rapid assembly period ended early , limiting the fraction of accreted stars .
We conclude by providing detailed quantitative predictions for the assembly history of the MW .