Action-space clustering of tidal streams to infer the Galactic potential

Understand

We present a new method for constraining the Milky Way halo gravitational potential by simultaneously fitting multiple tidal streams.

• This method requires full three-dimensional positions and velocities for all stars to be fit, but does not require identification of any specific stream or determination of stream membership for any star.
• We exploit the principle that the action distribution of stream stars is most clustered when the potential used to calculate the actions is closest to the true potential.
• Clustering is quantified with the Kullback-Leibler Divergence (KLD), which also provides conditional uncertainties for our parameter estimates.