The information content in cold stellar streams

Understand

Cold stellar streams---produced by tidal disruptions of clusters---are long-lived, coherent dynamical features in the halo of the Milky Way.

• Due to their different ages and different positions in phase space, different streams tell us different things about the Galaxy.
• Here we employ a Cramer--Rao (CRLB) or Fisher-matrix approach to understand the quantitative information content in eleven known streams (ATLAS, GD-1, Hermus, Kwando, Orinoco, PS1A, PS1C, PS1D, PS1E, Sangarius and Triangulum).
• This approach depends on a generative model, which we have developed previously, and which permits calculation of derivatives of predicted stream properties with respect to Galaxy and stream parameters.