Exciting the magnetosphere of the magnetar CXOU J164710.2-455216 in Westerlund 1 - M. P. Muno; B. M. Gaensler; J. S. Clark; R. de Grijs; D. Pooley; I. R. Stevens; S. F. Portegies Zwart (Monthly Notices of the Royal Astronomical Society, 2007)