A Magnetar and Friends in the Galactic Super Star Cluster Westerlund 1

We are requesting a single XMM observation (45 ks) to determine whether the 10.6s Xray pulsar that we recently discovered in the Galactic super star clusterWesterlund 1 is a magnetar. The pulsar is notable because, as a member ofWesterlund 1, we know that the initial mass of the pulsar.s progenitor was atleast 40 Msun. Measuring the Bfield strength would reveal the role of magneticfields in allowing 30 Msun stars to lose 95% of their mass and become neutronstars. Westerlund 1 also may harbor 10 more compact objects that would bedetectable with XMM. Discovering these would add significantly to the handful ofobservational limits on the mapping between initial stellar masses and thecompact objects they leave behind. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]