A Pulsar Search of AX J1838.0-0655: Powering HESS J1837-069

There is compelling evidence that the Xray source AX J1838.00655 is associatedwith HESS J1837069, an extended TeV gammaray source. Imaging with Chandra hasresolved AX J1838.00655 into a point source surrounded by a bright nebula.Therefore, this is almost certainly a young (<20 kyr), highly energetic (4E36ergs/s) pulsar powering a substantial wind nebula. We propose to use XMMNewtonto detect the expected pulsations, critical for determining the energetics ofthe pulsar, which is needed to account for the size and displacement of the TeVnebula from its pulsar power source. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]