X-ray Counterparts of Be Gamma-ray Binary Candidates

The AGILE and Fermi missions have detected hundreds of unidentified GeV sources in the Galactic plane, but only a handful have been correlated with X-ray or optical counterparts. Several of these are high mass X-ray binaries that also exhibit MeV, GeV, and/or TeV emission, leading to a new class of "gamma-ray binaries". More than half of all HMXB contain Be stars, and likewise most of the known gamma-ray binaries are Be star systems. We have identified three new Be stars that may be associated with GeV point sources, and we propose XMM-Newton observations to measure the position, flux, and spectral properties of the X-ray counterparts. Our modest time request will help identify several unknown GeV point sources, potentially doubling the number of known Be/gamma-ray binaries.