4 2009 Fermi Symposium, Washington, D.C., Nov. 2-5 eConf C091122 Acknowledgments ray emission observed by LAT is probably negligible. Furthermore, the pulsar wind interaction model of [28] predicts gamma-ray spectra that extend well above 1 GeV into the TeV domain, with possible spec- tral turnovers and breaks above ∼ 100 GeV. These high cutoff energies are at odds with our observed spectral break energy in the GeV range. To explain a GeV spectral break in the pulsar wind interaction model, the maximum energy of the accelerated par- ticles should be limited to a few GeV; this scale is below the injection energies expected for electrons and positrons from the inner pulsar magnetospheres, which may range up to TeV energies [29]. Conse- quently, pulsar wind interactions should play a mi- nor role in the acceleration of electrons and positrons in 47 Tuc. This is consistent with the model of [24], which suggests that the direct conversion efficiency of spin-down energy into gamma rays, η$_{γ}$ , is consid- erably larger than the efficiency η$_{e}$ ± for electron and positron production. We cannot exclude, however, the possibility that pulsar wind interactions contribute at a low level to the gamma-ray signal we detected from 47 Tuc. Because TeV gamma-ray emission from 47 Tuc has not yet been detected [30], we cannot place firm constraints on that contribution. Until now the study of close binary systems in globular clusters has mainly relied on X-ray obser- vations. Such studies, however, are hampered by the fact that a large variety of binary systems emit X-rays [cataclysmic variables (CVs), low-mass x-ray binaries (LMXBs), chromospherically active main-sequence bi- naries (BY Dras/RS CVns), and MSPs] and that it is difficult to assess the nature of the sources from X-ray observations alone (however, see [11]). X-ray stud- ies must therefore be backed up by multiwavelength identification programs that help to disentangle these source populations. High-energy gamma-ray obser- vations are unique in that they should be sensitive mainly to the pulsar populations. This is illustrated by Fermi observations of our own Galaxy that have revealed that pulsars form the largest and most lumi- nous point-source population in this energy domain. No CVs, LMXBs, or BY Dras have so far been de- tected in high-energy gamma rays [31]. It thus seems rather likely that pulsars (and MSPs in particular) are also the primary population of gamma-ray sources in globular clusters. The Fermi LAT Collaboration is supported by NASA and the U.S. Department of Energy; the Com- missariat ` a l’Energie Atomique and CNRS/Institut National de Physique Nuclaire et de Physique des Particules (France); the Agenzia Spaziale Italiana and Istituto Nazionale di Fisica Nucleare (Italy); the Ministry of Education, Culture, Sports, Science and Technology, High Energy Accelerator Research Or- ganization (KEK), and Japan Aerospace Exploration Agency (Japan); and the K. A. Wallenberg Founda- tion, Swedish Research Council, and National Space Board (Sweden). Additional support was provided by the Istituto Nazionale di Astrofisica (Italy) and the Centre National Etudes Spatiales (France). [1] Clark, G. W., ApJ, 199, L143 (1975). [2] Verbunt, F., Hut, P., IAU Symp, 125, 187 (1987). [3] Gendre, B., Barret, D., Webb, N.A., A&A 403, 11 (2003). [4] Pooley, D., et al., ApJ. 591, L131 (2003). [5] Hut, P., et al., PASP, 104, 981 (1992). [6] Alpar, M.A., Cheng, A.F., Ruderman, M.A., Shaham, J., Nature 300, 728 (1982). [7] Abdo, A. A., et al., ApJ. 699, 1171 (2009). [8] Abdo, A. A., et al., Science 325, 848 (2009) [9] Camilo, F., Rasio, F.A., ASP Conf. Ser. 328, 147 (2005). [10] McLaughlin, D.E., et al., ApJ. Suppl. Ser. 166, 249 (2006). [11] Grindlay, J. E., Heinke, C., Edmonds, P.D., Murray, S. S., Science 292, 2290 (2001) [12] Heinke, C. O., et al., ApJ. 625, 796 (2005). [13] Camilo, F., Lorimer, D.R., Freire, P., Lyne, A.G., Manchester, R.N., ApJ. 535, 975 (2000). [14] Atwood, W.B., Abdo, A.A, Ackermann, M., et al., ApJ, 697, 1071 (2009) [15] McLaughlin, D.E., Anderson, J., Meylan, G., et al., ApJS, 166, 249 (2006) [16] Howell, J. H., Guhathakurta, P., Gilliland, R. L., PASP, 112, 1200 (2000) [17] Michelson, P.F., et al., ApJ. 435, 218 (1994). [18] Fierro, J.M. et al., ApJ. 447, 807 (1995). [19] [Manandhar, R.P., Grindlay, J.E., Thompson, D.J., A&A Suppl. Ser., 120, 255 (1996). [20] Freire, P.C et al., MNRAS, 340, 1359 (2003). [21] Wei, D.M., Cheng, K.S., Lu, T., ApJ. 468, 207 (1996). [22] Zhang, L., Cheng, K.S., A&A, 398, 639 (2003). [23] Harding, A.K., Usov, V.V., Muslimov, A.G., ApJ, 622, 531 (2005). [24] Venter, C., De Jager, O.C., ApJ, 680, L125 (2008). [25] Watters, K.P., Romani, R.W., Weltevrede, P., John- ston, S., ApJ. 695, 1289 (2009). [26] Harding, A.K., Muslimov, A.G., Zhang, B., ApJ, 576, 366 (2002). [27] McConnell, D., Deshpande, A.A., Connors, T., Ables,