sition due to inaccuracies in the point-spread function and the telescope alignment are estimated to be < 1’. The position of the gamma-ray source is spatially con- sistent with the location ( α 2000 = 0 $^{h}$24$^{m}$05 . $^{s}$67, δ 2000 = -72 $^{◦}$04’52 . $^{′′}$62) of the core of 47 Tuc [15]. We tested for a possible extent of the gamma-ray emission by fitting 2D Gaussian-shaped intensity profiles to the LAT data for which we adjusted the widths and po- sitions. We find that the emission is best fitted as a point source. From the decrease of the likelihood with increasing Gaussian width we derive an upper limit for the extent (FWHM) of 21’ (2 σ ). This limit is considerably larger than the 47 Tuc core radius of 25” [16], demonstrating that 47 Tuc’s core cannot be resolved by the LAT. We determined the gamma-ray spectrum of the LAT source by maximum likelihood fitting of the emis- sion in 10 logarithmically spaced energy bins covering the interval 200 MeV to 10 GeV (Fig. 2). The spec- trum reveals a relatively flat spectral energy distribu- tion with a clear cutoff at energies above a few GeV; it is well fitted by an exponentially cut-off power law that provides a 3 σ improvement upon a simple power law, with best-fitting spectral index Γ = 1.3 ± 0.3 and cutoff energy E$_{cut}$ = 2.5 ± 1$_{.}$6 0$_{.}$8 GeV. The system- atic uncertainty in the spectral index is estimated to be 0.1; that in the cut-off energy is estimated to be 0.3 GeV. By integrating the best-fitting model over the energy range 100 MeV to 10 GeV, we determined the integral photon flux in this band to be 2.6 ( ± 0.8) × 10 8 photons cm − 2 s − $^{1}$, which is slightly below the upper limit of 5 × 10 8 photons cm − 2 s − 1 reported by EGRET [17-19]. The photon flux corresponds to an energy flux of 2.5 ( ± 0.4) × 10 − 11 ergs cm − 2 s − $^{1}$. The systematic uncertainty in our fluxes is estimated to be < 10%. The overall detection significance of the source amounts to 17 σ . We searched for time variability of the gamma-ray signal by dividing our data set into equally sized time bins of durations 1 day, 1 week, 2 weeks, and 1 month. We detected no source at the location of 47 Tuc in any of the daily or weekly time bins, which indi- cates that the observed emission did not arise from short-duration flares. The LAT source was signifi- cantly detected in all 2-week and monthly time bins at a comparable flux level, which suggests that the source was steady over the period of observation. Us- ing ephemerides from [18] for 21 MSPs in 47 Tuc, we searched for gamma-ray pulsations in our data with- out finding any significant detection. The observed gamma-ray signal thus does not appear to be domi- nated by a single (or a few) known gamma-ray pulsars in 47 Tuc; this is in line with the absence of a single particularly powerful MSP in the cluster. Pulsed gamma-ray curvature radiation (and even- tually inverse Compton scattering) arising near the polar cap and/or in an outer magnetospheric gap in MSPs has been proposed as a possible source of high- 2009 Fermi Symposium, Washington, D.C., Nov. 2-5 2 eConf C091122 III. DISCUSSION FIG. 1: Fermi LAT gamma-ray image (200 MeV to 10 GeV) of a 1.5 ◦ × 1.5 ◦ region centered on the position of 47 Tuc. The map was adaptively smoothed by imposing a minimum signal-to-noise ratio of 5. A total of ∼ 290 counts were detected from the gamma-ray source. Black contours indicate the stellar density in 47 Tuc as derived from DSS2 red plates [32]. The white circle shows the 95% confidence region for the location of the gamma-ray source. The position of the LAT source coincides with the core region of 47 Tuc. FIG. 2: Spectral energy distribution (E $^{2}$dN$_{γ}$ /dE) of the Fermi source seen toward 47 Tuc. The solid line shows the fit of an exponentially cut-off power law obtained for the energy range 200 MeV to 20 GeV. The dashed line indicates the extrapolation of the fit to 100 MeV.