Fermi LAT 0.5–20 GeV (left) and 10–20 GeV (right) images of a 5° × 5° region centered on Terzan 5. The white circle shows the 95% confidence error circle of the gamma-ray source determined by using the 0.5–20 GeV image and gtfindsrc. The white crosses are the optical center of Terzan 5. In addition to Terzan 5, strong Galactic plane emission is also seen. Both images are smoothed by a 0 3 Gaussian function. The inset figures are the associated TS maps of the 2° × 2° region. All bright Fermi sources as well as the diffuse Galactic and extragalactic background emission are included in the background model. The black crosses denote the optical center of Terzan 5. The color scale indicates the TS value corresponding to the detection significance .