Relative flux (excess/background) map above 150 GeV around W51. Overlaid are contour levels from test statistics starting at 3 and increasing by one per contour. The map was smoothed with a Gaussian kernel of 0.085°. The green cross represents the center of the observations, while the green dashed circle represents the integration area. The black dot is the determined position of the centroid with the statistical uncertainties shown by the surrounding black ellipse. The region of shocked atomic and molecular gas (Koo & Moon 1997b,a) is represented by the red dashed ellipse. The blue diamond shows the position of the possible PWN CXO J192318.5+140305. In the left lower corner the Gaussian sigma of a point-like source (PSF) after the applied smearing is shown.