Measured E-mode angular power spectra for cosmic shear from the galaxy ellipticity in the Flagship simulation, after applying the expected survey footprint of the northern part of Euclid’s first data release (DR1). Shown for each tomographic redshift bin (numbered panels) are the cosmic shear signal of that bin (black) and the cross-correlations with both lower-numbered (blue) and higher-numbered (orange) bins. The shading of the colour indicates the difference between the two bin numbers. Galaxy ellipticities have intrinsic ellipticity variations (‘shape noise’), but no shape measurement error has been added here. Spectra are binned into 32 logarithmic bins. The y-axis changes to linear when crossing zero.