The innermost 200 pc of NGC 3156. The box indicates the 100 pc region that is used in our fit for the parameters of the surface brightness profile. Panels (I) and (II) show the WFC3/F475W observations and the model, respectively (on an arcsinh stretch). Panels (III) and (IV) show absolute and relative residuals for this fit, respectively (on a linear scale). The color scale of relative residuals ranges from −100% to +100%, as indicated by the bar. Large negative residuals are visible in the central pixels of the ATLAS3D surface brightness model, indicating that the fit severely overestimates the resolved and unresolved light from the very center of the galaxy. Our parametrization yields a flattened inner power law (﹩\gamma =1.2﹩) inside the break radius ﹩{R}_{{\rm{b}}}=20\;{\rm{pc}}﹩, which provides a much better parametrization of the observations, as can be seen by the relatively small residuals. A dust lane is visible in the top right of panels (I) and (IV).