CFHT MegaCam Hα+[NII] image of NGC 4569 and IC 3583 smoothed as in Fig. 1. The different low surface-brightness regions with Hα+[NII] emission are indicated with cyan polygons, and their surface brightness is listed in Table 3. The yellow elliptical aperture indicates the adopted extension of the galaxy within which its total Hα+[NII] flux has been measured (Table 1). The total emission within the tail has been measured within the large green polygon, while that of the nuclear outflow, within the blue polygon.