J1356+10. GTC continuum and Hα images. Contour levels in the continuum (first panel) and Hα images (second panel) start at 3σ and increase with factor ×2.5. For the Hα image, σ = 4.4 × 10⁻¹⁹ erg s⁻¹ cm⁻² pixel⁻¹. Galaxies G1, G3, G4 and possibly G2, G5, and G6 are members of the same group as the QSO2 (see text). The rectangular areas in the second panel are zoomed in the 3th (top rectangle) and 4th (bottom rectangle) panels. The contours in these trace the morphology within the high SB regions. The purple arrows in the last panel show the location of the giant 12 kpc bubble, the clumps and wisps identified by Greene et al. (2012). Additional faint Hα features are also indicated. Ionised gas is detected up to ∼16 kpc to the east and west of the long tidal filament (third panel).