Ionized gas morphology of UG101 and its companion UG101b, traced by rest-frame Hα emission. Flux values have been corrected for dust attenuation (see text), except for UG101b, where Hβ is not detected. Spaxels with (S/N)_Hα < 4 have been masked. A second colorbar shows the corresponding levels of surface density SFR (Σ_SFR), derived from the Hα emission line shown in the top panel (see text). The black cross marks the galaxy center, and the light blue contour shows the galaxy I-band boundaries (see text).