Program: GN-2020B-Q-109

The Taffy galaxy pair UGC 12915/4 (D ~ 62 Mpc) experienced a head-on collision 25-30 Myr ago that rised a bridge of atomic and molecular gas connecting both galaxies. Despite intense star formation is expected in such physical conditions, this system is not a strong IR emitter. Nine Ultra Luminous X-ray sources (ULXs) have been detected in the Taffy system. The brightest one is associated with an HII extragalactic region, while the origin of the other eight still has to be confirmed. The Taffy galaxies have been extensively studied in radio frequencies. However, they have been poorly studied in the optical and NIR. In this proposal we request deep g', r', i', z', H_alpha and H_alpha_C images of one Gemini-North field that will cover the whole Taffy system. With this images we will try to characterize the optical counterparts of several ULXs, detect addional extragalactic star-forming regions and identify low-mass galaxies of tidal origin. We expect that this additional information will help to better understand the physical processes involved in galaxies interactions.