Unveiling a cosmic tango: Integral field spectroscopy and numerical simulations of Arp 143’s interaction

We present spectral data cubes of the interacting galaxy system Arp\, 143, composed of the ring galaxy NGC\, 2445 and the lenticular galaxy NGC\, 2444, obtained with the imaging Fourier transform spectrometer SITELLE at the Canada-France-Hawaii Telescope. Our data allow to probe the kinematics of the interaction and the chemical properties of the ionized gas. Star-forming regions are almost exclusively found in the ring and nucleus of NGC\, 2445 with the exception of a few very faint ones discovered at the base of the long tidal plume extending north of NGC\, 2444. Analysis of the Hα velocity map reveals strong non-circular flows in the ring of NGC\, 2445, which is expanding. Its nucleus is off-centered with respect to the ring. Oxygen abundance in the ring is on average slightly sub-solar whereas it is close to solar in the nucleus. Broad-band images obtained with the Dragonfly Telephoto array allow to identify the tenuous stellar counterpart of the radio tidal plume. The interaction between the two galaxies is simulated with a chemodynamical evolution code; these simulations suggest that Arp\, 143 has resulted from a head-on collision between a S0 and a Sc spiral galaxy following a flyby encounter that triggered the formation of the long plume from debris of the disk galaxy.