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

Abstract

We present spectral data cubes of the interacting galaxy system $\rm Arp\, {1}$43, composed of the ring galaxy $\rm NGC\, {2}$445 and the lenticular galaxy $\rm NGC\, {2}$444, 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 $\rm NGC\, {2}$445 with the exception of a few very faint ones discovered at the base of the long tidal plume extending north of $\rm NGC\, {2}$444. Analysis of the $\rm H\alpha$ velocity map reveals strong non-circular flows in the ring of $\rm NGC\, {2}$445, 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 $\rm Arp\, {1}$43 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.