Abstract

Nearby merging pairs are unique laboratories in which one can study the gravitational effects on the individual interacting components. In this manuscript, we report the characterization of selected HII regions along the peculiar galaxy NGC2936, member of the galaxy pair Arp 142, an E+S interaction, known as 'The Penguin'. Using Gemini South spectroscopy, we have derived a high enhancement of the global star formation rate (SFR) = 35.9 M-circle dot yr(-1) probably stimulated by the interaction. Star-forming regions on this galaxy display oxygen abundances that are consistent with solar metallicities. The current data set does not allow us to conclude any clear scenario for NGC 2936. Diagnostic diagrams suggest that the central region of NGC2936 is ionized by active galactic nucleus (AGN) activity and the eastern tidal plume in NGC2936 is experiencing a burst of star formation, which may be triggered by the gas compression due to the interaction event with its elliptical companion galaxy: NGC2937. The ionization mechanism of these sources is consistent with shock models of low velocities of 200-300 km s(-1). The isophotal analysis shows tidal features on NGC2937: at inner radii non-concentric (or off-centring) isophotes, and at large radii, a faint excess of the surface brightness profile with respect to de Vaucouleurs law. By comparing the radial velocity profiles and morphological characteristics of Arp 142 with a library of numerical simulations, we conclude that the current stage of the system would be about 50 +/- 25 Myr after the first pericentre passage.