Program: GS-2007A-Q-76

This programme is a continuation of our spectroscopic study of Tidal Dwarf Galaxy (TDGs) candidates in minor merging systems using GMOS-S in long slit mode, requested as a poor weather programme (IQ=Any, CC=70) for Gemini South. These TDG candidates were detected during a survey of HII regions in systems from the Arp-Madore catalogue as presenting Halpha luminosities and corresponding star formation rates much larger than those found in normal HII regions in spiral galaxies. In order to confirm if those regions are real TDGs or very luminous HII region complexes, we propose to measure (a) their oxygen abundance (TDGs are metal poor compared to the HII regions), (b) their internal kinematics (TDGs should be kinematically decoupled from the velocity field of the parent galaxy). Combined with the photometric parameters from broad band and Halpha images (M_B, L(alpha), SFR) we may observationally confirm the possibility of formation of Tidal Dwarf Galaxies during the interaction of galaxies with different masses (minor mergers). Otherwise, as very little information exists on the individual systems targeted in this programme, and not much more on the more generic topic of individual, spatially resolved, star forming regions in minor mergers, the observations requested here would be valuable by themselves as we can study the individual kinematics and physical conditions of the HII regions and star formation complexes in the parent galaxies.