Program: GN-2015B-Q-65

During tidal interactions between gas rich pirs of galaxies, large amounts of debris can be expelled, which later can collapse and form small galaxies, known as Tidal Dwarf galaxies. Born out of collapsing debris, according to $\Lambda$CDM cosmology based modelling, they are expected to be dark matter free. However establishing the absence of dark matter in TDGs is an observational challange mainly due to sensitivity requirements of the experiment. Here we propose, long slit spctroscopy of a TDG from our sample -- the TDG of Arp 202, with an aim to study the major axis kinematics of the Halpha emission. Our observations will allow us to estimate the velocity gradient along the major axis and the metallicity of the TDG, give an idea of the TDG's rotation pattern, constrain its dynamical mass and estimate its dark matter content. Observations of this kind are crucial as very few studies have been carrid out till date to unambiguously rule out the presence of dark matter in TDGs as proposed by the $\Lambda$CDM based models. High sensitivity and high resolution are the crucial necessities for this experiment. For the low surface brightness objects we are studying, Gemini/GMOS is ideal to reach reasonable SNR with a practical exposure time.