The polar ring galaxy AM 2040-620 and its possible companion

Abstract

Polar ring galaxies (PRGs) are peculiar systems where a gas-rich, nearly polar ring surrounds a host galaxy. They are the result of galaxy interactions that form mainly by tidal accretion of material from a gas rich donor galaxy. There is a number of formation mechanisms for PRGs: minor or major mergers, tidal accretion events, or direct cold gas accretion from filaments of the cosmic web. These objects can be used to probe the three-dimensional shape of dark matter haloes, provided that the ring is in equilibrium with the gravitational potential of the host galaxy. The polar ring galaxy, AM 2040-620, which has not yet been well studied, is the subject of this work. This galaxy contains an almost perpendicular warped ring and one possible companion galaxy to the NW. The radial velocity of this object is 3301\pm65 km/s and is part of a group of fifteen possible polar ring galaxies, according to the literature. In order to better understand this system, images and long slit spectra were observed with the 1.60 m OPD/LNA telescope. In the I band image, the outer parts of the ring are not symmetrical. A disturbance in the Eastern side and a faint plume were detected. Two small satellites are located to the north. The bulge is elliptical but not perfectly symmetrical in this image. The B-band image shows material that extends beyond the ring in the western and eastern directions. After processing, the B-image shows that the possible companion galaxy 2MASX J20441668-6158092 has a tidally disturbed disk. Its radial velocity is unknown, but the spectroscopy, which is still under analysis, will furnish this information.