ИСТИНА

Polar‐ring galaxies are common among the multi‐spin composite systems. The different mechanisms of their formation were proposed: a major dissipative merging, a tidal accretion from gas‐rich companion, a cold accretion of pristine low‐metallicity gas along a filament. We performed a long‐slit spectroscopy of the sample of polar‐ring galaxies selected from Sloan‐based Polar Ring Catalog at the 6‐m SAO RAS telescope. We analyzed the mechanisms of gas excitation and gas chemical abundance distribution in the sample galaxies. No any significant metallicity gradient was observed. In most cases our results allowed us to rule out the cold accretion scenario, for which we could expect the gas chemical abundance of the polar disc much lower in comparison with the main disc of the galaxy.