* Astronomy

Title: Lenticular galaxy IC 719: current building of the counterrotating large-scale stellar disk
Authors: Ivan Yu. Katkov, Olga K. Sil'chenko, Victor L. Afanasiev

We have obtained and analysed long-slit spectral data for the lenticular galaxy IC 719. In this gas-rich S0 galaxy, its large-scale gaseous disk counterrotates the global stellar disk. Moreover in the IC 719 disk we have detected a secondary stellar component corotating the ionised gas. By using emission-line intensity ratios, we have proved the gas excitation by young stars and so are claiming current star formation, most intense in a ring-like zone at the radius of 10" (1.4 kpc). The oxygen abundance of the gas in the starforming ring is about half of the solar abundance. Since the stellar disk remains dynamically cool, we conclude that smooth prolonged accretion of the external gas from a neighbouring galaxy provides current building of the thin large-scale stellar disk.

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