Extended Gaseous Disk in the S0 Galaxy NGC 4143

We present the results of our spectroscopic study of the lenticular galaxy NGC 4143-a peripheral member of the Ursa Major cluster. Using the observations at the 6-m SAO RAS telescope with the SCORPIO-2 instrument and the archival data of panoramic spectroscopy with the SAURON instrument at the WHT, we have detected an extended inclined gaseous disk in this lenticular galaxy with a spin approximately opposite in direction to the spin of the stellar disk up to a distance of about 3.5 kpc from the center. The galaxy images in the Ha and [N II] lambda 6583 emission lines obtained at the 2.5-m CMO SAI MSU telescope with the MaNGaL instrument have shown that the emission lines are excited by a shock wave. A spiral structure absent in the stellar disk of the galaxy is clearly seen in the brightness distribution of ionized-gas lines (H alpha and [N II] from the MaNGaL data and [O III] from the SAURON data). A complex analysis of both the distribution of Lick indices along the radius and the integrated colors, including the ultraviolet measurements with the GALEX space telescope and the near-infrared measurements with the WISE space telescope, has shown that there has been no star formation in the galaxy, possibly, for the last 10 Gyr. Thus, the recent external-gas accretion event in NGC 4143 was not accompanied by star formation, probably, due to an inclined direction of the gas inflow onto the disk.