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We have fulfilled a detailed long-slit spectroscopic analysis for two SB0 galaxies -- NGC 1533 and NGC 1543, -- belonging to the Dorado group. Our spectral data reveal asymmetric decoupled kinematics of the stars and ionised gas in these barred lenticular galaxies that give evidences for external origin of the gas in the rings. We have calculated the star formation rates in the rings by using the ultraviolet fluxes of the rings corrected for the foreground and intrinsic absorption; and we have estimated parameters of the stellar populations in the inner parts of the galaxies confirming that they are old -- except the nucleus of NGC 1543, which demonstrates signatures of re-juvenation less than 5 Gyr ago., Comment: 15 pages, 12 figures. Accepted to the MNRAS

Stellar counter-rotation in disk galaxies directly relates to the complex phenomenon of the disk mass assembly believed to be driven by external processes, such as accretion and mergers. The detailed study of such systems makes it possible to reveal the source of external accretion and establish the details of this process. In this paper, we investigate the galaxy PGC 66551 (MaNGA ID 1-179561) which hosts two large-scale counter-rotating (CR) stellar disks identified in the Sloan Digital Sky Survey MaNGA data and then confirmed using deep follow-up spectroscopy with the 10m Southern African Large Telescope. We measured the properties of ionized gas and stellar populations of both CR disks in PGC 66551. We found that the CR disk is compact, contains young stars with subsolar metallicity, and has a stellar mass of $5\times10^{9}$ M$_\odot$ which amounts to $\approx$20% of the galaxy's total. Surprisingly, the main 8 Gyr old disk has a significantly lower metallicity of -0.8 dex than other CR galaxies. We developed a simple analytic model of the history of the metal enrichment, which we applied to PGC 66551 and constrained the parameters of the galactic outflow wind, and estimated the metallicity of the infalling gas that formed the CR disk to be -0.9 ... -0.5 dex. Our interpretation prefers a merger with a gas-rich satellite over cold accretion from a cosmic filament as a source of gas, which then formed the CR disk in PGC 66551., Comment: 19 pages, 11 figures, accepted for publication in ApJ

The new observational data concerning distribution, excitation, and kinematics of the ionized gas in the giant early-type disk galaxy NGC 2655 obtained at the 6m telescope of the Special Astrophysical Observatory (SAO RAS) and at the 2.5m telescope of the Caucasian Mountain Observatory of the Sternberg Astronomical Institute (CMO SAI MSU) are presented in this work. The joint analysis of these and earlier spectral observations has allowed us to make a conclusion about multiple nature of the gas in NGC 2655. Together with a proper large gaseous disk experiencing regular circular rotation in the equatorial plane of the stellar potential of the galaxy for billions years, we observe also remnants of a merged small satellite having striked the central part of NGC 2655 almost vertically for some 10 million years ago., Comment: 22 pages, 8 figures, to appear in the Astrophysical Bulletin 2022, no.4