ИСТИНА

Galactic discs are composed of different substructures generally rotating in the same direction. However, there are known cases where galaxies hosting two prominent stellar counter-rotating (CR) discs. The formation of such substructures as well as their influence on galaxy evolution is still not fully understood. Using publicly available data of the SDSS MaNGA DR17 survey we identified a sample of ~50 counter-rotating stellar disc galaxies. Here we present a detailed investigation of one galaxy from the sample -- PGC 066551 which also has been followed up with deep long-slit spectroscopy at 11m SALT telescope (South Africa). Applying full-spectral fitting and non-parametrical stellar LOSVD recovery technique we found that secondary counter-rotating disc contributes ~50% in the integral light. We found that, unlike other CR galaxies, PGC 66551 has a way metal-poor and old main stellar disc. Using a toy model of chemical evolution, we argue that such properties of the stellar populations could have formed if the galaxy experienced an episode of gas removal in the past, which may be driven by powerful AGN activity.