The SAMI galaxy survey: impact of black hole activity on galaxy spin–filament alignments

Abstract

ABSTRACT The activity of central supermassive black holes might affect the alignment of galaxy spin axes with respect to the closest cosmic filaments. We exploit the Sydney–AAO Multi-object Integral-field Galaxy Survey to study possible relations between black hole activity and the spin–filament alignments of stars and ionized gas separately. To explore the impact of instantaneous black hole activity, active galaxies are selected according to emission-line diagnostics. Central stellar velocity dispersion (σc) is used as a proxy for black hole mass and its integrated activity. We find evidence for the gas spin–filament alignments to be influenced by AGN, with Seyfert galaxies showing a stronger perpendicular alignment at fixed bulge mass with respect to galaxies, where ionization is consequence of low-ionization nuclear emission-line regions (LINERs) or old stellar populations (retired galaxies). On the other hand, the greater perpendicular tendency for the stellar spin–filament alignments of high-bulge mass galaxies is dominated by retired galaxies. Stellar alignments show a stronger correlation with σc compared to the gas alignments. We confirm that bulge mass (Mbulge) is the primary parameter of correlation for both stellar and gas spin–filament alignments (with no residual dependency left for σc), while σc is the most important property for secular star formation quenching (with no residual dependency left for Mbulge). These findings indicate that Mbulge and σc are the most predictive parameters of two different galaxy evolution processes, suggesting mergers trigger spin–filament alignment flips and integrated black hole activity drives star formation quenching.