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

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 (σ_c) 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 σ _c compared to the gas alignments. We confirm that bulge mass (M_bulge) is the primary parameter of correlation for both stellar and gas spin-filament alignments (with no residual dependency left for σ _c), while σ _c is the most important property for secular star formation quenching (with no residual dependency left for M_bulge). These findings indicate that M_bulge and σ _c 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.