Description
Gas inflows shape galaxy evolution by enhancing star formation (SF), forming nuclear rings/discs, and fuelling AGNs, which trigger outflows and cause quenching. Understanding the mechanisms driving inflows to galactic nuclei is therefore crucial. One well-established mechanism causing gas inflows is bar-driven extended shocks, which manifest as coherent velocity jumps in kinematic maps. Despite extensive research, whether the dominant mechanism of gas inflows to galactic nuclei is analogous to extended shocks in bars remains unclear. Using MUSE, we searched for extended shocks in gas kinematics of 21 nearby galaxies. We find a lower limit of 52% in our sample exhibiting extended shocks within their 1 kiloparsec, all occurring in barred galaxies. Unbarred galaxies lack extended shocks, which implies the critical role of bars in facilitating gas inflows to the galactic nuclei. Investigating how extended shocks relate to dominant nuclear activity, we show that while the presence of nuclear bars is linked to AGN activity, in their absence, inflow primarily fuels SF. Further we correlate the extended shock characteristics and the presence of nuclear bars and rings in our sample. A strong correlation emerges between presence of extended shocks and nuclear rings, supporting the role of gas inflows in nuclear ring formation. Our study supports extended shocks as a dominant mechanism for nuclear gas inflows, shaping central morphology and driving nuclear activity.
