IFU observations of the inner 200 pc of NGC 4546: gas rotation, non-circular motions, and ionized outflows

We present a detailed analysis of the ionized gas distribution and kinematics in the inner similar to 200 pc of NGC 4546, host of a low-luminosity active galactic nucleus (LLAGN). Using GMOS-IFU observations, with a spectral coverage of 4736-6806 angstrom and an angular resolution of 0.7 arcsec, we confirm that the nuclear emission is consistent with photoionization by an AGN, while the gas in the circumnuclear region may be ionized by hot low-mass evolved stars. The gas kinematics in the central region of NGC 4546 presents three components: (i) a disc with major axis oriented along a position angle of 43 degrees +/- 3 degrees, counter rotating relative to the stellar disc; (ii) non-circular motions, evidenced by residual velocities of up to 60 km s(-1), likely associated with a previous capture of a dwarf satellite by NGC 4546; and (iii) nuclear outflows in ionized gas, identified as a broad component (sigma similar to 320 km s(-1)) in the line profiles, with a mass outflow rate of (M) over dot(out)=0.3 +/- 0.1 M-circle dot yr(-1) and a total mass of M-out = (9.2 +/- 0.8) x 103 M-circle dot in ionized gas, corresponding to less than 3 per cent of the total mass of ionized gas in the inner 200 pc of NGC 4546. The kinetic efficiency of the outflow is roughly 0.1 per cent, which is smaller than the outflow coupling efficiencies predicted by theoretical studies to AGN feedback become efficient in suppressing star formation in the host galaxy.

Automated summary

This study presents a detailed analysis of the ionized gas distribution and kinematics in NGC 4546, revealing the presence of an active galactic nucleus, evolved stars, and various components of gas flow in the central region.