The MEGARA view of outflows in LINERs

Abstract

Context. Feedback processes, in particular those driven by outflows, are believed to play a major role in galaxy evolution. Outflows are believed to be ubiquitous in all active galactic nuclei (AGNs), although their presence in low luminosity AGNs, in particular for Low-Ionisation Nuclear Emission line Regions (LINERs), has only started to be explored. Their properties (geometry, mass, and energetics) are still far from being properly characterised. Aims. The main goal is to use integral field spectroscopic data from the MEGARA instrument at the Gran Telescopio Canarias (GTC) to analyse a small sample of nine LINERs, candidates of hosting ionised gas outflows. We aim to study the main emission lines in the optical wavelength range to identify their properties and physical origin. Methods. We obtained data cubes in several bands at the lowest (R similar to 6000) and highest (R similar to 20 000) spectral resolution of MEGARA. We modelled and subtracted the stellar continuum to obtain the ionised gas contribution, and then fitted the emission lines to extract their kinematics (velocity and velocity dispersion). We identified outflows as a secondary component in the emission lines and obtained their main properties. Results. The primary component of the emission lines was typically associated with gas in the galactic disc. For some objects, there is an enhanced-sigma region typically co-spatial with the secondary component. We associated it to turbulent gas produced due to the interaction with the outflows. We find signatures of outflows in six LINERs, with mass outflow rates ranging from 0.004 to 0.4 M-circle dot yr(-1) and energy rates from similar to 10(38) to similar to 10(40) erg s(-1). Their mean electronic density is 600 cm(-3), extending to distances of similar to 400 pc at an (absolute) velocity of similar to 340 km s(-1) (on average). They tend to be compact and unresolved, although for some sources they are extended with a bubble-like morphology. Conclusions. Our results confirm the existence of outflows in the best LINER candidates identified using previous long-slit spectroscopic and imaging data. These outflows do not follow the scaling relations obtained for more luminous AGNs. For some objects we discuss jets as the main drivers of the outflows.