Publication: Unexplored outflows in nearby low luminosity AGNs: the case of NGC 1052
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Context. Multi-phase outflows play a central role in galaxy evolution shaping the properties of galaxies. Understanding outflows and their effects in low luminosity active galactic nuclei (AGNs), such as low ionisation nuclear emission line regions (LINERs), is essential. LINERs bridge the gap between normal and active galaxies, being the most numerous AGN population in the local Universe. Aims. Our goal is to analyse the kinematics and ionisation mechanisms of the multi-phase gas of NGC 1052, the prototypical LINER, in order to detect and map the ionised and neutral phases of the putative outflow. Methods. We obtained Very Large Telescope MUSE and Gran Telescopio Canarias MEGARA optical integral field spectroscopy data for NGC 1052. In addition to stellar kinematics maps, by modelling spectral lines with multiple Gaussian components, we obtained flux, kinematic, and excitation maps of both ionised and neutral gas. Results. The stars are distributed in a dynamically hot disc (V/σ ∼ 1.2), with a centrally peaked velocity dispersion map (σ_(c) = 201 +/- 10 km s^(-1)) and large observed velocity amplitudes (∆V = 167 +/- 19 km s^(-1)). The ionised gas, probed by the primary component is detected up ∼30'' (∼3.3 kpc) mostly in the polar direction with blue and red velocities (|V|< 250 km s^(-1)). The velocity dispersion map shows a notable enhancement (σ > 90 km s^(-1)) crossing the galaxy along the major axis of rotation in the central 10''. The secondary component has a bipolar morphology, velocity dispersion larger than 150 km s^(-1), and velocities up to 660 km s^(-1). A third component is detected with MUSE (and barely with MEGARA), but it is not spatially resolved. The broad-line region (BLR) component (used to model the broad Hα emission only) has a full width at half maximum of 2427 +/- 332 and 2350 +/- 470 km s^(-1) for MUSE and MEGARA data, respectively. The maps of the NaD absorption indicate optically thick neutral gas with complex kinematics. The velocity field is consistent with a slow rotating disc (∆V = 77 +/- 12 km s^(-1)), but the velocity dispersion map is off-centred without any counterpart in the (centrally peaked) flux map. Conclusions. We found evidence of an ionised gas outflow (secondary component) with a mass of 1.6 +/- 0.6 x 10^(5) Mꙩ, and mass rate of 0.4 +/- 0.2 Mꙩ yr^(-1). The outflow is propagating in a cocoon of gas with enhanced turbulence and might be triggering the onset of kiloparsec-scale buoyant bubbles (polar emission), both probed by the primary component. Taking into account the energy and kinetic power of the outflow (1.3 +/- 0.9 x 10^(53) erg and 8.8 +/- 3.5 x 10^(40) erg s^(-1), respectively) as well as its alignment with both the jet and the cocoon, and that the gas is collisionally ionised (due to gas compression), we consider that the most likely power source of the outflow is the jet, although some contribution from the AGN is possible. The hints of the presence of a neutral gas outflow are weak.
© S. Sawada-Satoh et al. 2022. The authors acknowledge the anonymous referee for her/his instructive comments that helped to improve the presentation of this paper. S.C., I.M., J.M. and L.H.M. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV2017-0709). These authors are also supported by the Spanish Ministry of Economy and Competitiveness under grants no. AYA2016-76682-C3 and PID2019-106027GB-C41. L.H.M. acknowledges financial support under the FPI grant BES-2017-082471. A.G.d.P. and A.C.M. acknowledge the grant RTI-2018-096188-B-I00. L.H.G. acknowledges funds by ANID – Millennium Science Initiative Program – ICN12_009 awarded to the Millennium Institute of Astrophysics (MAS). F.L.F. acknowledges support from PRIN MIUR project ‘Black Hole winds and the Baryon Life Cycle of Galaxies: the stone-guest at the galaxy evolution supper’, contract no. 2017PH3WAT. C.R.A. acknowledges financial support from the European Union’s Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement No 860744 (BiD4BESt) and from the State Research Agency (AEI-MCINN) and the Spanish MCINN under grant ‘Feeding and feedback in active galaxies’, with reference PID2019-106027GB-C42. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We acknowledge the usage of the HyperLeda database (http://leda. univ-lyon1.fr). This work has made extensive use of IRAF and Python, particularly with astropy http://www.astropy.org (Astropy Collaboration 2013, 2018), matplotlib (Hunter 2007), numpy and lmfit. This paper made use of the plotting package jmaplot, developed by Jesús Maíz Apellániz available at: https://jmaiz.cab.inta-csic.es/software/ jmaplot/current/html/jmaplot_overview.html. This research has made use of the Skycat tool that combines visualisation of images and access to catalogues and archive data for astronomy. In particular, EXTRACTOR as part of the GAIA (Graphical Astronomy and Image Analysis Tool) package. We thanks J. Perea Duarte for the technical support and B. Perez for the calculation of gas metallicity.