The nuclear region of NGC 613-II. Kinematics and stellar archaeology

Abstract

In this work, we continue the study of the central region of NGC 613 by da Silva, Menezes & Steiner (Paper I), by analysing the stellar and gas kinematics and the stellar archaeology in optical and near-infrared data cubes. The high spatial resolution of the Gemini Multi-Object Spectrograph (GMOS) data cube allowed the detection, using spectral synthesis methods, of an inner circumnuclear ring, with a radius of ∼1 arcsec, composed of ∼109-yr stellar populations. Such a ring is located between the nucleus and the circumnuclear ring composed by H ii regions detected in previous works. Besides that, there is a stellar rotation around the nucleus and the rings follow the same direction of rotation with different velocities. The intensity-weighted average stellar velocity dispersion at the centre is 92 ± 3 km s-1. Three distinct gas outflow components were detected. The direction of the outflow observed with the H α emission line is compatible with the direction of the previously observed radio jet. The direction of one of the outflows detected in the [O iii]λ5007 emission coincides with the axis of the ionization cone. There is no difference regarding the stellar populations and the stellar kinematics along the double stellar emission, probably separated by a dust lane as mentioned in Paper I, confirming that they are part of the same structure. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.