Investigating the impact of quasar-driven outflows on galaxies at z ∼ 0.3–0.4

Abstract

Aims. We present a detailed study of the kinematics of 19 type 2 quasars (QSO2s) with redshifts in the range 0.3 < z < 0.41 and [OIII] luminosities of L[OIII] > 108.5 L⊙. We aim to advance our understanding of the active galactic nucleus (AGN) feedback phenomenon by correlating outflow properties with (i) young stellar populations (YSPs) with ages < 100 Myr, (ii) the optical morphology and the environment of the galaxies, and (iii) the radio luminosity. Methods. We characterized the ionized gas kinematics using the [OIII]λ5007 Å emission line profiles detected in intermediate spectral resolution (R ∼ 1500–2500) optical spectra of the QSO2s. To do this, we employed three different outflow detection methods: multicomponent parametric, flux-weighted nonparametric, and peak-weighted nonparametric. Results. We detect ionized outflows in 18 of the 19 QSO2s using the parametric analysis, and in all of them using the nonparametric methods. We find higher outflow masses using the parametric analysis (average log MOF(M⊙) = 6.47  ±  0.50), and higher mass rates and kinetic powers with the flux-weighted nonparametric method (MOF = 4.0  ±  4.4 M⊙ yr−1 and Ekin = 41.9  ±  0.6 erg s−1). However, when we use the parametric method and the maximum outflow velocities (vmax), we measure the highest outflow mass rates and kinetic energies (MOF = 23  ±  35 M⊙ yr−1 and log(Ekin) = 42.9  ±  0.6 erg s−1). We do not find any significant correlation between the outflow properties and the previously mentioned AGN and galaxy-wide properties. Conclusions. Four of the five QSO2s without a YSP of age < 100 Myr show highly disturbed kinematics, whereas only 5 out of the 14 QSO2s with YSPs show similarly asymmetric [OIII] profiles. Despite the small sample size, this might be indicative of negative feedback. The lack of a correlation between the outflow properties and the galaxies optical morphologies might be due to their different dynamical timescales (millions of years in the case of the outflows versus billions of years in the case of galaxy mergers). Last, the small radio luminosity range covered by our sample, log(L5 GHz) = [22.1, 24.7] W Hz−1, may impede the detection of any correlation between radio emission and outflow properties.