|
Description
We present the first results from the KMOS (K-band Multi-Object Spectrograph) AGN (active galactic nuclei) Survey at High redshift (KASHz), a VLT/KMOS integral-field spectroscopic (IFS) survey of z>~0.6 AGN. We present galaxy-integrated spectra of 89 X-ray AGN (L_2-10keV_= 10^42^-10^45^erg/s), for which we observed [OIII] (z~1.1-1.7) or H{alpha} emission (z~0.6-1.1). The targets have X-ray luminosities representative of the parent AGN population and we explore the emission-line luminosities as a function of X-ray luminosity. For the [OIII] targets, ~50 per cent have ionized gas velocities indicative of gas that is dominated by outflows and/or highly turbulent material (i.e. overall line widths >~600km/s). The most luminous half (i.e. L_X_>6x10^43^erg/s) have a>~2 times higher incidence of such velocities. On the basis of our results, we find no evidence that X-ray obscured AGN are more likely to host extreme kinematics than unobscured AGN. Our KASHzsample has a distribution of gas velocities that is consistent with a luminosity-matched sample of z<0.4 AGN. This implies little evolution in the prevalence of ionized outflows, for a fixed AGN luminosity, despite an order-of-magnitude decrease in average star formation rates over this redshift range. Furthermore, we compare our H{alpha} targets to a redshift-matched sample of star-forming galaxies and despite a similar distribution of H{alpha} luminosities and likely star formation rates, we find extreme ionized gas velocities are up to ~10 times more prevalent in the AGN-host galaxies. Our results reveal a high prevalence of extreme ionized gas velocities in high-luminosity X-ray AGN and imply that the most powerful ionized outflows in high-redshift galaxies are driven by AGN activity.
|
