We present intermediate-resolution, wide-wavelength coverage spectra for a complete sample of 14 compact radio sources taken with the aim of investigating the impact of the nuclear activity on the circumnuclear interstellar medium (ISM) in the early stages of radio source evolution. We observe spatially extended line emission (up to ∼20 kpc) in the majority of sources which is consistent with a quiescent halo. In the nuclear apertures we observe broad, highly complex emission-line profiles. Multiple Gaussian modelling of the [O III]λ5007 line reveals between two and four components which can have velocity widths [full width at halfmaximum (FWHM)] and blueshifts relative to the halo of up to ∼2000 km s −1 . We interpret these broad, blueshifted components as material in outflow and discuss the kinematical evidence for jet-driven outflows as previously proposed for PKS 1549−79 and PKS 1345+12. Comparisons with samples in the literature show that compact radio sources harbour more extreme nuclear kinematics than their extended counterparts, a trend seen within our sample with larger velocities in the smaller sources. The observed velocities are also likely to be influenced by source orientation with respect to the observer's line of sight. Nine sources have associated H I absorption. In common with the optical emission-line gas, the H I profiles are often highly complex with the majority of the detected components significantly blueshifted, tracing outflows in the neutral gas. The sample has been tested for stratification in the ISM (FWHM/ionization potential/critical density) as suggested by Holt, Tadhunter & Morganti for PKS 1345+12 but we find no significant trends within the sample using a Spearman rank analysis. This study supports the idea that compact radio sources are young radio-loud active galactic nuclei observed during the early stages of their evolution and currently shedding their natal cocoons through extreme circumnuclear outflows.

We use high-resolution (0.5 arcsec) CO(2−1) observations performed with the Atacama Large Millimetre/submillimetre Array to trace the kinematics of the molecular gas in the Seyfert 2 galaxy IC 5063. The data reveal that the kinematics of the gas is very complex. A fast outflow of molecular gas extends along the entire radio jet (∼1 kpc), with the highest outflow velocities about 0.5 kpc from the nucleus, at the location of the brighter hot spot in the western lobe. The ALMA data show that a massive, fast outflow with velocities up to 650 km s −1 of cold molecular gas is present, in addition to the outflow detected earlier in warm H 2 , H i and ionized gas. All phases of the gas outflow show similar kinematics. IC 5063 appears to be one of the best examples of the multi-phase nature of AGN-driven outflows. Both the central AGN and the radio jet could energetically drive the outflow, however, the characteristics of the outflowing gas point to the radio jet being the main driver. This is an important result because IC 5063, although one of the most powerful Seyfert galaxies, is a relatively weak radio source (P 1.4 GHz = 3 × 10 23 W Hz −1 ). All the observed characteristics can be described by a scenario of a radio plasma jet expanding into a clumpy medium, interacting directly with the clouds and inflating a cocoon that drives a lateral outflow into the interstellar medium. This model is consistent with results obtained by recent simulations. A stronger, direct interaction between the jet and a gas cloud is present at the location of the brighter western lobe. This interaction may also be responsible for the asymmetry in the radio brightness of the two lobes. Even assuming the most conservative values for the conversion factor CO-to-H 2 , we find that the mass of the outflowing gas is between 1.9 and 4.8 × 10 7 M , of which between 0.5 and 1.3 × 10 7 M is associated with the fast outflow at the location of the western lobe. These amounts are much larger than those of the outflow of warm gas (molecular and ionized) and somewhat larger than of the H i outflow. This suggests that most of the observed cold molecular outflow is due to fast cooling after being shocked. This gas is the end product of the cooling process, although some of it could be the result of only partly dissociated clouds. Our CO observations demonstrate that fast outflows of substantial masses of molecular gas can be driven by relativistic jets, although in the case of IC 5063 the outflows are not fast enough to remove significant amounts of gas from the galaxy and the effects are limited to the central ∼0.5 kpc from the centre.

It is the twentieth anniversary of the publication of the seminal papers by Magorrian et al. and Silk & Rees which, along with other related work, ignited an explosion of publications connecting active galactic nuclei (AGN)-driven outflows to galaxy evolution. With a surge in observations of AGN outflows, studies are attempting to directly test AGN feedback models using the outflow properties. With a focus on outflows traced by optical and CO emission lines, we discuss significant challenges which greatly complicate this task from both an observational and theoretical perspective. We highlight observational uncertainties involved, and the assumptions required, when deriving kinetic coupling efficiencies (i.e., outflow kinetic power as a fraction of AGN luminosity) from typical observations. Based on recent models we demonstrate that extreme caution should taken when comparing observationally-derived kinetic coupling efficiencies to coupling efficiencies from fiducial feedback models.During the 1950s and 1960s, it was established that a massive and powerful energy source was required to explain the exceptional luminosities generated by a class of extragalactic objects now known as active galactic nuclei (AGN)[1, 2, 3]. The energy source was heavily debated[4, 5] but the prevailing idea was the accretion of matter onto black holes residing within the nuclei of galaxies [6], that grow at a rate ofṀ BH and have bolometric luminosities of,The inferred very high mass-to-energy conversion efficiency of η r ≈ 0.1 [7,8] and high black hole masses (i.e., millions to billions that of the Sun) implies that over the lifetime of a typical black hole, the net energy emitted greatly exceeds the binding energy of their host galaxies [9]. It was quickly appreciated that the tremendous amount of energy from AGN could influence galaxy evolution. With effective mechanical (via the jets of charged particles observed in some AGN) or radiative coupling, it became clear that they could heat gas in and around galaxies [10,11]. Consequently, AGN became a popular explanation for the "excess energy" observed in galaxy clusters [12]. The constant heating of hot gas around galaxies is sometimes referred to as a "maintenance mode" of AGN feedback [9] and now has convincing evidence due to observed X-ray cavities associated with radio jets and lobes [13].An "explosion" of energy from the most luminous AGN (quasars) was also presented from the 1980s as a mechanism to enrich the intergalactic medium and trigger star formation, even to the point of forming entire galaxies [14,15]. Furthermore, in 1988 Sanders et al. proposed that ultraluminous infrared galaxies host dust enshrouded quasars whose radiation pressure will subsequently drive high velocity (≈100 km s −1 ), high mass outflows that potentially remove or destroy molecular gas [16]. In this article we focus on warm ionised and cold molecular outflows, driven by strong AGN radiation fields or radio jets, and their impact upon the host galaxies. This is sometimes referred to as a "quasar mod...

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A B S T R A C TThe nature of the optical-radio correlations for powerful radio galaxies is investigated using spectroscopic observations of a complete sample of southern 2-Jy radio sources. In line with previous work, we find that significant correlations exist between the luminosities of the [O III]l5007, [O II]l3727 and Hb emission lines and the radio luminosity. However, our observations are not easily reconciled with the idea that these correlations are caused by the increase in the power of the photoionizing quasar as the jet power increases, with average ISM properties not changing appreciably with redshift or radio power: not only do we find that the scatter in the L ½O iiiÿ versus L radio correlation is significantly larger than in L ½O iiÿ versus L radio and L Hb versus L radio correlations, but the ionization state deduced from the emission lines does not increase with radio power as predicted by the simple, constant ISM, photoionization model. We conclude that (a) there exists a considerable range in the quasar ionizing luminosity at a given redshift, and (b) the mean density of the emission-line clouds is larger in the highredshift/high-power radio sources. The latter density enhancement may be either a consequence of the increased importance of jet-cloud interactions or, alternatively, the result of a higher pressure in the confining hot ISM, in the high-redshift objects.Apart from the general scatter in the correlations, we identify a distinct group of objects with [O III]l5007 luminosities which are more than an order of magnitude lower than in the general population radio galaxies at similar redshift. These weak-line radio galaxies (WLRGs) are likely to be sources in which the central ionizing quasars are particularly feeble.Deep spectra show that many of the sources in our sample are broad-line radio galaxies (BLRGs). The fact that the BLRGs are observed out to the redshift limit of the survey, overlapping in redshift with the quasars, argues against the idea that BLRGs are simply the low-radio-power counterparts of high-power, high-redshift quasars. Either there exists a considerable range in the intrinsic luminosities of the broad-line AGN for a given redshift or radio power, or the BLRGs represent partially obscured quasars. The degree of scatter present in the L ½O iiiÿ versus L radio correlation supports the former possibility.