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The jets of radio AGN provide one of the most important forms of AGN feedback, yet considerable uncertainties remain about how they are triggered. Since the molecular gas reservoirs of the host galaxies can supply key information about the dominant triggering mechanism(s), here we present Atacama Large Millimeter/sub-millimeter Array (ALMA) CO(1-0) observations of a complete sample of 29 powerful radio AGN ($P_{1.4GHz} > 10^{25}$ W Hz$^{-1}$ and $0.05 < z < 0.3$) with an angular resolution of about 2 - 3 arcsec (corresponding to 2 - 8 kpc). We detect molecular gas with masses in the range $10^{8.9} < M_{H_2} < 10^{10.2}$ M$_{\odot}$ in the early-type host galaxies of 10 targets, while for the other 19 sources we derive upper limits. The detection rate of objects with such large molecular masses -- $34\pm9$% -- is higher than in the general population of non-active early-type galaxies (ETG: $<$10%). The kinematics of the molecular gas are dominated in most cases by rotating disk-like structures, with diameters up to 25 kpc. Compared with the results for samples of quiescent ETG in the literature, we find a larger fraction of more massive, more extended and less settled molecular gas structures. In most of the CO-detected sources, the results are consistent with triggering of the AGN as the gas settles following a merger or close encounter with a gas-rich companion. However, in a minority of objects at the centres of rich clusters of galaxies, the accretion of gas cooling from the hot X-ray halos is a plausible alternative to galaxy interactions as a triggering mechanisms., Comment: 25 pages, 10 figures, accepted for publication in MNRAS

We present MEGARA (Multi-Espectr\'ografo en GTC de Alta Resoluci\'on para Astronom\'ia) Integral Field Unit (IFU) observations of 5 local type-2 quasars (QSO2s, z $\sim 0.1$) from the Quasar Feedback (QSOFEED) sample. These active galactic nuclei (AGN) have bolometric luminosities of 10$^{45.5-46}$ erg/s and stellar masses of $\sim$10$^{11}$ M$_{\odot}$. We explore the kinematics of the ionized gas through the [O~III]$\lambda$5007 $\r{A}$ emission line. The nuclear spectra of the 5 QSO2s, extracted in a circular aperture of $\sim$ 1.2" ($\sim$ 2.2 kpc) in diameter, show signatures of high velocity winds in the form of broad (full width at half maximum; 1300$\leq$FWHM$\leq$2240 km/s and blueshifted components. We find that 4 out of the 5 QSO2s present outflows that we can resolve with our seeing-limited data, and they have radii ranging from 3.1 to 12.6 kpc. In the case of the two QSO2s with extended radio emission, we find that it is well-aligned with the outflows, suggesting that low-power jets might be compressing and accelerating the ionized gas in these radio-quiet QSO2s. In the four QSO2s with spatially resolved outflows, we measure ionized mass outflow rates of 3.3-6.5 Msun/yr when we use [S~II]-based densities, and of 0.7-1.6 Msun/yr when trans-auroral line-based densities are considered instead. We compare them with the corresponding molecular mass outflow rates (8 - 16 Msun/yr), derived from CO(2-1) ALMA observations at 0.2" resolution. Both phases show lower outflow mass rates than those expected from observational scaling relations where uniform assumptions on the outflow properties were adopted. This might be indicating that the AGN luminosity is not the only driver of massive outflows and/or that these relations need to be re-scaled using accurate outflow properties. We do not find a significant impact of the outflows on the global star formation rates., Comment: 24 pages, 13 figures and 4 tables. Accepted for publication in A&A; A&A 665, A55 (2023); doi: 10.1051/0004-6361/202347715

We present a detailed study of the kinematics of 19 QSO2s in the range 0.3 10^{8.5}$L$_{\odot}$. We aim at advancing our understanding of the AGN feedback phenomenon by correlating outflow properties with the presence of young stellar populations (YSPs) with ages <100 Myr, the optical morphology and the environment of the galaxies, and the radio luminosity. We characterize the ionized gas kinematics using the [OIII]$\lambda$5007$\r{A}$ profiles, through three different outflow detection methods: multi-component parametric and flux-weighted and peak-weighted non-parametric. We detect ionized outflows in 18 QSO2s using the parametric analysis, and in all of them using the non-parametric methods. We find higher outflow masses using the parametric analysis (log M$_{OF}$(M$_{\odot}$)=6.47$\pm$0.50), and larger mass rates and kinetic powers with the flux-weighted non-parametric method (\.M$_{OF}$=4.0$\pm$4.4 M$_{\odot}$ yr$^{-1}$ and log(\.E$_{kin}$)=41.9$\pm$0.6 erg~s$^{-1}$). However, it is when we use the parametric method and the maximum outflow velocities that we measure the highest outflow mass rates and kinetic energies (23$\pm$35 M$_{\odot}$ yr$^{-1}$ and 42.9$\pm$0.6 erg s$^{-1}$). We do not find any significant correlation between the outflow properties and the previously mentioned galaxy properties. 4 out of 5 QSO2s without a YS<100 Myr show highly disturbed kinematics, whereas only 5 out of the 14 QSO2s with YSPs show similarly asymmetric [OIII] profiles. This might be indicative of negative feedback. The lack of correlation between the outflow properties and the presence of mergers in different interaction stages might be due to their different dynamical timescales. Lastly, the small radio luminosity range covered by our sample may be impeding the detection of any correlation between radio emission and outflow properties., Comment: 26 pages, 9 figures. Accepted for publication in A&A

The triggering mechanism for the most luminous, quasar-like active galactic nuclei (AGN) remains a source of debate, with some studies favouring triggering via galaxy mergers, but others finding little evidence to support this mechanism. Here, we present deep Isaac Newton Telescope/Wide Field Camera imaging observations of a complete sample of 48 optically-selected type 2 quasars $-$ the QSOFEED sample (L$_{\rm [OIII]}>$10$^{8.5}$$L_{\odot}$; $z < 0.14$). Based on visual inspection by eight classifiers, we find clear evidence that galaxy interactions are the dominant triggering mechanism for quasar activity in the local universe, with 65$^{+6}_{-7}$ per cent of the type 2 quasar hosts showing morphological features consistent with galaxy mergers or encounters, compared with only 22$^{+5}_{-4}$ per cent of a stellar-mass- and redshift-matched comparison sample of non-AGN galaxies $-$ a 5$\sigma$ difference. The type 2 quasar hosts are a factor 3.0$^{+0.5}_{-0.8}$ more likely to be morphologically disturbed than their matched non-AGN counterparts, similar to our previous results for powerful 3CR radio AGN of comparable [OIII] emission-line luminosity and redshift. In contrast to the idea that quasars are triggered at the peaks of galaxy mergers as the two nuclei coalesce, and only become visible post-coalescence, the majority of morphologically-disturbed type 2 quasar sources in our sample are observed in the pre-coalescence phase (61$^{+8}_{-9}$ per cent). We argue that much of the apparent ambiguity that surrounds observational results in this field is a result of differences in the surface brightness depths of the observations, combined with the effects of cosmological surface brightness dimming., Comment: Accepted for publication in MNRAS. 17 pages, 7 figures

Although the ultraluminous infrared radio galaxy 4C12.50 at z=0.12 is a promising candidate to reveal how radio induced feedback may regulate star formation in galaxies, we find no solid evidence for current or past impact of this mechanism on the evolution of this system, neither by clearing out the dusty central cocoon efficiently, nor by suppressing star formation. We study in detail for the first time the hot (>~1500 K) molecular gas in this object. The potential impact of the radio jet on this gas phase, as well as on the star formation activity, are investigated. 4C12.50 hosts (2.1+/-0.4)x1e4 Msun of hot molecular gas. An unusually high rotational temperature T =3020+/-160 K is inferred. The molecular gas mass obeys a power law temperature distribution d(M(H2))/dT ~ T^-5 from T~300 K and up to ~3000 K. Both results support that shocks (probably induced by the radio jet) contribute to the heating and excitation of the hot molecular gas. A molecular outflow is not detected. The coupling of the outflowing ionized and neutral outflows with the hot molecular gas is poor. We find no evidence for star formation supression. NIR and MIR integral field spectroscopy at very high spatial resolution (for instance, with the JWST) would be of key value to further investigate these issues., Comment: Accepted for publication in A&A,18 pages, 13 figures

Mrk 477 is the closest type-2 quasar (QSO2), at a distance of 163 Mpc. This makes it an ideal laboratory for studying the interplay between nuclear activity and star formation with a great level of detail and signal-to-noise. In this Letter we present new mid-infrared (mid-IR) imaging and spectroscopic data with an angular resolution of 0.4 arcsec (~300 pc) obtained with the Gran Telescopio Canarias (GTC) instrument CanariCam. The N-band (8-13 micron) spectrum of the central ~400 pc of the galaxy reveals [S IV]10.51 micron emission, but no 8.6 or 11.3 micron PAH features, which are commonly used as tracers of recent star formation. This is in stark contrast with the presence of a nuclear starburst of ~300 pc in size, an age of 6 Myr, and a mass of 1.1x10^8 Msun, as constrained from ultraviolet Hubble Space Telescope observations. Considering this, we argue that even the more resilient, neutral molecules that mainly produce the 11.3 micron PAH band are most likely being destroyed in the vicinity of the active nucleus despite the relatively large X-ray column density, of log N_H=23.5 cm^-2, and modest X-ray luminosity, of 1.5x10^43 erg/s. This highlights the importance of being cautious when using PAH features as star formation tracers in the central region of galaxies to evaluate the impact of feedback from active galactic nuclei., Comment: 7 pages, 3 figures. A&A Letters accepted version including proof corrections

The far-IR/sub-mm wavelength range contains a wealth of diagnostic information that is important for understanding the role of radio AGN in galaxy evolution. Here we present the results of Herschel PACS and SPIRE observations of a complete sample of 46 powerful 2Jy radio AGN at intermediate redshifts (0.05 < z < 0.7), which represent the deepest pointed observations of a major sample of radio AGN undertaken by Herschel. In order to assess the importance of non-thermal synchrotron emission at far-IR wavelengths, we also present new APEX sub-mm and ALMA mm data. We find that the overall incidence of non-thermal contamination in the PACS bands ($<$200$\mu$m) is in the range 28 -- 43%; however, this rises to 30 -- 72% for wavelengths ($> $200$\mu$m) sampled by the SPIRE instrument. Non-thermal contamination is strongest in objects with compact CSS/GPS or extended FRI radio morphologies, and in those with type 1 optical spectra. Considering thermal dust emission, we find strong correlations between the 100 and 160$\mu$m monochromatic luminosities and AGN power indicators, providing further evidence that radiation from the AGN may be an important heating source for the far-IR emitting dust. Clearly, AGN contamination -- whether by the direct emission from synchrotron-emitting lobes and cores, or via radiative heating of the cool dust -- needs to be carefully considered when using the far-IR continuum to measure the star formation rates in the host galaxies of radio AGN., Comment: 22 pages, 8 figures, Accepted in MNRAS

We analyze Near-Infrared Integral Field Spectrograph (NIFS) observations of the type-2 quasar (QSO2) SDSS J094521.33+173753.2 to investigate its warm molecular and ionized gas kinematics. This QSO2 has a bolometric luminosity of 10$^{45.7}$ erg s$^{-1}$ and a redshift of z = 0.128. The K-band spectra provided by NIFS cover a range of 1.99-2.40 $\mu$m where low-ionization (Pa$\alpha$ and Br$\delta$), high ionization ([S XI]$\lambda$1.920 $\mu$m and [Si~VI]$\lambda$1.963 $\mu$m) and warm molecular lines (from H$_2$ 1-0S(5) to 1-0S(1)) are detected, allowing us to study the multi-phase gas kinematics. Our analysis reveals gas in ordinary rotation in all the emission lines detected and also outflowing gas in the case of the low- and high-ionization emission lines. In the case of the nuclear spectrum, which corresponds to a circular aperture of 0.3\arcsec~(686 pc) in diameter, the warm molecular lines can be characterized using a single Gaussian component of full width at half maximum (FWHM)= 350-400 km s$^{-1}$, while Pa$\alpha$, Br$\delta$, and [Si~VI] are best fitted with two blue-shifted Gaussian components of FWHM$\sim$800 and 1700 km s$^{-1}$, in addition to a narrow component of $\sim$300 km s$^{-1}$. We interpret the blue-shifted broad components as outflowing gas, which reaches the highest velocities, of up to $-$840 km s$^{-1}$, in the south-east direction (PA$\sim$125$^{\circ}$), extending up to a distance of $\sim$3.4 kpc from the nucleus. The ionized outflow has a maximum mass outflow rate of $\dot{\text{{M}}}_{\text{{out, max}}}$=42-51 M$_\odot$ yr$^{-1}$, and its kinetic power represents 0.1$\%$ of the quasar bolometric luminosity., Comment: 24 pages, 20 figures and 5 tables. Accepted for publication in A&A

We use deep Herschel observations of the complete 2Jy sample of powerful radio AGNs in the local universe (0.05 < z < 0.7) to probe their cool interstellar medium (ISM) contents and star-forming properties, comparing them against other samples of nearby luminous AGNs and quiescent galaxies. This allows us to investigate triggering and feedback mechanisms. We find that the dust masses of the strong-line radio galaxies (SLRGs) in our sample are similar to those of radio-quiet quasars, and that their median dust mass (Mdust = 2 x 10^7 Msun) is enhanced by a factor ~200 compared to that of non-AGN ellipticals, but lower by a factor ~16 relative to that of local ultra-luminous infrared galaxies (UILRGs). Along with compelling evidence for merger signatures in optical images, the SLRGs in our sample also show relatively high star-formation efficiencies, despite the fact that many of them fall below the main sequence for star forming galaxies. Together, these results suggest that most of our SLRGs have been re-triggered by late-time mergers that are relatively minor in terms of their gas contents. In comparison with the SLRGs, the radio AGNs with weak optical emission lines (WLRGs) and edge-darkened radio jets (FRIs) have both lower cool ISM masses and star-formation rates (by a factor of >30), consistent with being fuelled by a different mechanism (e.g. the direct accretion of hot gas)., Comment: 20 pages, 8 figures, accepted for publication in MNRAS

We present CO(2-1) and adjacent continuum observations of 7 nearby radio-quiet type-2 quasars (QSO2s) obtained with ALMA at ~0.2" resolution (370 pc at z~0.1). The CO morphologies are diverse, including disks and interacting systems. Two of the QSO2s are red early-type galaxies with no CO(2-1) detected. In the interacting galaxies, the central kpc contains 18-25% of the total cold molecular gas, whereas in the spirals it is only 5-12%. J1010+0612 and J1430+1339 show double-peaked CO morphologies which do not have optical counterparts. Based on our analysis of the ionized and molecular kinematics and mm continuum emission, these CO morphologies are most likely produced by AGN feedback in the form of outflows, jets, and/or shocks. The CO kinematics of the QSO2s are dominated by rotation but also reveal noncircular motions. According to our analysis of the kinematics, these noncircular motions correspond to molecular outflows mostly coplanar with the CO discs in four of the QSO2s, and either to a coplanar inflow or vertical outflow in the case of J1010+0612. These outflows represent 0.2-0.7% of the QSO2s' total molecular gas mass and have maximum velocities of 200-350 km/s, radii from 0.4 to 1.3 kpc, and outflow rates of 8-16 Msun/yr. These properties are intermediate between those of the mild molecular outflows measured for Seyferts, and the fast and energetic outflows of ULIRGs. This suggests that it is not only AGN luminosity that drives massive molecular outflows. Other factors such as jet power, coupling between winds, jets, and/or ionized outflows and the CO discs, and amount or geometry of dense gas in the nuclear regions might be also relevant. Thus, although we do not find evidence for a significant impact of quasar feedback on the total molecular gas reservoirs and SFRs, it appears to be modifying the distribution of cold molecular gas in the central kpc of the galaxies., Comment: 29 pages including 18 figures, 7 tables and appendices. A&A accepted version including minor edits

Investigation of the triggering mechanisms of radio AGN is important for improving our general understanding of galaxy evolution. In the first paper in this series, detailed morphological analysis of high-excitation radio galaxies (HERGs) with intermediate radio powers suggested that the importance of triggering via galaxy mergers and interactions increases strongly with AGN radio power and weakly with optical emission-line luminosity. Here, we use an online classification interface to expand our morphological analysis to a much larger sample of 155 active galaxies (3CR radio galaxies, radio-intermediate HERGs and Type 2 quasars) that covers a broad range in both 1.4 GHz radio power and [OIII]$\lambda$5007 emission-line luminosity. All active galaxy samples are found to exhibit excesses in their rates of morphological disturbance relative to 378 stellar-mass- and redshift-matched non-active control galaxies classified randomly and blindly alongside them. These excesses are highest for the 3CR HERGs (4.7$\sigma$) and Type 2 quasar hosts (3.7$\sigma$), supporting the idea that galaxy mergers provide the dominant triggering mechanism for these subgroups. When the full active galaxy sample is considered, there is clear evidence to suggest that the enhancement in the rate of disturbance relative to the controls increases strongly with [OIII]$\lambda$5007 emission-line luminosity but not with 1.4 GHz radio power. Evidence that the dominant AGN host types change from early-type galaxies at high radio powers to late-type galaxies at low radio powers is also found, suggesting that triggering by secular, disk-based processes holds more importance for lower-power radio AGN., Comment: Accepted for publication in MNRAS. 21 pages, 11 figures. Supplementary information will be available online with the published journal article (also available from the corresponding author by request)

We present observations obtained with the VLT/MUSE optical integral field spectrograph of the radio source 3C277.3, located at a redshift of 0.085 and associated with the galaxy Coma A. An emission line region fully enshrouds the double-lobed radio source, which is ~60 kpc x 90 kpc in size. Based on the emission line ratios, we identified five compact knots in which the gas ionization is powered by young stars located as far as ~60 kpc from the host. The emission line filaments surrounding the radio emission are compatible with ionization from fast shocks (with a velocity of 350-500 km/s), but a contribution from star formation occurring at the edges of the radio source is likely. Coma A might be a unique example in the local Universe in which the expanding outflow triggers star formation throughout the whole radio source., Comment: Pre-proofs version - Accepted for publication in A&A

Emission-line variability studies have the potential to provide key information about the structures of the near-nuclear outflow regions of AGN. Here we present a VLT/Xshooter spectrum of the nucleus of the ULIRG F01004-2237 that was taken in August 2018, about 8 yr after a major flare in its integrated optical emission. Compared with our WHT/ISIS spectrum from September 2015, the broad, red wings of the emission lines most closely associated with the flaring event, including HeII(4686), NIII(4100,4640) and HeI(5876), have substantially declined in flux. In contrast, the broad, blue wings that dominate the [OIII], [NeIII], [NeV] and [OI] forbidden lines have increased in flux by a factor 1.4 - 4.4 (depending on the line). Moreover, the [FeVII](6087) line is detected in the new spectrum for the first time. We interpret these results in terms of a light echo from the outflowing warm gas: the direct emission from the flaring event is continuing to fade, but due to light travel time effects we are only now observing the impact of the flare on the emission from the extended outflow region. Unless the outflow is confined to a small range of angles close to our line of sight, these observations imply that the outflow must be relatively compact (r<50 pc). In terms of the nature of the flare event, we speculate that the properties of the F01004-2237 flare may be the result of a tidal disruption event (TDE) occurring in an object with pre-existing AGN activity., Comment: 12 pages, 8 figures, accepted for publication in MNRAS

Measuring the star-forming properties of AGN hosts is key to our understanding of galaxy formation and evolution. However, this topic remains debated, partly due to the difficulties in separating the infrared (i.e. 1--1000 $\mu$m) emission into AGN and star-forming components. Taking advantage of archival far-infrared data from Herschel, we present a new set of AGN and galaxy infrared templates, and introduce the spectral energy distribution fitting code IRAGNSEP. Both can be used to measure infrared host galaxy properties, free of AGN contamination. To build these, we used a sample of 100 local ($z$ < 0.3), low-to-high luminosity AGNs (i.e. $L_{\rm bol}~\sim~10^{42--46}~\rm erg~s^{-1}$), selected from the 105-month Swift - BAT X-ray survey, which have archival Spitzer - IRS spectra and Herschel photometry. We first built a set of seven galaxy templates using a sample of 55 star-forming galaxies selected via infrared diagnostics. Using these templates, combined with a flexible model for the AGN contribution, we extracted the intrinsic infrared emission of our AGN sample. We further demonstrate that we can reduce the diversity in the intrinsic shapes of AGN spectral energy distributions down to a set of three AGN templates, of which two represent AGN continuum, and one represents silicate emission. Our results indicate that, on average, the contribution of AGNs to the far-infrared ($\lambda~\gtrsim$ 50 $\mu$m) is not as high as suggested by some recent work. We further show that the need for two infrared AGN continuum templates could be related to nuclear obscuration, where one of our templates appears dominated by the emission of the extended polar dust., Comment: 20 pages (38 pages including appendices), 19 figures, 6 tables, Accepted for publication in MNRAS

Active galactic nuclei (AGN) feedback operated by the expansion of radio jets can play a crucial role in driving gaseous outflows on galaxy scales. Galaxies hosting young radio AGN, whose jets are in the first phases of expansion through the surrounding interstellar medium (ISM), are the ideal targets to probe the energetic significance of this mechanism. In this paper, we characterise the warm ionised gas outflows in a sample of nine young radio sources from the 2Jy sample, combining X-shooter spectroscopy and Hubble Space Telescope (HST) imaging data. We find that the warm outflows have similar radial extents (~0.06-2 kpc) as radio sources, consistent with the idea that `jet mode' AGN feedback is the dominant driver of the outflows detected in young radio galaxies. Exploiting the broad spectral coverage of the X-shooter data, we have used the ratios of trans-auroral emission lines of [SII] and [OII] to estimate the electron densities, finding that most of the outflows have gas densities ($\log( n_e~cm^{-3})~3-4.8 $), which we speculate could be the result of compression by jet-induced shocks. Combining our estimates of the emission-line luminosities, radii, and densities, we find that the kinetic powers of the warm outflows are a relatively small fraction of the energies available from the accretion of material onto the central supermassive black hole (SMBH), reflecting AGN feedback efficiencies below 1% in most cases. Overall, the warm outflows detected in our sample are strikingly similar to those found in nearby ultraluminous infrared galaxies (ULIRGs), but more energetic and with a high feedback efficiencies on average than the general population of nearby AGN of similar bolometric luminosity; this is likely to reflect a high degree of coupling between the jets and the near-nuclear ISM in the early stages of radio source evolution., Comment: 26 pages, 7 Figures, 15 Tables (excluding Appendix), accepted for publication in A&A

Considerable uncertainties remain about the nature of warm, AGN-driven outflows and their impact on the evolution of galaxies. This is because the outflows are often unresolved in ground-based observations. As part of a project to study the AGN outflows in some of the most rapidly evolving galaxies in the local Universe, here we present HST/STIS observations of F14394+5332E that resolve the sub-kpc warm outflow for the first time in a ULIRG. The observations reveal a compact, high-ionization outflow region (r_max~0.9 kpc) set in a more extensive (r_max~1.4 kpc) halo that is kinematically quiescent and has a lower ionization state. A large line width (600 < FWHM < 1500 km/s) is measured throughout the outflow region, and the outflowing gas shows a steep velocity gradient with radius, with the magnitude of the blueshifted velocities increasing from ~500 to 1800 km/s from the inner to the outer part of the outflow. We interpret the observations in terms of the local acceleration, and hydrodynamic destruction, of dense clouds as they are swept up in a hot, low density wind driven by the AGN. We discuss the implications for measuring the mass outflow rates and kinetic powers for the AGN-driven outflows in such objects., Comment: 10 pages, 5 figures

We explore the distribution of RMS=SFR/SFR_MS (where SFR_MS is the star formation rate of "Main Sequence" star-forming galaxies) for AGN hosts at z=1. We split our sample into two bins of X-ray luminosity divided at Lx=2x10^43erg s-1 to investigate whether the RMS distribution changes as a function of AGN power. Our main results suggest that, when the RMS distribution of AGN hosts is modelled as a log-normal distribution (i.e. the same shape as that of MS galaxies), galaxies hosting more powerful X-ray AGNs (i.e. Lx>2x10^43erg s-1) display a narrower RMS distribution that is shifted to higher values compared to their lower Lx counterparts. In addition, we find that more powerful X-ray AGNs have SFRs that are more consistent with that of MS galaxies compared to lower Lx AGNs. Despite this, the mean SFRs (as opposed to RMS) measured from these distributions are consistent with the previously observed flat relationship between SFR and Lx. Our results suggest that the typical star-forming properties of AGN hosts change with Lx , and that more powerful AGNs typically reside in more MS-like star-forming galaxies compared to lower Lx AGNs., Comment: 6 pages, 4 figures, Accepted for publication in MNRAS Letter

We study the morphological and structural properties of the host galaxies associated with 57 optically-selected luminous type 2 AGN at $z\sim$0.3-0.4: 16 high-luminosity Seyfert 2 (HLSy2, 8.0$\le$log($L_{\rm [OIII]}/L_{\odot})<$8.3) and 41 obscured quasars (QSO2, log($L_{\rm [OIII]}/L_{\odot})\ge$8.3). With this work, the total number of QSO2 at $z<1$ with parametrized galaxies increases from $\sim$35 to 76. Our analysis is based on HST WFPC2 and ACS images that we fit with {\sc GALFIT}. HLSy2 and QSO2 show a wide diversity of galaxy hosts. The main difference lies in the higher incidence of highly-disturbed systems among QSO2. This is consistent with a scenario in which galaxy interactions are the dominant mechanism triggering nuclear activity at the highest AGN power. There is a strong dependence of galaxy properties with AGN power (assuming $L_ {\rm [OIII]}$ is an adequate proxy). The relative contribution of the spheroidal component to the total galaxy light (B/T) increases with $L_ {\rm [OIII]}$. While systems dominated by the spheoridal component spread across the total range of $L_ {\rm [OIII]}$, most disk-dominated galaxies concentrate at log($L_{\rm [OIII]}/L_{\odot})<$8.6. This is expected if more powerful AGN are powered by more massive black holes which are hosted by more massive bulges or spheroids. The average galaxy sizes ($\langle r_{\rm e} \rangle$) are 5.0$\pm$1.5 kpc for HLSy2 and 3.9$\pm$0.6 kpc for HLSy2 and QSO2 respectively. These are significantly smaller than those found for QSO1 and narrow line radio galaxies at similar $z$. We put the results of our work in context of related studies of AGN with quasar-like luminosities., Comment: 23 pages, 6 figures. Accepted for publication in MNRAS

Young radio AGN are pivotal for our understanding of many of the still-debated aspects of AGN feedback. In this paper we present a study of the interstellar medium in the compact, peaked-spectrum radio galaxy PKSB1934-63 using X-shooter observations. Most of the warm ionized gas resides within a circum-nuclear disk with a radius of about 200pc that is likely to constitute the gas reservoir from which the central black hole feeds. On the other hand, we find a biconical outflow of warm ionized gas with an estimated radius of 59+/-12pc. This matches the radial extent of the radio source and suggests that the outflow is jet driven. Thanks to the superior wavelength coverage of the data, we can estimate the density of the warm ionized gas using the trans-auroral line technique, and we find that the outflowing gas has remarkably high density, up to n_e~10^5.5cm^-3 . The estimated mass outflow rate is low (M_dot=10^-3 - 10^-1 M_solar/yr) and the AGN feedback operates at relatively low efficiency (E_dot/L_bol~10^-4 - 10^-3 %), in contrast to predictions of theoretical models. In addition, optical and near-IR line ratios show that the expansion of the radio source drives fast shocks (with velocities v>500km/s) that ionize and accelerate the outflowing gas. At odds with the properties of other compact, peaked-spectrum radio sources hosting warm ionized gas outflows, we do not find signs of kinematically disturbed or outflowing gas in phases colder than the warm ionized gas. We argue that this is due to the young age of our source and thus to the recent nature of the AGN-ISM interaction, and suggest that cold gas forms within the outflowing material and the shock-ionized outflowing gas of PKSB1934-63 did not have enough time to cool down, and accumulate in a colder phase. This scenario is also supported by the multi-phase outflows of other compact and young radio sources in the literature., Comment: 21 pages, 23 figures, 2 tables. Accepted for publication in A&A, new version with language editor comments applied

As part of the QUADROS project to quantify the impact of AGN-driven outflows in rapidly evolving galaxies in the local universe, we present observations of 8 nearby ULIRGs ($0.04 < z < 0.2$) taken with the ISIS spectrograph on the \textit{William Herschel Telescope} (WHT), and also summarise the results of the project as a whole. Consistent with \cite{Rose2018}, we find that the outflow regions are compact (0.08 < $R_{[OIII]}$ < 1.5 kpc), and the electron densities measured using the [SII], [OII] trans-auroral emission-line ratios are relatively high (2.5 < log n$_{e}$(cm$^{-3}$) < 4.5, median log n$_{e}$(cm$^{-3})\sim 3.1$). Many of the outflow regions are also significantly reddened (median E(B-V) $\sim$ 0.5). Assuming that the de-projected outflow velocities are represented by the 5$\rm^{th}$ percentile velocities ($v_{05}$) of the broad, blueshifted components of [OIII]$\lambda$5007, we calculate relatively modest mass outflow rates ($0.1 < \dot{M} < 20$ M$_{\odot}$ yr$^{-1}$, median $\dot{M}$ $\sim$ 2 M$_{\odot}$ yr$^{-1}$), and find kinetic powers as a fraction of the AGN bolometric luminosity ($\dot{F} = \dot{E}/L_{bol}$) in the range 0.02 < $\dot{F}$ < 3 \%, median $\dot{F}$ $\sim$ 0.3 \%). The latter estimates are in line with the predictions of multi-stage outflow models, or single-stage models in which only a modest fraction of the initial kinetic power of the inner disk winds is transferred to the larger-scale outflows. Considering the QUADROS sample as a whole, we find no clear evidence for correlations between the properties of the outflows and the bolometric luminosities of the AGN, albeit based on a sample that covers a relatively small range in $L_{bol}$. Overall, our results suggest that there is a significant intrinsic scatter in outflow properties of ULIRGs for a given AGN luminosity., Comment: 25 pages, 11 figures, 11 tables, accepted for publication in MNRAS

The true importance of the warm, AGN-driven outflows for the evolution of galaxies remains uncertain. Measurements of the radial extents of the outflows are key for quantifying their masses and kinetic powers, and also establishing whether the AGN outflows are galaxy-wide. Therefore, as part of a larger project to investigate the significance of warm, AGN-driven outflows in the most rapidly evolving galaxies in the local universe, here we present deep Hubble Space Telescope ( HST) narrow-band [OIII]$\lambda$5007 observations of a complete sample of 8 nearby ULIRGs with optical AGN nuclei. Combined with the complementary information provided by our ground-based spectroscopy, the HST images show that the warm gas outflows are relatively compact for most of the objects in the sample: in three objects the outflow regions are barely resolved at the resolution of HST ($0.065 < R_{[OIII]} < 0.12$ kpc); in a further four cases the outflows are spatially resolved but with flux weighted mean radii in the range $0.65 < R_{[OIII]} < 1.2$ kpc; and in only one object (Mrk273) is there clear evidence for a more extended outflow, with a maximum extent of $R_{[OIII]}\sim5$ kpc. Overall, our observations show little evidence for the galaxy-wide outflows predicted by some models of AGN feedback., Comment: 14 pages, 3 figures, accepted for publication in MNRAS

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., Comment: Authors' version (all referee comments addressed). 7 pages + references. Published in Nature Astronomy

This paper presents the spatially resolved star formation history (2D-SFH) of a small sample of four local mergers: the early-stage mergers IC1623, NGC6090, and the Mice, and the more advanced merger NGC2623, by analyzing IFS data from the CALIFA survey and PMAS in LArr mode. Full spectral fitting techniques are applied to the datacubes to obtain the spatially resolved mass growth histories, the time evolution of the star formation rate intensity ($\Sigma_{SFR}$), and the local specific star formation rate, over three different timescales (30 Myr, 300 Myr, and 1 Gyr). The results are compared with non-interacting Sbc--Sc galaxies, to quantify if there is an enhancement of the star formation and to trace its time scale and spatial extent. Our results for the three LIRGs (IC1623W, NGC6090, and NGC2623) show that a major phase of star formation is occurring in time scales of 10$^{7}$ yr to few 10$^{8}$ yr, with global SFR enhancements of $\sim$2--6 with respect to main-sequence star forming (MSSF) galaxies. In the two early-stage mergers IC1623W and NGC6090, which are between first pericenter passage and coalescence, the most remarkable increase of the SFR with respect to non-interacting spirals occurred in the last 30 Myr, and it is spatially extended, with enhancements of factors 2--7 both in the centres ($r <$ 0.5 half light radius, HLR), and in the disks ($r >$ 1 HLR). In the more advanced merger NGC 2623 an extended phase of star formation occurred on a longer time-scale of $\sim$1 Gyr, with a SFR enhancement of a factor $\sim$2--3 larger than the one in Sbc--Sc MSSF galaxies over the same period, probably relic of the first pericenter passage epoch. A SFR enhancement in the last 30 Myr is also present, but only in NGC2623 centre, by a factor 3. In general, the spatially resolved SFHs of the LIRG-mergers are consistent with the predictions from high spatial resolution simulations., Comment: 17 pages, 7 figures, 2 tables, accepted for publication in Astronomy & Astrophysics, abstract abridged for arXiv submission

We report on a detailed study of the stellar populations and ionized gas properties in the merger LIRG NGC 2623, analysing optical Integral Field Spectroscopy from the CALIFA survey and PMAS LArr, multiwavelength HST imaging, and OSIRIS narrow band H$\alpha$ and [NII]$\lambda$6584 imaging. The spectra were processed with the STARLIGHT full spectral fitting code, and the results compared with those for two early-stage merger LIRGs (IC 1623 W and NGC 6090), together with CALIFA Sbc/Sc galaxies. We find that NGC 2623 went through two periods of increased star formation (SF), a first and widespread episode, traced by intermediate-age stellar populations ISP (140 Myr-1.4 Gyr), and a second one, traced by young stellar populations YSP ($<$140 Myr), which is concentrated in the central regions ($<$1.4 kpc). Our results are in agreement with the epochs of the first peri-center passage ($\sim$200 Myr ago) and coalescence ($<$100 Myr ago) predicted by dynamical models, and with high resolution merger simulations in the literature, consistent with NGC 2623 representing an evolved version of the early-stage mergers. Most ionized gas is concentrated within $<$2.8 kpc, where LINER-like ionization and high velocity dispersion ($\sim$220 km/s) are found, consistent with the previously reported outflow. As revealed by the highest resolution OSIRIS and HST data, a collection of HII regions is also present in the plane of the galaxy, which explains the mixture of ionization mechanisms in this system. It is unlikely that the outflow in NGC 2623 will escape from the galaxy, given the low SFR intensity ($\sim$0.5 M$_{\odot}$yr$^{-1}$kpc$^{-2}$), the fact that the outflow rate is 3 times lower than the current SFR, and the escape velocity in the central areas higher than the outflow velocity., Comment: 22 pages, 24 figures, accepted for publication in A&A

The 2Jy sample is a survey of radio galaxies with flux densities above 2 Jy at 2.7 GHz. As part of our ongoing work on the southern subset of 2Jy sources, in paper I of this series we analysed the X-ray cores of the complete 2Jy sample with redshifts 0.05

The role of major mergers in galaxy evolution is investigated through a detailed characterization of the stellar populations, ionized gas properties, and star formation rates (SFR) in the early-stage merger LIRGs IC 1623 W and NGC 6090, by analysing optical Integral Field Spectroscopy (IFS) and high resolution HST imaging. The spectra were processed with the Starlight full spectral fitting code, and the emission lines measured in the residual spectra. The results are compared with control non-interacting spiral galaxies from the CALIFA survey. Merger-induced star formation is extended and recent, as revealed by the young ages (50-80 Myr) and high contributions to light of young stellar populations (50-90$\%$), in agreement with merger simulations in the literature. These early-stage mergers have positive central gradients of the stellar metallicity, with an average $\sim$0.6 Z$_{\odot}$. Compared to non-interacting spirals, they have lower central nebular metallicity, and flatter profiles, in agreement with the gas inflow scenario. We find that they are dominated by star formation, although shock excitation cannot be discarded in some regions, where high velocity dispersion is found (170-200 km s$^{-1}$). The average SFR in these early-stage mergers ($\sim$23-32 M$_{\odot}$ yr$^{-1}$) is enhanced with respect to main-sequence Sbc galaxies by factors of 6-9, slightly above the predictions from classical merger simulations, but still possible in about 15$\%$ of major galaxy mergers, where U/LIRGs belong.

Tidal disruption events (TDEs), in which stars are gravitationally disrupted as they pass close to the supermassive black holes in the centres of galaxies, are potentially important probes of strong gravity and accretion physics. Most TDEs have been discovered in large-area monitoring surveys of many 1000s of galaxies, and the rate deduced for such events is relatively low: one event every 10$^4$ - 10$^5$ years per galaxy. However, given the selection effects inherent in such surveys, considerable uncertainties remain about the conditions that favour TDEs. Here we report the detection of unusually strong and broad helium emission lines following a luminous optical flare (Mv < -20.1 mag) in the nucleus of the nearby ultra-luminous infrared galaxy F01004-2237. The particular combination of variability and post-flare emission line spectrum observed in F01004-2237 is unlike any known supernova or active galactic nucleus. Therefore, the most plausible explanation for this phenomenon is a TDE -- the first detected in a galaxy with an ongoing massive starburst. The fact that this event has been detected in repeat spectroscopic observations of a sample of 15 ultra-luminous infrared galaxies over a period of just 10 years suggests that the rate of TDEs is much higher in such objects than in the general galaxy population., Comment: 17 pages, 4 figures, accepted for publication in Nature Astronomy

The origin of the unification model for Active Galactic Nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden broad-line region (HBLR) of nearby Sy2s started, but polarized broad lines have only been detected in 30-40% of the nearby Sy2s observed to date. Here we present new VLT/FORS2 optical spectropolarimetry of a sample of 15 Sy2s, including Compton-thin and Compton-thick sources. The sample includes six galaxies without previously published spectropolarimetry, some of them normally treated as non-hidden BLR (NHBLR) objects in the literature, four classified as NHBLR, and five as HBLR based on previous data. We report >=4{\sigma} detections of a HBLR in 11 of these galaxies (73% of the sample) and a tentative detection in NGC 5793, which is Compton-thick according to the analysis of X-ray data performed here. Our results confirm that at least some NHBLRs are misclassified, bringing previous publications reporting differences between HBLR and NHBLR objects into question. We detect broad H{\alpha} and H{\beta} components in polarized light for 10 targets, and just broad H{\alpha} for NGC 5793 and NGC 6300, with line widths ranging between 2100 and 9600 km/s. High bolometric luminosities and low column densities are associated with higher polarization degrees, but not necessarily with the detection of the scattered broad components., Comment: 18 pages, 19 figures (including appendices). Accepted in MNRAS

We present a detailed study of the complex ionization structure in a small (~250 pc) extended narrow line region (ENLR) cloud near Centaurus A using the Multi Unit Spectroscopic Explorer. This cloud is located in the so-called outer filament of ionized gas (about 15 kpc from the nucleus) where jet-induced star formation has been suggested to occur by different studies. We find that, despite the small size, a mixture of ionization mechanisms is operating, resulting in considerable complexity in the spatial ionization structure. The area includes two H II regions where star formation is occurring and another location where star formation must have ceased very recently. Interestingly, the extreme Balmer decrement of one of the star forming regions (H_alpha/H_beta~6) indicates that it is still heavily embedded in its natal cocoon of gas and dust. At all three locations a continuum counterpart is found with spectra matching those of O/B stars local to Centaurus A. The H II regions are embedded in a larger gas complex which is photoionized by the radiation of the central active galactic nucleus (AGN), but the O/B stars affect the spatial ionization pattern in the ENLR cloud very locally. In particular, in the surroundings of the youngest star forming region, we can isolate a tight mixing sequence in the diagnostic diagram going from gas with ionization due to a pure stellar continuum to gas only photoionized by the AGN. These results emphasize the complexity and the mixture of processes occurring in star forming regions under the influence of an AGN radiation. This is relevant for our understanding of AGN-induced star formation suggested to occur in a number of objects, including this region of Centaurus A. They also illustrate that these young stars influence the gas over only a limited region., Comment: 7 pages, 7 figures, 1 table, accepted for publication in A&A

We present deep new GTC/OSIRIS narrow-band images and optical WHT/ISIS long-slit spectroscopy of the merging system Mrk273 that show a spectacular extended halo of warm ionised gas out to a radius of $\sim45$ kpc from the system nucleus. Outside of the immediate nuclear regions (r > 6 kpc), there is no evidence for kinematic disturbance in the ionised gas: in the extended regions covered by our spectroscopic slits the emission lines are relatively narrow (FWHM $\lesssim$ 350 km$\rm s^{-1}$) and velocity shifts small (|$\Delta$V| $\lesssim{} $250 km$\rm s^{-1}$). This is despite the presence of powerful near-nuclear outflows (FWHM > 1000 km$\rm s^{-1}$; |$\Delta$V| > 400 km$\rm s^{-1}$; r < 6 kpc). Diagnostic ratio plots are fully consistent with Seyfert 2 photo-ionisation to the NE of the nuclear region, however to the SW the plots are more consistent with low-velocity radiative shock models. The kinematics of the ionised gas, combined with the fact that the main structures are aligned with low-surface-brightness tidal continuum features, are consistent with the idea that the ionised halo represents tidal debris left over from a possible triple-merger event, rather than a reservoir of outflowing gas., Comment: 5 pages, 3 figures, accepted for publication in MNRAS Letters

Newly born and young radio sources are in a delicate phase of their life. Their jets are fighting their way through the surrounding gaseous medium, strongly experiencing this interaction while, at the same time, impacting and affecting the interstellar medium (ISM). Here we present the results from two studies of HI (in absorption) and molecular gas illustrating what can be learned from these phases of the gas. We first describe a statistical study with the WSRT. The study shows that the young radio sources not only have an higher detection rate of HI, but also systematically broader and more asymmetric HI profiles, most of them blueshifted. This supports the idea that we are looking at young radio jets making their way through the surrounding ISM, which also appears to be, on average, richer in gas than in evolved radio sources. Signatures of the impact of the jet are seen in the kinematics of the gas. However, even among the young sources, we identify a population that remains undetected in HI even after stacking their profiles. Orientation effects can only partly explain the result. These objects either are genuinely gas-poor or have different conditions of the medium, e.g. higher spin temperature. We further present the ALMA study of molecular gas in IC5063 to trace in detail the jet impacting the ISM. The kinematics of the cold, molecular gas co-spatial with the radio plasma shows this process in action. The ALMA data reveal a fast outflow of molecular gas extending along the entire radio jet (~1 kpc), with the highest outflow velocities at the location of the brighter hot-spot. We propose a scenario where the radio jet is expanding into a clumpy medium, interacting directly with the clouds and inflating a cocoon that drives a lateral outflow into the ISM., Comment: Proceedings of the "5th Workshop on Compact Steep Spectrum and GHz-peaked Spectrum Radio Sources". To be published in Astronomische Nachrichten (6 pages, 6 figures)

We present optical imaging and long slit spectroscopic observations of 9 luminous type 2 AGNs within the redshift range 0.3

We study the physical and kinematic properties of the narrow line region (NLR) of the nearest obscured quasar MRK 477 (z=0.037), using optical and near-infrared spectroscopy. We explore a diversity of aspects that provide a more complete understanding of the nature of this object, example of a type 2 quasar in the nearby Universe, as well as a starburst-AGN hybrid system [abridged]., Comment: Accepted for publication in MNRAS. 20 pages, 15 figures

High-resolution (0.5 arcsec) CO(2-1) observations performed with the Atacama Large Millimetre/submillimetre Array have been used to trace the kinematics of the molecular gas in the Seyfert 2 galaxy{IC~5063}. Although one of the most radio-loud Seyfert galaxy, IC~5063 is a relatively weak radio source (P_1.4GHz = 3 x 10^23 W Hz^-1). 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 W lobe. 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 suggests that most of the observed cold molecular outflow is due to fast cooling of the gas after the passage of a shock and that it is the end product of the cooling process., Comment: To appear in ASP Conference Series, proceedings of "Revolution in Astronomy with ALMA: The 3rd year" (Tokyo, Japan, December 2014), eds. D. Iono, A. Wootten, L. Testi (submitted version), 4 pages, 2 figures

We use deep Herschel Space Observatory observations of a 90% complete sample of 32 intermediate-redshift 2Jy radio galaxies (0.05 < z < 0.7) to estimate the dust masses of their host galaxies and thereby investigate the triggering mechanisms for their quasar-like AGN. The dust masses derived for the radio galaxies (7.2x10^5 < M_d < 2.6x10^8 M_sun) are intermediate between those of quiescent elliptical galaxies on the one hand, and ultra luminous infrared galaxies (ULIRGs) on the other. Consistent with simple models for the co-evolution of supermassive black holes and their host galaxies, these results suggest that most of the radio galaxies represent the late time re-triggering of AGN activity via mergers between the host giant elliptical galaxies and companion galaxies with relatively low gas masses. However, a minority of the radio galaxies in our sample (~20%) have high, ULIRG-like dust masses, along with evidence for prodigious star formation activity. The latter objects are more likely to have been triggered in major, gas-rich mergers that represent a rapid growth phase for both their host galaxies and their supermassive black holes., Comment: 5 pages, 2 figures, accepted for publication in MNRAS Letters

We present high-angular (~0.4") resolution mid-infrared (MIR) polarimetric observations in the 8.7 ${\mu}$m and 11.6 ${\mu}$m filters of Cygnus A using CanariCam on the 10.4-m Gran Telescopio CANARIAS. A highly polarized nucleus is observed with a degree of polarization of 11${\pm}$3% and 12${\pm}$3% and position angle of polarization of 27${\pm}$8 degrees and 35${\pm}$8 degrees in a 0.38" (~380 pc) aperture for each filter. The observed rising of the polarized flux density with increasing wavelength is consistent with synchrotron radiation from the pc-scale jet close to the core of Cygnus A. Based on our polarization model, the synchrotron emission from the pc-scale jet is estimated to be 14% and 17% of the total flux density in the 8.7 ${\mu}$m and 11.6 ${\mu}$m filters, respectively. A blackbody component with a characteristic temperature of 220 K accounts for >75% of the observed MIR total flux density. The blackbody emission arises from a combination of (1) dust emission in the torus; and (2) diffuse dust emission around the nuclear region, but the contributions of the two components cannot be well constrained in these observations., Comment: 8 pages, 2 figures (Accepted for publication in ApJ)

We present an analysis of 2.05 $\mu$m Hubble Space Telescope (HST) polarimetric data for a sample of 13 nearby Fanaroff-Riley type II (FRII) 3CR radio sources ($0.03

Massive outflows driven by active galactic nuclei (AGN) are widely recognised to play a key role in the evolution of galaxies, heating the ambient gas, expelling it from the nuclear regions, and thereby affecting the star formation histories of the galaxy bulges. It has been proposed that the powerful jets of relativistic particles launched by some AGN can both accelerate and heat the molecular gas, which often dominates the mass budgets of the outflows. However, clear evidence for this mechanism in the form of detailed associations between the molecular gas kinematics and features in the radio-emitting jets has been lacking. Here we show that the warm molecular hydrogen gas in the western radio lobe of the Seyfert galaxy IC5063 is moving at high velocities - up to 600 km/s - relative to the galaxy disk. This suggests that the molecules have been accelerated by fast shocks driven into the interstellar medium (ISM) by the expanding radio jets. These results demonstrate the general feasibility of accelerating molecular outflows in fast shocks driven by AGN., Comment: 9 pages, 3 figures. Published online in Nature on 6th July 2014. There exist minor stylistic differences with the published version

It remains uncertain which continuum and emission line diagnostics best indicate the bolometric powers of active galactic nuclei (AGNs), especially given the attenuation caused by the circumnuclear material and the possible contamination by components related to star formation. Here we use mid-IR spectra along with multiwavelength data to investigate the merit of various diagnostics of AGN radiative power, including the mid-IR [Ne III] lambda25.89 mum and [O IV] lambda25.89 mum fine-structure lines, the optical [O III] lambda5007 forbidden line, and mid-IR 24 mum, 5 GHz radio, and X-ray continuum emission, for complete samples of 46 2Jy radio galaxies (0.05 < z < 0.7) and 17 3CRR FRII radio galaxies (z < 0.1). We find that the mid-IR [O IV] line is the most reliable indicator of AGN power for powerful radio-loud AGNs. By assuming that the [O IV] is emitted isotropically, and comparing the [O III] and 24 mum luminosities of the broad- and narrow-line AGNs in our samples at fixed [O IV] luminosity, we show that the [O III] and 24 mum emission are both mildly attenuated in the narrow-line compared to the broad-line objects by a factor of #2. However, despite this attenuation, the [O III] and 24 mum luminosities are better AGN power indicators for our sample than either the 5 GHz radio or the X-ray continuum luminosities. We also detect the mid-IR 9.7 mum silicate feature in the spectra of many objects but not ubiquitously: at least 40% of the sample shows no clear evidence for these features. We conclude that, for the majority of powerful radio galaxies, the mid-IR lines are powered by AGN photoionization., Comment: Matches the ApJ accepted version

We carry out a systematic study of the X-ray emission from the active nuclei of the 0.02

We present the analysis of infrared HST and Spitzer data for a sample of 13 FRII radio galaxies at 0.03

We present a CO(1-0) survey for cold molecular gas in a representative sample of 13 high-z radio galaxies (HzRGs) at 1.4

We present the results of a comparison between the environments of 1) a complete sample of 46 southern 2Jy radio galaxies at intermediate redshifts (0.05 < z < 0.7), 2) a complete sample of 20 radio-quiet type-2 quasars (0.3 < z < 0.41), and 3) a control sample of 107 quiescent early-type galaxies at 0.2 < z < 0.7 in the Extended Groth Strip (EGS). The environments have been quantified using angular clustering amplitudes (Bgq) derived from deep optical imaging data. Based on these comparisons, we discuss the role of the environment in the triggering of powerful radio-loud and radio-quiet quasars. When we compare the Bgq distributions of the type-2 quasars and quiescent early-type galaxies, we find no significant difference between them. This is consistent with the radio-quiet quasar phase being a short-lived but ubiquitous stage in the formation of all massive early-type galaxies. On the other hand, PRGs are in denser environments than the quiescent population, and this difference between distributions of Bgq is significant at the 3 sigma level. This result supports a physical origin of radio loudness, with high density gas environments favouring the transformation of AGN power into radio luminosity, or alternatively, affecting the properties of the supermassive black holes themselves. Finally, focussing on the radio-loud sources only, we find that the clustering of weak-line radio galaxies (WLRGs) is higher than the strong-line radio galaxies (SLRGs), constituting a 3 sigma result. 82% of the 2Jy WLRGs are in clusters, according to our definition (Bgq > 400) versus only 31% of the SLRGs., Comment: 17 pages + Appendix, accepted for publication in MNRAS

We present an optical spectroscopic study of a 90% complete sample of 17 nearby ULIRGs with optical Seyfert nuclei, with the aim of investigating the nature of the nuclear warm gas outflows. A high proportion (94%) of our sample show disturbed emission line kinematics in the form of broad (FWHM > 500 km s-1) and/or strongly blueshifted (\Delta V < -150 km s-1) emission line components. This proportion is significantly higher than found in a comparison sample of non-Sy ULIRGs (19%). We also find evidence that the [OII]5007,4959 emission lines in Sy-ULIRGs are broader and more asymmetric that in samples of non-ULIRG Seyferts. The Sy-ULIRG sample encompasses a wide diversity of emission line profiles. In most individual objects we are able to fit the profiles of all the emission lines with a kinematic model derived from the strong [OIII]4959,5007 lines, using between 2 and 5 Gaussian components. From these fits we derive diagnostic line ratios that are used to investigate the ionization mechanisms for the different kinematic components. We show that, in general, the line ratios are consistent with gas of super-solar abundance photoionized by a combination of AGN and starburst activity, with an increasing contribution from the AGN with increasing FWHM of the individual kinematic components, and the AGN contribution dominating for the broadest components. However, shock ionization cannot be ruled out in some cases. Our derived upper limits on the mass outflows rates and kinetic powers of the emission line outflows show that they can be as energetically significant as the neutral and molecular outflows in ULIRGs-consistent with the requirements of the hydrodynamic simulations that include AGN feedback. However, the uncertainties are large, and more accurate estimates of the radii, densities and reddening of the outflows are required to put these results on a firmer footing., Comment: 34 pages including appendix. Accepted for publication in MNRAS

The high-redshift radio galaxy MRC 1138-262 (`Spiderweb Galaxy'; z = 2.16), is one of the most massive systems in the early Universe and surrounded by a dense `web' of proto-cluster galaxies. Using the Australia Telescope Compact Array, we detected CO(1-0) emission from cold molecular gas -- the raw ingredient for star formation -- across the Spiderweb Galaxy. We infer a molecular gas mass of M(H2) = 6x10^10 M(sun) (for M(H2)/L'(CO)=0.8). While the bulk of the molecular gas coincides with the central radio galaxy, there are indications that a substantial fraction of this gas is associated with satellite galaxies or spread across the inter-galactic medium on scales of tens of kpc. In addition, we tentatively detect CO(1-0) in the star-forming proto-cluster galaxy HAE 229, 250 kpc to the west. Our observations are consistent with the fact that the Spiderweb Galaxy is building up its stellar mass through a massive burst of widespread star formation. At maximum star formation efficiency, the molecular gas will be able to sustain the current star formation rate (SFR ~ 1400 M(sun)/yr, as traced by Seymour et al.) for about 40 Myr. This is similar to the estimated typical lifetime of a major starburst event in infra-red luminous merger systems., Comment: 7 pages, 3 figures - accepted for publication in MNRAS

We present optical, infrared and radio observations of the powerful FRII radio source PKS0347+05 (z=0.3390), and demonstrate that it is a rare example of a radio-loud/radio-quiet double AGN system, comprising a weak line radio galaxy (WLRG) separated by 25 kpc (in projection) from a Seyfert 1 nucleus at the same redshift. Our deep Gemini optical images show a highly disturbed morphology, with a warped dust lane crossing through the halo and nuclear regions of the radio galaxy host, tidal tails, and a bridge connecting the radio galaxy to the Seyfert 1 nucleus. Spectral synthesis modelling of our Gemini optical spectrum of the radio galaxy shows evidence for a reddened young stellar population of age <100 Myr. Further evidence for recent star formation activity in this source is provided by the detection of strong PAH features in mid-IR Spitzer/IRS spectra. Together, these observations support a model in which both AGN have been triggered simultaneously in a major galaxy merger. However, despite the presence of a powerful FRII radio source, and the apparently plentiful supply of fuel provided by the merger, the nucleus of the radio galaxy shows only weak, low ionization emission line activity. We speculate that the fuel supply to nuclear regions of the radio galaxy has recently switched off (within the last ~10^6 yr), but the information about the resulting decrease in nuclear AGN activity has yet to reach the extended lobes and hotspots of the FRII radio source. Based on this scenario, we estimate that powerful, intermediate redshift FRII radio sources have lifetimes of t\sim 5x10^6 yr. Overall, our observations emphasise that the fuelling of AGN activity in major galaxy mergers is likely to be highly intermittent., Comment: 12 pages, 10 figures, accepted for publication in MNRAS

PKS B2152-699 has radio power characteristic of sources that dominate radio feedback. We present new deep ATCA, Chandra and optical observations, and test the feedback model. We report the first high-resolution observations of the radio jet. The inner jet extends ~8.5 kpc towards an optical emission-line High Ionization Cloud (HIC) before taking a zig-zag path to an offset position. Jet X-ray synchrotron radiation is seen. The HIC is associated with 0.3 keV X-ray gas of anomalously low metallicity. On larger scales the radio galaxy displays all three X-ray features that together confirm supersonic expansion of the lobes into the external medium: gas cavities, inverse-Compton emission showing excess internal lobe pressure, and high-contrast arms of temperature above the ~1 keV ambient medium. The well-formed S lobe on the counterjet side is expanding with a Mach number 2.2-3. We estimate a cavity power ~3x10^43 ergs/s, which falls well below previously reported correlations with radio power. The total inferred time-averaged jet power, ~4x10^44 ergs/s, is dominated by the kinetic and thermal energy of shocked gas, and if used instead would bring the source into better agreement with the correlations. The S hotspot is the more complex, with a spiral polarization structure. Its bright peak emits synchrotron X-rays. The fainter N hotspot is particularly interesting, with X-rays offset in the direction of the incoming jet by ~1 arcsec relative to the radio peak. Here modest (delta ~ 6) relativistic beaming and a steep radio spectrum cause the jet to be X-ray bright through inverse-Compton scattering before it decelerates. With such beaming, a modest proton content or small departure from minimum energy in the jet will align estimates of the instantaneous and time-averaged jet power. The hotspots suggest acceleration of electrons to a maximum energy ~10^13 eV in the jet termination shocks., Comment: Acccepted for publication in MNRAS. 17 pages, 19 figs. Some figures reduced in quality

We present deep Spitzer/IRS spectra for complete samples of 46 2Jy radio galaxies (0.0575%) than their more extended counterparts (=15 -- 25%). We discuss this result in the context of a possible bias towards the selection of compact radio sources triggered in gas-rich environments., Comment: 33 pages, 14 Figures, Accepted for publication in ApJ