Taking snapshots of the jet-ISM interplay with ALMA

We present an update of our on-going project to characterise the impact of radio jets on the ISM by tracing molecular gas at high spatial resolution using ALMA. The radio active galactic nuclei (AGN) studied show recently born radio jets. In this stage, the plasma jets can have the largest impact on the ISM, as also predicted by state-of-the-art simulations. The two targets have quite different ages, allowing us to get snapshots of the effects of radio jets as they grow. Interestingly, both also host powerful quasar emission. The largest mass outflow rate of molecular gas is found in a radio galaxy hosting a newly born radio jet emerging from an obscuring cocoon of gas and dust. Although the mass outflow rate is high (few hundred Msun/yr), the outflow is limited to the inner few hundred pc region. In a second object, the jet is larger (a few kpc) and is in a more advanced evolutionary phase. In this object, the distribution of the molecular gas is reminiscent of what is seen, on larger scales, in cool-core clusters hosting radio galaxies. Gas deviating from quiescent kinematics is not very prominent, limited only to the very inner region, and has a low mass outflow rate. Instead, on kpc scales, the radio lobes appear associated with depressions in the distribution of the molecular gas, suggesting they have broken out from the dense nuclear region. The AGN does not appear to be able at present to stop the star formation observed in this galaxy. These results suggest that the effects of the radio source start in the first phases by producing outflows which, however, tend to be limited to the kpc region. After that, the effects turn into producing large-scale bubbles which could, in the long term, prevent the surrounding gas from cooling. Our results characterise the effect of radio jets in different phases of their evolution, bridging the studies done for radio galaxies in clusters.Comment: 5 Pages 2 figures; Proceedings IAU Symposium No. 359, "Galaxy evolution and feedback across different environments", T. Storchi-Bergmann, R. Overzier, W. Forman & R. Riffel, ed

Outflow densities and ionisation mechanisms in the NLRs of the prototypical Seyfert galaxies NGC 1068 and NGC 4151

Despite being thought to play an important role in galaxy evolution, the true impact of outflows driven by active galactic nuclei (AGN) on their host galaxies is unclear. In part, this may be because electron densities of outflowing gas are often underestimated: recent studies that use alternative diagnostics have measured much higher densities than those from commonly used techniques, and consequently find modest outflow masses and kinetic powers. Furthermore, outflow ionisation mechanisms - which are often used to probe acceleration mechanisms - are also uncertain. To address these issues, we have analysed archival HST/STIS spectra of the inner regions (r<160pc) of the nearby prototypical Seyfert galaxies NGC 1068 and NGC 4151, which show evidence of warm-ionised outflows driven by the central AGN. We derive high electron densities ($10^{3.6}$<$n_e$<$10^{4.8}$cm$^{-3}$) using the transauroral [OII] and [SII] emission lines ratios for the first time with spatially-resolved observations. Moreover, we find evidence that the gas along the radio axis in NGC 1068 has a significant AGN-photoionised matter-bounded component, and there is evidence for shock-ionisation and/or radiation-bounded AGN-photoionisation along the radio axis in NGC 4151. We also note that the outflow extents are similar to those of the radio structures, consistent with acceleration by jet-induced shocks. Taken together, our investigation demonstrates the diversity of physical and ionisation conditions in the narrow line regions of Seyfert galaxies, and hence reinforces the need for robust diagnostics of outflowing gas densities and ionisation mechanisms.Comment: 21 pages, 13 figures, accepted for publication in MNRA

BeppoSAX Observations of 2 Jy Lobe-dominated Broad-Line Sources: the Discovery of a Hard X-ray Component

We present new BeppoSAX LECS, MECS, and PDS observations of five lobe-dominated, broad-line active galactic nuclei selected from the 2 Jy sample of southern radio sources. These include three radio quasars and two broad-line radio galaxies. ROSAT PSPC data, available for all the objects, are also used to better constrain the spectral shape in the soft X-ray band. The collected data cover the 0.1 - 10 keV energy range, reaching 40 keV for one source. Detailed spectral fitting shows that all sources have a flat hard X-ray spectrum with energy index alpha_x ~ 0.75 in the 2 - 10 keV energy range. This is a new result, which is at variance with the situation at lower energies where these sources exhibit steeper spectra. Spectral breaks ~0.5 at 1 - 2 keV characterize the overall X-ray spectra of our objects. The flat, high-energy slope is very similar to that displayed by flat-spectrum/core-dominated quasars, which suggests that the same emission mechanism (most likely inverse Compton) produces the hard X-ray spectra in both classes. Contrary to the optical evidence for some of our sources, no absorption above the Galactic value is found in our sample. Finally, a (weak) thermal component is also present at low energies in the two broad-line radio galaxies included in our study.Comment: 4 pages, LateX, 3 figures. Uses espcrc2.sty. To appear in: "The Active X-ray Sky: Results from BeppoSAX and Rossi-XTE", Rome, Italy, 21-24 October, 1997, Eds.: L. Scarsi, H. Bradt, P. Giommi and F. Fior

High-Resolution Mid-Infrared Morphology of Cygnus A

We present subarcsecond resolution mid-infrared images at 10.8 and 18.2 microns of Cygnus A. These images were obtained with the University of Florida mid-IR camera/spectrometer OSCIR at the Keck II 10-m telescope. Our data show extended mid-IR emission primarily to the east of the nucleus with a possible western extension detected after image deconvolution. This extended emission is closely aligned with the bi-conical structure observed at optical and near-IR wavelengths by the HST. This emission is consistent with dust heated from the central engine of Cygnus A. We also marginally detect large-scale low level emission extending > 1.5 kpc from the nucleus which may be caused by in-situ star formation, line emission, and/or PAH contamination within the bandpass of our wide N-band filter.Comment: 20 pages, 8 figures, accepted for publication in the Astrophysical Journa

Extended Warm Gas in the ULIRG Mrk273: Galactic Outflows and Tidal Debris

We present new HST ACS medium- and narrow-band images and long-slit, optical (4000 - 7200A) spectra obtained using the Isaac Newton Telescope (INT) on La Palma, of the merging system Mrk273. The HST observations sample the [OIII]4959,5007 emission from the galaxy and the nearby continuum. The images show that the morphologies of the extended continuum and the ionised gas emission from the galaxy are decoupled, extending almost perpendicular to each other. In particular, we detect for the first time a spectacular structure of ionised gas in the form of filaments extending ~23 kpc to the east of the nuclear region. The quiescent ionised gas kinematics at these locations suggests that these filaments are tidal debris left over from a secondary merger event that are illuminated by an AGN in the nuclear regions. The images also reveal a complex morphology in the nuclear region of the galaxy for both the continuum and the [OIII] emission. Kinematic disturbance, in the form of broad (FWHM > 500 km s-1) and/or strongly shifted (abs(\DeltaV) >150 km s-1) emission line components, is found at almost all locations within a radius of ~4 kpc to the east and west of the northern nucleus. We fit the profiles of all the emission lines of different ionisation with a kinematic model using up to 3 Gaussian components. From these fits we derive diagnostic line ratios that are used to investigate the ionisation mechanisms at the different locations in the galaxy. We show that, in general, the line ratios are consistent with photoionization by an AGN as the main ionisation mechanism. Finally, the highest surface brightness [OIII] emission is found in a compact region that is coincident with the so-called SE nuclear component. The compactness, kinematics and emission line ratios of this component suggest that it is a separate nucleus with its own AGN.Comment: Accepted for Publication in A&

Dominant Nuclear Outflow Driving Mechanisms in Powerful Radio Galaxies

In order to identify the dominant nuclear outflow mechanisms in Active Galactic Nuclei, we have undertaken deep, high resolution observations of two compact radio sources (PKS 1549-79 and PKS 1345+12) with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope. Not only are these targets known to have powerful emission line outflows, but they also contain all the potential drivers for the outflows: relativistic jets, quasar nuclei and starbursts. ACS allows the compact nature (<0.15") of these radio sources to be optically resolved for the first time. Through comparison with existing radio maps we have seen consistency in the nuclear position angles of both the optical emission line and radio data. There is no evidence for bi-conical emission line features on the large-scale and there is a divergance in the relative position angles of the optical and radio structure. This enables us to exclude starburst driven outflows. However, we are unable to clearly distinguish between radiative AGN wind driven outflows and outflows powered by relativistic radio jets. The small scale bi-conical features, indicative of such mechanisms could be below the resolution limit of ACS, especially if aligned close to the line of sight. In addition, there may be offsets between the radio and optical nuclei induced by heavy dust obscuration, nebular continuum or scattered light from the AGN.Comment: 9 pages, 8 figures, emulateapj, ApJ Accepte

A near-infrared study of the multi-phase outflow in the type-2 quasar J1509+0434

Based on new near-infrared spectroscopic data from the instrument EMIR on the 10.4 m Gran Telescopio Canarias (GTC) we report the presence of an ionized and warm molecular outflow in the luminous type-2 quasar J150904.22+043441.8 (z = 0.1118). The ionized outflow is faster than its molecular counterpart, although the outflow sizes that we derive for them are consistent within the errors (1.34±0.18 kpc and 1.46±0.20 kpc respectively). We use these radii, the broad emission-line luminosities and in the case of the ionized outflow, the density calculated from the trans-auroral [OII] and [SII] lines, to derive mass outflow rates and kinetic coupling efficiencies. Whilst the ionized and warm molecular outflows represent a small fraction of the AGN power (≤0.033% and 0.0001% of Lbol respectively), the total molecular outflow, whose mass is estimated from an assumed warm-to-cold gas mass ratio of 6× 10−5, has a kinetic coupling efficiency of ∼1.7%Lbol. Despite the large uncertainty, this molecular outflow represents a significant fraction of Lbol and it could potentially have a significant impact on the host galaxy. In addition, the quasar spectrum reveals bright and patchy narrow Paα emission extending out to 4″ (8 kpc) South-East and North-West from the active nucleus.Includes Horizon 202

Coronal-Line Forest AGN: the best view of the inner edge of the AGN torus?

We introduce Coronal-Line Forest Active Galactic Nuclei (CLiF AGN), AGN which have a rich spectrum of forbidden high-ionization lines (FHILs, e.g. [FeVII], [FeX] and [NeV]), as well as relatively strong narrow ($\sim$300 km s$^{-1}$) H$\alpha$ emission when compared to the other Balmer transition lines. We find that the kinematics of the CLiF emitting region are similar to those of the forbidden low-ionization emission-line (FLIL) region. We compare emission line strengths of both FHILs and FLILs to CLOUDY photoionization results and find that the CLiF emitting region has higher densities (10$^{4.5}$ $<$ n$_H$ $<$ 10$^{7.5}$ cm$^{-3}$) when compared to the FLIL emitting region (10$^{3.0}$ $<$ n$_H$ $<$ 10$^{4.5}$ cm$^{-3}$). We use the photoionization results to calculate the CLiF regions radial distances (0.04 $<$ R$_{CLiF}$ $<$ 32.5 pc) and find that they are comparable to the dust grain sublimation distances (0.10 $<$ R$_{SUB}$ $<$ 4.3 pc). As a result we suggest that the inner torus wall is the most likely location of the CLiF region, and the unusual strength of the FHILs is due to a specific viewing angle giving a maximal view of the far wall of the torus without the continuum being revealed.Comment: 22 pages, 14 Figures and 12 Tables. Resubmitted to MNRAS after minor correction