C. M. Harrison

Kiloparsec-scale outflows are prevalent among luminous AGN: outflows and feedback in the context of the overall AGN population

In this chapter we aim to address the question: how common are kilo-parsec scale ionised outflows in the host galaxies of powerful active galactic nuclei (AGN; i.e., quasars) and what are their properties (e.g., spatial extents, morphologies and energetics)? We select 16 targets for spatially-resolved spectroscopy (i.e., integral field unit [IFU] observations) from a well-constrained parent sample of \(\approx \)24,000 AGN. This means that we can place our observations into the context of the overall AGN population and therefore learn about the population as a whole. Our targets are \(z<0.2\) type 2 quasars that are radio-quiet, with star formation rates (\(\lesssim \)[10–100]\(\mathrm{M}_{\odot }\,\mathrm{yr}^{-1}\)) that are consistent with normal star-forming galaxies. We present Gemini-GMOS IFU observations covering the [O iii]\(\lambda \lambda 4959,5007\) and H\(\beta \) emission lines. We find high-velocity ionised gas (velocity widths \({\approx }600\)–1500 km s\(^{-1}\); maximum velocities \({\le }1700\) km s\(^{-1}\)) with observed spatial extents of \(\gtrsim \)(6–16) kpc in all targets. We show that our targets are representative of \(z<0.2\), type 2 quasars and that ionised outflows are not only common but also in \(\ge \)70 % (3\(\sigma \) confidence) of cases, they are extended over kiloparsec scales. Both star formation and AGN activity appear to be energetically viable to drive the outflows and we find no definitive evidence that favours one process over the other. Although uncertain, we derive mass outflow rates (typically \({\approx }10 \times \) the SFRs), kinetic energies (\({\approx }0.5\)–10 % of \(L_{\mathrm{AGN}}\)) and momentum rates (typically \({\gtrsim }[10\)–\(20]\times L_{\mathrm{AGN}}/c\)) consistent with theoretical models that predict that AGN-driven outflows play a significant role in shaping the evolution of galaxies.

An ALMA survey of sub-millimetre galaxies in the extended chandra deep field south: The far-infrared properties of SMGs

We exploit Atacama Large Millimeter Array (ALMA) 870 mu m observations of sub-millimetre sources in the Extended Chandra Deep Field South to investigate the far-infrared properties of high-redshift sub-millimetre galaxies (SMGs). Using the precisely located 870 mu m ALMA positions of 99 SMGs, together with 24 mu m and radio imaging, we deblend the Herschel/SPIRE imaging to extract their far-infrared fluxes and colours. The median redshifts for ALMA LESS (ALESS) SMGs which are detected in at least two SPIRE bands increases with wavelength of the peak in their spectral energy distributions (SEDs), with z = 2.3 +/- 0.2, 2.5 +/- 0.3 and 3.5 +/- 0.5 for the 250, 350 and 500 mu m peakers, respectively. 34 ALESS SMGs do not have a >3 sigma counterpart at 250, 350 or 500 mu m. These galaxies have a median photometric redshift derived from the rest-frame UV-mid-infrared SEDs of z = 3.3 +/- 0.5, which is higher than the full ALESS SMG sample; z = 2.5 +/- 0.2. We estimate the far-infrared luminosities and characteristic dust temperature of each SMG, deriving L-IR = (3.0 +/- 0.3) x 10(12) L-circle dot (SFR = 300 +/- 30 M-circle dot yr(-1)) and T-d = 32 +/- 1 K. The characteristic dust temperature of these high-redshift SMGs is Delta T-d = 3-5K lower than comparably luminous galaxies at z = 0, reflecting the more extended star formation in these systems. We show that the contribution of S-870 mu m >= 1 mJy SMGs to the cosmic star formation budget is 20 per cent of the total over the redshift range z similar to 1-4. Adopting an appropriate gas-to-dust ratio, we estimate a typical molecular mass of the ALESS SMGs of M-H2 = (4.2 +/- 0.4) x 10(10) M-circle dot. Finally, we show that SMGs with S-870 mu m > 1 mJy (L-IR greater than or similar to 10(12) L-circle dot) contain similar to 10 per cent of the z similar to 2 volume-averaged H-2 mass density.

Energetic galaxy-wide outflows in high-redshift ultraluminous infrared galaxies hosting AGN activity

We present integral field spectroscopy observations, covering the [O iii] λλ4959, 5007 emission-line doublet of eight high-redshift (z = 1.4–3.4) ultraluminous infrared galaxies (ULIRGs) that host active galactic nucleus (AGN) activity, including known submillimetre luminous galaxies. The targets have moderate radio luminosities that are typical of high-redshift ULIRGs (L1.4 GHz = 1024–1025 W Hz−1) and therefore are not radio-loud AGNs. We decouple kinematic components due to the galaxy dynamics and mergers from those due to outflows. We find evidence in the four most luminous systems ( erg s−1) for the signatures of large-scale energetic outflows: extremely broad [O iii] emission (full width at half-maximum ≈ 700–1400 km s−1) across ≈4–15 kpc, with high velocity offsets from the systemic redshifts (up to ≈850 km s−1). The four less luminous systems have lower quality data displaying weaker evidence for spatially extended outflows. We estimate that these outflows are potentially depositing energy into their host galaxies at considerable rates (–1045 erg s−1); however, due to the lack of constraints on the density of the outflowing material and the structure of the outflow, these estimates should be taken as illustrative only. Based on the measured maximum velocities (vmax ≈ 400–1400 km s−1) the outflows observed are likely to unbind some fraction of the gas from their host galaxies, but are unlikely to completely remove gas from the galaxy haloes. By using a combination of energetic arguments and a comparison to ULIRGs without clear evidence for AGN activity, we show that the AGN activity could be the dominant power source for driving all of the observed outflows, although star formation may also play a significant role in some of the sources.

Narrow-line region gas kinematics of 24 264 optically selected AGN: the radio connection

Using a sample of 24 264 optically selected active galactic nuclei (AGNs) from the SDSS DR7 data base, we characterize how the profile of the [O III] λ5007 emission line relates to bolometric luminosity (LAGN), Eddington ratio, radio loudness, radio luminosity (L1.4 GHz) and optical class (i.e. broad/narrow-line Seyfert 1, type 2) to determine what drives the kinematics of this kpc-scale line emitting gas. First, we use spectral stacking to characterize how the average [O III] λ5007 profile changes as a function of these five variables. After accounting for the known correlation between LAGN and L1.4 GHz, we report that L1.4 GHz has the strongest influence on the [O III] λ5007 profile, with AGNs of moderate radio luminosity (L1.4 GHz = 1023–1025 W Hz−1) having the broadest [O III] λ5007 profiles. Conversely, we find only a modest change in the [O III] λ5007 profile with increasing radio loudness and find no significant difference between the [O III] λ5007 profiles of broad- and narrow-line Seyfert 1s. When binned according to Eddington ratio, only the AGNs in our highest bin (i.e. >0.3) show any signs of having broadened [O III] λ5007 profiles, although the small numbers of such extreme AGNs in our sample mean we cannot rule out that other processes (e.g. radio jets) are responsible for this broadening. The [O III] λ5007 profiles of type 1 and type 2 AGNs show the same trends in terms of line width, but type 1 AGNs display a much stronger ‘blue wing’, which we interpret as evidence of outflowing ionized gas. We perform multicomponent fitting to the Hβ, [O III] λλ4959, 5007, [N II] λλ6548, 6584 and Hα lines for all the AGNs in our sample to calculate the proportions of AGNs with broad [O III] λ5007 profiles. The individual fits confirm the results from our stacked spectra; AGNs with L1.4 GHz > 1023 W Hz−1 are roughly five times more likely to have extremely broad [O III] λ5007 lines (full width at half-maximum, FWHMAvg > 1000 km s−1) compared to lower L1.4 GHz AGNs, and the width of the [O III] λ5007 line peaks in moderate-radio-luminosity AGNs (L1.4 GHz ∼ 1024 W Hz−1). Our results are consistent with the most disturbed gas kinematics being induced by compact radio cores (rather than powerful radio jets), although broadened [O III] λ5007 lines are also present, but much rarer, in low-L1.4 GHz systems. Our catalogue of multicomponent fits is freely available as an online resource for statistical studies of the kinematics and luminosities of the narrow- and broad-line AGN regions and the identification of potential targets for follow-up observations at http://sites.google.com/site/sdssalpaka.

A remarkably flat relationship between the average star formation rate and AGN luminosity for distant X-ray AGN

In this study, we investigate the relationship between the star formation rate (SFR) and AGN luminosity (LAGNLAGN) for ∼2000 X-ray detected AGN. The AGN span over three orders of magnitude in X-ray luminosity (1042<L2−8keV<1045.5ergs−11042<L2−8keV<1045.5ergs−1) and are in the redshift range z = 0.2–2.5. Using infrared (IR) photometry (8–500 μmμm), including deblended Spitzer and Herschel images and taking into account photometric upper limits, we decompose the IR spectral energy distributions into AGN and star formation components. Using the IR luminosities due to star formation, we investigate the average SFRs as a function of redshift and AGN luminosity. In agreement with previous studies, we find a strong evolution of the average SFR with redshift, tracking the observed evolution of the overall star-forming galaxy population. However, we find that the relationship between the average SFR and AGN luminosity is broadly flat at all redshifts and across all the AGN luminosities investigated; in comparison to previous studies, we find less scatter amongst the average SFRs across the wide range of AGN luminosities investigated. By comparing to empirical models, we argue that the observed flat relationship is due to short time-scale variations in AGN luminosity, driven by changes in the mass accretion rate, which wash out any underlying correlations between SFR and LAGNLAGN. Furthermore, we show that the exact form of the predicted relationship between SFR and AGN luminosity (and its normalization) is highly sensitive to the assumed intrinsic Eddington ratio distribution.

The KMOS Redshift One Spectroscopic Survey (KROSS): dynamical properties, gas and dark matter fractions of typical z ∼ 1 star-forming galaxies

The KMOS Redshift One Spectroscopic Survey (KROSS) is an ESO guaranteed time survey of 795 typical star-forming galaxies in the redshift range z=0.8-1.0 with the KMOS instrument on the VLT. In this paper we present resolved kinematics and star formation rates for 584 z~1 galaxies. This constitutes the largest near-infrared Integral Field Unit survey of galaxies at z~1 to date. We demonstrate the success of our selection criteria with 90% of our targets found to be Halpha emitters, of which 81% are spatially resolved. The fraction of the resolved KROSS sample with dynamics dominated by ordered rotation is found to be 83

Integral field spectroscopy of 2.0< z<2.7 submillimetre galaxies: Gas morphologies and kinematics

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The SCUBA-2 Cosmology Legacy Survey: 850 μm maps, catalogues and number counts

5%. However, when compared with local samples these are turbulent discs with high gas to baryonic mass fractions, ~35%, and the majority are consistent with being marginally unstable (Toomre Q~1). There is no strong correlation between galaxy averaged velocity dispersion and the total star formation rate, suggesting that feedback from star formation is not the origin of the elevated turbulence. We postulate that it is the ubiquity of high (likely molecular) gas fractions and the associated gravitational instabilities that drive the elevated star-formation rates in these typical z~1 galaxies, leading to the ten-fold enhanced star-formation rate density. Finally, by comparing the gas masses obtained from inverting the star-formation law with the dynamical and stellar masses, we infer an average dark matter to total mass fraction within 2.2

The KMOS AGN Survey at High redshift (KASHz) : the prevalence and drivers of ionized outflows in the host galaxies of X-ray AGN.

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Mid-infrared luminous quasars in the GOODS–Herschel fields: a large population of heavily obscured, Compton-thick quasars at z ≈ 2

(9.5kpc) of 65