We present integral field unit observations covering the [O iii]λλ4959, 5007 and Hβ emission lines of 16 z < 0.2 type 2 active galactic nuclei (AGN). Our targets are selected from a well-constrained parent sample of ≈24 000 AGN so that we can place our observations into the context of the overall AGN population. Our targets are radio quiet with star formation rates (SFRs; ≲[10–100] M_⊙ yr⁻¹) that are consistent with normal star-forming galaxies. We decouple the kinematics of galaxy dynamics and mergers from outflows. We find high-velocity ionized gas (velocity widths ≈600–1500 km s⁻¹; maximum velocities ≤1700 km s⁻¹) with observed spatial extents of ≳(6–16) kpc in all targets and observe signatures of spherical outflows and bi-polar superbubbles. We show that our targets are representative of z < 0.2, luminous (i.e. L_[O iii] > 10^41.7 erg s⁻¹) type 2 AGN and that ionized outflows are not only common but also in ≥70 per cent (3σ confidence) of cases, they are extended over kiloparsec scales. Our study demonstrates that galaxy-wide energetic outflows are not confined to the most extreme star-forming galaxies or radio-luminous AGN; however, there may be a higher incidence of the most extreme outflow velocities in quasars hosted in ultraluminous infrared galaxies. 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 highly uncertain, we derive mass outflow rates (typically ≈10 times the SFRs), kinetic energies (≈0.5–10 per cent of L_AGN) and momentum rates (typically ≳10–20 × L_AGN/c) consistent with theoretical models that predict AGN-driven outflows play a significant role in shaping the evolution of galaxies.

We exploit Atacama Large Millimeter Array (ALMA) 870 μm 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 μm ALMA positions of 99 SMGs, together with 24μm 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 μm peakers, respectively. 34 ALESS SMGs do not have a >3σ counterpart at 250, 350 or 500 μm. 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) × 10¹² L_⊙ (SFR = 300 ± 30 M_⊙ yr⁻¹) and T_d = 32 ± 1 K. The characteristic dust temperature of these high-redshift SMGs is ΔT_d = 3–5 K 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 μm ≥ 1 mJy SMGs to the cosmic star formation budget is 20 per cent of the total over the redshift range z ∼ 1–4. Adopting an appropriate gas-to-dust ratio, we estimate a typical molecular mass of the ALESS SMGs of $$M_{\rm H_2}$$ = (4.2 ± 0.4) × 10¹⁰ M_⊙. Finally, we show that SMGs with S_870 μm > 1 mJy (L_IR ≳ 10¹² L_⊙) contain ∼ 10 per cent of the z ∼ 2 volume-averaged H₂ mass density.

We present a catalogue of ∼3000 submillimetre sources detected (≥3.5σ) at 850 μm over ∼5 deg² surveyed as part of the James Clerk Maxwell Telescope (JCMT) SCUBA-2 Cosmology Legacy Survey (S2CLS). This is the largest survey of its kind at 850 μm, increasing the sample size of 850 μm selected submillimetre galaxies by an order of magnitude. The wide 850 μm survey component of S2CLS covers the extragalactic fields: UKIDSS-UDS, COSMOS, Akari-NEP, Extended Groth Strip, Lockman Hole North, SSA22 and GOODS-North. The average 1σ depth of S2CLS is 1.2 mJy beam⁻¹, approaching the SCUBA-2 850 μm confusion limit, which we determine to be σ_c ≈ 0.8 mJy beam⁻¹. We measure the 850 μm number counts, reducing the Poisson errors on the differential counts to approximately 4 per cent at S₈₅₀ ≈ 3 mJy. With several independent fields, we investigate field-to-field variance, finding that the number counts on 0.5°–1° scales are generally within 50 per cent of the S2CLS mean for S₈₅₀ > 3 mJy, with scatter consistent with the Poisson and estimated cosmic variance uncertainties, although there is a marginal (2σ) density enhancement in GOODS-North. The observed counts are in reasonable agreement with recent phenomenological and semi-analytic models, although determining the shape of the faint-end slope (S₈₅₀ < 3 mJy) remains a key test. The large solid angle of S2CLS allows us to measure the bright-end counts: at S₈₅₀ > 10 mJy there are approximately 10 sources per square degree, and we detect the distinctive up-turn in the number counts indicative of the detection of local sources of 850 μm emission, and strongly lensed high-redshift galaxies. All calibrated maps and the catalogue are made publicly available.

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 (L_AGN), Eddington ratio, radio loudness, radio luminosity (L_1.4 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 L_AGN and L_1.4 GHz, we report that L_1.4 GHz has the strongest influence on the [O iii] λ5007 profile, with AGNs of moderate radio luminosity (L_1.4 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 L_1.4 GHz > 10²³ W Hz⁻¹ are roughly five times more likely to have extremely broad [O iii] λ5007 lines (full width at half-maximum, FWHM_Avg > 1000 km s⁻¹) compared to lower L_1.4 GHz AGNs, and the width of the [O iii] λ5007 line peaks in moderate-radio-luminosity AGNs (L_1.4 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-L_1.4 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.