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We present adaptive optics assisted, spatially resolved spectroscopy of a sample of nine Hα-selected galaxies at z = 0.84-2.23 drawn from the HiZELS narrow-band survey. These galaxies have star formation rates of 1-27 M yr −1 and are therefore representative of the typical high-redshift star-forming population. Our ∼kpc-scale resolution observations show that approximately half of the sample have dynamics suggesting that the ionized gas is in large, rotating discs. We model their velocity fields to infer the inclination-corrected, asymptotic rotational velocities. We use the absolute B-band magnitudes and stellar masses to investigate the evolution of the B-band and stellar-mass Tully-Fisher relationships. By combining our sample with a number of similar measurements from the literature, we show that, at fixed circular velocity, the stellar mass of star-forming galaxies has increased by a factor of 2.5 between z = 2 and 0, whilst the rest-frame B-band luminosity has decreased by a factor of ∼ 6 over the same period. Together, these demonstrate a change in mass-to-light ratio in the B band of (M/L B )/(M/L B ) z=0 ∼ 3.5 between z = 1.5 and 0, with most of the evolution occurring below z = 1. We also use the spatial variation of [N II]/Hα to show that the metallicity of the ionized gas in these galaxies declines monotonically with galactocentric radius, with an average log(O/H)/ R = −0.027 ± 0.005 dex kpc −1 . This gradient is consistent with predictions for high-redshift disc galaxies from cosmologically based hydrodynamic simulations.

We present adaptive optics assisted integral field spectroscopy of nine Hα-selected galaxies at z = 0.84-2.23 drawn from the HiZELS narrow-band survey. Our observations map the kinematics of these star-forming galaxies on ∼ kpc-scales. We demonstrate that within the ISM of these galaxies, the velocity dispersion of the star-forming gas (σ) follows a scaling relation σ ∝ Σ 1/n SFR + constant (where Σ SFR is the star formation surface density and the constant includes the stellar surface density). Assuming the disks are marginally stable (Toomre Q = 1), this follows from the Kennicutt-Schmidt relation (Σ SFR = AΣ n gas ), and we derive best fit parameters of n = 1.34 ± 0.15 and A = 3.4 +2.5 −1.6 × 10 −4 M ⊙ yr −1 kpc −2 , consistent with the local relation, and implying cold molecular gas masses of M gas = 10 9−10 M ⊙ and molecular gas fractions M gas / (M gas + M ⋆ ) = 0.3 ± 0.1, with a range of 10 -75%. We also identify eleven ∼ kpc-scale star-forming regions (clumps) within our sample and show that their sizes are comparable to the wavelength of the fastest growing mode. The luminosities and velocity dispersions of these clumps follow the same scaling relations as local Hii regions, although their star formation densities are a factor ∼ 15 ± 5 × higher than typically found locally. We discuss how the clump properties are related to the disk, and show that their high masses and luminosities are a consequence of the high disk surface density.

Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractWe present deep, high-resolution (0 03, 200 pc) ALMA Band 7 observations covering the dust continuum and [C II] λ157.7 μm emission in four z∼4.4-4.8 sub-millimeter galaxies (SMGs) selected from the ALESS and AS2UDS surveys. The data show that the rest-frame 160 μm (observed 345 GHz) dust emission is consistent with smooth morphologies on kpc scales for three of the sources. One source, UDS 47.0, displays apparent substructure, but this is also consistent with a smooth morphology-as indicated by simulations showing that smooth exponential disks can appear clumpy when observed at the high angular resolution (0 03) and depth of these observations (s~-27 47 345 GHz μJy beam −1 ). The four SMGs are bright [C II] emitters. We extract [C II] spectra from the high-resolution data, and recover ∼20%-100% of the [C II] flux and ∼40%-80% of the dust continuum emission, compared to the previous lower-resolution observations. When tapered to 0 2 resolution, our maps recover ∼80%-100% of the continuum emission, indicating that ∼60% of the emission is resolved out on ∼200 pc scales. We find that the [C II] emission in high-redshift galaxies is more spatially extended than the rest-frame 160 μm dust continuum by a factor of 1.6±0.4. By considering the [ ] L C II /L FIR ratio as a function of the star formation rate surface density (S SFR ), we revisit the [C II] deficit and suggest that the decline in the [ ] L C II /L FIR ratio as a function of S SFR is consistent with local processes. We also explore the physical drivers that may be responsible for these trends and can give rise to the properties found in the densest regions of SMGs.

We report the discovery of a gravitationally lensed hyperluminous infrared galaxy (intrinsic L IR ≈ 10 13 L ) with strong radio emission (intrinsic L 1.4GHz ≈ 10 25 W Hz −1 ) at z = 2.553. The source was identified in the citizen science project SPACE WARPS through the visual inspection of tens of thousands of iJK s colour composite images of Luminous Red Galaxies (LRGs), groups and clusters of galaxies and quasars. Appearing as a partial Einstein ring (r e ≈ 3 ) around an LRG at z = 0.2, the galaxy is extremely bright in the sub-millimetre for a cosmological source, with the thermal dust emission approaching 1 Jy at peak. The redshift of the lensed galaxy is determined through the detection of the CO(3→2) molecular emission line with the Large Millimetre Telescope's Redshift Search Receiver and through [O III] and Hα line detections in the near-infrared from Subaru/IRCS. We have resolved the radio emission with high resolution (300-400 mas) eMERLIN L-band and VLA C-band imaging. These observations are used in combination with the near-infrared imaging to construct a lens model, which indicates a lensing magnification of μ ≈ 10. The source reconstruction appears to support a radio morphology comprised of a compact (< 250 pc) core and more extended component, perhaps indicative of an active nucleus and jet or lobe.