@article{11576,
  abstract     = {We use new near-infrared spectroscopic observations to investigate the nature and evolution of the most luminous Hα emitters at z ∼ 0.8–2.23, which evolve strongly in number density over this period, and compare them to more typical Hα emitters. We study 59 luminous Hα emitters with LHα > L∗Hα⁠, roughly equally split per redshift slice at z ∼ 0.8, 1.47 and 2.23 from the HiZELS and CF-HiZELS surveys. We find that, overall, 30 ± 8 per cent are active galactic nuclei [AGNs; 80 ± 30 per cent of these AGNs are broad-line AGNs, BL-AGNs], and we find little to no evolution in the AGN fraction with redshift, within the errors. However, the AGN fraction increases strongly with Hα luminosity and correlates best with LHα/L∗Hα(z)⁠. While LHα ≤ L∗Hα(z) Hα emitters are largely dominated by star-forming galaxies (>80 per cent), the most luminous Hα emitters (⁠LHα>10L∗Hα(z)⁠) at any cosmic time are essentially all BL-AGN. Using our AGN-decontaminated sample of luminous star-forming galaxies, and integrating down to a fixed Hα luminosity, we find a factor of ∼1300 evolution in the star formation rate density from z = 0 to 2.23. This is much stronger than the evolution from typical Hα star-forming galaxies and in line with the evolution seen for constant luminosity cuts used to select ‘ultraluminous’ infrared galaxies and/or sub-millimetre galaxies. By taking into account the evolution in the typical Hα luminosity, we show that the most strongly star-forming Hα-selected galaxies at any epoch (⁠LHα>L∗Hα(z)⁠) contribute the same fractional amount of ≈15 per cent to the total star formation rate density, at least up to z = 2.23.},
  author       = {Sobral, David and Kohn, Saul A. and Best, Philip N. and Smail, Ian and Harrison, Chris M. and Stott, John and Calhau, João and Matthee, Jorryt J},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution, galaxies: high-redshift, cosmology: observations},
  number       = {2},
  pages        = {1739--1752},
  publisher    = {Oxford University Press},
  title        = {{The most luminous H α emitters at z ∼ 0.8–2.23 from HiZELS: Evolution of AGN and star-forming galaxies}},
  doi          = {10.1093/mnras/stw022},
  volume       = {457},
  year         = {2016},
}

@article{11580,
  abstract     = {We present results from the largest contiguous narrow-band survey in the near-infrared. We have used the wide-field infrared camera/Canada–France–Hawaii Telescope and the lowOH2 filter (1.187 ± 0.005 μm) to survey ≈10 deg2 of contiguous extragalactic sky in the SA22 field. A total of ∼6000 candidate emission-line galaxies are found. We use deep ugrizJK data to obtain robust photometric redshifts. We combine our data with the High-redshift(Z) Emission Line Survey (HiZELS), explore spectroscopic surveys (VVDS, VIPERS) and obtain our own spectroscopic follow-up with KMOS, FMOS and MOSFIRE to derive large samples of high-redshift emission-line selected galaxies: 3471 Hα emitters at z = 0.8, 1343 [O III] + Hβ emitters at z = 1.4 and 572 [O II] emitters at z = 2.2. We probe comoving volumes of >106 Mpc3 and find significant overdensities, including an 8.5σ (spectroscopically confirmed) overdensity of Hα emitters at z = 0.81. We derive Hα, [O III] + Hβ and [O II] luminosity functions at z = 0.8, 1.4, 2.2, respectively, and present implications for future surveys such as Euclid. Our uniquely large volumes/areas allow us to subdivide the samples in thousands of randomized combinations of areas and provide a robust empirical measurement of sample/cosmic variance. We show that surveys for star-forming/emission-line galaxies at a depth similar to ours can only overcome cosmic-variance (errors <10 per cent) if they are based on volumes >5 × 105 Mpc3; errors on L* and ϕ* due to sample (cosmic) variance on surveys probing ∼104 and ∼105 Mpc3 are typically very high: ∼300 and ∼40–60 per cent, respectively.},
  author       = {Sobral, D. and Matthee, Jorryt J and Best, P. N. and Smail, I. and Khostovan, A. A. and Milvang-Jensen, B. and Kim, J.-W. and Stott, J. and Calhau, J. and Nayyeri, H. and Mobasher, B.},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution, galaxies: formation, galaxies: luminosity function, mass function, cosmology: observations, early Universe, large-scale structure of Universe},
  number       = {3},
  pages        = {2303--2323},
  publisher    = {Oxford University Press},
  title        = {{CF-HiZELS, an ∼10 deg2 emission-line survey with spectroscopic follow-up: Hα, [O III] + Hβ and [O II] luminosity functions at z = 0.8, 1.4 and 2.2 }},
  doi          = {10.1093/mnras/stv1076},
  volume       = {451},
  year         = {2015},
}

@article{11583,
  abstract     = {Candidate galaxies at redshifts of z ∼ 10 are now being found in extremely deep surveys, probing very small areas. As a consequence, candidates are very faint, making spectroscopic confirmation practically impossible. In order to overcome such limitations, we have undertaken the CF-HiZELS survey, which is a large-area, medium-depth near-infrared narrow-band survey targeted at z = 8.8 Lyman α (Lyα) emitters (LAEs) and covering 10 deg2 in part of the SSA22 field with the Canada–France–Hawaii Telescope (CFHT). We surveyed a comoving volume of 4.7 × 106 Mpc3 to a Lyα luminosity limit of 6.3 × 1043舁erg舁s−1. We look for Lyα candidates by applying the following criteria: (i) clear emission-line source, (ii) no optical detections (ugriz from CFHTLS), (iii) no visible detection in the optical stack (ugriz > 27), (iv) visually checked reliable NBJ and J detections and (v) J − K ≤ 0. We compute photometric redshifts and remove a significant amount of dusty lower redshift line-emitters at z ∼ 1.4 or 2.2. A total of 13 Lyα candidates were found, of which two are marked as strong candidates, but the majority have very weak constraints on their spectral energy distributions. Using follow-up observations with SINFONI/VLT, we are able to exclude the most robust candidates as LAEs. We put a strong constraint on the Lyα luminosity function at z ∼ 9 and make realistic predictions for ongoing and future surveys. Our results show that surveys for the highest redshift LAEs are susceptible of multiple contaminations and that spectroscopic follow-up is absolutely necessary.},
  author       = {Matthee, Jorryt J and Sobral, David and Swinbank, A. M. and Smail, Ian and Best, P. N. and Kim, Jae-Woo and Franx, Marijn and Milvang-Jensen, Bo and Fynbo, Johan},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: evolution, galaxies: high-redshift, cosmology: observations, dark ages, reionization, first stars},
  number       = {3},
  pages        = {2375--2387},
  publisher    = {Oxford University Press},
  title        = {{A 10 deg2 Lyman α survey at z=8.8 with spectroscopic follow-up: Strong constraints on the luminosity function and implications for other surveys}},
  doi          = {10.1093/mnras/stu392},
  volume       = {440},
  year         = {2014},
}