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

D. Sobral, J. Matthee, P. N. Best, I. Smail, A. A. Khostovan, B. Milvang-Jensen, J.-W. Kim, J. Stott, J. Calhau, H. Nayyeri, B. Mobasher

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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 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.
Original languageEnglish
Pages (from-to)2303-2323
JournalMonthly Notices of the Royal Astronomical Society
Volume451
Issue number3
DOIs
Publication statusPublished - 1 Aug 2015
Externally publishedYes

Keywords

  • galaxies: evolution
  • galaxies: formation
  • galaxies: luminosity function
  • mass function
  • cosmology: observations
  • early Universe
  • large-scale structure of Universe

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