CF-HiZELS, a 10 deg${}^2$ emission-line survey with spectroscopic follow-up: Hα, [OIII]+Hβ and [OII] luminosity functions at z=0.8, 1.4 and 2.2

Abstract

We present results from the largest contiguous narrow-band survey in the near-infrared. We have used WIRCam/CFHT and the lowOH2 filter (1.187$\pm$0.005 $\mu$m) to survey ~10 deg${}^2$ 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 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 H$\alpha$ emitters at z=0.8, 1343 [OIII]+H$\beta$ emitters at z=1.4 and 572 [OII] emitters at z=2.2. We probe co-moving volumes of >10${}^6$ Mpc${}^3$ and find significant over-densities, including an 8.5$\sigma$ (spectroscopically confirmed) over-density of H$\alpha$ emitters at z=0.81. We derive H$\alpha$, [OIII]+H$\beta$ and [OII] 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 sub-divide the samples in thousands of randomised 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%) if they are based on volumes >5x10${}^5$ Mpc${}^3$; errors on $L^{\ast }$ and ${\varphi }^{\ast }$ due to sample (cosmic) variance on surveys probing ~10${}^4$ Mpc${}^3$ and ~10${}^5$ Mpc${}^3$ are typically very high: ~300% and ~40-60%, respectively.

22 pages, 15 figures, accepted for publication in MNRAS. Full catalogue of line emitters available in FITS format with final MNRAS published paper

References in corpus (3)

• Identification of the brightest Lyα emitters at z=6.6: implications for the evolution of the luminosity function in the re-ionisation era
• Evolution of the H$\beta$+[OIII] and [OII] luminosity functions and the [OII] star-formation history of the Universe up to $z$ ~ 5 from HiZELS
• The rise and fall of star-formation in $\mathbf{z}\sim 0.2$ merging galaxy clusters

Cited by in corpus (2)

• Identification of the brightest Lyα emitters at z=6.6: implications for the evolution of the luminosity function in the re-ionisation era
• Evolution of the H$\beta$+[OIII] and [OII] luminosity functions and the [OII] star-formation history of the Universe up to $z$ ~ 5 from HiZELS