2015/02/23 by David Sobral, Sobral, David, Jorryt Matthee +19 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Instrumentation and Methods for Astrophysics (astro-ph.IM)
paper · pdf · doi:10.48550/arxiv.1502.06602
openalex publication_date 2015/02/23 · openalex created_date 2024/04/10 · openalex updated_date 2026/07/28
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±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 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 [OIII]+Hβ emitters at z=1.4 and 572 [OII] emitters at z=2.2. We probe co-moving volumes of >106 Mpc3 and find significant over-densities, including an 8.5σ (spectroscopically confirmed) over-density of Hα emitters at z=0.81. We derive Hα, [OIII]+Hβ 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 >5x105 Mpc3; errors on L^* and ϕ^* due to sample (cosmic) variance on surveys probing ~104 Mpc3 and ~105 Mpc3 are typically very high: ~300% and ~40-60%, respectively.