We present results of a survey for Lyα emitters at z ≈ 4.86 based on optical narrowband (λc = 7126 Å, Δλ = 73 Å) and broadband (B, V, r', i', and z') observations of the Cosmic Evolution Survey field using Suprime-Cam on the Subaru Telescope. We find 79 Lyα emitter (LAE) candidates at z ≈ 4.86 over a contiguous survey area of 1.83 deg2, down to the Lyα line flux of 1.47 × 10 -17erg s-1 cm-2. We obtain the Lyα luminosity function with a best-fit Schechter parameters of logL * = 42.9+0.5-0.3 erg s-1 and φ* = 1.2+8.0-1.1 × 10 -4 Mpc-3 for α = -1.5 (fixed). The two-point correlation function for our LAE sample is ξ (r) = (r/4.4+5.7 -2.9 Mpc)-1.90±0.22. In order to investigate the field-to-field variations of the properties of Lyα emitters, we divide the survey area into nine tiles of 0°5 × 0°5 each. We find that the number density varies with a factor of ≃2 from field to field with high statistical significance. However, we find no significant field-to-field variance when we divide the field into four tiles with 0.7 × 0°7 each. We conclude that at least 0.5 deg2 survey area is required to derive averaged properties of LAEs at z ∼ 5, and our survey field is wide enough to overcome the cosmic variance.
- Galaxies: distances and redshifts
- Galaxies: evolution
- Galaxies: luminosity function
- Mass function
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science