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Published May 1, 2009 | Erratum + Published
Journal Article Open

Photometric Properties of Lyα Emitters at z ≈ 4.86 in the COSMOS 2 Square Degree Field


We present results of a survey for Lyα emitters at z ≈ 4.86 based on optical narrowband (λ_c = 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 deg^2, down to the Lyα line flux of 1.47 × 10^(–17) erg s^(-1) cm^(–2). We obtain the Lyα luminosity function with a best-fit Schechter parameters of log L* = 42.9^(+0.5)_(–0.3) erg s^(-1) and Ф* = 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 deg^2 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.

Additional Information

© 2009 The American Astronomical Society. Received 2008 August 8; accepted 2009 February 2; published 2009 April 16. The HST COSMOS Treasury program was supported through NASA grant HST-GO-09822. We greatly acknowledge the contributions of the entire COSMOS collaboration consisting of more than 70 scientists. We thank Masami Ouchi for useful discussion and the anonymous referee for valuable comments. We also thank the Subaru Telescope staff for their invaluable help. This work was financially supported in part by the JSPS (Nos. 15340059 and 17253001).

Attached Files

Published - Shioya2009p2247Astrophys_J.pdf

Erratum - Shioya2009p5115Astrophys_J.pdf


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