Title: Properties of Lyman alpha emitters at z=4.86 and z=5.70 in the COSMOS 2 square degree field
Author(s): Yasuhiro Shioya, Yoshiaki Taniguchi, Takashi Murayama, Shunji S. Sasaki, Tohru Nagao,
Tomoki Saito, Yuko Ideue, Kenta L. Matsuoka, Jonathan R. Trump, & Nick Scoville
Abstract:
We present results of surveys for Ly alpha emitters (LAEs) at z =4.86 and z=5.70 based on optical narrowband (NB711 and NB816) and broadband (B, V, rf, if, and zf) observations of the Cosmic Evolution Survey (COSMOS) field using Suprime-Cam on the Subaru Telescope. We find 79 LAE candidates at z=4.86 and 119 LAE candidates at z=5.70 over a contiguous survey area of about 2 deg^2. We obtain the Ly alpha luminosity function with a best-fit Schechter parameters of log L^* = 42.9^+0.5_-0.3 ergs s^-1 and phi^* = 1.2^+8.0_-1.1 x 10^-4 Mpc^-3 for alpha=-1.5 (fixed) and the two-point correlation function of xi(r) = (r/4.4^+5.7_-2.9 Mpc)^-1.90+/-0.22 for LAEs at z=4.86.
In order to investigate the field-to-field variations of the properties of LAEs at z=4.86, we divide the survey area into nine tiles of 0.5 deg x 0.5 deg 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 deg x 0.7 deg 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.
We have also ACS images and multi-wavelength photometric data (include J, Ks, and Spitzer IRAC band) of our LAE sample. We will discuss the morphologies and the stellar populations of LAEs at z=4.86 and 5.70.
Abstract should be within about 250 words.