CHARACTERIZATION OF THE DISTRIBUTION OF THE Lyα EMITTERS IN THE 53W002 FIELD AT z=2.4

We present the results of our wide-field narrowband imaging of the field around the radio galaxy 53W002 at z = 2.390 with Subaru/Suprime-Cam. A custom-made filter, NB413, centered at 4140 angstrom with a width of 83 angstrom is used to observe the 31' x 24' area around the radio galaxy. We detected 204 Ly alpha emitters (LAEs) at z = 2.4 with a rest-frame equivalent width larger than 25 angstrom to the depth of 26 AB mag (in NB413). The entire LAE population in the 53W002 field has an average number density and distributions of equivalent width and size that are similar to those of other fields at z similar to 2. We identify a significant high-density region (53W002F-HDR) that spreads over approximate to 5' x 4' near 53W002, where the LAE number density is nearly four times as large as the average of the entire field. Using the probability distribution function of density fluctuation, we evaluate the rareness probability of 53W002F-HDR to be 0.9(-0.62)(+2.4)%, which corresponds to a moderately rich structure. No notable environmental dependency at the comoving scale of 10 Mpc is found for the distributions of the Ly alpha equivalent width and luminosity in the field. We also detected four Ly alpha blobs, one of which is newly discovered. They are all located in the rims of high-density regions. The biased location and unique morphologies in Ly alpha suggest that galaxy interaction plays a key role in their formation.