Characterization of the distribution of the Lly\alpha emitters in the 53W002 field at z = 2.4

Abstract

We present the results of our wide-field narrow band 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 \AA\ with the width of 83 \AA\ 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 \AA\ 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 ~ 2. We identify a significant high density region (53W002F-HDR) that spreads over ~ 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 the 53W002F-HDR to be 0.9^{+2.4}_{-0.62}%, 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 4 Ly\alpha blobs (LABs), one of which is newly discovered. They are all found to be located in the rims of high density regions. The biased location and unique morphologies in Ly\alpha suggest that galaxy interaction play a key role in their formation.