A Search For Ly Alpha Emitters Around A Concentrated Region Of Strong Ly Alpha Absorbers At Z=2.3

In order to investigate the physical relationship between strong Ly alpha absorbers (log N-HI >= 20.0 cm(-2)) such as damped Ly a absorption systems (DLAs) and young star-forming galaxies at high redshift, we have conducted narrow-band observations of Ly a emitters (LAEs) in a concentrated region of strong Ly alpha absorbers at z = 2.3, the J1230+34 field. Using a catalog of Ly alpha absorbers with log N-HI >= 20.0 cm(-2) based on the Baryon Oscillation Spectroscopic Survey, we found six fields where three or more absorbers are concentrated within a (50 Mpc)(3) cubic box in the comoving scale. Among them, we focus on the J1230+34 field, where two DLAs and two sub-DLAs are present. Our narrow-band imaging observations with Subaru/Suprime-Cam using a custom-made filter, NB400 (lambda(c) = 4003 angstrom and FWHM = 92 angstrom) yield a sample of 149 LAEs in this field. In the large scale (similar to 50 Mpc), we have found no differences between the obtained Ly a luminosity function and those in the blank fields at similar redshifts. We also compare the frequency distribution of the Ly a rest-frame equivalent width (EW0) in the target field and other fields including both overdensity region and blank field, but find no differences. On the other hand, in the small scale (similar to 10 Mpc), we have found a possible overdensity of LAEs around a DLA with the highest HI column density (N-HI = 21.08 cm(-2)) in the target field while there are no density excesses around the other absorbers with a lower N-HI.