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arXiv · 1703.05756

A search for Ly-alpha emitters around a concentrated-region of strong Ly-alpha absorbers at z=2.3

Kazuyuki Ogura·Tohru Nagao·Masatoshi Imanishi·Nobunari Kashikawa·Yoshiaki Taniguchi·Masaru Kajisawa·Masakazu A. R. Kobayashi·Yoshiki Toba·Kodai Nobunara
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Abstract

In order to investigate the physical relationship between strong Ly-alpha absorbers (logN_HI>20.0 cm^-2) such as damped Ly-alpha absorption systems (DLAs) and young star-forming galaxies at high redshift, we have conducted narrow-band observations of Ly-alpha 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 logN_HI>20.0 cm^-2 based on the baryon oscillation spectroscopic survey (BOSS), we found 6 fields where 3 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 2 DLAs and 2 sub-DLAs present. Our narrow-band imaging observations with Subaru/Suprime-Cam using a custom-made filter, NB400 (lambda_c=4003 A and FWHM=92 A) yield a sample of 149 LAEs in this field. In the large scale (~50 Mpc), we have found no differences between the obtained Ly-alpha luminosity function and those in the blank fields at similar redshifts. We also compare the frequency distribution of the Ly-alpha rest-frame equivalent width (EW_0) 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 (~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 excess around the other absorbers with a lower N_HI.

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Kazuyuki Ogura, Tohru Nagao, Masatoshi Imanishi, Nobunari Kashikawa, Yoshiaki Taniguchi, Masaru Kajisawa, Masakazu A. R. Kobayashi, Yoshiki Toba, Kodai Nobunara. 2017-03-16. A search for Ly-alpha emitters around a concentrated-region of strong Ly-alpha absorbers at z=2.3. https://doi.org/10.1093/pasj%2Fpsx027

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