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Subaru Seminars are usually held in Room 104 of the Hilo Base Facility, adjacent to the main lobby. Everyone is welcome to attend. If you would like to give a seminar, please contact Subaru seminar organizers (Thayne Currie, Tae-Soo Pyo, Nagayoshi Ohashi) by email : (please change"_at" to @).

June 5, Monday, 11am in 104B

" A search for Ly-alpha emitters around concentrated strong Ly-alpha absorbers at z=2.3 "

Kazuyuki Ogura (Ehime University)

In this seminar, I will present about my latest paper (Ogura et al. 2017) related to the relationship between damped Ly-alpha absorption systems (DLAs) and Ly-alpha emitters (LAE). The DLA is a class of quasar absorption-line systems with N_HI>10^20.3 cm^-2 and is a key population to understand the early phase of galaxy evolution. This is because DLAs dominate the neutral-gas content in a wide redshift range and they are thought to be gas reservoirs for the star-formation in the high-z Universe. The LAE are also important as a population of young galaxies with typical mass and age of 10^8–10^9 M_sun and order of 100 Myr, respectively. Although most of the galaxy counterparts that have been identified to date show the Ly-alpha emission, the relation between those two population is still unclear. Here we focus on concentrated regions of DLAs to investigate the physical relationship between DLAs and LAEs and conducted narrow-band imaging observation of LAEs. We have found no difference between properties of LAEs, such as Ly-alpha luminosity function and the distribution of rest-frame equivalent wifth, in the target field and those in blank fields at similar redshift in the 50 Mpc scale. On the other hand, in the 10 Mpc scale, we have found a possible overdensity of LAEs around a DLA. This DLA has higher HI column density (logN_HI=21.08 cm^-2) than any other absorbers in the target field. These results imply a possible interrelation between DLAs with high N_IH and LAEs.

Seminars are also held at JAC, CFHT, and IfA.

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