S18A0051abst

S18A0051

We propose Subaru/FOCAS optical spectroscopy of extremely strong emission line galaxies at z∼0.4−0.9 discovered with Subaru/Hyper Suprime Cam (HSC). The candidates are selected by using the HSC broad-band excess and are expected to have extremely strong emission lines with the rest-frame equivalent width of >2000 Å, which is stronger by a factor of up to 10 than that of similar objects previously found. These objects are expected to have very low metallicity and extreme ionization properties compared to normal star-forming galaxies, which resembles the nature of very high-redshift galaxies. In this proposal, we aim to significantly detect multiple emission lines in the rest-frame optical wavelength region including a very weak [OIII]4363 line from 10 candidates at z∼0.6 and 10 candidates at z∼0.8 to measure their accurate oxygen abundance and examine the ionization state by using the emission line diagnostics. This program is the first step in our project to study the nature and the redshift evolution of this new galaxy population systematically, and complete investigation of this population will provide us a great improvement of our fundamental understanding of galaxy formation and evolution in the early Universe.

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This document was translated from L^AT_EX by H^EV^EA.