High-z extremely metal poor galaxies (EMPGs) are key to understanding the early stage of galaxy formation. Color excesses in broadband images have successfully pinpointed strong-line star-forming galaxies of EMPGs in the local universe as well as young population at high redshift (z>2). Applying these established color-excess techniques to the CEERS images recently taken with JWST/NIRCam, we have identified 10 objects whose 1–5µm colors are consistent with z∼ 5 EMPGs having unprecedentedly low metallicities <0.01Z⊙, all of the 10 objects have PopIII-like colors explained with strong hydrogen Balmer lines with negligibly weak metal emission (e.g. [O iii]5007) that have not been reported so far. Here we propose deep LRIS spectroscopy for the 10 candidates of z∼ 5 EMPGs. These spectroscopy will allow us to confirm the existence of high-z objects with such characteristic colors and/or, in case contrary to our expectation, to reveal physical origins of these objects with multiple lines. A successful confirmation will pave the way for NIRSpec spectroscopy at 2–5µm for metallicity determinations and for witnessing a high-z very early galaxy that will be a precious laboratory of early galaxy formation.
This document was translated from LATEX by HEVEA.