Oral Presentation

The environmental impacts on the mass-metallicity relation at z=1.52.

Author(s): Shigeru Namiki (SOKENDAI, NAOJ)

Presenter: Shigeru Namiki (SOKENDAI, NAOJ)

As a demonstration study of galaxy cluster science in the era of PFS+ULTIMATE, we present the results of our near-infrared (NIR) spectroscopic observations of a rich cluster candidate around a radio galaxy at z = 1.52 (4C65.22) with Subaru/MOIRCS and LBT/LUCI. We observed 71 galaxies mostly on the star-forming main sequence in this region, and successfully measured the redshifts of 39 galaxies with a redshift spike at z=1.52. Our spectroscopic data also suggest a hint of
large-scale filaments/sheet-like structures crossing at the highest-density cluster core. By stacking the spectra and using N2 method, we show that the Mass-Metallicity Relation (MZR) in this cluster is consistent with that of field galaxies at the same epoch, suggesting that the chemical enrichment in galaxies is not significantly affected by its surrounding environment at least in this cluster region. However, the environmental impacts on the chemical evolution in galaxies is still under debate, mainly due to the limited number of deep NIR spectroscopy for distant clusters. We believe that the combination of PFS and ULTIMATE-Subaru will significantly increase the cluster sample size (out to z>2) and allow us to perform this discussion over cosmic time across the wider environmental range.