The 3D large scale structures of star forming galaxies and the projection corrected environmental effects back to z=1.5 revealed by the novel double narrow-band filter technique

Galaxies are distributed inhomogeneously on small scales in the Universe and thus define large-scale structures. Understanding the evolution of galaxies is to determine precisely how galaxies change their properties as a result of the hierarchical growth of large-scale structures. The difficulty is the need for accurate determination of the redshift to determine the precise environment of the galaxies. We present a very unique and novel method to estimate accurate redshifts of star-forming galaxies by measuring the flux ratio of the same emission line observed through two adjacent narrow-band filters. We apply this method to our NB921 and new NB926 data taken with Hyper Suprime-Cam on the Subaru Telescope. We obtain redshifts for [OII] emission line galaxies at z ∼ 1.5, [OIII] emission line galaxies at z~ 0.84 and [Ha] emission-line galaxies at z~0.41. This allows us to reveal 3D structures and can correct the projection effect. The projected celestial distribution does not precisely trace the real distribution of galaxies, indicating the importance of the three-dimensional view of structures to properly identify and quantify galaxy environments. We then investigate the projection corrected environmental dependence of galaxy properties.