Diffuse Lyalpha nebulae around high-redshift star-forming galaxies, or Lyα halos (LAHs), are now known to be ubiquitous. Because properties of LAH should depend on both surrounding matter distribution and ionizing/Lyα sources, it is natural to think that there exists dependence on environments. However, previous works suffered from small number statistics and peculiarity of probed protoclusters, and contradictory results have been reported. We propose narrow-band observations for a massive protocluster around a QSO pair at z=3.3, which is originally found by HSC-SSP survey, in order to establish a reliable and statistical sample for investigations of LAH around Lyα emitters (LAEs). Our well-chosen field enables us to probe the effect of strong ionizing sources (QSOs) and overdense environment at the same time. With >3000 LAEs, we will try to reveal what is the cause of the size difference of LAHs by stacking Lyα images. In addition, as the target field contains a pair QSO and a massive overdensity, discovery of a number of giant Lyα nebulae is highly likely. These serve as an invaluable sample of future follow-up with new generation IFUs and also JWST to reveal the behavior of gas in massive galaxies and the IGM.
This document was translated from LATEX by HEVEA.