We present cosmological (30-400Mpc) distributions of neutral hydrogen (HI) in the intergalactic medium (IGM) traced by Ly{alpha} emitters (LAEs) and QSOs at z=2.1-2.5, selected with the data of the ongoing Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) and the eBOSS survey. Motivated by a previous study of Mukae et al., we investigate spatial correlations of LAEs and QSOs with HI tomography maps reconstructed from HI Ly{alpha} forest absorption in the spectra of background galaxies and QSOs obtained by the CLAMATO survey and this study, respectively. In the cosmological volume far from QSOs, we find that LAEs reside in regions of strong HI absorption, i.e., HI rich, which is consistent with results of previous galaxy-background QSO pair studies. Moreover, there is an anisotropy in the HI distribution plot of transverse and line-of-sight distances; on average the HI absorption peak is blueshifted by ~200km/s from the LAE Ly{alpha} redshift, reproducing the known average velocity offset between the Ly{alpha} emission redshift and the galaxy systemic redshift. We have identified a ~40Mpc scale volume of HI underdensity that is a candidate for a giant HII bubble, where six QSOs and an LAE overdensity exist at =2.16. The coincidence of the QSO and LAE overdensities with the HI underdensity indicates that the ionizing photon radiation of the QSOs has created a highly ionized volume of multiple proximity zones in a matter overdensity. Our results suggest an evolutionary picture where H i gas in an overdensity of galaxies becomes highly photoionized when QSOs emerge in the galaxies.

Cone search capability for table J/ApJ/903/24/table2 (HETDEX LAEs in the COSMOS Field)

Cone search capability for table J/ApJ/903/24/table3 (HETDEX LAEs in the EGS field)

Cone search capability for table J/ApJ/903/24/table4 (Foreground QSOs in the EGS field)

Cone search capability for table J/ApJ/903/24/table5 (Background QSOs in the EGS field)