Three-dimensional Distribution Map of Hi Gas and Galaxies around an Enormous Lyα Nebula and Three QSOs at z = 2.3 Revealed by the Hi Tomographic Mapping Technique

Shiro Mukae, Masami Ouchi, Zheng Cai, Khee Gan Lee, J. Xavier Prochaska, Sebastiano Cantalupo, Yoshiaki Ono, Zheng Zheng, Kentaro Nagamine, Nao Suzuki, John D. Silverman, Toru Misawa, Akio K. Inoue, Joseph F. Hennawi, Yuichi Matsuda, Ken Mawatari, Yuma Sugahara, Takashi Kojima, Takatoshi Shibuya, Yuichi HarikaneSeiji Fujimoto, Yi Kuan Chiang, Haibin Zhang, Ryota Kakuma

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


We present an IGM H i tomographic map in a survey volume of 16 × 19 × 131 h-3 commoving Mpc3 (cMpc3) centered at MAMMOTH-1 nebula and three neighboring quasars at z = 2.3. The MAMMOTH-1 nebula is an enormous Lyα nebula (ELAN), hosted by a type-II quasar dubbed MAMMOTH1-QSO, that extends over 1 h-1 cMpc with no clear physical origin. Here we investigate the H i-gas distribution around MAMMOTH1-QSO with the ELAN and three neighboring type-I quasars, making the IGM H i tomographic map with a spatial resolution of 2.6 h -1 cMpc. Our H i tomographic map is reconstructed with H i Lyα forest absorption of bright background objects at z = 2.4-2.9: one eBOSS quasar and 16 Keck/LRIS galaxy spectra. We estimate the radial profile of H i overdensity for MAMMOTH1-QSO, and find that MAMMOTH1-QSO resides in a volume with fairly weak H i absorption. This suggests that MAMMOTH1-QSO may have a proximity zone where quasar illuminates and photoionizes the surrounding H i gas and suppresses H i absorption, and that the ELAN is probably a photoionized cloud embedded in the cosmic web. The H i radial profile of MAMMOTH1-QSO is very similar to those of three neighboring type-I quasars at z = 2.3, which is compatible with the AGN unification model. We compare the distributions of the H i absorption and star-forming galaxies in our survey volume, and identify a spatial offset between density peaks of star-forming galaxies and H i gas. This segregation may suggest anisotropic UV background radiation created by star-forming galaxy density fluctuations.

Original languageEnglish
Article number45
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 2020 Jun 10

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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