학술논문
3D Distribution Map of HI Gas and Galaxies Around an Enormous Ly$\alpha$ Nebula and Three QSOs at $z=2.3$ Revealed by the HI Tomographic Mapping Technique
Document Type
Working Paper
Author
Mukae, Shiro; Ouchi, Masami; Cai, Zheng; Lee, Khee-Gan; Prochaska, J. Xavier; Cantalupo, Sebastiano; Zheng, Zheng; Nagamine, Kentaro; Suzuki, Nao; Silverman, John D.; Misawa, Toru; Inoue, Akio K.; Hennawi, Joseph F.; Matsuda, Yuichi; Mawatari, Ken; Sugahara, Yuma; Kojima, Takashi; Ono, Yoshiaki; Shibuya, Takatoshi; Harikane, Yuichi; Fujimoto, Seiji; Chiang, Yi-Kuan; Zhang, Haibin; Kakuma, Ryota
Source
Subject
Language
Abstract
We present an IGM HI tomography map in a survey volume of $16 \times 19 \times 131 \ h^{-3} {\rm comoving \ Mpc}^{3}$ (cMpc$^3$) centered at MAMMOTH-1 nebula and three neighbouring quasars at $z=2.3$. MAMMOTH-1 nebula is an enormous Ly$\alpha$ nebula (ELAN), hosted by a type-II quasar dubbed MAMMOTH1-QSO, that extends over $1\ h^{-1}$ cMpc with not fully clear physical origin. Here we investigate the HI-gas distribution around MAMMOTH1-QSO with the ELAN and three neighbouring type-I quasars, making the IGM HI tomography map with a spatial resolution of $2.6\ h^{-1}$ cMpc. Our HI tomography map is reconstructed with HI Ly$\alpha$ 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 HI flux overdensity for MAMMOTH1-QSO, and find that MAMMOTH1-QSO resides in a volume with significantly weak HI absorption. This suggests that MAMMOTH1-QSO has a proximity zone where quasar illuminates and photo-ionizes the surrounding HI gas and suppresses HI absorption, and that the ELAN is probably a photo-ionized cloud embedded in the cosmic web. The HI radial profile of MAMMOTH1-QSO is very similar to those of three neighbouring type-I quasars at $z=2.3$, which is compatible with the AGN unification model. We compare the distributions of the HI absorption and star-forming galaxies in our survey volume, and identify a spatial offset between density peaks of star-forming galaxies and HI gas. This segregation may suggest anisotropic UV background radiation created by star-forming galaxy density fluctuations.
Comment: 15 pages, 9 figures. Accepted for Publication in ApJ
Comment: 15 pages, 9 figures. Accepted for Publication in ApJ