MAMMOTH-Subaru. IV. Large Scale Structure and Clustering Analysis of Lyα Emitters and Lyα Blobs at z = 2.2–2.3

Abstract

We report the large scale structure and clustering analysis of Ly α emitters (LAEs) and Ly α blobs (LABs) at z = 2.2–2.3. Using 3341 LAEs, 117 LABs, and 58 bright (Ly α luminosity L _Ly _α > 10 ^43.4 erg s ^−1 ) LABs at z = 2.2–2.3 selected with Subaru/Hyper Suprime-Cam, we calculate the LAE overdensity to investigate the large scale structure at z = 2. We show that 79% of LABs and 83% of bright LABs are located in overdense regions, which is consistent with the trend found by previous studies that LABs are generally located in overdense regions. We find that one of our eight fields, dubbed J1349, contains 39/117 ≈ 33% of our LABs and 22/58 ≈ 38% of our bright LABs. A unique and overdense $2{4}^{{\prime} }\times 1{2}^{{\prime} }$ (40 × 20 comoving Mpc ^2 ) region (J1347 protocluster) has 12 LABs (eight bright LABs). By comparing to SSA22, which is one of the most overdense LAB regions found by previous studies, we show that the J1347 protocluster region has a higher bright LAB density than the SSA22 protocluster region with a 1 σ significance. We calculate the angular correlation functions (ACFs) of LAEs and LABs in the unique J1349 field and fit the ACFs with a power-law function to measure the slopes. The bright LABs show a 5 σ larger slope, suggesting that bright LABs are more clustered than faint LAEs. Our LABs have a large galaxy bias of ∼5–7, which suggests that LABs generally reside in more massive dark matter halos (halo masses M ≳ 10 ^13 M _⊙ ) than faint LAEs.

Keywords

• Galaxies
• Lyα galaxies
• High-redshift galaxies