@article{0c669fed879544ae99a3143d238097bb,
title = "The environments of Ly α blobs - I. Wide-field Ly α imaging of TN J1338-1942, a powerful radio galaxy at z ≃ 4.1 associated with a giant Ly a nebula",
abstract = "We exploit wide-field Ly α imaging with Subaru to probe the environment around TN J1338-1942, a powerful radio galaxy with a > 100 kpc Ly α halo at z = 4.11. We used a sample of Ly α emitters (LAEs) down to log (LLyα[ erg s-1]) ~ 42.8 to measure the galaxy density around TN J1338-1942, compared to a control sample from a blank field taken with the same instrument. We found that TN J1338-1942 resides in a region with a peak overdensity of δLAE = 2.8 ± 0.5 on scales of 8 h -1 Mpc (on the sky) and 112 h -1 Mpc (line of sight) in comoving coordinates. Adjacent to this overdensity, we found a strong underdensity where virtually no LAEs are detected. We used a semi-analytical model of LAEs derived from the Millennium Simulation to compare our results with theoretical predictions. While the theoretical density distribution is consistent with the blank field, overdense regions such as that around TN J1338-1942 are very rare, with a number density of 6.4 × 10-8 Mpc-3 (comoving), corresponding to the densest < 0.4 percentile at z ≃ 4.1. We also found that the Ly a luminosity function in the TN J1338-1942 field differs from that in the blank field: the number of bright LAEs (log(LLyα[ergs-1]) ≳ 43.3) is enhanced, while the number of fainter LAEs is relatively suppressed. These results suggest that some powerful radio galaxies associated with Ly α nebulae reside in extreme overdensities on ~3-6 Mpc scales, where star formation and AGN activity may be enhanced via frequent galaxy mergers or high rates of gas accretion from the surroundings.",
keywords = "Galaxies: evolution, Galaxies: formation, Galaxies: high-redshift, Galaxies: individual: TN J1338-1942",
author = "Tomoki Saito and Yuichi Matsuda and Lacey, {Cedric G.} and Ian Smail and Alvaro Orsi and Baugh, {Carlton M.} and Inoue, {Akio K.} and Ichi Tanaka and Toru Yamada and Kouji Ohta and Breuck, {Carlos De} and Tadayuki Kodama and Yoshiaki Taniguchi",
note = "Funding Information: We acknowledge the anonymous referee, who gave us important and practically useful comments to improve the draft. We thank Masami Ouchi for providing the data of luminosity functions, and giving us useful comments. We thank Yi-Kuan Chiang, Roderik Overzier, Surhud More, John Silverman, MasaoMori, andTakatoshi Shibuya for having discussion over this work, and giving us valuable comments. This work was supported by the FIRST programme 'Subaru Measurements of Images and Redshifts (SuMIRe)', World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan. This work was supported in part by the Science and Technology Facilities Council rolling grant ST/I001166/1 to the ICC. Calculations were partly performed on the ICC Cosmology Machine, which is part of the DiRAC Facility jointly funded by STFC and Durham University. YM acknowledges support from JSPS KAKENHI grant number 20647268. IS acknowledges support from STFC (ST/I001573/1), the ERC Advanced Investigator programme DUSTYGAL 321334 and a Royal Society/Wolfson Merit Award. The data were in part obtained from SMOKA, which is operated by the Astronomy Data Center, National Astronomical Observatory of Japan. Publisher Copyright: {\textcopyright} 2015 The Authors.",
year = "2015",
month = mar,
day = "11",
doi = "10.1093/mnras/stu2538",
language = "English",
volume = "447",
pages = "3069--3086",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "4",
}