Galaxy overdensities around distant QSOs and their contribution to the cosmic reionization revealed with millimeter and optical wide-field observations

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K14752
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 16010:Astronomy-related
• Research Institution: The University of Tokyo
• Principal Investigator: Ono Yoshiaki 東京大学, 宇宙線研究所, 助教 (60631116)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 銀河進化 / 銀河形成 / 高赤方偏移銀河 / 多波長観測

Outline of Final Research Achievements

In this study, we have applied a convolutional neural network to multiwavelength imaging data obtained with Subaru Hyper Suprime-Cam (HSC) to efficiently construct a large sample of Lya-emitting star-forming galaxies at redshifts from 2.2 to 7.0. We have also spectroscopically identified overdense regions of star-forming galaxies at high redshift using Keck and Gemini, and detected significant cross-correlations with submillimeter galaxies by comparing their sky distributions. In addition, we have observed the CO molecular gas emission lines from the spectroscopically confirmed bright star-forming galaxies at redshift around 6 with ALMA and estimated their molecular gas mass densities.

Free Research Field

天文学

Academic Significance and Societal Importance of the Research Achievements

本研究で構築した大規模なLya輝線銀河サンプルはその後，光度関数や角度相関関数，空間的なLya輝線プロファイルなどといった統計的な性質の議論につながった．また，星形成銀河の高密度領域とサブミリ銀河の間の有意な相互相関は，ダストに覆われていない星形成がダストに覆われた星形成と同じような場所で起きていたことを示唆している．さらに，赤方偏移6程度の明るい星形成銀河の分子ガス質量密度について，静止系IR光度とUV光度の和をもとに求めた星形成率密度とともに過去の結果と比較したところ，赤方偏移6程度でも平均的には近傍の結果と矛盾しないことがわかった．