2024/11/08 by Jiangtao Li, Xiaodi Yu, Li, Jiang-Tao +46 · 1 citation
Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #Atomic and Subatomic Physics Research #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Magnetic confinement fusion research #Nuclear Physics and Applications
paper · pdf · doi:10.48550/arxiv.2411.05396
openalex publication_date 2024/11/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The He II reionization epoch is expected to take place at z∼3-5. In this stage, the helium and metals in the inter-galactic medium (IGM) are further ionized with additional contributions from harder non-stellar sources, and some large-scale gravitationally bound systems approach virialization. The "Probing the He II re-Ionization ERa via Absorbing C IV Historical Yield (HIERACHY)" program utilizes high- and medium-resolution spectra of bright background quasars at z≈3.9-5.2 to investigate Lyα, C IV, and other metal absorption lines during this epoch. Additionally, we employ narrow-band imaging to search for Lyα emitters associated with C IV absorbers, alongside multi-wavelength observations to identify and study particularly intriguing cases. In this paper, we present the design of the HIERACHY program, its current status, major scientific goals, and examples of initial data products from completed Magellan/MIKE, MagE spectroscopy, and MDM imaging observations. We also provide a brief outlook on future multi-wavelength observations that may significantly impact the related science.