Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) – XV. Constraining the cosmic reionization at 5.5 < z < 7. Issue 1 (24th September 2022)

• Record Type: Journal Article
• Authors: Lu, Ting-Yi; Goto, Tomotsugu; Hashimoto, Tetsuya; Santos, Daryl Joe D; Wong, Yi Hang Valerie; Kim, Seong Jin; Hsiao, Tiger Y-Y; Kilerci, Ece; Ho, Simon C-C; Nagao, Tohru; Matsuoka, Yoshiki; Onoue, Masafusa; Toba, Yoshiki
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 517:Issue 1(2022)
• Page Start: 1264
• Page End: 1281
• Publication Date: 2022-09-24
• Subjects: (galaxies:) intergalactic medium -- (galaxies:) quasars:absorption lines -- (galaxies:) quasars: general -- (cosmology:) observations -- (cosmology:) dark ages, reionization, first stars; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac2681
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Revealing the cosmic hydrogen reionization history is one of the main goals of the modern cosmology. z > 5 quasars (QSOs) have been used as back-lights to investigate the evolution of the intervening intergalactic medium (IGM) during the cosmic reionization since their first discovery. However, due to the small population of luminous QSOs (∼130 QSOs known to date), a tight constraint on the reionization history has not yet been placed. In this work, we aim to tighten the constraint using the 93 QSOs (5.5 < z < 7.1) recently discovered in the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQS) project. This is the largest QSO sample used to constrain the epoch of reionization. We measure the mean IGM Ly α transmission and the QSO near-zone size using the UV spectra of these QSOs. The mean IGM Ly α transmission rises above zero at z ≲ 6, indicating the end of the reionization. The near-zone sizes of the SHELLQs QSOs are consistent with sizes spanned by QSOs of lifetime t q ∼ 1–100 Myr in simulations. Due to the scatter created by the low signal-to-noise spectra and large Ly α redshift uncertainty, we cannot conclude whether the redshift evolution of the near-zone size is affected by the reionization effect.