Revealing reionization with the thermal history of the intergalactic medium: new constrainst from the Lyα flux power spectrum

Boera, Elisa; Becker, George D.; Bolton, James S; Nasir, Fahad

Abstract

We present a new investigation of the thermal history of the intergalactic medium (IGM) during and after reionization using the Lyman-α forest flux power spectrum at 4.0 z 5.2. Using a sample of 15 high– resolution spectra, we measure the flux power down to the smallest scales ever probed at these redshifts (−1 log(k/km −1 s) −0.7). These scales are highly sensitive to both the instantaneous temperature of the IGM and the total energy injected per unit mass during and after reionization. We measure temperatures at the mean density of T 0 ∼ 7000-8000 K, consistent with no significant temperature evolution for redshifts 4.2 z 5.0. We also present the first observational constraints on the integrated IGM thermal history, finding that the total energy input per unit mass increases from u 0 ∼ 4.6 eV m −1 p to 7.3 eV m −1 p from z ∼ 6 to 4.2 assuming a Λ-CDM cosmology. We show how these results can be used simultaneously to obtain information on the timing and the sources of the reionization process. Our first proof of concept using simplistic models of instantaneous reionization produces results comparable to and consistent with the recent Planck constraints, favoring models with z rei ∼ 8.5 +1.1 −0.8 .

Citation

Boera, E., Becker, G. D., Bolton, J. S., & Nasir, F. (2019). Revealing reionization with the thermal history of the intergalactic medium: new constrainst from the Lyα flux power spectrum. Astrophysical Journal, 872(1), 1-35. https://doi.org/10.3847/1538-4357/aafee4

• Journal Article Type: Article
• Acceptance Date: Jan 9, 2019
• Online Publication Date: Feb 14, 2019
• Publication Date: Feb 20, 2019
• Deposit Date: Mar 1, 2019
• Publicly Available Date: Mar 1, 2019
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 872
• Issue: 1
• Pages: 1-35
• DOI: https://doi.org/10.3847/1538-4357/aafee4
• Keywords: Cosmology; Early universe; Methods, observational; Quasars; Absorption lines
• Public URL: https://nottingham-repository.worktribe.com/output/1505158
• Publisher URL: https://iopscience.iop.org/article/10.3847/1538-4357/aafee4
• Additional Information: Available on arXiv preprint server: https://arxiv.org/abs/1809.06980. © Copyright 2019 IOP Publishing
• Contract Date: Mar 1, 2019