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

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


Elisa Boera

George D. Becker

Fahad Nasir


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 .


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 Ly? flux power spectrum. Astrophysical Journal, 872(1), 1-35.

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
Keywords Cosmology; Early universe; Methods, observational; Quasars; Absorption lines
Public URL
Publisher URL
Additional Information Available on arXiv preprint server: © Copyright 2019 IOP Publishing


Revealing Reionization with the Thermal History of the Intergalactic Medium (2.6 Mb)

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