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          Institute: MPI für Astrophysik     Collection: Cosmology     Display Documents

ID: 10788.0, MPI für Astrophysik / Cosmology
Constraints on reionization from the thermal history of the intergalactic medium
Authors:Theuns, T.; Schaye, J.; Zaroubi, S.; Kim, T. S.; Tzanavaris, P.; Carswell, B.
Date of Publication (YYYY-MM-DD):2002
Title of Journal:The Astrophysical Journal
Journal Abbrev.:Astrophys. J.
Issue / Number:2
Start Page:L103
End Page:L106
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:The temperature of the diffuse, photoheated intergalactic medium (IGM) depends on its reionization history because the thermal timescales are long. The widths of the hydrogen Lyalpha absorption lines seen in the spectra of distant quasars that arise in the IGM can be used to determine its temperature. We use a wavelet analysis of the Lyalpha forest region of quasar spectra to demonstrate that there is a relatively sudden increase in the line widths between redshifts z approximate to 3.5 and 3.0, which we associate with entropy injection resulting from the reionization of He II. The subsequent falloff in temperature after z approximate to 3.5 consistent with a thermal evolution dominated by adiabatic expansion. If, as expected, the temperature also drops rapidly after hydrogen reionization, then the high temperatures inferred from the line widths before He II reionization imply that hydrogen reionization occurred below redshift z = 9.
Free Keywords:cosmology : observations; cosmology : theory; galaxies : formation; intergalactic medium; quasars : absorption lines
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astrophysik
External Affiliations:Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA,; England; Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England; Inst Adv Study, Sch Nat Sci, Princeton, NJ 08540 USA; Max Planck Inst Astrophys, D-85741 Garching, Germany; European So Observ, D-85748 Garching, Germany
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