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arXiv · 0710.4522

A Century of Cosmology: A Direct Precision Measurement of the Intergalactic Lyman-alpha Opacity at 2<z<4.2

C. -A. Faucher-Giguere·J. X. Prochaska·A. Lidz·L. Hernquist·M. Zaldarriaga
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Abstract

We directly measure the evolution of the intergalactic Lyman-alpha effective optical depth, tau_eff, over the redshift range 2 is <1% at z=2, 4% at z=3, and 12% at z=4. We provide estimates of the level of absorption arising from metals in the Ly-alpha forest based on both direct and statistical metal removal results in the literature, finding that this contribution is ~6-9% at z=3 and decreases monotonically with redshift. The high precision of our measurement indicates significant departures from the best-fit power-law redshift evolution, particularly near z=3.2.

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C. -A. Faucher-Giguere, J. X. Prochaska, A. Lidz, L. Hernquist, M. Zaldarriaga. 2007-10-24. A Century of Cosmology: A Direct Precision Measurement of the Intergalactic Lyman-alpha Opacity at 2<z<4.2. https://doi.org/10.1393/ncb%2Fi2008-10500-4

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