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The He II Opacity of the Lyman-alpha Forest and the Intergalactic Medium

Wei Zheng·Arthur F. Davidsen·Gerard A. Kriss
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Abstract

Based on the empirical formulas governing the distribution of Ly-a forest absorption, we use a Monte-Carlo technique to calculate the average HeII optical depth produced by these forest lines. A substantial contribution to HeII absorption arises from extremely tenuous regions of intergalactic gas that are beyond the observational limits for HI absorption.

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Wei Zheng, Arthur F. Davidsen, Gerard A. Kriss. 1997-11-12. The He II Opacity of the Lyman-alpha Forest and the Intergalactic Medium. https://doi.org/10.1086/300230

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