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arXiv · 1403.5898

Background power subtraction in Lyman-alpha forest

Vid Iršič·Anže Slosar
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Abstract

When measuring the one-dimensional power spectrum of the Ly$α$ forest, it is common to measure the power spectrum in flux fluctuations red-ward of the Ly$α$ emission of quasars and subtract this power from the measurements of the Ly$α$ flux power spectrum. This removes excess power present in the Ly$α$ forest which is believed to be dominated by metal absorption by the low-redshift metals uncorrelated with the neutral hydrogen aborbing in Ly$α$. In this brief report we note that, assuming the contaminants are additive in optical depth, the correction contains a second order term. We estimate the magnitude of this term for two currently published measurements of the 1D Ly$α$ flux power spectrum and show that it is negligible for the current generation of measurements. However, future measurements will have to take this into account when errorbars improve by a factor of two or more.

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Vid Iršič, Anže Slosar. 2014-05-12. Background power subtraction in Lyman-alpha forest. https://doi.org/10.1103/physrevd.89.107301

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