Abstract
The estimation of elemental abundances in the intergalactic medium (IGM) often requires ionization corrections and therefore knowledge of the radiation field. The He II/H I ratio η provides an estimate of the hardness of the ionizing radiation and can be used to study variations of the UV background with redshift and/or density. Systematic uncertainties in the measurement of the He II/H I ratio may arise from the assumption of turbulent line broadening. Therefore, taking into account a temperature when analyzing the He II Lyα forest could improve the estimation of scales and amplitudes of UV background fluctuations. Furthermore, an independent estimate of the temperature of the absorbing material could provide, at least in principle, constraints on the thermal state of the IGM.
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Fechner, C. (2008). Using the HeII Lyα Forest to Constrain the Temperature of the IGM. In: Santos, N.C., Pasquini, L., Correia, A.C.M., Romaniello, M. (eds) Precision Spectroscopy in Astrophysics. ESO Astrophysics Symposia. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-75485-5_64
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DOI: https://doi.org/10.1007/978-3-540-75485-5_64
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