Journal Article

The low-redshift evolution of the Lyman-β forest

Tom Theuns, Anthony Leonard and George Efstathiou

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 297, issue 2, pages L49-L52
Published in print June 1998 | ISSN: 0035-8711
Published online June 1998 | e-ISSN: 1365-2966 | DOI:
The low-redshift evolution of the Lyman-β forest

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The low-redshift evolution of the intergalactic medium is investigated using hydrodynamic cosmological simulations. The assumed cosmological model is a critical density cold dark matter universe. The imposed uniform background of ionizing radiation has the amplitude, shape and redshift evolution as computed from the observed quasar luminosity function by Haardt & Madau. We have analysed simulated Lyman-α spectra using Voigt-profile fitting, mimicking the procedure with which quasar spectra are analysed. Our simulations reproduce the observed evolution of the number of Lyman-α absorption lines over the whole observed interval of z = 0.5 to 4. In particular, our simulations show that the decrease in the rate of evolution of Lyman-α absorption lines at z ≤ 2, as observed by the Hubble Space Telescope, can be explained by the steep decline in the photoionizing background resulting from the rapid decline in quasar numbers at low redshift.

Keywords: hydrodynamics; quasars: absorption lines; cosmology: theory; large-scale structure of Universe

Journal Article.  0 words. 

Subjects: Astronomy and Astrophysics

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