X iv : a st ro - p h / 04 02 34 7 v 1 1 3 Fe b 20 04 The Evolution of the Intergalactic Medium Transmission to Redshift Six
نویسنده
چکیده
We have measured the transmission of the Lyα forest produced by neutral hydrogen scattering in the intergalactic medium between redshifts 2 and 6.3 using high signal to noise, high resolution (R ≥ 5000) observations of 50 quasars spread over the redshift range. We use a uniform set of 15Å intervals covering Lyα, Lyβ, and Lyγ absorption regions to tabulate the forest transmission as a function of redshift. The transmitted fractions show a relatively smooth evolution over the entire range of redshifts, which can be modelled with a smoothly decreasing ionization rate. Previous claims of an abrupt change at z ∼ 6 appear in part to be a consequence of an incorrect conversion of Lyβ to Lyα optical depths. The tabulated transmissions can be used to calculate the colors of objects with a specified input spectrum as a function of redshift. We calculate the colors of a flat f ν galaxy with a large intrinsic continuum break, as an important example.
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ar X iv : a st ro - p h / 04 02 02 0 v 1 1 Fe b 20 04 Perspective from a Younger Generation – The Astro - Spectroscopy of Gisbert
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