Nonequilibrium carbon ionization states and the extragalactic far-UV background with He2 absorption

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/4154

Title:	Nonequilibrium carbon ionization states and the extragalactic far-UV background with He2 absorption
Authors:	Vasiliev, Evgenii O. Sethi, S.K. Nath, Biman B.
Keywords:	Cosmology: theory Diffuse radiation Intergalatic medium Quasars: general
Issue Date:	Jan-2011
Publisher:	Springer
Citation:	Astrophysics and Space Science, 2011, Vol.335, p211
Abstract:	Using nonequilibrium calculations of the ionic states and the recently calculated extragalactic ultraviolet background radiation with absorption by intergalactic HeII we determine the ratios of CIII to CIV expected at z ∼ 2–3, as functions of metallicity, gas density and temperature. We constrain the spectrum of the extragalactic ultraviolet background radiation by fitting the observed abundance ratios carbon ions at these redshifts with those expected from different models of the background radiation. Our analysis of the observed ratios shows that ‘delayed reionization’ models, which assume a large fraction of HeII at z ∼ 3, is not favored by data. Our results suggest that HeII reionization was inhomogeneous, consistent with the predictions from recent simulations.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/4154
ISSN:	0004-640X 1572-946X (Online)
Alternative Location:	http://adsabs.harvard.edu/doi/10.1007/s10509-010-0585-6 http://dx.doi.org/10.1007/s10509-010-0585-6
Copyright:	2011 Springer.
Appears in Collections:	Research Papers (A&A)

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