Friday, 13 February 2009

A downturn in intergalactic CIV as redshift 6 is approached

From Ryan-Weber et al. ( Caption reads:
"Figure 5. Cosmological mass density of C IV as a function of redshift. The blue squares show the measurements by Songaila (2001), the red triangle is from Pettini et al. (2003), and the green triangle is the value deduced here. All values plotted have been reduced to the ‘737’ cosmology adopted in the present work. Error bars are 1-sigma. While this plot shows the actual values of C Iv measured, they are not strictly comparable because each of the three surveys had a different sensitivity limit. This issue is discussed in detail in the text (section 5)."

The authors claim that the this downturn of metals implies a deficiency of ionizing photons at high-z (that is, there would not be enough photons to keep the universe ionized).

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