METALLICITY OF THE INTERGALACTIC MEDIUM USING PIXEL STATISTICS. II. THE DISTRIBUTION OF METALS AS TRACED BY C IV

摘要: We measure the distribution of carbon in intergalactic medium as a function redshift z and overdensity δ. Using hydrodynamical simulation to link H I absorption density temperature absorbing gas, model for UV background radiation, we convert ratios C IV pixel optical depths into abundances. For median metallicity this technique was described tested Paper series. Here generalize it reconstruct full probability abundance apply 19 high-quality quasar spectra. find that is spatially highly inhomogeneous well by lognormal fixed δ z. data range log = -0.5-1.8 1.8-4.1, renormalized version 2001 Haardt & Madau radiation from galaxies quasars, [C/H] -3.47 + 0.08(z - 3) 0.65(log 0.5) scatter σ([C/H]) 0.76 0.02(z 0.23(log 0.5). Thus, significant trends with but no evidence evolution. These measurements imply gas accounts cosmic -2.80 ± 0.13 (ΩC ≈ 2 × 10-7), The dominant source systematic error spectral shape background, harder spectra yielding higher While errors due uncertainties hardness may exceed quoted statistical < 10, stress backgrounds differ significantly our fiducial give unphysical results. measured strictly independent shape, provided uniform. also present III/C ratio (which rule out temperatures high enough collisional ionization be important observed IV) evolution effective Lyα depth.