Astrophys. J., 708, 868-908 (2010/January-1)
The last eight-billion years of intergalactic C IV evolution.
COOKSEY K.L., THOM C., PROCHASKA J.X. and CHEN H.-W.
Abstract (from CDS):
We surveyed the Hubble Space Telescope UV spectra of 49 low-redshift quasars for z < 1 C IV candidates, relying solely on the characteristic wavelength separation of the doublet. After consideration of the defining traits of C IV doublets (e.g., consistent line profiles, other associated transitions, etc.), we defined a sample of 38 definite (group G = 1) and five likely (G = 2) doublets with rest equivalent widths Wr for both lines detected at. We conducted Monte Carlo completeness tests to measure the unblocked redshift (Δz) and co-moving path length (ΔX) over which we were sensitive to C IV doublets of a range of equivalent widths and column densities. The absorber line density of (G = 1+2) doublets is for log N(C+3) ≥ 13.2, and has not evolved significantly since z = 5. The best-fit power law to the G = 1 frequency distribution of column densities has coefficient k = 0.67+0.18–0.16x10–14 cm2 and exponent αN= -1.50+0.17 –0.19, where N0= 1014 cm2. Using the power-law model of f(N(C+3)), we measured the C+3 mass density relative to the critical density: for 13 ≤ log N(C+3) ≤ 15. This value is a 2.8±0.7 increase in compared to the error-weighted mean from several 1 < z < 5 surveys for C IV absorbers. A simple linear regression to over the age of the universe indicates that has slowly but steadily increased from z = 5 -> 0, with.
intergalactic medium - quasars: absorption lines - techniques: spectroscopic
VizieR on-line data:
<Available at CDS (J/ApJ/708/868): targets.dat table1.dat table2.dat>
In tables, HE0226-4410 is a misprint for HE 0226-4110.
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