Chandra X-Ray Observatory ( CXO ) ACIS-S spectra of three quasars which lie behind three foreground damped Ly \alpha ( DLA ) absorbers are analyzed in order to attempt to determine the amount of photoelectric absorption due to metals present in their x-ray spectra .
These absorbers are the three largest neutral hydrogen column density absorption-line systems known at low redshift ( 0.313 \leq z _ { abs } \leq 0.524 ) .
They have HI column densities which lie in the range 3 \times 10 ^ { 21 } \lesssim N _ { HI } \lesssim 5 \times 10 ^ { 21 } atoms cm ^ { -2 } .
At these redshifts the amount of photoelectric absorption at x-ray energies is primarily an indicator of the oxygen abundance .
Since the column densities of these systems are so high , one would expect accurate metallicity measurements of them to yield a robust estimate of the column-density-weighted cosmic neutral-gas-phase metallicity at z \approx 0.4 .
We consider cases where the DLA gas has solar element abundance ratios and ones with the \alpha -group element abundance ratios enhanced .
For the adopted assumptions , the column-density-weighted cosmic neutral-gas-phase metallicity of the non-enhanced elements ( e.g .
Zn ) at z \approx 0.4 likely lies in the range \approx 0.04 - 0.38 Z _ { \odot } .