Chandra detection of X-ray absorption associated with a damped Ly alpha system

We have observed three quasars, PKS 1127-145, Q1331-171, and Q0054-144, wit h the ACIS-S aboard the Chandra X-Ray Observatory in order to measure soft X-ray absorption associated with intervening 21 cm and damped Ly alpha abso rbers. For PKS 1127-145, we detect absorption that, if associated with an i ntervening z(abs) = 0.312 absorber, implies a metallicity of 23% solar. If the absorption is not at z(abs) = then the metallicity is still constrained to be less than 23% solar. The advantage of the X-ray measurement is that the derived metallicity is insensitive to ionization, inclusion of an atom in a molecule, or depletion onto grains. The X-ray absorption is mostly due to oxygen and is consistent with the oxygen abundance of 30% solar derived from optical nebular emission lines in a foreground galaxy at the redshift of the absorber. For Q1331+171 and Q0054+144, only upper limits were obtai ned, although the exposure times were intentionally short, since for these two objects we were interested primarily in measuring flux levels to plan f or future observations. The imaging results are presented in a companion pa per.