The Correlated Variations of C IV Narrow Absorption Lines and Quasar Continuum

We assemble 207 variable quasars from the Sloan Digital Sky Survey, all with at least 3 observations, to analyze C IV narrow absorption doublets, and obtain 328 C IV narrow absorption line systems. We find that 19 out of 328 C IV narrow absorption line systems were changed by vertical bar Delta W-r(lambda 1548)vertical bar >= 3 sigma(Delta Wr lambda 1548) on timescales from 15.9 to 1477 days at rest-frame. Among the 19 obviously variable C IV systems, we find that (1) 14 systems have relative velocities upsilon(r) > 0.01c and 4 systems have upsilon(r) > 0.1c, where c is the speed of light; (2) 13 systems are accompanied by other variable C IV systems; (3) 9 systems were changed continuously during multiple observations; and (4) 1 system with upsilon(r) = 16,862 km s(-1) was enhanced by Delta W-r lambda 1548 = 2.7(sigma Delta Wr lambda 1548) in 0.67 day at rest-frame. The variations of absorption lines are inversely correlated with the changes in the ionizing continuum. We also find that large variations of C IV narrow absorption lines are form differently over a short timescale.