Variability Tests for Intrinsic Absorption Lines in Quasar Spectra

Quasar spectra have a variety of absorption lines whose origins range fromenergetic winds expelled from the central engines to unrelated, intergalacticclouds. We present multi-epoch, medium resolution spectra of eight quasars atz~2 that have narrow ``associated'' absorption lines (AALs, within $\pm$5000 kms^{-1} of the emission redshift). Two of these quasars were also knownpreviously to have high-velocity mini-broad absorption lines (mini-BALs). Weuse these data, spanning ~17 years in the observed frame with two to fourobservations per object, to search for line strength variations as anidentifier of absorption that occurs physically near (``intrinsic'' to) thecentral AGN. Our main results are the following: Two out of the eight quasars with narrowAALs exhibit variable AAL strengths. Two out of two quasars with high-velocitymini-BALs exhibit variable mini-BAL strengths. We also marginally detectvariability in a high-velocity narrow absorption line (NAL) system, blueshifted\~32,900 km s^{-1}$ with respect to the emission lines. No other absorptionlines in these quasars appeared to vary. The outflow velocities of the variableAALs are 3140 km s^{-1} and 1490 km s^{-1}. The two mini-BALs identify muchhigher velocity outflows of ~28,400 km s^{-1} and ~52,000 km s^{-1}. Ourtemporal sampling yields upper limits on the variation time scales from 0.28 to6.1 years in the quasar rest frames. The corresponding minimum electrondensities in the variable absorbers, based on the recombination time scale, are\~40,000 cm^{-3} to ~1900 cm^{-3}. The maximum distances of the absorbers fromthe continuum source, assuming photoionization with no spectral shielding,range from ~1.8 kpc to ~7 kpc.Comment: 16 pages, 4 figures, ApJ, accepte