Associated absorption lines ( AALs ) are valuable probes of the gaseous environments near quasars .
Here we discuss high-resolution ( 6.7 km s ^ { -1 } ) spectra of the AALs in the radio-loud quasar 3C 191 ( redshift z = 1.956 ) .
The measured AALs have ionizations ranging from Mg i to N v , and multi-component profiles that are blueshifted by \sim 400 to \sim 1400 km s ^ { -1 } relative to the quasar ’ s broad emission lines .
These data yield the following new results .

1 ) The strengths of excited-state Si ii ^ { * } AALs indicate a density of \sim 300 cm ^ { -3 } in the Si ^ { + } gas .

2 ) If the gas is photoionized , this density implies a distance of \sim 28 kpc from the quasar .
Several arguments suggest that all of the lines form at approximately this distance .

3 ) The characteristic flow time from the quasar is thus \sim 3 \times 10 ^ { 7 } yr .

4 ) Strong Mg i AALs identify neutral gas with very low ionization parameter and high density .
We estimate n _ { H } \gtrsim 5 \times 10 ^ { 4 } cm ^ { -3 } in this region , compared to \sim 15 cm ^ { -3 } where the N v lines form .

5 ) The total column density is N _ { H } \lesssim 4 \times 10 ^ { 18 } cm ^ { -2 } in the neutral gas and N _ { H } \sim 2 \times 10 ^ { 20 } cm ^ { -2 } in the moderately ionized regions .
These column densities are consistent with 3C 191 ’ s strong soft X-ray flux and the implied absence of soft X-ray absorption .

6 ) The total mass in the AAL outflow is M \sim 2 \times 10 ^ { 9 } M _ { \odot } , assuming a global covering factor ( as viewed from the quasar ) of \sim 10 % .

7 ) The absorbing gas only partially covers the background light source ( s ) along our line ( s ) of sight , requiring absorption in small clouds or filaments < 0.01 pc across .
The ratio N _ { H } / n _ { H } implies that the clouds have radial ( line-of-sight ) thicknesses \lesssim 0.2 pc .

These properties might characterize a sub-class of AALs that are physically related to quasars but form at large distances .
We propose a model for the absorber in which pockets of dense neutral gas are surrounded by larger clouds of generally lower density and higher ionization .
This outflowing material might be leftover from a blowout associated with a nuclear starburst , the onset of quasar activity or a past broad absorption line ( BAL ) wind phase .