We present a detailed and statistical analysis of the column densities and Doppler b parameters of Mg ii absorbing clouds at redshifts 0.4 \leq z \leq 1.2 .
We draw upon the HIRES/Keck data ( \Delta v \simeq 6.6 km s ^ { -1 } ) and Voigt profile ( VP ) fitting results presented by Churchill & Vogt ( Paper I ) .
The sample is comprised of 175 clouds from 23 systems along 18 quasar lines of sight .
In order to better understand whether the inferred physical conditions in the absorbing clouds could be “ false ” conditions , which can arise due to the non–uniqueness inherent in parameterizing complex absorption profiles , we performed extensive simulations of the VP analyses presented in this paper .
In brief , we find : ( 1 ) The Fe ii and Mg ii column densities are correlated at the 9 \sigma level .
There is a 5 \sigma anti–correlation between the Mg i /Mg ii column density ratio and the Mg ii column density .
( 2 ) Power–law fits to the column density distributions for Mg ii , Fe ii , and Mg i yielded power–law slopes of \simeq - 1.6 , -1.7 , and -2.0 , respectively .
( 3 ) The observed peaks of the Doppler parameter distributions were \sim 5 km s ^ { -1 } for Mg ii and Fe ii and \sim 7 km s ^ { -1 } for Mg i .
The clouds are consistent with being thermally broadened , with temperatures in the 30–40,000 K range .
( 4 ) A two–component Gaussian model to the velocity two–point correlation function ( TPCF ) yielded velocity dispersions of 54 km s ^ { -1 } and 166 km s ^ { -1 } .
The narrow component has roughly twice the amplitude of the broader component .
The width and amplitude of the broader component decreases as equivalent width increases .
( 5 ) From photoionization models we find that the column density ratios are most consistent with being photoionized by the ultraviolet extragalactic ionizing background , as opposed to stellar radiation .
Based upon the Mg i to Mg ii column density ratios , it appears that at least two–phase ionization models are required to explain the data .