. The total ionizing luminosity used is $L_{\rm ion}=2.5 \times 10^{44}$ .

We have taken two representative ionization parameters: $\log \xi =2.08$ \[1\], and $\log \xi =1.15$ \[1\]. We call them medium ionization plasma (MIP, represented by wabs1) and low ionization plasma (LIP, represented by wabs2), respectively. Finally due to our interest in testing the sensitivity of the line strengths with the gas density, we run $n_{H}=10^{[5,6,7,8,9,10,11,12,13,14,15,16,17,18]}$ , and $N_H=$\[1,0.1\]$\times 10^{22}$ , for each of the two ionization states, resulting in 28 points in the grid, making it a modest resolution density-COG grid for warm absorber in AGNs.

[trunk-1]{}: The identification list model \[trunk1\] {#trunk-1-the-identification-list-model-trunk1 .unnumbered}
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We have developed a simple algorithm to identify observed absorption spectral features. The identification is performed by comparing both the line wavelength and optical depth with those computed theoretically in our grid of models. For each model we choose the 500 strongest features, which results in a total of 14,000 theoretical absorption lines (500 $\times$ 14$n_H$ $\times$ 2$N_H$). We shall refer to this as our [*identification list*]{}. The simplest way to identify an observed line is to compare its measured wavelength with the theoretical values. However, one must also allow for the possibility 