deletions | additions       diff --git a/subsection_Comparison_with_X_ray__.tex b/subsection_Comparison_with_X_ray__.tex  index a9e6c09..c6261c0 100644  --- a/subsection_Comparison_with_X_ray__.tex  +++ b/subsection_Comparison_with_X_ray__.tex 
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\subsection{Comparison with X-ray-selected AGN pairs}  Both \cite{Liu_2011} \citet{Liu_2011}  and \cite{Koss_2012} \citet{Koss_2012}  use imaging spectroscopy to select data points for dual (pair) AGN samples.Dual samples. Dual  AGN with small pair separation are used for analysis in both studies, with most of the Lui AGN detections at separation less than 100 kpc, and those of \cite{Koss_2012} \citet{Koss_2012}  found at separations less than 30 kpc. Both papers note that the luminosities of AGN pairs increase with a decrease in separation between galaxies (in a pair), suggesting that mergers promote AGN activity (\cite{Liu_2011} , \cite{Koss_2012}). (\cite{Liu_2011},Koss_2012}).  Both papers also acknowledge the limitations experienced in selecting the appropriate sample data due to SDSS’ fixed fiber size. On this point, Koss notes that due to SDSS fiber being 3”, it is less sensitive to smaller physical scales. Koss studies a sample of 167 X-ray selected AGN pairs at $z<0.05$ from the Burst Alert Telescope (BAT) survey. BAT provides data for a systematic search for hard X-ray sources using a 1.4 steradian field-of-view. Using the following criteria: radial velocity differences $< 300 km s^{−1}$ between AGN (in dual AGN), AGN pair separation between 1 and 100 kpc (to exclude sources classified as composites by their optical emission line properties), as sample selection criteria. At separation $<15 kpc$ ,Koss defined a sample of 16 out of 167 pairs from BAT, and 20 out of 1988 pair were identified from the SDSS. Koss' aim was to discover the the peak black hole growth during the merging process paying particular attention to the relationship between dual AGNs and the stellar mass ratios or ANG in paired samples.   The study by \cite{Koss_2012} \citet{Koss_2012}  provides evidence for merging events enhancing AGN activity as their results show that the X-ray luminosity of both AGN (in an AGN pair), increases strongly with decreasing pair separation. Lastly, results from \cite{Koss_2012} \citet{Koss_2012}  lead them to conclude that this suggests that dual AGN activation may be much more common at higher redshifts as they discovered that galaxy mergers increase with redshift. Both studies show that an increase in AGN activity due to mergers even though AGN selection criterion , and emission mechanism (radio versus X-ray) differ.