deletions | additions       diff --git a/subsection_Comparison_with_X_ray__.tex b/subsection_Comparison_with_X_ray__.tex  index 3ec6b47..a9e6c09 100644  --- a/subsection_Comparison_with_X_ray__.tex  +++ b/subsection_Comparison_with_X_ray__.tex 
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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} 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} 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.