deletions | additions       diff --git a/subsection_Comparison_with_X_ray__.tex b/subsection_Comparison_with_X_ray__.tex  index d3abd3f..c3aa9f3 100644  --- a/subsection_Comparison_with_X_ray__.tex  +++ b/subsection_Comparison_with_X_ray__.tex 
...
Koss studies a sample of 167 X-ray selected AGN pairs at $z<0.05$ from the BAT survey. Using the following: radial velocity differences $< 300 km.s^{−1}$, pair separation from 1 to 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. This study also encounters limitations due to the SDSS hardware, causing incompleteness data collection at close scales (small redshift). These limitations are overcome by using emission line diagnostics.   The study by \cite{Koss_2011} provides \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.