@Krogager2012; @Rahmati2014; @Fumagalli2015]. In combination with a small projected separation to the absorption, which causes the quasar to dominate the light-throughout in a blended point spread function (PSF), this has led to a low average detection rate ($\sim 10~\%$) of confirmed counterparts [@Moller1998; @Christensen2007; @Monier2009; @Fynbo2010; @Fynbo2011; @Meiring2011; @Krogager2012; @Noterdaeme2012; @Peroux2012; @Fynbo2013; @Krogager2013; @Rahmani2016]. This has prevented us from characterising the connection the majority of absorbers hold to their galaxy hosts. But presumably, sub-DLAs and DLAs on average sample different environments.

The DLA population contains the bulk of neutral gas throughout cosmic time [$\Omega_\mathrm{\ion{H}{i}}^{\text{DLA}} \gtrsim 80\%$; @Prochaska2005; @Noterdaeme2009; @Noterdaeme2012b], and displays a weak redshift-evolution by a factor of $\sim 3$ from redshift $z\sim 5$ to the local universe [@Neeleman2016b]. Sub-DLAs account for the bulk of the remaining fraction in the redshift range $1.5 < z < 5.0$ [$\Omega_\mathrm{\ion{H}{i}}^{\text{sub-DLA}} \sim 8-20\%$; @Zafar2013a], the Lyman limit systems (LLS, ) and Ly$\alpha$ forest only contributing minor fractions to the total neutral gas content [@Songaila2010].

The chemical enrichment of the DLA population evolves from $\sim 1$ percent solar metallicity at $z=5$ to $\sim 10$ percent solar in the local universe, with a $\sim 2$dex metallicity-spread at all redshifts [@Pettini1994; @Ledoux2002; @Prochaska2003; @Rafelski2014]. This evolution 