deletions | additions       diff --git a/introduction.tex b/introduction.tex  index e853ac2..6c26824 100644  --- a/introduction.tex  +++ b/introduction.tex 
...
In \citet{2009A&A...493..579G} we showed that this inner X-ray emission can be explained by shock heating of a 400-500~km~s$^{-1}$ fast component. For the case of DG~Tau the mass flux in this component can be less than $10^{-4}$ of the total mass flux in the jet or even lower if the same material is reheated in several consecutive shocks. If the density in the fast outflow is $>10^5$~cm$^{-3}$ then the cooling length of this shock is only a few AU and thus it would be unresolved and outshined by the more luminous emission from the more massive, but slightly slower jet component, that is responsible for the optical emission.  In this article we explain how such a shock can be caused by the recollimation of the inner jet due to the shape of the boundary between stellar winds and disk winds similar to the work of \citet{http://adsabs.harvard.edu/abs/2012MNRAS.422.2282K} \citet{2012MNRAS.422.2282K}  for relativistic jets. In section~\ref{sect:model} XXX. We end with a summary in section~\ref{sect:summary}.