What is an alignment vector?
An alignment vector is a representation of the difference in retention time between an ion in one of your runs and the equivalent ion in the alignment reference run.
In the Review Alignment screen, the alignment vectors are displayed in the Vector Editing pane as a vertical line going from the position — or, more correctly, the retention time — of the ion in the selected run to the position of the equivalent ion in the alignment reference, with a circle surrounding the location in the alignment reference:
Typically, the alignment vectors are blue (indicating that they have been created by using automatic alignment), while any that have been defined manually are displayed in red.