On the Analysis of DLA Kinematics
  We discuss two mistreatments of damped Lya (DLA) kinematic analysis that were
first performed by Haehnelt, Steinmetz, & Rauch (1998; hereafter HSR98) and
have recently been repeated by Hong et al. (2010; arXiv:1008.4242v1,
arXiv:1008.4242v2; hereafter H10). Each mistreatment led to the improper
excising of simulated absorption profiles. Specifically, their analyses are
strictly biased against DLA sightlines that have low HI column density log NHI
< 20.5, very high NHI values, and (for all NHI) sightlines with low velocity
width Dv (<30 km/s for HSR98; <[20-30] km/s for H10). None of these biases
exist in the observational analysis. We suspect these mistreatments compromise
the results that followed. Hopefully this posting will prevent their repetition
in the future.
