Trial dispersion measure spacing in fast radio burst searches with HEIMDALL

Abstract: Fast radio bursts (FRBs) are brief flashes of emission detectable to cosmological distances. Cosmology applications rely on an understanding of how the detected sample relates to the underlying population. To this end we examine the dispersion measure tolerance' parameter employed by the FRB search tool \textsc{heimdall} and provide the relation between this and minimum search depth. Several FRB samples can beretro-fitted' using this to more properly account for survey completeness.