Fast radio burst energy function in the presence of $\rm DM_{host}$ variation

Understand

Fast radio bursts (FRBs) have been found in great numbers, but the physical mechanism of these sources is still a mystery.

• The redshift evolutions of the FRB energy distribution function and the volumetric rate shed light on the origin of FRBs.
• However, such estimations rely on the dispersion measurement (DM)-redshift ($z$) relationship.
• A few FRBs that have been detected recently show large excess DMs beyond the expectation from the cosmological and Milky Way contributions, which indicates large spread of DMs from their host galaxies.