Dispersion measure ( DM ) of Fast Radio Bursts ( FRBs ) are commonly used as a indicator of distance assuming that DM in excess of the expected amount within the Milky Way in the direction of each FRB arise mostly from the inter-galactic medium .
However , the assumption might not be true if , for example , most FRB progenitors are embedded in ionized circumstellar material ( CSM , e.g .
supernova remnant ) .
In this study , we jointly analyze distributions of DM , flux density , and fluence of the FRB samples observed by the Parkes telescope and the Australian Square Kilometre Array Pathfinder ( ASKAP ) using analytical models of FRBs , to constrain fractions of various DM components that shape the overall DM distribution and emission properties of FRBs .
Comparing the model predictions with the observations we find that the typical amount of DM in each FRB host galaxy is \sim 120 cm ^ { -3 } pc which is naturally explained as a combination of interstellar medium ( ISM ) and halo of an ordinary galaxy , without additional contribution from ionized CSM that is directly associated with an FRB progenitor .
Furthermore , we also find that observed flux densities of FRBs do not statistically suffer strong K -correction , i.e .
the typical luminosity density of FRBs does not significantly change within the range of emitting frequency \nu _ { rest } \sim 1–4 GHz .