Dispersion measure
= Dispersion measure
{title2=$\mathrm{DM}=\int n_e\,dl$}
{wiki}
The integrated <Electron> number density along the line of sight, conventionally quoted in $\mathrm{pc\,cm^{-3}}$. A <dispersion measure> is a column, not a unique distance: converting it into distance requires a model of the <interstellar medium>. A clumpy nearby column and a longer dilute column can give the same <pulsar dispersion delay>.