Computes p(DM) where DM follows a lognormal distribution with
parameters given in natural log space. Includes the 1/DM Jacobian
for conversion from log to linear probability density.
Parameters:
DM (float or array_like) – Dispersion measure values (linear scale).
*args (tuple) – (logmean, logsigma) - mean and standard deviation in natural log space.
Returns:
Probability density p(DM) such that integral p(DM) dDM = 1.