PIEMD potential

[CHEN Chian-Chou (T.C.)]

Hi all,

I’m trying to compute magnification factors for a set of sources that have foreground galaxies with estimated stellar masses and redshifts.
I’m now constructing potentials based on these foregrounds and I see that the most typical model for lenstool is the PIEMD profile, for which I agree is more physically motivated than SIS.
However i’m not sure I’m doing the right thing in estimating the relevant parameters for PIEMD.

What I’m doing now is to use the stellar mass and redshift information to infer halo mass based on some stellar-to-halo mass relations.
I then treat the halo mass as the total mass for the potential for which I use to estimate the velocity dispersion (v_dsip). I also treat the viral radius as the cut-off radius for the PIEMD profile.
Does this sound reasonable to people?

What makes me not so sure about is that by comparing to the best-fit cluster potentials provided on the website the cut-off radius appears too large.
For example for a galaxy with a stellar mass of 1e11 solar masses the velocity dispersion is about 160km/s but a cutoff radius is about 500kpc.
Comparing to cluster potentials with similar velocity dispersions the cutoff radii are often only about 50-100 kpc.

This level of difference does affect my results to some extend so I’d like to validate the procedure if possible. Thanks in advance!

Cheers,
TC