These are the different types of models that psphot takes:

(these are located in psModules/src/objects/models)

psphot name filename function comment
PS_MODEL_GAUSS pmModel_GAUSS.c exp(-z) Pure gaussian
PS_MODEL_PGAUSS pmModel_PGAUSS.c 1 / (1 + z + z2/2 + z3/6) Gaussian taylor expansion
PS_MODEL_PS1_V1 pmModel_PS1_V1.c 1 / (1 + kz + z(3.33/2)) (z = r2, so r3.33) power-law with fitted linear term
PS_MODEL_QGAUSS pmModel_QGAUSS.c 1 / (1 + kz + z2.25) power-law with fitted linear term
PS_MODEL_RGAUSS pmModel_RGAUSS.c 1 / (1 + z + zalpha) power-law with fitted slope
PS_MODEL_SERSIC pmModel_SERSIC.c f = exp(-zn)