On the cosmic distance duality relation and strong gravitational lens power law density profile

Many new strong gravitational lensing (SGL) systems have been discovered in the last two decades with the advent of powerful new space and ground-based telescopes. The effect of the lens mass model (usually the power-law mass model) on cosmological parameters constraints has been performed recently in literature. In this paper, by using SGL systems and Supernovae type Ia observations, we explore if the power-law mass density profile (rho proportional to r(-gamma)) is consistent with the cosmic distance duality relation (CDDR), D-L(1 + z)(-2)/D-A = eta(z) = 1, by considering different lens mass intervals. It has been obtained that the verification of the CDDR validity is significantly dependent on lens mass interval considered: the sub-sample with sigma(ap) >= 300 km/s (where sigma(ap) is the lens apparent stellar velocity dispersion) is in full agreement with the CDDR validity, the sub-sample with intermediate sigma(ap) values (200 <= sigma(ap) < 300) km/s is marginally consistent with eta = 1 and, finally, the sub-sample with low sigma(ap) values (sigma(ap) < 200 km/s) ruled out the CDDR validity with high statistical confidence. Therefore, if one takes the CDDR as guarantee, our results suggest that using a single density profile is not suitable to describe lens with low sigma(ap) values and it is only an approximate description to lenses with intermediate mass interval.

Automated summary

Using strong gravitational lensing systems and Type Ia supernovae observations, this paper explores the consistency of the power-law mass density profile with the cosmic distance duality relation and finds that the verification of the relation is dependent on the lens mass interval considered. The study suggests that a single density profile may not be suitable for describing lenses with low apparent stellar velocity dispersion values, and is only an approximate description for lenses within an intermediate mass interval.