Non-parametric strong lens inversion of SDSS J1004+4112

TL;DR

This paper applies a non-parametric strong lens inversion method to the SDSS J1004+4112 system, accurately modeling its mass distribution and predicting multiple images, including a central one, consistent with observations.

Contribution

It demonstrates the effectiveness of a non-parametric inversion approach in modeling complex lens systems and constrains the mass profile using multiple observational constraints.

Findings

Mass within 60 kpc: 2.5x10^13 M_O

Mass within 110 kpc: 6.1x10^13 M_O

Mass profile compatible with elliptical NFW profile

Abstract

In this article we study the well-known strong lensing system SDSS J1004+4112. Not only does it host a large-separation lensed quasar with measured time-delay information, but several other lensed galaxies have been identified as well. A previously developed strong lens inversion procedure that is designed to handle a wide variety of constraints, is applied to this lensing system and compared to results reported in other works. Without the inclusion of a tentative central image of one of the galaxies as a constraint, we find that the model recovered by the other constraints indeed predicts an image at that location. An inversion which includes the central image provides tighter constraints on the shape of the central part of the mass map. The resulting model also predicts a central image of a second galaxy where indeed an object is visible in the available ACS images. We find masses of 2.5x10^13 M_O and 6.1x10^13 M_O within a radius of 60 kpc and 110 kpc respectively, confirming the results from other authors. The resulting mass map is compatible with an elliptical generalization of a projected NFW profile, with r_s = 58_{-13}^{+21} arcsec and c_vir = 3.91 +/- 0.74. The orientation of the elliptical NFW profile follows closely the orientation of the central cluster galaxy and the overall distribution of cluster members.