Cosmic Horseshoe (J1148+1930) Ha and OIII spectra

In addition to the spectacular Einstein ring, this systems shows a radial arc. We obtained the redshift of the radial arc counter image z_s,r_=1.961+/-0.001 from Gemini observations.

To disentangle the dark and luminous matter, we consider three different profiles for the dark matter distribution: a power-law profile, the NFW, and a generalized version of the NFW profile. For the luminous matter distribution, we base it on the observed light distribution that is fitted with three components: a point mass for the central light component resembling an active galactic nucleus, and the remaining two extended light components scaled by a constant M/L. To constrain the model further, we include published velocity dispersion measurements of the lens galaxy and perform a self-consistent lensing and axisymmetric Jeans dynamical modeling.