The Bullet Cluster revisited: New results from new constraints and improved strong lensing modeling technique
We present a new detailed parametric strong lensing mass reconstruction of the Bullet Cluster (1E 0657-56) at z=0.296, based on new WFC3 and ACS HST imaging and VLT/FORS2 spectroscopy. The strong lensing constraints undergone deep revision, there are 14 (6 new and 8 previously known) multiply imaged systems, of which 3 have spectroscopically confirmed redshifts (including 2 newly measured). The reconstructed mass distribution includes explicitly for the first time the combination of 3 mass components: i) the intra-cluster gas mass derived from X-ray observation, ii) the cluster galaxies modeled by their Fundamental Plane (elliptical) and Tully-Fisher (spiral) scaling relations and iii) dark matter. The best model has an average rms value of 0.158" between the predicted and measured image positions for the 14 multiple images considered. The derived mass model confirms the spacial offset between the X-ray gas and dark matter peaks. The galaxy halos to total mass fraction is found to be f_s=11+/-5% for a total mass of 2.5+/-0.1 x10^14 solar mass within a 250 kpc radial aperture.