Diego, J.M., Broadhurst, T., Wong, J., Silk, J., Lim, J., Zheng, W., Lam, D., Ford, H. A free-form mass model of the Hubble Frontier Fields cluster AS1063 (RXC J2248.7-4431) with over one hundred constraints, 2016, Monthly Notices of the Royal Astronomical Society, 459, 3447

MNRAS459, 3447-3459 (2016)

doi:10.1093/mnras/stw865 (pdf)


We derive a free-form mass distribution for the massive cluster AS1063 (z = 0.348) using the completed optical imaging from the Hubble Frontier Fields programmme. Based on a subset of 11 multiply lensed systems with spectroscopic redshift, we produce a lens model that is accurate enough to secure new multiply lensed systems, totalling over a 100 arclets, and to estimate their redshifts geometrically. Consistency is found between this precise model and that obtained using only the subset of lensed sources with spectroscopically measured redshifts. Although a relatively large elongation of the mass distribution is apparent relative to the X-ray map, no significant offset is found between the centroid of our mass distribution and that of the X-ray emission map, suggesting a relatively relaxed state for this cluster. For the well-resolved lensed images, we provide detailed model comparisons to illustrate the precision of our model and hence the reliability of our de-lensed sources. A clear linear structure is associated with one such source extending 23 kpc in length, that could be an example of jet-induced star formation, at redshift z ≈ 3.1.

Keywords: galaxies: clusters: general, dark matter