Lessons from the first multiply imaged supernova: A revised
  Light-Traces-Mass strong lensing model for the galaxy cluster MACS
  J1149.5+2223
  Our light-traces-mass (LTM) strong-lensing model for MACS J1149.5+2223 has
played several key roles over the last decade: it aided the identification of
multiple images in this cluster and the study of MACS1149-JD1 at redshift
$z\simeq9$, it was used to estimate the properties of the first multiply imaged
supernova, Refsdal, in its discovery paper, and of the first caustic crossing
event by a cluster, Lensed Star 1. Supernova Refsdal supplied an invaluable
opportunity to conduct a blind test of the ability of common lens-modeling
techniques to accurately describe the properties of SN Refsdal's images and
predict the reappearance of one of its counter images that was due about a year
post-discovery of the original Einstein cross. Thanks to this practice, in
which our submitted model yielded some outlying results, we located a numerical
artifact in the time delay (TD) calculation part of the code, which was now
fixed. This artifact did not influence the reproduction of multiple images
(i.e., the deflection fields -- which are those constrained directly from the
observations) or the derived mass model, and so it remained unnoticed prior to
supernova Refsdal, emphasizing the importance of blind tests in astronomy. Here
we update our model and present revised LTM measurements for Refsdal. These are
important not only for completing the LTM view of the Refsdal event, but also
because they affect the range of values predicted from different lens-modeling
techniques and thus the range of systematic uncertainties for the TD
calculation and the resulting Hubble constant.
