Exploiting the fundamentally achromatic nature of gravitational lensing, we
present a lens model for the massive galaxy cluster SMACSJ0723.3-7323 (SMACS
J0723, z=0.388) that significantly improves upon earlier work. Building on
strong-lensing constraints identified in prior Hubble Space Telescope (HST)
observations, the mass model utilizes 21 multiple-image systems, 16 of which
were newly discovered in Early Release Observation (ERO) data from the James
Webb Space Telescope (JWST). The resulting lens model maps the cluster mass
distribution to an RMS spatial precision of 1.08'' and is publicly available at
https://www.dropbox.com/sh/3iatmz5k4hafzqf/AAAh0JvLgpBVoLp6qsxYZkFGa?dl=0 .
Consistent with previous analyses, our study shows SMACSJ0723.3-7323 to be well
described by a single large-scale component centered on the location of the
brightest cluster galaxy, however JWST data point to the need for two
additional diffuse components west of the cluster, which in turn accounts for
all the currently identified multiply imaged systems. A comparison of the
galaxy distribution, the mass distribution, and gas distribution in the core of
SMACS0723 based on HST, JWST, and Chandra data reveals a fairly concentrated
regular elliptical profile along with tell-tale signs of recent merger
activity, possibly proceeding aligned closely to our line of sight. The
exquisite sensitivity of JWST's NIRCAM reveals in spectacular fashion both the
extended intra-cluster-light distribution and numerous star-forming clumps in
magnified background galaxies. The high-precision lens model derived here for
SMACSJ0723-7323 demonstrates impressively the power of combining HST and JWST
data for unprecedented studies of structure formation and evolution in the
distant Universe.Comment: Updated to match the version submitted to ApJ - analysis, results and
conclusions are unchanged. Link to the lensing outputs:
https://www.dropbox.com/sh/3iatmz5k4hafzqf/AAAh0JvLgpBVoLp6qsxYZkFGa?dl=