A Spectroscopic View of the JWST/GTO Strong Lensing Cluster A1489
  We discuss a spectroscopic survey of the strong lensing cluster A1489 that
includes redshifts for 195 cluster members along with central velocity
dispersions for 188 cluster members. The caustic technique applied to the
redshift survey gives the dynamical parameters $M_{200} = (1.25~\pm~0.09)
\times 10^{15}~M_\odot$, $r_{200} = 1.97~\pm~{0.05}$ Mpc, and a cluster line-of
sight velocity dispersion $1150~\pm~{72}~$km$~$s$^{-1}$ within $r_{200}$. These
parameters are very similar to those of other strong lensing systems with
comparably large Einstein radii. We use the spectroscopy and deep photometry to
demonstrate that A1489 is probably dynamically active; its four BCGs have
remarkably different rest frame radial velocities. Like other massive strong
lensing clusters, the velocity dispersion function for members of A1489 shows
an excess for dispersions $\geq~250~$km$~$s$^{-1}$. The central dispersions
also provide enhanced constraints on future lensing models.
