Abstract

We present a catalog of spectroscopic redshifts for SPT-CLJ0615-5746, the most distant cluster in the Reionization Lensing Cluster Survey. Using Nod & Shuffle multislit observations with LDSS-3 on Magellan, we identify similar to 50 cluster members and derive a cluster redshift of z(c) = 0.972, with a velocity dispersion of sigma = 1244 +/- 162 km s(-1). We calculate a cluster mass using a sigma(200) - M-200 scaling relation of M-200 = (9.6 +/- 3.5) x 10(14) M-circle dot, in agreement with previous, independent mass measurements of this cluster. In addition, we examine the kinematic state of SPT-CLJ0615-5746, taking into consideration prior investigations of this system. With an elongated profile in lensing mass and X-ray emission, a non-Gaussian velocity dispersion that increases with clustercentric radius, and a brightest cluster galaxy not at rest with the bulk of the system, there are multiple cluster properties that, while not individually compelling, combine to paint a picture that SPT-CLJ0615-5746 is currently being assembled.