Discovery of a Rich Cluster at z = 1.63 using the Rest-Frame 1.6um
  "Stellar Bump Sequence" Method
  We present a new two-color algorithm, the "Stellar Bump Sequence" (SBS), that
is optimized for robustly identifying candidate high-redshift galaxy clusters
in combined wide-field optical and mid-infrared (MIR) data. The SBS algorithm
is a fusion of the well-tested cluster red-sequence method of Gladders & Yee
(2000) with the MIR 3.6um - 4.5um cluster detection method developed by
Papovich (2008). As with the cluster red-sequence method, the SBS identifies
candidate overdensities within 3.6um - 4.5um color slices, which are the
equivalent of a rest-frame 1.6um stellar bump "red-sequence". In addition to
employing the MIR colors of galaxies, the SBS algorithm incorporates an
optical/MIR (z' - 3.6um) color cut. This cut effectively eliminates foreground
0.2 < z < 0.4 galaxies which have 3.6um - 4.5um colors that are similarly red
as z > 1.0 galaxies and add noise when searching for high-redshift galaxy
overdensities. We demonstrate using the z ~ 1 GCLASS cluster sample that
similar to the red sequence, the stellar bump sequence appears to be a
ubiquitous feature of high-redshift clusters, and that within that sample the
color of the stellar bump sequence increases monotonically with redshift and
provides photometric redshifts accurate to dz = 0.05. We apply the SBS method
in the XMM-LSS SWIRE field and show that it robustly recovers the majority of
confirmed optical, MIR, and X-ray-selected clusters at z > 1.0 in that field.
Lastly, we present confirmation of SpARCS J022427-032354 at z = 1.63, a new
cluster detected with the method and confirmed with 12 high-confidence
spectroscopic redshifts obtained using FORS2 on the VLT. We conclude with a
discussion of future prospects for using the algorithm.
