X-ray Observations of a SZ Discovered Cluster at z=1.45

We propose to use XMMNewton to observe an exceptional cluster at z1.45discovered via the SunyaevZeldovich (SZ) effect by the South Pole Telescope(SPT). The cluster, SPTCLJ21094626, is the highest redshift cluster yetdiscovered by SPT, with a Spitzeroptical redsequence redshift of z1.45. Wepredict that SPTCL J21094626 has a mass of 4.0e14 M_sun, an Xray temperatureof 5.9 keV, and an Xray luminosity of 9.8e44 ergs/s. These properties wouldplace SPTCL J21094626 amongst the most massive known clusters at z > 1.4, andan important system to study the earliest forming massive clusters. We arerequesting a 60 ksec observation, enough to obtain 1500 Xray photons, measurean Xray luminosity and temperature, and to assess the dynamical state of this exceptional young cluster. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]