We propose XMM-Newton+HST observations of the new, extremely X-ray luminous cluster ClGJ120959.0+495352 (z=0.90), discovered through our combined search of RASS and SDSS data. Optical and SZ data suggest that it is an excellent candidate for a very massive, dynamically relaxed cooling-core cluster, which are extremely rare at high z. The XMM-Newton data will provide the first resolved X-ray imaging of the system to confirm its dynamical state and constrain both the temperature profile and global cluster properties. The HST data will provide complementary constraints on the cluster mass and dynamical state from strong and weak lensing, enabling the comparison to scaling relations and the assessment if the cluster's discovery is in line with standard cosmological expectations. We propose to obtain a 2x2 ACS/F606W mosaic (same orientation) plus central WFC3/IR F105W+F140W observations for the cluster ClGJ120959.0+495352. In addition, parallel observations are obtained in the same instrument/filter configurations. The primary ACS tiles are split into 4 exposures each, accompanied by 2 WFC3/IR parallel exposures in F105W and F140W each. Here we employ a 3x enlarged version of the ACS-WFC-DITHER-BOX pattern, in order to optimize image quality both in the ACS and WFC3/IR frames. For the WFC3/IR primary observations, we employ a 3 position dither pattern which is large enough to dither over blobs. At each position one F105W and one F140W exposure is taken, as well as one ACS F606W parallel. We have manually entered all dithers as POS-TARGET, in order to enable modification of the exposure times and instrument configurations at each dither step. Low sky conditions are required for all exposures. COSMOLOGY Default false false false false false SUPPORTED CLUSTER OF GALAXIES GRAVITATIONAL LENS HIGH REDSHIFT CLUSTER J2000 J2000 ACS/WFC Imaging No No F606W WFC3/IR Imaging No No F105W WFC3/IR Imaging No No F140W Hst Same orient constraint links visits (01 02 03 04) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13493 :visit-id "01" :proposal-version -1 :trans-version "20130502" :date "26-Jun-2013 14:12:36.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 40.0 :data-volume 1955120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13493 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13493 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2622 :al-overhead-at-end 0 :internal-dur-at-end 1018 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3049 :pcs-gap 427 ) false 1 0 Hst Same orient constraint links visits (01 02 03 04) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13493 :visit-id "02" :proposal-version -1 :trans-version "20130502" :date "26-Jun-2013 14:12:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 40.0 :data-volume 1955120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13493 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13493 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2622 :al-overhead-at-end 0 :internal-dur-at-end 1018 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3049 :pcs-gap 427 ) false 1 0 Hst Same orient constraint links visits (01 02 03 04) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13493 :visit-id "03" :proposal-version -1 :trans-version "20130502" :date "26-Jun-2013 14:12:51.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 40.0 :data-volume 1955120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13493 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13493 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2622 :al-overhead-at-end 0 :internal-dur-at-end 1018 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3049 :pcs-gap 427 ) false 1 0 Hst Same orient constraint links visits (01 02 03 04) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13493 :visit-id "04" :proposal-version -1 :trans-version "20130502" :date "26-Jun-2013 14:12:57.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 40.0 :data-volume 1955120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13493 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13493 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2622 :al-overhead-at-end 0 :internal-dur-at-end 1018 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3049 :pcs-gap 427 ) false 1 0 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13493 :visit-id "05" :proposal-version -1 :trans-version "20130502" :date "26-Jun-2013 14:52:54.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 40.0 :data-volume 1984240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13493 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13493 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2622 :al-overhead-at-end 0 :internal-dur-at-end 1056 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "Y" :pcs-visibility 3049 :pcs-gap 427 ) true 1 0