0 Assigned ID: 784 ----- Attempting Submission 1 (Fri Apr 11 20:40:13 GMT 2014) ----- 0 Understanding the In-Situ Star Formation in a z=1.7 Cluster Core Galaxy We have discovered a rare beast of a central galaxy within a z=1.7 rich galaxy cluster (estimated ~4x10^14 Msun), forming stars at a prodigious rate of 1200 Msun/yr. This system is infrared bright and its SED and the detection of PAHs at the cluster redshift, implies the IR luminosity is dominated by star formation. Such an extreme system has to date, only been confirmed in the z=0.6 Phoenix cluster (McDonald et al. 2012, 2013, 2014), whereas this object is observed at a much earlier and more active epoch of galaxy and cluster evolution. Here we propose deep HST imaging with WFC3 F160W/F105W to investigate the morphology of the BCG galaxy and its nearest neighbours. Our main goal is to understand the physical processes fuelling the intense starburst, be it a major merger or infalling gas from a cooling flow. We will also characterize the morphological properties (with color information) of the central BCG. These data will be the first of their kind at this redshift and will relate overall formation and evolution of the central galaxy massive parent halo at a cosmological epoch where these processes may begin to dominate. This phase II proposal outlines observations of one high redshift galaxy cluster, spectroscopically confirmed; specificially the central brightest galaxy which appears to have some unusual activity. The four total orbits of observation alloted to the proposal are split up into two visits each of two orbits. Each visit is characterized by a single spectral element used for all observations in the visit: F160W for visit 01 and F105W for visit 02. Each visit consists of eight total exposures which are alloted in the following manner Orbit 1 : direct(A1), offset, direct(B1), offset, direct(C1), offset, direct(D1) Orbit 2 : direct(A2), offset, direct(B2), offset, direct(C2), offset, direct(D2) where A*,B*,C*,D* are locations specified by the POS TARG keyword and that utilize a combination of interger and interger+1/2 pixel shifts. This is very similar to the strategy adopted in program 12590. The difference between A1 and A2 (B1 and B2 etc.) is a constant -1/4 pixel offset in both the X and Y directions, as specified by the POS TARG keyword, between orbit 1 and orbit 2. We utilize this dither stragetgy to 1) enable rejection of hot/bad pixels and 2) improve sampling of the PSF by using HST's ability to offset by 1/2 pixel and 1/4 pixel increments. Rather than adopt the standard WFC3-IR-DITHER-BOX pattern, which uses only 1-4 pixel offsets, we adopt our modified version to employ a slightly larger pattern to avoid bad pixels that come in clumps. This is similar to the strategy adopted in program 12177. We also set the dither pattern explicity using the POS TARG keyword rather than a preset dither pattern so that the dithers can be spread out over two full orbits and overheads associated with pointing maneuvers are reduced. The dither pattern is as follows: Orbit 1 POS TARG : (0,0) (1.355,0.424) (0.881,1.212) (-0.474,0.788) pixels : (0,0) (10.0,3.5) (6.5,10.0) (-3.5,6.5) Orbit 2 POS TARG : (-0.340,-0.030) (1.321,0.394) (0.847,1.182) (-0.508,0.758) pixels : (-0.25,-0.25) (9.75,3.25) (6.25,9.75) (-3.75,6.25) No attempt is made to dither over the "Death Star" as dithers larger than ~1.0" run the risk of introducing differential distortions. The same dither pattern is used for both visits to the target for the sake of uniformity. COSMOLOGY 12 Regular false false false false false SUPPORTED CLUSTER OF GALAXIES COOLING FLOW HIGH REDSHIFT CLUSTER INTERACTING GALAXY RICH CLUSTER J2000 J2000 WFC3/IR Imaging No No F105W WFC3/IR Imaging No No F160W Timing link suitability includes constraints ([02 After 01 by 35.0 to 39.0 days]) The scheduling data was generated by CASM 23.0. CASM was run in Phase II mode. 1423305826000 210.72631452973326 (Tic-Visit :proposal-id 13747 :visit-id "01" :proposal-version -1 :trans-version "20150128" :date "05-May-2015 15:23:24.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1577024 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13747 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13747 :visit-id "01" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2783 :al-overhead-at-end 122 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3024 :pcs-gap 0 ) true 1 0 POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. To move the inter-chip gap in the UV off of the center of the IR FOV, we would like a large y-offset with a maximum value such that the IR has full UVIS coverage. In order to find guide stars, however, we are free to move the x-offset. Timing link suitability includes constraints ([02 After 01 by 35.0 to 39.0 days] [03 After 02 by 35.0 to 39.0 days]) The scheduling data was generated by CASM 23.0. CASM was run in Phase II mode. 1426337679000 178.14896827840488 (Tic-Visit :proposal-id 13747 :visit-id "02" :proposal-version -1 :trans-version "20150128" :date "05-May-2015 15:23:20.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1577024 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13747 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13747 :visit-id "02" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2783 :al-overhead-at-end 122 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3024 :pcs-gap 0 ) true 1 0 POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. To move the inter-chip gap in the UV off of the center of the IR FOV, we would like a large y-offset with a maximum value such that the IR has full UVIS coverage. In order to find guide stars, however, we are free to move the x-offset. Timing link suitability includes constraints ([03 After 02 by 35.0 to 39.0 days] [04 After 03 by 35.0 to 39.0 days]) The scheduling data was generated by CASM 23.0. CASM was run in Phase II mode. 1429374484000 135.67714843975352 (Tic-Visit :proposal-id 13747 :visit-id "03" :proposal-version -1 :trans-version "20150128" :date "05-May-2015 15:20:58.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1577024 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13747 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13747 :visit-id "03" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2783 :al-overhead-at-end 122 :internal-dur-at-end 485 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3024 :pcs-gap 0 ) true 1 0 POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. To move the inter-chip gap in the UV off of the center of the IR FOV, we would like a large y-offset with a maximum value such that the IR has full UVIS coverage. In order to find guide stars, however, we are free to move the x-offset. Timing link suitability includes constraints ([04 After 03 by 35.0 to 39.0 days]) The scheduling data was generated by CASM 23.0. CASM was run in Phase II mode. /private/var/folders/8k/sxlgy5ts2xdbykzf_vw6jrfw0001c5/T/OPVisit9116078732248906301.xml (Tic-Visit :proposal-id 13747 :visit-id "04" :proposal-version -1 :trans-version "20150128" :date "06-May-2015 10:10:51.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1577024 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13747 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13747 :visit-id "04" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2781 :al-overhead-at-end 122 :internal-dur-at-end 485 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3024 :pcs-gap 0 ) true 1 0 POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. POS TARG set to minimize IR blob overlap, similar to the "E" patterns from the Dahlen 2010 dithering strategies ISR. To move the inter-chip gap in the UV off of the center of the IR FOV, we would like a large y-offset with a maximum value such that the IR has full UVIS coverage. In order to find guide stars, however, we are free to move the x-offset.