Scientific Category is a required field. Science Keywords: Select from 2 to 5 items. 0 Assigned ID: 1307 ----- Attempting Submission 1 (Tue Dec 29 14:41:44 GMT 2020) ----- joint nrao 0 ----- Attempting Submission 1 (Tue Feb 02 03:48:00 GMT 2021) ----- First Radio Observations of the Brightest Object at z > 5 A recently discovered z = 5.04 lensed galaxy, COOLJ1241+2219, has an AB magnitude z = 20.5, making it is the brightest known z > 5 galaxy at OIR wavelengths by a factor of five. It is lensed by a galaxy cluster with spectroscopic z = 1.002, and a preliminary lens model indicates that the mass of that cluster core is ~10^14 solar masses. The observed rest-wavelength UV of the lensed galaxy indicates formation of massive stars in the recent past, yet an upper limit of 2 mJy/beam at 314 GHz from the SMA indicates there is little dust in a warm neutral medium. It is not, therefore, one of the usual SMG detected by millimeter-wave and FIR surveys, it is something new: a galaxy in the early Universe where star formation is already in decline. We propose a first look of this source in the radio at the high end of the VLA Ka band, which includes the CO J=2-1 line, for three 4-hour sessions that should detect the galaxy's remaining star-forming molecular material. A three-orbit joint request to HST will provide data to refine the lens model and allow inversion of the lens to reconstruct the unlensed galaxy. The target is the brightest z>5 galaxy known. It is lensed by a foregound poor galaxy cluster at z=1, into a lensed arc. The lensing configuration suggest that a few tens of arcsecs around the lens center are of most interest, i.e. the target is extended but not large. There are no orient constraints. Observations are one orbit in ACS in F606W, one orbit in ACS with F814W, and one orbit WFC3-IR in F110W and F160W. For each ACS orbit we have programmed a simple 4-point dither sequence. Each exposure is 515 seconds, and the dither sequence is the standard ACS-WRFC-DITHER-BOX. No need to fill the chip gap, since the target fits readily on one chip. We have chosen the chip 2 potining aperture, because that seems to do a slightly better job of likely avoiding a star on the field edges that is in the FOV at some orients. For the WFC3-IR orbit, we want a minimum of 4 dithered images per filter. Going to more than 4 images with reasonably balanced exposure times seemed impossible due to buffer dump contraints; hence we have programmed 4 images per filter using the WFC3-IR-DITHER-BOX-MIN pattern. We will correct for the IR blobs using a model-based flatfielding technique that we have used previously on similar data. Buffer dump contraints limit choices here: we've pushed any extra time from a simple 50/50 split into the F160W filter (which is notionally a bit slower) and used SPARS25 readout in one instance and SPARS50 in the other. n/a 6 false false false false false false false SUPPORTED CLUSTER OF GALAXIES GRAVITATIONAL LENS HIGH REDSHIFT CLUSTER POOR CLUSTER J2000 J2000 WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F160W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 2 false POS-TARG DITHER 0.262 LINE 0.192 false false 68.14 4 18.39 ACS-WFC-DITHER-BOX 3 false /Users/gladders/OP-cache/phase2_z5-v01.xml The scheduling data was generated by CASM 29.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16484 :visit-id "01" :proposal-version -1 :trans-version "20200619" :date "01-Feb-2021 21:22:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1136896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16484 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16484 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2774 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3157 :pcs-gap 0 ) true 1 0 /Users/gladders/OP-cache/phase2_z5-v02.xml The scheduling data was generated by CASM 29.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16484 :visit-id "02" :proposal-version -1 :trans-version "20200619" :date "01-Feb-2021 21:22:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1136896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16484 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16484 :visit-id "02" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2774 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3157 :pcs-gap 0 ) true 1 0 /Users/gladders/OP-cache/phase2_z5-v03.xml The scheduling data was generated by CASM 29.0. CASM was run in Phase II mode. 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