Co-I affiliation updated 1130136243 Assigned ID: 1707 ----- Attempting Submission 1 (Thu Apr 08 20:44:33 GMT 2021) ----- HST Phase I Proposal 1707 successfully submitted. Receipt: # 1707-1 ----- Attempting Submission 2 (Fri Apr 09 04:47:03 GMT 2021) ----- HST Phase I Proposal 1707 successfully submitted. Receipt: # 1707-2 ----- Attempting Submission 3 (Fri Apr 09 15:05:02 GMT 2021) ----- HST Phase I Proposal 1707 successfully submitted. Receipt: # 1707-3 ----- Attempting Submission 4 (Fri Apr 09 17:50:50 GMT 2021) ----- HST Phase I Proposal 1707 successfully submitted. Receipt: # 1707-4 ----- Attempting Submission 5 (Fri Apr 09 18:01:52 GMT 2021) ----- This target is not used in this proposal. Updated timing constraints to hopefully improve schedulability while better implementing our preference for a long time baseline: 2: 60 – 300 days after epoch 1 3: 150 – 450 days after epoch 1 4: 300 – 750 days after epoch 1 -1722465357 ----- Attempting Submission 1 (Wed Jul 28 20:22:37 GMT 2021) ----- HST Phase II Proposal 16668 successfully submitted. Receipt: # 16668-1 ----- Attempting Submission 2 (Thu Jul 29 11:40:30 GMT 2021) ----- HST Phase II Proposal 16668 successfully submitted. Receipt: # 16668-2 ----- Attempting Submission 3 (Thu Jul 29 14:07:31 GMT 2021) ----- The primary target "Earendel" is included as Target 2 for visual confirmation that it will be well observed in all epochs. All pointings are centered on the galaxy cluster (Target 1). Monitoring Earendel, the Lensed z~6 Star Three strongly magnified individual stars have been discovered in z~1 galaxies thanks to temporary boosts from microlensing. All were discovered as transient events that have since faded. Now a more persistent and distant lensed star has been discovered at z~6, named "Earendel" ("morning light"). Its extremely high magnification has persisted for 3.5 years between HST observations, consistent with microlensing simulations of this object. But HST monitoring of the z~1 stars revealed things weren't always as they seemed. Here we propose the first repeat monitoring of Earendel in the same WFC3/IR filter, with 4 more epochs F110W imaging. These data will yield Earendel's baseline flux to better constrain its magnification, and thus luminosity and mass. Current HST data suggest it is likely very massive > 50 M_sun. And at z~6, it is likely low metallicity < 0.2 Z_sun. Very massive low metallicity stars are extremely rare in the local group and thus hard to study locally. Such stars are the likely progenitors of ~30 M_sun black holes measured by LIGO gravitational wave detections. But models of their evolutionary tracks are highly uncertain. Remarkably, this isolated z~6 star may offer the best opportunity to pinpoint the giant branch of a low metallicity massive star. Approved JWST GO observations will constrain the star's temperature, putting a z~6 star on the H-R diagram with a luminosity (and mass) precision significantly improved by this HST proposal. To support the various communities interested in these results, we waive any proprietary period to the data, in the same spirit as the previous HST observations and approved JWST observations of this exciting target. We will obtain 4 orbits of WFC3/IR F110W imaging of WHL0137-08, aligned with the previous HST imaging of that galaxy cluster core. We request 4 separate visits, each 1 orbit long, separated by 3 or more months. *** Longer time baselines are preferable: Visit #1 as early as possible in Cycle 29 and Visit #4 as late as needed to accommodate scheduling other programs. Within each orbit, we will obtain 4 images in a single filter, using small dithers to optimally sample the PSF and ultimately improve the spatial resolution of the stacked drizzled images. Between orbits / epochs, we will perform a larger dither (and/or different roll angle) to cover the WFC3/IR "death star" and other artifacts (IR blobs), as well as the ACS chip gap in parallel. Special Requirements: 1) 4 epochs (1 orbit per epoch), each 3 or more months apart (e.g., Oct, Feb, Jun, Sept.) 2) Low backgrounds when possible 3) Position Angle to overlap parallel imaging with existing HST imaging when possible We do not request mitigation of helium Earthshine, which is rare and not expected to impact a significant fraction of our data. We prefer to perform all dithers in the same orbit for optimal pixel sampling rather than splitting orbits to avoid helium. Co-I's include team members of the previous HST and upcoming JWST observing programs (PI Coe) of this target as well as the Earendel discovery paper (Welch et al., in prep.). Coe and Welch are Co-PIs of this proposal. * z ~ 1 lensed stars & microlensing: Pat Kelly, Jose Maria Diego, Steve Rodney * High-redshift galaxies: Dan Coe, Marusa Bradac, Victoria Strait, Larry Bradley, Jane Rigby, Masami Ouchi, Rogier Windhorst, Adi Zitrin, Brenda Frye, Erik Zackrisson, Anton Vikaeus * Lens modeling: Keren Sharon, Adi Zitrin, Guillaume Mahler, Ana Acebron, Brian Welch, Michael Florian, Masamune Oguri * Stellar evolution: Selma de Mink, Frank Timmes, Ebraheem Farag * ICL: Yoli Jimenez, Paola Dimauro * Supernovae: Steve Rodney, Lou Strolger, Kyle O'Connor * HST image reduction: Roberto Avila Stellar Physics and Stellar Types Galaxies 0 false false false false true false false false SUPPORTED CLUSTER OF GALAXIES GRAVITATIONAL LENS RICH CLUSTER YES WHL-J24.3324-8.477 J2000 J2000 STAR SUPERGIANT O NO Our primary target, included for visual confirmation that it will be well observed in all epochs. J2000 J2000 WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F110W ACS/WFC Imaging No No F435W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W Timing link suitability includes constraints ([22 After 11 by 60.0 to 300.0 days] [33 After 11 by 150.0 to 450.0 days] [44 After 11 by 300.0 to 750.0 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /Users/dcoe/MyProposals/HSTCycle29/Earendel/phase2/OP-cache/HST16668-v11.xml (Tic-Visit :proposal-id 16668 :visit-id "11" :proposal-version -1 :trans-version "20210514" :date "29-Jul-2021 07:33:23.0" :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 20.0 :data-volume 2129216 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16668 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16668 :visit-id "11" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2690 :al-overhead-at-end 0 :internal-dur-at-end 828 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([22 After 11 by 60.0 to 300.0 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /Users/dcoe/MyProposals/HSTCycle29/Earendel/phase2/OP-cache/HST16668-v22.xml (Tic-Visit :proposal-id 16668 :visit-id "22" :proposal-version -1 :trans-version "20210514" :date "29-Jul-2021 07:36:24.0" :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 20.0 :data-volume 2129216 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16668 :visit-id "22" :obset-id "22" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16668 :visit-id "22" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2690 :al-overhead-at-end 0 :internal-dur-at-end 828 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([33 After 11 by 150.0 to 450.0 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /Users/dcoe/MyProposals/HSTCycle29/Earendel/phase2/OP-cache/HST16668-v33.xml (Tic-Visit :proposal-id 16668 :visit-id "33" :proposal-version -1 :trans-version "20210514" :date "29-Jul-2021 07:36:31.0" :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 20.0 :data-volume 2129216 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16668 :visit-id "33" :obset-id "33" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16668 :visit-id "33" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2690 :al-overhead-at-end 0 :internal-dur-at-end 828 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([44 After 11 by 300.0 to 750.0 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /Users/dcoe/MyProposals/HSTCycle29/Earendel/phase2/OP-cache/HST16668-v44.xml (Tic-Visit :proposal-id 16668 :visit-id "44" :proposal-version -1 :trans-version "20210514" :date "29-Jul-2021 07:36:36.0" :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 20.0 :data-volume 2129216 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16668 :visit-id "44" :obset-id "44" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16668 :visit-id "44" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2690 :al-overhead-at-end 0 :internal-dur-at-end 828 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 1 0