0 Assigned ID: 196 ----- Attempting Submission 1 (Thu Apr 04 15:12:45 GMT 2019) ----- HST Phase I Proposal 196 (Proposal.apt) successfully submitted. Receipt: # 196-1 ----- Attempting Submission 2 (Thu Apr 04 15:15:18 GMT 2019) ----- HST Phase I Proposal 196 (Proposal.apt) successfully submitted. Receipt: # 196-2 ----- Attempting Submission 3 (Thu Apr 04 15:15:55 GMT 2019) ----- HST Phase I Proposal 196 (Proposal.apt) successfully submitted. Receipt: # 196-3 ----- Attempting Submission 4 (Thu Apr 04 19:15:47 GMT 2019) ----- Request to repeat an observation due to HST safing. -578485558 ----- Attempting Submission 1 (Mon Jul 22 22:08:14 GMT 2019) ----- ----- Attempting Submission 2 (Fri Feb 28 04:42:42 GMT 2020) ----- I've ran the Orbit Planner and Visit Planner with no errors, but the APT won't allow me to submit. Since this is a resubmition, it should be ok. UV to NIR Study of the the First Robust Pulsational or Pair Instability Supernova and its Low Metallicity Environment SN2016iet is an unprecedented supernova in terms of its temporal evolution, spectra, and environment. The light curve exhibits two distinct peaks separated by 100 days, and slowly decline by only 5 mag in 2.5 years. The spectra are dominated by a blue continuum and low velocity calcium and oxygen lines with an unusually high Ca/O ratio, but lack hydrogen or helium. The SN is located at an unusually large offset (16 kpc, 5 effective radii) from a low metallicity dwarf galaxy (0.1 Zsun, 3e8 Msun). Modeling of the SN data indicates that it is powered by interaction of 20-85 Msun of ejecta with 35 Msun of H/He-free circumstellar material (CSM), ejected in the final decade before explosion. Thus, the progenitor's CO core shortly before explosion was 55-120 Msun, placing it in the regime of pulsational pair instability or pair instability explosions, further supported by the low metallicity. This is the first robust case for such an origin based directly on a large progenitor mass and low metallicity. We request observations of this unprecedented SN to achieve several goals that can only be done with HST: (i) track the SN emission at >1000 days post explosion, as it fades below ground-based capabilities, to track the large-scale CSM; (ii) use NIR data to search for the first time for evidence of dust formation in H/He-poor CSM interaction; (iii) measure the UV brightness of the host galaxy to precisely determine its star formation activity and escape fraction of ionizing radiation; and (iv) search for a potential underlying galaxy at the SN position, which from existing limits will be <1e-3 L*. This will be accomplished with 4 orbits in Cycle 27 and 3 orbits in Cycle 28. We request 4 orbits in Cycle 27 to observe SN2016iet at R.A.=12:32:33.23, decl.=+27:07:15.49 (J2000) to be observed during the early half of cycle 27, due to the fading nature of the source. The 4 orbits need not be done consequtively nor in a particular order, but they should be done within 30 days of each other. We split the 4 orbits into 2 distinct visits of 2 orbits each to aid the scheduler without increasing the overheads to much. One visit with WFC3/IR with one orbit dedicated to the F110W filter, and one orbit to the F160W filter. For the second visit one orbit should be done with ACS/WFC with the F625W filter, and a second orbit with WFC3/UVIS wit the F225W filter. For each orbit we request 4 individual exposures, dithered with a box pattern. Both visits should be scheduled within 30 days of each other, due to the fading nature of the supernova. This multi-cycle proposal has three additional orbits scheduled during Cycle 28 to obtain templates after the supernova has faded. We request these during the late half of Cycle 28. One ACS/WFC orbit with filter F625W, one WFC3/IR orbit with filter F110W, and one orbit with the F160W filter. Mr. Sebastian Gomez is a PhD student working on studies of exotic supernovae under the supervision of Dr. Edo Berger. The proposed observations will form an important part of his thesis work. Mr. Gomez has no prior HST proposals, but Co-I's Berger, Mr. Peter Blanchard, and Mr. Matt Nicholl have been PIs of over 10 HST programs, and have ample experience with HST data analysis (ACS, WFC3, COS, STIS). These prior HST programs specifically include studies of late-time emission of rare superluminous supernovae, with a similar observational setup to that proposed here. Mr. Gomez has broad experience with the analysis of ground-based optical/NIR data (Magellan, MMT, Gemini) and has recently submitted the discovery paper for SN2016iet -- the target proposed here. Mr. Gomez will lead all aspects of the project (data reduction, scientific analysis, publication of the results) and the co-Is will provide scientific and data analysis guidance on specific aspects (Villar: SN modeling, Patton: host galaxy models; Hosseinzadeh/Chornock: interpretation). Stellar Physics 6 false false false false false false false SUPPORTED STAR SUPERNOVA NO J2000 J2000 ACS/WFC Imaging No No F625W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F160W WFC3/UVIS Imaging No No F225W ACS/WFC Imaging No No F625W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F160W POS-TARG DITHER DITHER 4 23.02 WFC3-IR-DITHER-BOX-MIN 35.212 false 74.653 true 0.365 89.287 0.572 4 0.713 POS-TARG WFC3-IR-DITHER-BOX-UVIS 18.528 1 false POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 2 false POS-TARG DITHER 0.262 LINE 0.192 false false 68.14 4 18.39 ACS-WFC-DITHER-BOX 3 false Timing link suitability includes constraints ([Group (01 02) Within 30.0 days]) The scheduling data was generated by CASM 27.2. CASM was run in Phase II mode. 1575247539000 304.35216019201357 (Tic-Visit :proposal-id 15863 :visit-id "01" :proposal-version -1 :trans-version "20190514" :date "22-Jul-2019 12:54:59.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1114160 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15863 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15863 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2699 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15863 :visit-id "01" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2699 :al-overhead-at-end 0 :internal-dur-at-end 348 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) false 2 0 Timing link suitability includes constraints ([Group (01 02) Within 30.0 days]) The scheduling data was generated by CASM 27.2. CASM was run in Phase II mode. 1575418365000 303.3742764607385 (Tic-Visit :proposal-id 15863 :visit-id "02" :proposal-version -1 :trans-version "20190514" :date "18-Jul-2019 17:53:05.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15863 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 15863 :visit-id "02" :obset-id "A2" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15863 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2830 :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 3165 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15863 :visit-id "02" :orbit-number 2 :pcs-time 333 :si-vis-utilization 2830 :al-overhead-at-end 122 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) false 2 0 The scheduling data was generated by CASM 27.2. CASM was run in Phase II mode. 1586532160000 161.33343312522862 (Tic-Visit :proposal-id 15863 :visit-id "52" :proposal-version -1 :trans-version "20190514" :date "27-Feb-2020 23:41:54.0" :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 1154992 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15863 :visit-id "52" :obset-id "52" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15863 :visit-id "52" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2830 :al-overhead-at-end 122 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) true 1 0