0 Assigned ID: 5590 ----- Attempting Submission 1 (Tue Mar 26 19:52:41 GMT 2024) ----- FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser 0 ----- Attempting Submission 1 (Thu Aug 15 19:33:17 GMT 2024) ----- HST Phase II Proposal 17738 successfully submitted. Receipt: # 17738-1 ----- Attempting Submission 2 (Tue Dec 17 20:59:51 GMT 2024) ----- ----- Attempting Submission 3 (Fri Feb 07 17:41:15 GMT 2025) ----- ----- Attempting Submission 5 (Tue Feb 11 21:37:17 GMT 2025) ----- ----- Attempting Submission 6 (Mon Aug 11 16:24:01 GMT 2025) ----- ----- Attempting Submission 7 (Fri Mar 20 19:03:08 GMT 2026) ----- Only change here is addition of new visit 9 - HOPR repeat of visit 3. Warnings for other visits were already there and are not an issue. Probing Magnetar Energy Input with the First Sample of Late-Time Superluminous Supernovae Since the discovery of hydrogen-poor superluminous supernovae (SLSNe) over a decade ago, research has focused on identifying the source of their enormous luminosities that can reach up to a hundred times brighter than normal supernovae. Early on, it was realized that the standard radioactive decay model that powers normal supernovae is unable to explain these events. Since then, light curve modeling of large samples, spectral modeling of both early and late-time nebular spectra, and analyses of their dwarf host galaxies have pointed towards a scenario in which the spin-down of a newly-formed magnetar central engine provides energy that is thermalized in the SN ejecta and radiated in the UV/optical. Perhaps the best evidence in favor of this model are the recent HST observations of two events at 400-1100 days after peak that match the power-law decline predicted by magnetar energy input. These observations strongly motivate new observations of a large and diverse sample to measure the distribution of power-law slopes and assess whether the diversity evident in the early light curves of SLSNe correlates with diversity at late times. We therefore propose to observe 8 new SLSNe each at three epochs spread accross Cycles 32, 33, and 34 (plus one template observation of an old event). As the late-time optical light curve is highly sensitive to the thermalization of the magnetar's energy, a key goal is to compare our observations with recent radiative transfer simulations to infer properties of the magnetar wind nebulae, the region where the magnetar's energy is transfered to the ejecta. This will be the most comprehensive test to date of the magnetar model for SLSNe. In Cycle 32 we will observe 9 superluminous supernovae one time each in a single filter, 8 with WFC3/UVIS and one with ACS/WFC. Each visit will consist of a dithered observation (standard ACS or WFC3 dither pattern) in one filter lasting one orbit. We will observe 8 of these supernovae two additional times, once in Cycle 33 and a final epoch in Cycle 34. Dr. Peter Blanchard is a research scientist working on observations of superluminous supernovae. Dr. Blanchard has extensive experience analyzing data from ACS/WFC, the instrument proposed for in this program, obtained through a previous HST program led by Dr. Blanchard. Dr. Blanchard has published five papers using HST and JWST data, including both archival and new observations led by Dr. Blanchard. Prof. Edo Berger is an expert on many types of transient phenomena including supernovae and gamma-ray bursts and has led several previous HST programs. Drs. Sebastian Gomez, Daichi Hiramatsu, and Harsh Kumar are supernova experts assisting with the ground-based observations of the proposed targets and have previously led HST programs. Stellar Physics and Stellar Types 6 false false false false false false false SUPPORTED EXT-STAR SUPERNOVA J2000 J2000 EXT-STAR SUPERNOVA J2000 J2000 EXT-STAR SUPERNOVA J2000 J2000 EXT-STAR SUPERNOVA J2000 J2000 EXT-STAR SUPERNOVA J2000 J2000 EXT-STAR SUPERNOVA J2000 J2000 EXT-STAR SUPERNOVA J2000 J2000 EXT-STAR SUPERNOVA J2000 J2000 ACS/WFC Imaging No No F625W ACS/WFC Imaging No No F625W ACS/WFC Imaging No No F850LP ACS/WFC Imaging No No F775W ACS/WFC Imaging No No F775W ACS/WFC Imaging No No F775W ACS/WFC Imaging No No F775W ACS/WFC Imaging No No F775W ACS/WFC Imaging No No F625W POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 2 false POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 3 false The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v01.xml (Tic-Visit :proposal-id 17991 :visit-id "01" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:58:16.0" :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 17991 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2593 :al-overhead-at-end 119 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2976 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v02.xml (Tic-Visit :proposal-id 17991 :visit-id "02" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:58:17.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17991 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2598 :al-overhead-at-end 119 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v03.xml 1769660234000 315.7512467654251 (Tic-Visit :proposal-id 17991 :visit-id "03" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:58:17.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17991 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "03" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2684 :al-overhead-at-end 123 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3064 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v04.xml (Tic-Visit :proposal-id 17991 :visit-id "04" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:58:17.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17991 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "04" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2592 :al-overhead-at-end 119 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2974 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v05.xml (Tic-Visit :proposal-id 17991 :visit-id "05" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:58:18.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17991 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "05" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2595 :al-overhead-at-end 119 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2977 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v06.xml (Tic-Visit :proposal-id 17991 :visit-id "06" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:58:18.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17991 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "06" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2598 :al-overhead-at-end 119 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v07.xml (Tic-Visit :proposal-id 17991 :visit-id "07" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:58:19.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17991 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "07" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2610 :al-overhead-at-end 119 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2992 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v08.xml (Tic-Visit :proposal-id 17991 :visit-id "08" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:58:19.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17991 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "08" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2595 :al-overhead-at-end 119 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2977 :pcs-gap 0 ) true 1 0 /Users/peterblanchard/Desktop/17991_updatedphase2/OP-cache/17991_updated-v09.xml The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17991 :visit-id "09" :proposal-version -1 :trans-version "20250929" :date "20-Mar-2026 14:57:59.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17991 :visit-id "09" :obset-id "09" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17991 :visit-id "09" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2684 :al-overhead-at-end 123 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3064 :pcs-gap 0 ) true 1 0