0 Assigned ID: 5464 ----- Attempting Submission 1 (Tue Mar 26 16:10:15 GMT 2024) ----- HST Phase I Proposal 5464 successfully submitted. Receipt: # 5464-1 ----- Attempting Submission 2 (Tue Mar 26 16:17:43 GMT 2024) ----- HST Phase I Proposal 5464 successfully submitted. Receipt: # 5464-2 ----- Attempting Submission 3 (Tue Mar 26 18:00:55 GMT 2024) ----- HST Phase I Proposal 5464 successfully submitted. Receipt: # 5464-3 ----- Attempting Submission 4 (Tue Mar 26 21:03:07 GMT 2024) ----- Adjusted the exposure time in the different gratings in visits 1 and 2. The overall exposure time per orbit did not change. Updated ETC calculations 1176984820 ----- Attempting Submission 1 (Thu Aug 15 22:45:08 GMT 2024) ----- HST Phase II Proposal 17764 successfully submitted. Receipt: # 17764-1 ----- Attempting Submission 2 (Fri Aug 16 00:39:26 GMT 2024) ----- ----- Attempting Submission 3 (Thu Mar 27 00:47:05 GMT 2025) ----- ----- Attempting Submission 4 (Fri Aug 08 15:06:52 GMT 2025) ----- ----- Attempting Submission 5 (Fri Aug 08 21:00:07 GMT 2025) ----- These have all been run During the red supergiants phase, the progenitors of hydrogen-rich Type IIP/L supernovae undergo substantial mass loss. However, there is no first principle theory that predicts the mass-loss rate. Furthermore, prescriptions based on observations vary by orders of magnitude. Additionally, observations of supernovae during the early evolution, can show evidence of even higher mass-loss rates occurring just prior to explosion, although it is unknown what fraction of supernovae this occurs in. While optical spectra can detect the highest mass-loss rates via narrow high-ionization lines that disappear within 2 weeks of explosion, the ultraviolet is sensitive to the full range of possible mass loss, with the majority of strong resonance lines occurring in the far ultraviolet (FUV) as well as continuum emission from the ejecta's interaction with circumstellar material. In this way, FUV spectra can be used to characterize the density, location, and composition of the circumstellar material. Despite these strong indicators, only one Type IIP/L supernova has been observed in the FUV within a week of explosion. This is because only about one Type IIP/L supernova per year is discovered young, unextincted, and close enough for FUV study and these observations require a disruptive ToO to execute. We propose a disruptive ToO to obtain FUV and NUV observations of an infant, nearby, Type IIP/L supernova to understand the red supergiant mass loss and the diversity of supernovae in the UV. Beyond the local universe, these observations are critical for understanding the high redshift supernovae, which may be some of the first single objects observable in the early universe. We will trigger this ToO on a Type II supernova that is UV bright and discovered within 24 hours of explosion. We would like the First visit to execute as soon as possible with the second visit executing a day later and the third visit a day after that. The final visit will execute 7 days after the last visit. We request a full GS acquisition at the beginning of each orbit as the supernova will change on the timescale of a day and thus these observations are not repeatable. The Distance less than 40 Mpc team uses 0.4m prompt telescopes in Chile, Australia, and Canada to search for supernovae in galaxies within 40 Mpc with a 12 hour cadence at Dec <+20 and 24 hour cadence above. We routinely discover supernovae within 40 Mpc, averaging about 10 supernovae per year discovered within a day of explosion. We are also members of the Global Supernova Project which has access to robotic telescopes for imaging and spectroscopy around the world. Additionally, we have an active Swift GI program to observe supernovae with a 6 hour cadence. We recently discovered SN 2022acko and triggered an HST disruptive Target of Opportunity proposal, using the same trigger criteria described in this proposal. With the program we obtained and published the first early FUV observations of a Type II Supernova, with the first observation occurring 5 days after explosion. This proposal builds on our lessons learned from that process, adding the G430L grating and GS acquition for each orbit. K. A. Bostroem is a former member of the STIS team at STScI and has extensive experience with the STIS, Swift, Gemini, and Keck data reduction. Her research focuses on understanding the progenitors of hydrogen-rich CC SNe. She is the PI of programs to obtain HST/STIS UV data SN2022acko and SN2023ixf. M. Lundquist is an active member of the DLT40 team and specializes in the reduction and analysis of Gemini and Keck observations. He is currently a staff astronomer at the W. M. Keck Observatory. Prior to joining the DLT40 team, he worked as a Gemini Science Fellow at the Gemini Observatories. J. Andrews is an active member of the DLT40 team, has expertise observing with HST/STIS, and is an assistant astronomer at the Gemini Observatory. Her research focuses on characterizing the progenitors of core collapse (CC) SNe, specifically focusing on their mass-loss history via circumstellar interaction. D. Sand is the co-PI of the DLT40 survey and an expert in the progenitors of Type Ia SNe and SN environments. He has extensive experience with Swift, and Gemini observations of SNe and their environments. S. Valenti is the PI of our HST Cycle 28 and 29 program. He is the co-PI of DLT40. He has worked comprehensively on core collapse supernovae (CC SNe). M. Shrestha is a Postdoctoral Research Associate at the University of Arizona. Her research focuses on the transients such as long gamma-ray bursts, core collapse (CC) SNe, and kilonova. She is part of DLT40 and SAGUARO collaborations. J. Jencson is an active member of the DLT40 team and has extensive experience in reducing and analyzing Swift observations of transients. His research focuses on multi-wavelength studies of hydrogen-rich transients and searches for dust-obscured transients and faint/failed SNe. G. Hosseinzadeh is an expert in early SN~Ia light curves and has experience analyzing early UV data. J. Pearson is focusing her thesis research on understanding the progenitors and environments of CC SNe and is an active member of the DLT40 team. Y. Dong is an senior graduate student in the DLT40 team and has experience analyzing both CC~SNe and SN~I. N. Meza is a graduate student in the DLT40 team focusing his thesis work on CC~SNe. E. Hoang is a graduate student in the DLT40 team focusing on stripped-envelope SNe. D. Janzen is a member of the SkyNet team which is responsible for maintaining the telescopes that the DLT40 team uses for their search. S. Jha is an expert in Type Ia supernovae and the PI of a program on SALT to obtain spectra of supernova transients. SALT is ideally located for obtaining rapid classification spectra of supernovae discovered by our Australian telescope. A. P. Ravi is a postdoc in the DLT40 team and has expertise in high energy emission from supernovae. He leads the UC Davis NIR observing program. D. Mehta is a graduate student in the DLT40 team focusing on short plateau SNe. Stellar Physics and Stellar Types Stellar Populations and the Interstellar Medium 6 false true false false false false SUPPORTED EXT-STAR SUPERNOVA SUPERNOVA TYPE II NO J2000 J2000 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 1754686726757 /private/var/folders/6l/54htg8p52b762n_6mhsb13v80000gn/T/OPVisit10381363732542538628.xml Timing link suitability includes constraints ([02 After 01 by 0.7 to 1.2 days]) The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. Please put a full GS acq at the beginning of each orbit so if one orbit fails the others have a chance of succeeding. I can adjust the exposure times if needed First epoch should be executed as soon as possible after trigger For SN with initial brightness around r=17 mag (Tic-Visit :proposal-id 17764 :visit-id "01" :proposal-version -1 :trans-version "20250321" :date "08-Aug-2025 13:58:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 317456 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17764 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17764 :visit-id "01" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17764 :visit-id "01" :obset-id "B1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17764 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2489 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17764 :visit-id "01" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2489 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17764 :visit-id "01" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2475 :al-overhead-at-end 0 :internal-dur-at-end 360 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) true 3 0 Waiting for a suitable supernova to explode. I understand this response time is likely a lower limit on what STScI is capable of but the sooner the better for this program 1754686709151 /private/var/folders/6l/54htg8p52b762n_6mhsb13v80000gn/T/OPVisit4586368906862962870.xml Timing link suitability includes constraints ([02 After 01 by 0.7 to 1.2 days] [03 After 02 by 0.7 to 1.0 days]) The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. Please put a full GS acq at the beginning of each orbit so if one orbit fails the others have a chance of succeeding. I can adjust the exposure times if needed Second epoch should be executed 24 hours after first visit For SN with initial brightness around r=17 mag If possible execute at same orientation as visit 1 (Tic-Visit :proposal-id 17764 :visit-id "02" :proposal-version -1 :trans-version "20250321" :date "08-Aug-2025 13:58:28.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 317456 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17764 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17764 :visit-id "02" :obset-id "A2" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17764 :visit-id "02" :obset-id "B2" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17764 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2489 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17764 :visit-id "02" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2489 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17764 :visit-id "02" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2475 :al-overhead-at-end 0 :internal-dur-at-end 360 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) true 3 0 Waiting for a suitable supernova to explode. 1754665028739 Timing link suitability includes constraints ([03 After 02 by 0.7 to 1.0 days] [04 After 03 by 6.0 to 8.0 days]) The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. Please put a full GS acq at the beginning of each orbit so if one orbit fails the others have a chance of succeeding. I can adjust the exposure times if needed Third epoch should be executed 24 hours after second visit and 48 hours after first visit For SN with initial brightness around r=17 mag If possible execute at same orientation as visit 1 (Tic-Visit :proposal-id 17764 :visit-id "03" :proposal-version -1 :trans-version "20250321" :date "08-Aug-2025 07:57:08.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 230048 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17764 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17764 :visit-id "03" :obset-id "A3" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17764 :visit-id "03" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2477 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17764 :visit-id "03" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2363 :al-overhead-at-end 0 :internal-dur-at-end 360 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) true 2 0 Waiting for a suitable supernova to explode. 1754665029548 Timing link suitability includes constraints ([04 After 03 by 6.0 to 8.0 days]) The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. Please put a full GS acq at the beginning of each orbit so if one orbit fails the others have a chance of succeeding. I can adjust the exposure times if needed fourth epoch should be executed 7 days after third visit For SN with initial brightness around r=17 mag If possible execute at same orientation as visit 1 (Tic-Visit :proposal-id 17764 :visit-id "04" :proposal-version -1 :trans-version "20250321" :date "08-Aug-2025 07:57:09.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 525504 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17764 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17764 :visit-id "04" :obset-id "A4" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17764 :visit-id "04" :obset-id "B4" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17764 :visit-id "04" :obset-id "C4" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17764 :visit-id "04" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2489 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17764 :visit-id "04" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2528 :al-overhead-at-end 198 :internal-dur-at-end 319 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17764 :visit-id "04" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2528 :al-overhead-at-end 198 :internal-dur-at-end 319 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17764 :visit-id "04" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2591 :al-overhead-at-end 0 :internal-dur-at-end 360 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) true 4 0 Waiting for a suitable supernova to explode.