0 Assigned ID: 1464 ----- Attempting Submission 1 (Mon Apr 05 06:28:03 GMT 2021) ----- HST Phase I Proposal 1464 successfully submitted. Receipt: # 1464-1 ----- Attempting Submission 2 (Fri Apr 09 03:22:13 GMT 2021) ----- HST Phase I Proposal 1464 successfully submitted. Receipt: # 1464-2 ----- Attempting Submission 3 (Fri Apr 09 23:36:29 GMT 2021) ----- HST Phase I Proposal 1464 successfully submitted. Receipt: # 1464-3 This target is not used in this proposal. LONG STIS MAMA SU LIKELY TO INTERSECT THE SAA LONG STIS MAMA SU LIKELY TO INTERSECT THE SAA Made the following change: Edited the 5th orbit of the 2nd visit to remove the UV exposure and increase the G430L and G750L exposure times such that there is a 2-to-1 ratio in exposure time between them. -1765319385 ----- Attempting Submission 1 (Tue Jul 20 02:39:41 GMT 2021) ----- HST Phase II Proposal 16656 successfully submitted. Receipt: # 16656-1 ----- Attempting Submission 2 (Fri Nov 12 22:28:43 GMT 2021) ----- HST Phase II Proposal 16656 successfully submitted. Receipt: # 16656-2 ----- Attempting Submission 3 (Mon Jul 11 17:56:16 GMT 2022) ----- HST Phase II Proposal 16656 successfully submitted. Receipt: # 16656-3 ----- Attempting Submission 4 (Mon Jul 11 19:34:59 GMT 2022) ----- ----- Attempting Submission 6 (Thu Oct 06 21:28:59 GMT 2022) ----- HST Phase II Proposal 16656 successfully submitted. Receipt: # 16656-6 ----- Attempting Submission 7 (Fri Oct 07 13:51:30 GMT 2022) ----- HST Phase II Proposal 16656 successfully submitted. Receipt: # 16656-7 ----- Attempting Submission 8 (Sun Nov 27 23:47:53 GMT 2022) ----- We address the issue of exceeding the nominal limit of 5 orbits per visit in the Proposal Description section. We also note that in previous years this same observing startegy was approved. Last year our contact scientist wrote: "After speaking with the LRP it looks like this program will be fine as is. They are confident that they will be able to schedule your program". We propose to obtain a series of three early-time UV spectra of one stripped-envelope core-collapse supernova (either a normal SN Ib or a normal SN Ic, whichever type is not observed in an approved Cycle 28 program), starting well before maximum brightness. The underlying nature of these objects, from the mass-loss process stripping the envelope to the details of the explosion mechanism, remain mysterious. Connections to gamma-ray bursts and X-ray flashes further motivate this study. Many high-redshift SNe are being found in deep transient surveys, but the ability to distinguish between thermonuclear Type Ia SNe and stripped-envelope core-collapse SNe requires thorough knowledge of the latter at UV wavelengths with a low-z object. By comparing the evolution of the spectra as the photosphere recedes to deeper layers of the ejecta with our time series of spectral models, we will gain a better understanding of the explosion mechanism and the degree of mixing during the explosion. Moreover, we should be able to determine the metal content of the progenitor's outer layers with our spectral models and compare with the measured metallicity of the environment. The heterogeneity seen in stripped-envelope SNe compels us to choose a normal SN Ib or SN Ic, objects with DIFFERENT characteristics than the ones that HST has observed in previous Cycles (SNe Ic-pec, IIb, Ibn), thereby gaining further insights into this unique class of cosmic explosion. We need to seize this opportunity now, while we have access to the space UV, and indeed the UV is an HST Cycle 29 priority. Obtain STIS UV spectra of one bright (Vmax < 15.5 mag), nearby, stripped-envelope SN as soon as possible after discovery (preferably at t < -7 d, relative to maximum brightness), with subsequent spectra taken at intervals of 5 days, for a total of 3 epochs (6 + 5 + 6 = 17 orbits total). The cadence of the spectral observations is determined from the timescale over which significant changes are observed in ground-based optical/near-UV spectra. -------- Realtime Justification -------- This is a disruptive ToO observation of a single bright SN. However, it is not an ultra-rapid (< 2 day turnaround) ToO. We will work with STScI staff to expedite the observations, and we will try to choose an object that minimizes the time between ToO activation and observations. If we trigger 13-14 days before maximum brightness, and we have a turnaround time of 4-7 days, the first observation will commence about 10-5 days before maximum light. We will use both the STIS/CCD and MAMA detectors to provide full wavelength coverage. The CCD observations can be done during the final MAMA orbit of each epoch. The spectra of SNe change on a timescale of 1-2 days at these early phases, so we prefer that the whole spectrum be obtained in a single visit. Although visits of 6 orbits using STIS/MAMA are discouraged owing to the interfering effects of the SAA, we hope that it will be possible, as it has been in previous cycles for this program. However, if this request cannot be accommodated in Cycle 29, we request visits not more than about 1 day from each other. We understand that in Cycle 29, we are strongly encouraged to structure our observations into visits of only 1-3 orbits duration each. As noted above, we prefer durations of up to 6 orbits (6, 5, and 6 for Visits 1, 2, and 3, respectively -- separated by about 5 days) because of the temporal variability of the supernova spectrum. However, we will be fine with restructuring our program to give a combination of 2-orbit or 3-orbit visits (3+3 = 6 and 3+2 = 5; 2+2+2 = 6 would be less desirable but still doable), if those shorter "subvisits" are within 1 day of teach other. There will be a loss of S/N at a given epoch, but we could still average the UV MAMA data from two reasonably closely spaced epochs. The optical CCD spectra take just 1 orbit (or a fraction of an orbit), so we would be able to use the optical spectra directly with the corresponding UV spectra, with no mixing of dates. We have considered the impact of reduced gyro operations on our program. They will not significantly impact this program. We will need to choose a target that has a suitable observing window in the immediate future (since this is a disruptive ToO). The orientation of the field is not relevant, nor is the spatial scan speed. ------ Calibration Justification ------- Our SN, which is optically bright, will have ground-based astrometry with respect to HST guide stars accurate to better than 0.2''. Using the STIS Acquisition ETC we find acquisition times of less than 1 min for all epochs, for the 0.2'' slit. Previously, we have successfully acquired SNe with STIS in this manner. --------- Additional Comments ---------- This is a ToO proposal. We will update our Phase 2 with the supernova coordinates as they become available. In order to make sure there are no bright objects in the target vicinity and to estimate the target UV flux, we will obtain rapid-response Swift/UVOT observations, as we have done in the past for this program. PI Alex Filippenko led the highly successful Lick Observatory Supernova Search for more than 2 decades, has been studying images and spectra of supernovae (SNe) for more than 3 decades, and has led numerous HST studies of nearby SNe (including HST UV spectral studies similar to the one proposed here). Schuyler Van Dyk is an expert in HST photometry of SNe and in the study of stripped-envelope SNe. Yi Yang and Kishore Patra are experts in spectropolarimetry (complementary data that we plan to obtain with ground-based telescopes). Avishay Gal-Yam is the science lead of core-collapse SN studies with the 47 square degree, high-cadence (<1 day) Zwicky Transient Factory and is one of the primary sources of suitable targets. Assaf Horesh is in expert in radio observations of SNe and will provide complementary radio data. Paolo Mazzali is an expert at modeling the spectra of SNe through different depths in the ejecta; his models will be compared with the data. Similarly, Marc Williamson will perform abundance (composition) tomography of the supernova using the TARDIS Monte-Carlo-based radiation transport code. Tyler Pritchard examines the UV properties of stripped-envelope SNe to quantify the impact on cosmological studies. Sergiy Vasylyev is a graduate student at UC Berkeley who will work (under Filippenko's supervision) on the analysis of the HST and complementary spectra. Maryam Modjaz has long been a leader in determining the metallicities of the environments of core-collapse SNe through studies of H II regions, as well as in studying optical spectral sequences of SNe Ib/Ic. Tom Matheson is an expert in the spectroscopic properties of supernovae, especially stripped-envelope core-collapse SNe. Nathan Smith is an expert in the properties and evolution of massive stars, and on spectroscopy of SNe. Ori Fox studies dust, its formation in SN ejecta, and how it affects SN photometry, spectra, and interpretations. Tom Brink has much experience obtaining and reducing ground-based spectra, and complementary data of this type will be obtained for the program. WeiKang Zheng is an expert at CCD imaging and photometry of SNe, both ground-based and HST; he will construct multifilter light curves of the object. The above investigators have fruitfully worked together in the past and have many joint HST papers. Overall, members of the team have published more than 100 papers based at least in part on HST data. They have previously conducted studies of HST UV spectra of stripped-envelope SNe (specifically SNe Ic-pec, IIb, and Ibn). Stellar Physics and Stellar Types 6 false false true false false false false SUPPORTED EXT-STAR SUPERNOVA NO Currently V~16.1 (Oct. 4). J2000 EXT-STAR SUPERNOVA Pending identification of a type Ib or Ic supernova identified well before maximum brightness. A young stripped-envelope core collapse supernova with Vmax<15.5 mag STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 1665149451805 Timing link suitability includes constraints ([02 After 01 by 3.0 to 7.0 days]) The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1665569646000 101.59481895273689 (Tic-Visit :proposal-id 16656 :visit-id "01" :proposal-version -1 :trans-version "20220630" :date "07-Oct-2022 09:30:51.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 652256 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16656 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16656 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "01" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "01" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "01" :orbit-number 5 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "01" :orbit-number 6 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 660 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) true 6 0 Target of Opportunity Our SN, though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. 1669652023685 /private/var/folders/z3/xy_g1v_s5fz9yrhzb8thz4cr0001qc/T/OPVisit5746883645597996245.xml Timing link suitability includes constraints ([03 After 02 by 3.0 to 7.0 days]) The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16656 :visit-id "02" :proposal-version -1 :trans-version "20220630" :date "28-Nov-2022 11:13:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 495680 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16656 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16656 :visit-id "02" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "02" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "02" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :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 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "02" :orbit-number 5 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 601 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) true 5 0 Our SN, though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. 1669661489912 /private/var/folders/z3/xy_g1v_s5fz9yrhzb8thz4cr0001qc/T/OPVisit11693283850331397522.xml The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16656 :visit-id "22" :proposal-version -1 :trans-version "20220630" :date "28-Nov-2022 13:51:29.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 495680 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16656 :visit-id "22" :obset-id "22" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16656 :visit-id "22" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "22" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "22" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "22" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :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 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "22" :orbit-number 5 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 601 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) true 5 0 Our SN, though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100. 1665149556598 Timing link suitability includes constraints ([03 After 02 by 3.0 to 7.0 days]) The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1666421210000 89.69999999999999 (Tic-Visit :proposal-id 16656 :visit-id "03" :proposal-version -1 :trans-version "20220630" :date "07-Oct-2022 09:32:36.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 652256 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16656 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16656 :visit-id "03" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "03" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "03" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "03" :orbit-number 5 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 85 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16656 :visit-id "03" :orbit-number 6 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 660 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) true 6 0 Target of Opportunity Our SN, though UV-faint, will be optically bright. Using the STIS Acquisition ETC and the spectrum of PTF12gzk obtained in Cycle 20, we find that a 2s exposure yields a S/N > 100.