Updated with Cycle 28 information. -950233203 Assigned ID: 146 ----- Attempting Submission 1 (Wed Mar 04 12:34:24 GMT 2020) ----- HST Phase I Proposal 146 successfully submitted. Receipt: # 146-1 ----- Attempting Submission 2 (Fri Mar 06 19:34:42 GMT 2020) ----- This target is not used in this proposal. Resubmission for HOPR 92522 for HST program 16189. Added ACQ between FUV and NUV orbits to alleviate tracking concerns over 5 orbit visit. Increaesed ACQ time from 3 to 10 seconds to account for fading source. Should be rescheduled in near future. Removed one orbit. 324665371 ----- Attempting Submission 1 (Tue Jun 30 12:55:56 GMT 2020) ----- ----- Attempting Submission 2 (Fri May 28 15:05:19 GMT 2021) ----- HST Phase II Proposal 16189 successfully submitted. Receipt: # 16189-2 ----- Attempting Submission 3 (Tue Jun 01 20:45:33 GMT 2021) ----- ----- Attempting Submission 4 (Thu Aug 19 19:19:05 GMT 2021) ----- ----- Attempting Submission 5 (Tue May 09 12:10:04 GMT 2023) ----- HST Phase II Proposal 16189 successfully submitted. Receipt: # 16189-5 ----- Attempting Submission 6 (Tue May 09 14:20:39 GMT 2023) ----- These are both ok, I think. Type Ia supernovae (SNe Ia) are well known for their use as precise cosmological distance indicators due to a standardizable peak luminosity resulting from a thermonuclear explosion. A growing subset of SNe Ia, however, show evidence for interaction with a dense circumstellar medium during the first year post-explosion, and sometimes longer (SNe Ia-CSM). The origin of this dense CSM is unknown and suggests either (a) the less typical single-degenerate progenitor scenario must be considered, or (b) the exploding star was not a thermonuclear explosion of a white dwarf at all (i.e., core collapse). The ultraviolet (UV) offers a unique opportunity to determine the true nature of the SNe Ia-CSM subclass. Unlike optical wavelengths, which can sometimes yield ambiguous classifications, the UV has distinguishing features due to its sensitivity to the composition of the optically thin ejecta that are illuminated by X-rays generated by shock interaction. Yet not a single UV spectrum exists for this subclass. Here we propose a non-disruptive ToO with HST/STIS to obtain 3 epochs (5 orbits each) of UV spectra of a SN Ia-CSM within 100 Mpc. This program will not only distinguish between the SN explosion mechanisms, but also trace CSM interaction, constrain the progenitor mass loss history, and identify late-time heating mechanisms of warm dust. Coinciding with Cycle 28's UV Initiative, this program offers new insights regarding both the progenitor and explosion characteristics of the SN Ia-CSM subclass. We propose to obtain 3 epochs (5 orbits each) of STIS-MAMA spectra of a single Type Ia-CSM supernova (SN Ia-CSM) within ~150 Mpc. The goal is to detect UV signatures that can distinguish between core-collapse and thermonuclear progenitor scenarios. These observations will also trace circumstellar interaction, constrain the progenitor mass loss, and identify late-time heating mechanisms for potential warm dust. The initial spectrum will be triggered as a non-disruptive ToO, *although observations should be scheduled as soon as possible*. Earlier observations will be more sensitive to the key UV iron-group features of thermnuclear explosions. As the SN evolves, reprocessed X-rays from shock interaction will illuminate the ejecta, reaching deeper layers as the ejecta expand. The second epoch should therefore be obtained ~2 months following the first epoch. The third epoch should be scheduled ~9 months after the first epoch. Each epoch will include observations in both the G140 and G230L bandpasses. We choose STIS over COS for several reasons. Most importantly, STIS offers spatially resolved spectra that exploit the intrinsically high resolution of HST over a large spectral range (accommodating both the C III] 1909 Ang and Mg II 2800 Ang lines). The long slit length will allow us to subtract contamination from zodiacal light, earthshine, the host galaxy, and H II regions. STIS also has superior sensitivity to COS in the NUV. While COS is optimized for isolated, faint point sources in the FUV with medium resolution, we would suffer from less wavelength coverage and require more integrations. We would also lose the advantages of the slit described above. *Impact of Gyros* This is a ToO. We have considered the impact of reduced gyro operations on our program. We will start with the assumption that gyro operations will be normal; our durations in this case should be 5, 5, and 5 orbits for Visits 1, 2, and 3 (respectively). Each visit requires 5 orbits because all exposures must be obtained at the same time given the rapid evolution of the SN light-curve. If the trigger occurs, or visits are scheduled, following the loss of a gyro and shorter visits are necessary, we will likely be able to restructure our visits with 3 FUV exposues and 2 NUV exposures. However, given the time sensitivity of the obsevations (the FUV and NUV must be taken at similar epochs), the first two visits cannot be separated by more than a few days. PI Dr. Ori Fox is an expert in SNe with shock interaction and has studied SNe Ia-CSM. He was the first author of Fox et al. (2015), which studies the Type Ia-CSM SNe 2012ca and 2013dn. He has worked extensively with HST UV data. A COS UV spectrum of SN 1993J resulted in Fox et al. (2014), a popular paper that detected the first surviving companion to a SN progenitor. He has also successfully obtained STIS spectra of two SNe IIn (2005ip and 2010jl). This work has resulted in a paper that is very near to submission to ApJ. For observations, data reduction, and analysis: Ms. K. Azalee Bostroem is an expert on HST UV data, as she used to work at STScI as a Research Instrument Analyst and was a critical part of the 1993J paper above (Fox et al. 2014). Professor Alex Filippenko has approved time on Keck and Lick that can provide for any necessary supporting ground-based observations. Professor Ryan Foley is an expert on SNe, specifically the Type Ia subclass, and an expert HST user. Dr. Melissa Graham is an expert on SNe Ia with significant experience in the UV. Professor Pat Kelly has long studied the properties of host galaxies of SNe. Dr. Jon Mauerhan is an expert on spectropolarimetry (completementary data that we plan to obtain with ground-based telescopes) and has much experience regarding the properties of massive stars. Dr. Francesco Taddia is an expert in SNe Ia-CSM studies. Stellar Physics and Stellar Types 6 false false true false false false false false SUPPORTED EXT-STAR SUPERNOVA SUPERNOVA TYPE IA NO EXT-STAR F0-F2 NO http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-info=XML&-out.add=.&-source=I/352/gedr3dis&-c=235.79967456886%2B17.81655760935&-c.rs=0.5 -3.155767575385198 mas/yr RA -5.888742957243794 mas/yr DEC J2000 Expected maximum local count rate of 10.4 counts/s/pixel (at 2900 Ang) and a global rate of 6200 counts/s, both of which are significantly below the STIS/MAMA limits given in Table 7.8 of the STIS Handbook. We find that we will be safe for an event like SN 1998S to within 7 Mpc, which we don't anticipate being a problem. Such a nearby and bright SN Ia-CSM should occur once every few decades, and in this rare (and exciting!) case, we would request a change to STIS/CCD+G230L. Type Ia-CSM within 150 Mpc STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/NUV-MAMA Spectroscopic No No G230L 2376 1683634004117 The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. /Users/ofox/Work/proposals/hubble/Cycle28/Ia-CSM2_16189/OP-cache/hopr_3-v01.xml Likely to acquire on bright SN. 1623771974000 145.28186846364127 (Tic-Visit :proposal-id 16189 :visit-id "01" :proposal-version -1 :trans-version "20230418" :date "09-May-2023 08:06:43.0" :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 1078880 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16189 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16189 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "01" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 2231 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "01" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 339 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "01" :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 Target-of-Opportunity. The initial spectrum will be triggered as a non-disruptive ToO, *although observations should be scheduled as soon as possible*. Used sn2008j-20080216.205-ui.flm (day 32 spectrum) normalized to V=16. SN should be bright during initial acquisition. Latest ETC calculation here: STIS.ta.1518260 Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). The FUV/G140L is plagued by varying geo-coronal emission as HST orbits. The downside to this is that the varying Ly/alpha could affect the nearby Oxygen (1300 Ang), which would be a very useful discriminator in the case of a core-collapse event (see original proposal). To monitor the geo-coronal emission at a resolution < 1 orbit, the contact scientist recommended that we utilize the time-tag exposures with a buffer readout time of t_orbit/2 = 3000/2 = 1500. So if you set the buffer time for G140L time-tag to 300 s, that would accommodate global rates of up to about 6600 c/s while keeping the total number of buffer dumps near the limit of 30 dumps/visit that we prefer to keep to. Perhaps that represents a reasonable compromise between doing an excessive number of buffer dumps and still covering yourself at higher count rates? In the unlikely event the target came out brighter than this, you'd probably have to modify the G230L observation anyway so you could change the G140L back to ACCUM mode at the same time. The main down side of TIME-TAG vs ACCUM is that with TIME-TAG you're effectively limited to global rates (source + detector background) of under about 20,000 c/s, and you need to set a reasonable upper limit to the expected count rate to be able to estimate the needed buffer time. So for a very bright target, you might have to switch back to ACCUM observations. See section 11.1.3 of the STIS IHB for additional details about TIME-TAG mode. Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). 1683634005977 The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. /Users/ofox/Work/proposals/hubble/Cycle28/Ia-CSM2_16189/OP-cache/hopr_3-vZ2.xml Likely to acquire on bright SN. 1681472773000 250.0 (Tic-Visit :proposal-id 16189 :visit-id "Z2" :proposal-version -1 :trans-version "20230418" :date "09-May-2023 08:06:45.0" :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 1078880 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16189 :visit-id "Z2" :obset-id "Z2" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16189 :visit-id "Z2" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z2" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z2" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 2231 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z2" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 339 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z2" :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 Target-of-Opportunity. The initial spectrum will be triggered as a non-disruptive ToO, *although observations should be scheduled as soon as possible*. Used sn2008j-20080216.205-ui.flm (day 32 spectrum) normalized to V=16. SN should be bright during initial acquisition. Latest ETC calculation here: STIS.ta.1518260 Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). The FUV/G140L is plagued by varying geo-coronal emission as HST orbits. The downside to this is that the varying Ly/alpha could affect the nearby Oxygen (1300 Ang), which would be a very useful discriminator in the case of a core-collapse event (see original proposal). To monitor the geo-coronal emission at a resolution < 1 orbit, the contact scientist recommended that we utilize the time-tag exposures with a buffer readout time of t_orbit/2 = 3000/2 = 1500. So if you set the buffer time for G140L time-tag to 300 s, that would accommodate global rates of up to about 6600 c/s while keeping the total number of buffer dumps near the limit of 30 dumps/visit that we prefer to keep to. Perhaps that represents a reasonable compromise between doing an excessive number of buffer dumps and still covering yourself at higher count rates? In the unlikely event the target came out brighter than this, you'd probably have to modify the G230L observation anyway so you could change the G140L back to ACCUM mode at the same time. The main down side of TIME-TAG vs ACCUM is that with TIME-TAG you're effectively limited to global rates (source + detector background) of under about 20,000 c/s, and you need to set a reasonable upper limit to the expected count rate to be able to estimate the needed buffer time. So for a very bright target, you might have to switch back to ACCUM observations. See section 11.1.3 of the STIS IHB for additional details about TIME-TAG mode. Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). 1683642019269 The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. /private/var/folders/yh/kl4y3s1x3_j3ywy3qq67g3vc0001kc/T/OPVisit17675028448378136068.xml Likely to acquire on bright SN. (Tic-Visit :proposal-id 16189 :visit-id "Z3" :proposal-version -1 :trans-version "20230418" :date "09-May-2023 10:20:18.0" :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 835744 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16189 :visit-id "Z3" :obset-id "Z3" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16189 :visit-id "Z3" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z3" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 306 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z3" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z3" :orbit-number 4 :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 4 0 Target-of-Opportunity. The initial spectrum will be triggered as a non-disruptive ToO, *although observations should be scheduled as soon as possible*. Used sn2008j-20080216.205-ui.flm (day 32 spectrum) normalized to V=16. SN should be bright during initial acquisition. Latest ETC calculation here: STIS.ta.1518260 Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). The FUV/G140L is plagued by varying geo-coronal emission as HST orbits. The downside to this is that the varying Ly/alpha could affect the nearby Oxygen (1300 Ang), which would be a very useful discriminator in the case of a core-collapse event (see original proposal). To monitor the geo-coronal emission at a resolution < 1 orbit, the contact scientist recommended that we utilize the time-tag exposures with a buffer readout time of t_orbit/2 = 3000/2 = 1500. So if you set the buffer time for G140L time-tag to 300 s, that would accommodate global rates of up to about 6600 c/s while keeping the total number of buffer dumps near the limit of 30 dumps/visit that we prefer to keep to. Perhaps that represents a reasonable compromise between doing an excessive number of buffer dumps and still covering yourself at higher count rates? In the unlikely event the target came out brighter than this, you'd probably have to modify the G230L observation anyway so you could change the G140L back to ACCUM mode at the same time. The main down side of TIME-TAG vs ACCUM is that with TIME-TAG you're effectively limited to global rates (source + detector background) of under about 20,000 c/s, and you need to set a reasonable upper limit to the expected count rate to be able to estimate the needed buffer time. So for a very bright target, you might have to switch back to ACCUM observations. See section 11.1.3 of the STIS IHB for additional details about TIME-TAG mode. Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Used sn2008j-20080216.205-ui.flm (day 32 spectrum) normalized to V=16. SN should be bright during initial acquisition. Latest ETC calculation here: STIS.ta.1518260 1683633440374 Timing link suitability includes constraints ([03 After 02 by 200.0 to 240.0 days] [02 After Z1 by 50.0 to 80.0 days]) The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. /Users/ofox/Work/proposals/hubble/Cycle28/Ia-CSM2_16189/OP-cache/hopr_3-v02.xml Likely to acquire on bright SN. 1631646669000 84.58221340604558 (Tic-Visit :proposal-id 16189 :visit-id "02" :proposal-version -1 :trans-version "20230418" :date "09-May-2023 07:57:19.0" :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 992288 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16189 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16189 :visit-id "02" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "02" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 306 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "02" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "02" :orbit-number 5 :pcs-time 392 :si-vis-utilization 2741 :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 Target-of-Opportunity. The initial spectrum will be triggered as a non-disruptive ToO, *although observations should be scheduled as soon as possible*. Used sn2008j-20080216.205-ui.flm (day 32 spectrum) normalized to V=16. SN should be bright during initial acquisition. Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Used sn2008j-20080216.205-ui.flm (day 32 spectrum) normalized to V=16. SN should be bright during initial acquisition. 1683634008024 Timing link suitability includes constraints ([03 After 02 by 200.0 to 240.0 days]) The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. /Users/ofox/Work/proposals/hubble/Cycle28/Ia-CSM2_16189/OP-cache/hopr_3-v03.xml Likely to acquire on bright SN. 1649160084000 240.0 (Tic-Visit :proposal-id 16189 :visit-id "03" :proposal-version -1 :trans-version "20230418" :date "09-May-2023 08:06:47.0" :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 1078880 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16189 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16189 :visit-id "03" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "03" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 2231 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "03" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 339 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "03" :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 Target-of-Opportunity. The initial spectrum will be triggered as a non-disruptive ToO, *although observations should be scheduled as soon as possible*. Used sn2008j-20080216.205-ui.flm (day 32 spectrum) normalized to V=16. SN should be bright during initial acquisition. Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). 1683634009966 Timing link suitability includes constraints ([02 After Z1 by 50.0 to 80.0 days]) The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. /Users/ofox/Work/proposals/hubble/Cycle28/Ia-CSM2_16189/OP-cache/hopr_3-vZ1.xml Likely to acquire on bright SN. 1627325922000 101.0 (Tic-Visit :proposal-id 16189 :visit-id "Z1" :proposal-version -1 :trans-version "20230418" :date "09-May-2023 08:06:49.0" :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 1078880 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16189 :visit-id "Z1" :obset-id "Z1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16189 :visit-id "Z1" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2763 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z1" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z1" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 2231 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z1" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2764 :al-overhead-at-end 0 :internal-dur-at-end 339 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3156 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16189 :visit-id "Z1" :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 Target-of-Opportunity. The initial spectrum will be triggered as a non-disruptive ToO, *although observations should be scheduled as soon as possible*. Used sn2008j-20080216.205-ui.flm (day 32 spectrum) normalized to V=16. SN should be bright during initial acquisition. Latest ETC calculation here: STIS.ta.1518260 Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). The FUV/G140L is plagued by varying geo-coronal emission as HST orbits. The downside to this is that the varying Ly/alpha could affect the nearby Oxygen (1300 Ang), which would be a very useful discriminator in the case of a core-collapse event (see original proposal). To monitor the geo-coronal emission at a resolution < 1 orbit, the contact scientist recommended that we utilize the time-tag exposures with a buffer readout time of t_orbit/2 = 3000/2 = 1500. So if you set the buffer time for G140L time-tag to 300 s, that would accommodate global rates of up to about 6600 c/s while keeping the total number of buffer dumps near the limit of 30 dumps/visit that we prefer to keep to. Perhaps that represents a reasonable compromise between doing an excessive number of buffer dumps and still covering yourself at higher count rates? In the unlikely event the target came out brighter than this, you'd probably have to modify the G230L observation anyway so you could change the G140L back to ACCUM mode at the same time. The main down side of TIME-TAG vs ACCUM is that with TIME-TAG you're effectively limited to global rates (source + detector background) of under about 20,000 c/s, and you need to set a reasonable upper limit to the expected count rate to be able to estimate the needed buffer time. So for a very bright target, you might have to switch back to ACCUM observations. See section 11.1.3 of the STIS IHB for additional details about TIME-TAG mode. Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits). Assuming 98S-like spectrum on day 14 (sn1998s-19980316.000-hst.fits).