0 Assigned ID: 935 ----- Attempting Submission 1 (Fri Mar 06 23:26:24 GMT 2020) ----- HST Phase I Proposal 935 successfully submitted. Receipt: # 935-1 ----- Attempting Submission 2 (Fri Mar 06 23:52:49 GMT 2020) ----- HST Phase I Proposal 935 successfully submitted. Receipt: # 935-2 ----- Attempting Submission 3 (Sat Mar 07 00:36:55 GMT 2020) ----- This target is not used in this proposal. If the target position is not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. If the target position is not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. INEFFICIENT ORDERING OF FP-POS POSITIONS Increase to acquisition exposures for the second epoch observations (03 and 04) to allow for potential fading of the source. 794362512 ----- Attempting Submission 1 (Mon Jun 29 12:40:33 GMT 2020) ----- ----- Attempting Submission 2 (Fri Feb 12 15:09:21 GMT 2021) ----- ----- Attempting Submission 3 (Fri Feb 12 17:37:20 GMT 2021) ----- ----- Attempting Submission 4 (Fri Feb 12 20:23:05 GMT 2021) ----- ----- Attempting Submission 5 (Mon Feb 15 18:02:00 GMT 2021) ----- The warnings are the same as for the previous submissions. HST Spectroscopy of a Fast-Rising Luminous Ultraviolet Transient The extremely luminous, fast, hot transient AT2018cow has provoked a reconsideration in our view of the transient sky. This event, by far the nearest example of the class of fast-rising luminous transients (sometimes referred to as FBOTs or FELTs), displayed an array of peculiar properties that highly strain theoretical models for what is possible in a supernova explosion. For all their peculiarities, however, fast-rising transients are not rare in a volumetric sense - and with ZTF and ATLAS both obtaining high-cadence observations of wide areas of the northern sky it is probable that another such event will be observed in the coming year. These are primarily ultraviolet phenomena, and UV spectroscopy has the power to reveal similarities or differences betwen this event and other known varieties of transient (including young CCSNe, superluminous SNe, and TDEs) that are not apparent in optical observations alone, and to discover (or rule out) the presence of a dense stellar wind around the progenitor. We propose to obtain target-of-opportunity UV spectroscopy of another event of this type in Cycle 28 to critically evaluate these links and secure the physical origins of this class while HST's unique UV spectroscopic resource is still available. This is a target of opportunity UV spectroscopy proposal that requires as fast turnaround as possible (but not an ultra-rapid response). Selection will be based on ground-based observations and we will supply a precise coordinate for the target as soon as possible. Observations will be requested in the COS/G140L and STIS/G230L grisms. Our nominal plan is to obtain two epochs separated by 1-2 week, although this may depend on the actual brightness and evolution of the target. Our group has extensive experience with ultraviolet spectroscopy and with fast optical transients. PI D. Perley, an assistant professor at LJMU, led an international collaboration to follow and has published a comprehensive paper on the early-through-late UVOIR observations of this object. Anna Ho, a graduate student at Caltech, led the long-wavelength follow-up and published a complementary paper on the X-ray, submillimeter and radio properties. Shri Kulkarni is a professor at Caltech and is an expert in transient astronomy and PI of the Zwicky Transient Facility. Lin Yan, Robert Quimby, and Ragnhild Lunnan are experts in superluminous supernovae (another class of hot, UV transient) and have published several papers on UV spectroscopy, and led previous HST ToO proposals on those events. Our team has proprietary access to ZTF, a fast-cadence wide-area optical survey that is well-suited to finding future examples of this class. We also have access to a variety of robotic follow-up resources to help rapidly confirm the fast-luminous nature of any candidate transient, including the Palomar 60-inch telescope and the Liverpool Telescope; plus target-of-opportunity programs on classical facilities such as Palomar and Keck. We are frequent users of Swift and have programs to study fast transients at other wavelengths, including the SMA and VLA. Stellar Physics and Stellar Types Supermassive Black Holes and Active Galaxies 6 false false true false false false false SUPPORTED EXT-STAR SUPERNOVA NO AT2021CSP J2000 u=17.5 EXT-STAR SUPERNOVA The target is unknown and will be discovered shortly before we request the observations. We will know the optical brightness and will have strong constraints (and by the time of observation, measurements) on the UV brightness as well. Our selection criteria are a fast rise (less than about 3 days from half-peak to peak), a high luminosity (M_UV ~< -20 in the UV), and a very high temperature (>15000 from UV/optical colors). A fast-rising, very luminous, hot thermal transient. COS/FUV Spectroscopic No No G140L 1280 STIS/NUV-MAMA Spectroscopic No No G230L 2376 Timing link suitability includes constraints ([03 After 01 by 8.0 to 16.0 days]) The scheduling data was generated by CASM 29.0. CASM was run in Phase II mode. Exposure times will need to be changed depending on the visibility duration of the actual target at the time of trigger. 1613677676000 279.85459700365055 (Tic-Visit :proposal-id 16212 :visit-id "01" :proposal-version -1 :trans-version "20200619" :date "12-Feb-2021 20:18:26.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 87360 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16212 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16212 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2750 :al-overhead-at-end 0 :internal-dur-at-end 38 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16212 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2751 :al-overhead-at-end 0 :internal-dur-at-end 331 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 2 0 Target of opportunity awaiting a suitable trigger from ZTF or another survey. The prototypical event of this class faded by 0.25 mag/day, so sooner is always better. A response slower than 4 days may be acceptable depending on the initial brightness of the event. This observation should take place as close in time as possible to the STIS observation. Timing link suitability includes constraints ([03 After 01 by 8.0 to 16.0 days]) The scheduling data was generated by CASM 29.0. CASM was run in Phase II mode. 1614181001000 277.3198126110268 (Tic-Visit :proposal-id 16212 :visit-id "03" :proposal-version -1 :trans-version "20200619" :date "15-Feb-2021 17:57:21.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 87360 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16212 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16212 :visit-id "03" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2750 :al-overhead-at-end 0 :internal-dur-at-end 38 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16212 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2751 :al-overhead-at-end 0 :internal-dur-at-end 331 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 2 0 Target of opportunity awaiting a suitable trigger from ZTF or another survey. This is a follow-up spectrum to be executed approximately 1-2 weeks after the first. Depending on the brightness and nature of evolution of the actual target we may wish to change the timescale. Timing link suitability includes constraints ([04 After 02 by 8.0 to 16.0 days]) The scheduling data was generated by CASM 29.0. CASM was run in Phase II mode. /private/var/folders/6l/d2vtb4894bs5t3xhhq13gv3h00023n/T/OPVisit8561194570137396799.xml Exposure times will need to be changed depending on the visibility duration of the actual target at the time of trigger. 1613649149000 282.9102456145947 (Tic-Visit :proposal-id 16212 :visit-id "02" :proposal-version -1 :trans-version "20200619" :date "16-Feb-2021 09:34:55.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 296128 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16212 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16212 :visit-id "02" :orbit-number 1 :pcs-time 301 :si-vis-utilization 2747 :al-overhead-at-end 0 :internal-dur-at-end 440 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 1 0 Target of opportunity awaiting a suitable trigger from ZTF or another survey. The prototypical event of this class faded by 0.25 mag/day, so sooner is always better. A response slower than 4 days may be acceptable depending on the initial brightness of the event. This observation should take place as close in time as possible to the COS observation. Timing link suitability includes constraints ([04 After 02 by 8.0 to 16.0 days]) The scheduling data was generated by CASM 29.0. CASM was run in Phase II mode. /private/var/folders/6l/d2vtb4894bs5t3xhhq13gv3h00023n/T/OPVisit7203332446495029145.xml (Tic-Visit :proposal-id 16212 :visit-id "04" :proposal-version -1 :trans-version "20200619" :date "16-Feb-2021 09:34:49.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 296128 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16212 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16212 :visit-id "04" :orbit-number 1 :pcs-time 301 :si-vis-utilization 2737 :al-overhead-at-end 0 :internal-dur-at-end 440 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3038 :pcs-gap 0 ) true 1 0 Target of opportunity awaiting a suitable trigger from ZTF or another survey. This is a follow-up spectrum to be executed approximately 1-2 weeks after the first. Depending on the brightness and nature of evolution of the actual target we may wish to change the timescale.