0 Assigned ID: 522 ----- Attempting Submission 1 (Fri Apr 11 15:17:43 GMT 2014) ----- 0 ----- Attempting Submission 1 (Thu Jul 03 18:00:16 GMT 2014) ----- ----- Attempting Submission 2 (Tue Nov 04 19:16:56 GMT 2014) ----- ----- Attempting Submission 3 (Tue Mar 31 17:53:15 GMT 2015) ----- The Stellar Origins of Supernovae Supernovae (SNe) have a profound effect on galaxies, and have been used as precise cosmological probes, resulting in the Nobel-distinguished discovery of the accelerating Universe. They are clearly very important events deserving of intense study. Yet, even with over 6300 IAU-designated SNe, we know relatively little about the stars which give rise to these powerful explosions. The main limitation has been the lack of spatial resolution in pre-SN imaging data. However, since 1999 our team has been at the vanguard of directly identifying SN progenitor stars in HST images. From this exciting line of study, the emerging trend from 9 detections for Type II-Plateau SNe is that their progenitors appear to be relatively low mass (8 to 20 Msun) red supergiants, although more cases are needed. Additionally, evidence is growing that the progenitors of Type II-narrow SNe may be related to luminous blue variables. However, the nature of the progenitors of Type Ib/c SNe, a subset of which are associated with the amazing gamma-ray bursts, remains ambiguous. Furthermore, we remain in the continually embarrassing situation that we still do not yet know which progenitor systems explode as Type Ia SNe, which are currently being used for precision cosmology. In Cycles 16, 17, and 20 we had great success with our approved ToO programs. As of this proposal deadline, we have had one trigger (SN 2014G) so far with our Cycle 21 program. We therefore propose to continue this project to determine the identities of the progenitors of 4 SNe within, generally, about 20 Mpc, which we expect to occur during Cycle 22, through ToO observations using WFC3/UVIS. We plan for four ToO triggers during Cycle 22. If we detect one or more candidate stellar objects within a 1-sigma positional uncertainty in ACS, WFPC2, or WFC3 pre-supernova archival image(s), we will request a trigger to pinpoint the location of the SN in the pre-SN images and attempt to confirm the progenitor candidate. Our plan is to image with WFC3/UVIS, to provide the highest possible spatial resolution. Our strategy, generally, is to acquire several short-exposure dithered images in V (F555W, 10-s) or I (F814W, 30-s), for the 3 core-collapse visits (which will likely best match with the available archival image data), and in U (F336W, 20-s) or B (F438W, 20-s) for a putative, nearby (<10 Mpc) SN Ia visit, since these SNe will likely be too bright in redder bands, but fade more rapidly in the blue. We will be using the UVIS2 1Kx1K subarray near amplifier C. Since the exposures are quite short, we will also be using post-flash with 12 e- for each exposure, in order to mitigate against CTE losses. The initial Phase II observations are meant to be representative of a typical trigger. Each of the four possible ToOs has an initial placeholder position of RA(J2000)=0, Dec(J2000)=0. We will likely request triggers when the SN is still fairly bright, depending on its age at discovery, but limit this, generally, to m >14 mag. We therefore may alter exposure times and bands, depending on the expected brightness of a given SN when it is scheduled and depending on the bands of the pre-SN images available for the SN site in the HST archive. This may also result in changes in the dither strategy for a given visit. The ToOs are not intended to be high-impact, and will be requested to occur after 2 to 3 weeks from discovery, so there should be no disruption of normal scheduling. RESOLVED STELLAR POPULATIONS 0 false false false false SUPPORTED STAR SUPERNOVA TYPE II J2000 J2000 STAR SUPERNOVA TYPE II J2000 J2000 STAR SUPERNOVA TYPE IB J2000 J2000 STAR SUPERNOVA TYPE IA J2000 J2000 B=16+/-0.5 WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F336W POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1 false The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13683 :visit-id "01" :proposal-version -1 :trans-version "20150609" :date "30-Sep-2015 12:18:18.0" :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 427792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13683 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13683 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2479 :al-overhead-at-end 83 :internal-dur-at-end 504 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13683 :visit-id "02" :proposal-version -1 :trans-version "20150609" :date "30-Sep-2015 12:18:21.0" :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 427792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13683 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13683 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2839 :al-overhead-at-end 83 :internal-dur-at-end 504 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. 1428889113000 283.4389850341564 (Tic-Visit :proposal-id 13683 :visit-id "03" :proposal-version -1 :trans-version "20150609" :date "30-Sep-2015 12:18:25.0" :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 427792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13683 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13683 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2479 :al-overhead-at-end 83 :internal-dur-at-end 504 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3556 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. 1416344246000 297.2731397002728 (Tic-Visit :proposal-id 13683 :visit-id "04" :proposal-version -1 :trans-version "20150609" :date "30-Sep-2015 12:18:28.0" :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 356496 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13683 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13683 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2251 :al-overhead-at-end 83 :internal-dur-at-end 426 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) true 1 0