12262( 6) - 28-Mar-2011 11:17:03 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12262 Version: 6 Check-in Time: 28-Mar-2011 11:17:03 STScI Edit Number: 1 Title Stellar Forensics II: A post-explosion view of the progenitors of core-collapse supernovae ------------------------------------------------------------------------------------ Type Cycle GO 18 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Justyn R. Maund University of Copenhagen, Niels Bohr Institute CoI: Dr. Stephen J. Smartt The Queen's University of Belfast N CoI: Dr. Robert M. Crockett University of Oxford N CoI: Dr. John J. Eldridge University of Cambridge N CoI: Dr. Seppo Mattila University of Turku N CoI: Mr. Morgan Fraser The Queen's University of Belfast N CoI: Dr. Richard Stancliffe Monash University N ------------------------------------------------------------------------------------ Abstract Recent studies have used high spatial resolution HST observations of supernova (SN) sites to directly identify the progenitors of core-collapse SNe on pre-explosion images. These studies have set constraints about the nature of massive stars and their evolution just prior to their explosion as SNe. Now, at late-times when the SNe have faded sufficiently, it is possible to return to the sites of these core-collapse SNe to search for clues about the nature of their progenitors. We request time to conduct deep, late-time, high-resolution imaging with WFC3/UVIS+IR and ACS/WFC of the sites of three core-collapse SNe 2008ax, 2008bk and 2008cn. We aim to: 1) Confirm our original identifications, made in pre-explosion images, by confirming that the progenitors are now missing; 2) Apply image subtraction techniques for this late-time imaging with our pre-explosion images to determine accurate photometry of the progenitors to constrain their temperatures and luminosities; and 3) study the stellar populations in the immediate vicinities of these SNe, previously obscured by the progenitor and the SN, to provide a measure of the progenitor's age, as well. For SN 2008ax we aim to determine the possible presence of a binary companion, as a persistent source at the SN location once the SN has faded and the progenitor has disappeared. HST provides the unique combination of high-resolution optical/IR imaging at very faint magnitudes that will facilitate this study. ------------------------------------------------------------------------------------ Observations Description ------------------------ We require imaging of three SN sites with pre-explosion observations in which the progenitors were detected. We aim to confirm the progenitor identification, through the stars' disappearance - and accurately measure the progenitors' photometric properties using image subtraction techniques. Multi-colour imaging will be used to probe the nature of the surrounding stellar population. The bands in which the SN sites will be observed are dictated by the nature of the available pre-explosion imaging. The three SN sites to be observed are those of SN 2008ax (3 orbits), 2008bk (1 orbit), 2008cn (2 orbits). Each SN site is to be visited once. In order to 12262( 6) - 28-Mar-2011 11:17:03 - [ 2] improve the spatial sampling, and improve the resolution, all observations are grouped into box dither patterns. To minimize the amount of time lost to reading out the detectors, subarrays will be adopted SN2008ax - WFC3 UVIS 1kx1k - Visit 1 - 3 orbits U F336W to reach down to 26 @ 3sigma B F438W to reach down to 27 @ 3 sigma V F606W to reach down to 27@ 5 sigma R F625W to reach down to 26.5 @ 3 sigma I F814W to reach down to 26.5 @ 3sigma all exposures times have been selected to only saturate stars above the limit of X ~ 20 (in Vega mags) in all bands SN2008bk - WFC3 UVIS 1kx1k & IR 512x512 - Visit 2 - 1 orbit I F814W UVIS to reach down to I=26 at 3 sigma J F125W IR to reach down to J=24 at 5 sigma (3 iterations of 4x2xSPAR25 - i.e. 4x50s exposures) - with this observation we are balancing the need for depth, against the possibility of saturating on surrounding stars (which we would also like to observe, as well as to avoid persistance issues with the detector) - estimate that the saturation limit J=17 should be brighter than surrounding stars H 160W IR to reach down to H = 24 at 3 sigma - similar ot the J band obs, use 2 iterations of 4x4xSPAR25 to avoid saturating stars up to limit of H=16.5 512x512 subarray is required to avoid being penalised by readout time SN2008cn - ACS/WFC 1kx1k - Visit 3 - 2 orbits B F435W to reach down to 27.5 at 3sigma V F555W to reach down to 27.5 at 3sigma I F814W to reach down to 27 at 3sigma Again saturation limit is set for stars brighter than X ~ 20 (vega mags) Real Time Justification ----------------------- Further to our request in the Phase I proposal, we have requested that the SN2008cn observation (visit 3) be scheduled in the second half of Cycle 18 - i.e. after Feb 1st 2011 Calibration Justification ------------------------- No special calibrations are required Additional Comments ------------------- ------------------------------------------------------------------------------------ 12262( 6) - 28-Mar-2011 11:17:03 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2008AX EXT-STAR, SUPERNOVA RA=12H30M40.8000S +/- 0.1", J2000 V = 25 +/- 0.1 DEC=+41D38'14.50" +/- 0.1" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2008BK EXT-STAR, SUPERNOVA RA=23H57M50.4200S +/- 0.1", J2000 V = 20 +/- 0.5 DEC=-32D33'21.50" +/- 0.1" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2008CN EXT-STAR, SUPERNOVA RA=12H40M55.6600S +/- 0.1", J2000 V = 25 +/- 0.1 DEC=-40D58'12.10" +/- 0.1" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 12262( 6) - 28-Mar-2011 11:17:03 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.173 Line_Spacing 0.112 Coordinate_Frame POS-TARG Pattern_Orient 23.884 Angle_Between_Sides 81.785 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.265 Line_Spacing 0.187 Coordinate_Frame POS-TARG Pattern_Orient 20.67 Angle_Between_Sides 69.05 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 12262( 6) - 28-Mar-2011 11:17:03 - [ 5] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Visit for SN2008AX Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2008AX WFC3/UVI ACCUM UVIS2-C1K F336W 1 426 S PATTERN 1 1 S 1C-SUB ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2008AX WFC3/UVI ACCUM UVIS2-C1K F625W 1 252 S PATTERN 1 2 S 1C-SUB ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2008AX WFC3/UVI ACCUM UVIS2-C1K F438W 1 400 S PATTERN 1 3 S 1C-SUB see below ------------------------------------------------------------------------------------------------------------------------------------ 4 SN2008AX WFC3/UVI ACCUM UVIS2-C1K F606W 1 275 S PATTERN 1 4 S 1C-SUB see below ------------------------------------------------------------------------------------------------------------------------------------ 5 SN2008AX WFC3/UVI ACCUM UVIS2-C1K F814W 1 400 S PATTERN 1 5 S 1C-SUB see below ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SN2008AX 1 WFC3/UVI ACCUM UVIS2-C1 F336W 1 none none none 1 N/A S K1C-SUB SN2008AX 1 WFC3/UVI ACCUM UVIS2-C1 F336W 2 none none none 1 N/A S K1C-SUB SN2008AX 1 WFC3/UVI ACCUM UVIS2-C1 F336W 3 none none none 1 N/A S K1C-SUB SN2008AX 1 WFC3/UVI ACCUM UVIS2-C1 F336W 4 none none none 1 N/A S K1C-SUB SN2008AX 2 WFC3/UVI ACCUM UVIS2-C1 F625W 1 none none none 1 N/A S K1C-SUB SN2008AX 2 WFC3/UVI ACCUM UVIS2-C1 F625W 2 none none none 1 N/A S K1C-SUB SN2008AX 2 WFC3/UVI ACCUM UVIS2-C1 F625W 3 none none none 1 N/A S K1C-SUB SN2008AX 2 WFC3/UVI ACCUM UVIS2-C1 F625W 4 none none none 2 273.0 S S K1C-SUB SN2008AX 3 WFC3/UVI ACCUM UVIS2-C1 F438W 1 none none none 2 421.0 S S K1C-SUB SN2008AX 3 WFC3/UVI ACCUM UVIS2-C1 F438W 2 none none none 2 421.0 S S K1C-SUB 12262( 6) - 28-Mar-2011 11:17:03 - [ 6] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SN2008AX 3 WFC3/UVI ACCUM UVIS2-C1 F438W 3 none none none 2 421.0 S S K1C-SUB SN2008AX 3 WFC3/UVI ACCUM UVIS2-C1 F438W 4 none none none 2 421.0 S S K1C-SUB SN2008AX 4 WFC3/UVI ACCUM UVIS2-C1 F606W 1 none none none 2 296.0 S S K1C-SUB SN2008AX 4 WFC3/UVI ACCUM UVIS2-C1 F606W 2 none none none 2 296.0 S S K1C-SUB SN2008AX 4 WFC3/UVI ACCUM UVIS2-C1 F606W 3 none none none 3 359.0 S S K1C-SUB SN2008AX 4 WFC3/UVI ACCUM UVIS2-C1 F606W 4 none none none 3 359.0 S S K1C-SUB SN2008AX 5 WFC3/UVI ACCUM UVIS2-C1 F814W 1 none none none 3 484.0 S S K1C-SUB SN2008AX 5 WFC3/UVI ACCUM UVIS2-C1 F814W 2 none none none 3 484.0 S S K1C-SUB SN2008AX 5 WFC3/UVI ACCUM UVIS2-C1 F814W 3 none none none 3 484.0 S S K1C-SUB SN2008AX 5 WFC3/UVI ACCUM UVIS2-C1 F814W 4 none none none 3 484.0 S S K1C-SUB 12262( 6) - 28-Mar-2011 11:17:03 - [ 7] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Visit for SN2008BK Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2008BK WFC3/UVI ACCUM UVIS2-C1K F814W 1 225 S GS ACQ SCENARIO SINGLE; S 1C-SUB PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2008BK WFC3/IR MULTIAC IRSUB512 F160W NSAMP=10, SAMP-SEQ=SPARS25 1 DEF PATTERN 2 2 CUM ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2008BK WFC3/IR MULTIAC IRSUB512 F125W NSAMP=6, SAMP-SEQ=SPARS25 1 DEF PATTERN 2 3 CUM ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SN2008BK 1 WFC3/UVI ACCUM UVIS2-C1 F814W 1 none none none 1 N/A S K1C-SUB SN2008BK 1 WFC3/UVI ACCUM UVIS2-C1 F814W 2 none none none 1 240.0 S S K1C-SUB SN2008BK 1 WFC3/UVI ACCUM UVIS2-C1 F814W 3 none none none 1 N/A S K1C-SUB SN2008BK 1 WFC3/UVI ACCUM UVIS2-C1 F814W 4 none none none 1 N/A S K1C-SUB SN2008BK 2 WFC3/IR MULTIAC IRSUB512 F160W 1 none none none 1 N/A CUM SN2008BK 2 WFC3/IR MULTIAC IRSUB512 F160W 2 none none none 1 N/A CUM SN2008BK 2 WFC3/IR MULTIAC IRSUB512 F160W 3 none none none 1 N/A CUM SN2008BK 2 WFC3/IR MULTIAC IRSUB512 F160W 4 none none none 1 N/A CUM SN2008BK 3 WFC3/IR MULTIAC IRSUB512 F125W 1 none none none 1 N/A CUM SN2008BK 3 WFC3/IR MULTIAC IRSUB512 F125W 2 none none none 1 N/A CUM SN2008BK 3 WFC3/IR MULTIAC IRSUB512 F125W 3 none none none 1 N/A CUM SN2008BK 3 WFC3/IR MULTIAC IRSUB512 F125W 4 none none none 1 N/A CUM 12262( 6) - 28-Mar-2011 11:17:03 - [ 8] Visit: 03 Visit Requirements: AFTER 01-FEB-2011:00:00:00 On Hold Comments: Additional Comments: Visit for SN2008CN Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2008CN ACS/WFC ACCUM WFC1-1K F555W 1 425 S PATTERN 3 1 see below ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2008CN ACS/WFC ACCUM WFC1-1K F814W 1 375 S PATTERN 3 2 see below ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2008CN ACS/WFC ACCUM WFC1-1K F435W 1 250 S PATTERN 3 3 see below ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SN2008CN 1 ACS/WFC ACCUM WFC1-1K F555W 1 none none none 1 465.0 S SN2008CN 1 ACS/WFC ACCUM WFC1-1K F555W 2 none none none 1 465.0 S SN2008CN 1 ACS/WFC ACCUM WFC1-1K F555W 3 none none none 1 465.0 S SN2008CN 1 ACS/WFC ACCUM WFC1-1K F555W 4 none none none 1 465.0 S SN2008CN 2 ACS/WFC ACCUM WFC1-1K F814W 1 none none none 1 415.0 S SN2008CN 2 ACS/WFC ACCUM WFC1-1K F814W 2 none none none 2 390.0 S SN2008CN 2 ACS/WFC ACCUM WFC1-1K F814W 3 none none none 2 390.0 S SN2008CN 2 ACS/WFC ACCUM WFC1-1K F814W 4 none none none 2 390.0 S SN2008CN 3 ACS/WFC ACCUM WFC1-1K F435W 1 none none none 2 265.0 S SN2008CN 3 ACS/WFC ACCUM WFC1-1K F435W 2 none none none 2 265.0 S SN2008CN 3 ACS/WFC ACCUM WFC1-1K F435W 3 none none none 2 265.0 S SN2008CN 3 ACS/WFC ACCUM WFC1-1K F435W 4 none none none 2 265.0 S 12262( 6) - 28-Mar-2011 11:17:03 - [ 9] Summary Form for Proposal 12262 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IRSUB512, UVIS2-C1K1C-SUB, WFC1-1K ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=10, NSAMP=6, SAMP-SEQ=SPARS25 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01-FEB-2011:00:00:00, GS ACQ SCENARIO SINGLE, PATTERN 1 1, PATTERN 1 2, PATTERN 1 3, PATTERN 1 4, PATTERN 1 5, PATTERN 2 2, PATTERN 2 3, PATTERN 3 1, PATTERN 3 2, PATTERN 3 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F125W, F160W, F336W, F435W, F438W, F555W, F606W, F625W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN2008AX, SN2008BK, SN2008CN ------------------------------------------------------------------------------------------------------------------------------------