14226( 2) - 13-Jul-2015 13:53:11 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14226 Version: 2 Check-in Time: 13-Jul-2015 13:53:11 STScI Edit Number: 0 Title Stellar Forensics VII: A post-explosion view of the progenitors of core-collapse supernovae ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Justyn Maund University of Sheffield Y CoI: Dr. John J. Eldridge The University of Auckland N CoI: Dr. Seppo Mattila University of Turku N CoI: Dr. Richard Stancliffe Universitat Bonn, Argelander Institute for N Astronomy CoI: Ms. Emma Reilly The Queen's University of Belfast 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 ACS WFC of the site of the core-collapse SN 2012ec. We aim to: 1) Confirm our original identification, made in pre-explosion HST images, by confirming that the progenitor is now missing; 2) Apply image subtraction techniques for this late-time imaging with our pre-explosion images to determine accurate photometry of the progenitor to constrain its temperature and luminosity; and 3) use the stellar population in the immediate vicinity of the SN to determine the reddening and extinction that affected the progenitor. HST provides the unique combination of high-resolution optical/IR imaging at very faint magnitudes that will facilitate this study. ------------------------------------------------------------------------------------ Observations Description ------------------------ We require deep three colour observations of the site of SN 2012ec in the galaxy NGC 1084. The observations will use the ACS WFC, with a 1kx1k subarray (to minimise overheads due to readout time). We will use the F475W, F606W and F814W filters. For each filter we will use a four point box dither pattern, to aid the removal of hot pixels and cosmic rays and to provide improved sampling of the PSF. The coordinates for the target, SN 2012ec, were retrieved from the CfA SN list (http://www.cbat.eps.harvard.edu/lists/Supernovae.html). These observations are intended to reach limiting magnitudes of m_F435W = 27, m_F555W = 27 and m_F814W = 26.5 at 3sigma. ------------------------------------------------------------------------------------ 14226( 2) - 13-Jul-2015 13:53:11 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN-2012EC EXT-STAR, K III-I, M RA=02H45M59.8800S, J2000 V = 27 III-I, STAR FORMING DEC=-07D34'27.00" REGION, SUPERNOVA, SUPERNOVA TYPE II Reference Frame: Other: SIMBAD Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 14226( 2) - 13-Jul-2015 13:53:11 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 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 ------------------------------------------------------------------------------------------------------------------------------------ 14226( 2) - 13-Jul-2015 13:53:11 - [ 4] Visit: 01 Visit Requirements: AFTER 01-MAR-2016:00:00:00 On Hold Comments: Additional Comments: There is no particular urgency for these observations, but the later they occur the better (so we have provided a suggested timing constraint of after 1st March 2016). Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN-2012EC ACS/WFC ACCUM WFC1-1K F475W 1 390 S PATTERN 1 1 (1560 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2012EC ACS/WFC ACCUM WFC1-1K F606W 1 235 S (940 PATTERN 1 2 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN-2012EC ACS/WFC ACCUM WFC1-1K F814W 1 432 S PATTERN 1 3 (1728 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2012EC 1 ACS/WFC ACCUM WFC1-1K F475W 1 none none none 1 N/A SN-2012EC 1 ACS/WFC ACCUM WFC1-1K F475W 2 none none none 1 N/A SN-2012EC 1 ACS/WFC ACCUM WFC1-1K F475W 3 none none none 1 N/A SN-2012EC 1 ACS/WFC ACCUM WFC1-1K F475W 4 none none none 1 N/A SN-2012EC 2 ACS/WFC ACCUM WFC1-1K F606W 1 none none none 1 N/A SN-2012EC 2 ACS/WFC ACCUM WFC1-1K F606W 2 none none none 1 N/A SN-2012EC 2 ACS/WFC ACCUM WFC1-1K F606W 3 none none none 2 N/A SN-2012EC 2 ACS/WFC ACCUM WFC1-1K F606W 4 none none none 2 N/A SN-2012EC 3 ACS/WFC ACCUM WFC1-1K F814W 1 none none none 2 N/A SN-2012EC 3 ACS/WFC ACCUM WFC1-1K F814W 2 none none none 2 N/A SN-2012EC 3 ACS/WFC ACCUM WFC1-1K F814W 3 none none none 2 N/A SN-2012EC 3 ACS/WFC ACCUM WFC1-1K F814W 4 none none none 2 N/A 14226( 2) - 13-Jul-2015 13:53:11 - [ 5] Summary Form for Proposal 14226 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1-1K ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01-MAR-2016:00:00:00, PATTERN 1 1, PATTERN 1 2, PATTERN 1 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W, F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN-2012EC ------------------------------------------------------------------------------------------------------------------------------------