12913( 2) - 09-Jul-2012 13:37:07 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12913 Version: 2 Check-in Time: 09-Jul-2012 13:37:07 STScI Edit Number: 0 Title The Peculiar Type Ia Supernova 2012Z: A Massive Star Progenitor? ------------------------------------------------------------------------------------ Type Cycle GO 20 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Saurabh W. Jha Rutgers the State University of New Jersey Y CoI: Mr. Curtis McCully Rutgers the State University of New Jersey N CoI: Dr. Ryan Foley Smithsonian Institution Astrophysical N Observatory CoI: Ms. Wen-fai Fong Harvard University N CoI: Prof. Robert P. Kirshner Harvard University N CoI: Dr. Howie Marion Harvard University N CoI: Dr. Adam Riess The Johns Hopkins University N ------------------------------------------------------------------------------------ Abstract Despite the tremendous importance of type Ia supernovae (SNe Ia), from their use as cosmological distance indicators to their contribution to the chemical enrichment of the Universe, we are still puzzled by the basic questions: what are their progenitor systems and how do they explode? Peculiar SNe Ia, objects that resemble normal SNe Ia spectroscopically, but lie off the one-parameter Phillips relationship the vast majority of SN Ia follow, play a useful role in answering these questions. By understanding what makes a small, but significant, fraction of SNe Ia different than their normal cousins, we may identify the key initial conditions and physical processes at work. Here we propose late-time HST WFC3/UVIS optical photometry of SN 2012Z, the most recent member of the peculiar SN 2002cx-like subclass of SNe Ia. We will compare our observations with extremely deep pre-explosion HST ACS images of the host galaxy NGC 1309, to test whether bright (M_I = -6) stars near the position of the SN are in fact coincident with it, testing a massive star progenitor hypothesis for this subclass of explosions, contrary to the most likely progenitor models for normal SNe Ia. We will also continue to follow the optical light curve of SN 2012Z to epochs later than any peculiar SNe Ia has been observed, in order to test signatures of explosion models for these objects. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose to obtain late-time optical WFC3/UVIS VrI photometry of SN 2012Z in NGC 1309 in two epochs, once during Cycle 20 (sometime approximately 400 to 600 days after SN maximum light), and again during Cycle 21 (sometime approximately 750 to 950 days past maximum). In the first epoch observations (between March and September 2013) we anticipate SN 2012Z will have V~22.3, r~22.5, and I~22.5, with an uncertainty of about 1 mag. To accurately measure the position of the SN, we require S/N >~ 20 in F555W, even in a pessimistic case (with the SN 1 mag below the prediction and near the end of the observing window). Based on the WFC3/UVIS exposure time calculator, and including overheads and two dithered exposures in each filter, 12913( 2) - 09-Jul-2012 13:37:07 - [ 2] our first epoch observations will fit comfortably within one orbit. The second epoch (Cycle 21) observations in 3 orbits will be submitted separately. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 12913( 2) - 09-Jul-2012 13:37:07 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN-2012Z EXT-STAR, SUPERNOVA RA=03H22M5.3500S +/- 0.1", J2000 V = 23 +/- 1 fading TYPE IA DEC=-15D23'15.60" +/- 0.1" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 12913( 2) - 09-Jul-2012 13:37:07 - [ 4] Visit: 01 Visit Requirements: SCHED 100%; BETWEEN 28-FEB-2013:23:59:59 AND 01-OCT-2013:00:00:01 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN-2012Z WFC3/UVI ACCUM UVIS2 F625W 1 281 S S ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2012Z WFC3/UVI ACCUM UVIS2 F814W 1 350 S S ------------------------------------------------------------------------------------------------------------------------------------ 3 SN-2012Z WFC3/UVI ACCUM UVIS2 F555W 1 350 S S ------------------------------------------------------------------------------------------------------------------------------------ 4 SN-2012Z WFC3/UVI ACCUM UVIS2 F555W 1 350 S POS TARG 0.099, 0.106 S ------------------------------------------------------------------------------------------------------------------------------------ 5 SN-2012Z WFC3/UVI ACCUM UVIS2 F814W 1 350 S POS TARG 0.099, 0.106 S ------------------------------------------------------------------------------------------------------------------------------------ 6 SN-2012Z WFC3/UVI ACCUM UVIS2 F625W 1 281 S POS TARG 0.099, 0.106 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-2012Z 1 WFC3/UVI ACCUM UVIS2 F625W none none none none 1 N/A S SN-2012Z 2 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S SN-2012Z 3 WFC3/UVI ACCUM UVIS2 F555W none none none none 1 N/A S SN-2012Z 4 WFC3/UVI ACCUM UVIS2 F555W none none none none 1 N/A S SN-2012Z 5 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S SN-2012Z 6 WFC3/UVI ACCUM UVIS2 F625W none none none none 1 N/A S 12913( 2) - 09-Jul-2012 13:37:07 - [ 5] Summary Form for Proposal 12913 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 28-FEB-2013:23:59:59 AND 01-OCT-2013:00:00:01, POS TARG 0.099, 0.106, SCHED 100% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W, F625W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN-2012Z ------------------------------------------------------------------------------------------------------------------------------------