15415( 5) - 08-Dec-2017 19:35:28 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15415 Version: 5 Check-in Time: 08-Dec-2017 19:35:28 STScI Edit Number: 0 Title One last peek at SN 2015F ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Or Graur Harvard University Y CoI: Dr. Adam Riess The Johns Hopkins University N CoI: Dr. Armin Rest Space Telescope Science Institute N CoI: Dr. Ivo Seitenzahl Australian National University N CoI: Prof. Benjamin John Shappee University of Hawaii N CoI: Dr. Michael Shara American Museum of Natural History N CoI: Dr. David R. Zurek American Museum of Natural History N CoI: Dr. Daniel J. Eisenstein Harvard University N ------------------------------------------------------------------------------------ Abstract As part of GO-14611, we have been observing the fading light curve of the Type Ia supernova (SN Ia) SN 2015F out to 920 days past maximum light. Following similar late-time observations of other SNe Ia, we expected the light curve of this SN to begin to decline at a slower rate as light from the long-lived 57Co decay chain begins to add a measurable boost to the light from the radioactive decay of 56Co. We have one last visit to this SN, on 29 Sep. 2017, but the data have already been surprising. The observations so far are still consistent with both scenarios: 56Co decay alone, as well as a combination of 56Co and 57Co decays. Either the light curve is still solely dominated by 56Co decay or the mass ratio of the two isotopes is much smaller than in other SNe Ia that have been followed out to similar late times. We ask for two more visits in with WFC3 in F555W (four orbits total) to follow the SN out to 1020 days past maximum light and conclusively discriminate between these two scenarios. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will schedule two visits to SN 2015F. In each visit, we will observe the SN in F555W using a 3-point line dither pattern in each orbit. The scheduling of the visits is important. We ask that the first visit be scheduled as early as possible (optimally before 5 December 2017), and that the second visit be scheduled between 22-28 January 2018. To make scheduing easier, we have allocated 1 orbit to the first visit, and 3 orbits to the second one. Please let us know if the first visit cannot be scheduled as early as desired, and we will change our phase II accordingly. ------------------------------------------------------------------------------------ 15415( 5) - 08-Dec-2017 19:35:28 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2015F EXT-STAR, SUPERNOVA RA=07H36M15.7600S, J2000 V = 27.6 +/- 0.5 TYPE IA DEC=-69D30'23.00" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 15415( 5) - 08-Dec-2017 19:35:28 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.135 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type LINE WFC3-UVIS-DITHER-LINE-3PT Pattern_Purpose DITHER DITHER Number_Of_Points 3 3 Point_Spacing 1 0.135 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 135 46.84 Angle_Between_Sides Center_Pattern NO NO ------------------------------------------------------------------------------------------------------------------------------------ 15415( 5) - 08-Dec-2017 19:35:28 - [ 4] Visit: 01 (SN 2015F +990) Visit Requirements: BEFORE 14-DEC-2017:00:00:00 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2015F WFC3/UVI ACCUM UVIS2 F555W 1 930 S PATTERN 1 1 S (2790 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 1 none none none 1 N/A S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 2 none none none 1 N/A S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 3 none none none 1 N/A S 15415( 5) - 08-Dec-2017 19:35:28 - [ 5] Visit: 02 (SN 2015F +1040) Visit Requirements: BETWEEN 22-JAN-2018:00:00:00 AND 28-JAN-2018:00:00:00 On Hold Comments: Additional Comments: This visit consists of three orbits, set up in a LINE dither pattern that uses the UVIS-DITHER-LINE-3PT as a subpattern. That way, each orbit is slightly shifted relative to the first orbit, and within each orbit the exposures are dithered along the 3PT pattern. 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 SN2015F WFC3/UVI ACCUM UVIS2 F555W 1 983 S PATTERN 2 1 S (9069 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 1 1 none none 1 N/A S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 1 2 none none 1 N/A S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 1 3 none none 1 N/A S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 2 1 none none 2 1094.0 S S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 2 2 none none 2 N/A S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 2 3 none none 2 N/A S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 3 1 none none 3 1094.0 S S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 3 2 none none 3 N/A S SN2015F 1 WFC3/UVI ACCUM UVIS2 F555W 3 3 none none 3 N/A S 15415( 5) - 08-Dec-2017 19:35:28 - [ 6] Summary Form for Proposal 15415 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BEFORE 14-DEC-2017:00:00:00, BETWEEN 22-JAN-2018:00:00:00 AND 28-JAN-2018:00:00:00, PATTERN 1 1, PATTERN 2 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN2015F ------------------------------------------------------------------------------------------------------------------------------------