12948( 2) - 25-Jun-2012 17:08:40 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12948 Version: 2 Check-in Time: 25-Jun-2012 17:08:40 STScI Edit Number: 0 Title Late Time STIS Spectroscopy of the Extremely Nearby Type Ia SN 2011fe ------------------------------------------------------------------------------------ Type Cycle GO 20 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Rollin Thomas Lawrence Berkeley National Laboratory Y CoI: Dr. Peter E. Nugent Lawrence Berkeley National Laboratory Y CoI: Dr. Eddie Baron University of Oklahoma Norman Campus N CoI: Dr. Daniel Kasen University of California - Berkeley N CoI: Dr. Mark Sullivan University of Oxford N CoI: Dr. Eric Hsiao Carnegie Institution of Washington N CoI: Dr. Mark M. Phillips Carnegie Institution of Washington N ------------------------------------------------------------------------------------ Abstract In the first 2-3 months after the explosion of a Type Ia supernova, the innermost layers of the ejecta are concealed from view by a brilliant pseudo-photosphere. Observations obtained many months later, when the ejecta become nebular, enable us to peer deep into these layers and probe different explosion physics than is possible earlier on --- but at a cost. By this point, the supernova has faded dramatically, so only the closest events may be observed. SN 2011fe is the nearest Type Ia supernova discovered in a quarter century. We propose to obtain STIS spectroscopy of this remarkable supernova, a year after explosion, and combine these space-based observations with ground-based optical and near-infrared spectroscopy for analysis. Using the focusing lens of radiative transfer simulations, we will constrain the amount of radioactive nickel produced in the explosion, explore the extent of large-scale hydrodynamical mixing, and reconstruct the abundance stratification of the innermost ejecta. SN 2011fe represents a unprecedented opportunity to study how Type Ia supernovae explode, and is likely to remain so for decades to come. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our goal is to obtain ultraviolet spectroscopy of the extremely nearby Type Ia supernova 2011fe in M101 using STIS, 13 months after it reached peak luminosity. We hope our observations can be carried out at the very start of Cycle 20, since the supernova will only continue to fade. We will combine these observations with complementary, time-coordinated ground-based optical and near-infrared observations, and analyze them together using comprehensive radiative transfer simulations. Comparing synthetic spectra to late-time observations will allow us to explore the extent of large-scale hydrodynamic mixing during the explosion, constrain the amount of radioactive nickel produced, and reconstruct the multi-dimensional distribution of the innermost ejecta. Careful examination of nebular phase lines will provide constraints on large-scale explosion asymmetry. We plan a total of 10 orbits split into 3 visits. Our strategy is to maximize 12948( 2) - 25-Jun-2012 17:08:40 - [ 2] S/N we can get in the NUV, but also obtain some optical spectroscopy that can retire risk associated with constraints on ground-based visibility of the target in late September. The first 2 visits are in the STIS/NUV-MAMA configuration. The first visit uses 5 orbits, the second uses 4. We dither along the slit at the end of every few orbits by 11 pixels to reduce the impact of hot pixels. The third and final visit uses the STIS/CCD G430L and G750L configurations in sequence in a single orbit. Exposure time and S/N are estimated by rescaling fluxes estimated from an HST spectrum of SN1992A obtained 291 days past peak and using the appropriate online STIS ETC's. We account for the fact that SN2011fe was over 10 times brighter than SN1992A at peak since it was much closer, and we also account for an additional ~100 days of decline in flux since our observations are later on the light curve of SN2011fe than those of SN1992A. Real Time Justification ----------------------- Our observations need to come as close to the beginning of Cycle 20 as possible. If the observations can be scheduled in September, this is not a problem for us at all. All 3 visits need to be scheduled as close together in time as is feasible. We understand the MAMA observing constraints prevent those visits from taking place in the same day. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 12948( 2) - 25-Jun-2012 17:08:40 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2011FE EXT-STAR, SUPERNOVA RA=14H03M5.8130S +/- 0.5", J2000 Z = V = 19.5 +/- 0.3 TYPE IA DEC=+54D16'25.36" +/- 0.5" 0.0008 Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 12948( 2) - 25-Jun-2012 17:08:40 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.275 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 12948( 2) - 25-Jun-2012 17:08:40 - [ 5] Visit: 01 Visit Requirements: PCS MODE FINE; BEFORE 03-OCT-2012:00:00:00; SEQ 01, 02, 03 WITHIN 3 D On Hold Comments: Additional Comments: Nebular UV STIS Spectroscopy of SN2011fe Visit 1 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2011FE STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 60 S ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2011FE STIS/NUV ACCUM 52X0.2 G230L 2376 2 2000 S PATTERN 1 2 -MAMA see below ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2011FE STIS/NUV ACCUM 52X0.2 G230L 2376 1 3085 S -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2011FE 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SN2011FE 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none 1 none 1 2295.0 S -MAMA SN2011FE 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none 2 none 2 3085 S -MAMA SN2011FE 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none 1 none 3 3085.0 S -MAMA SN2011FE 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none 2 none 4 3085 S -MAMA SN2011FE 3 STIS/NUV ACCUM 52X0.2 G230L 2376 none none none none 5 N/A -MAMA 12948( 2) - 25-Jun-2012 17:08:40 - [ 6] Visit: 02 Visit Requirements: PCS MODE FINE; BEFORE 03-OCT-2012:00:00:00 On Hold Comments: Additional Comments: Nebular UV STIS Spectroscopy of SN2011fe Visit 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2011FE STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 60 S ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2011FE STIS/NUV ACCUM 52X0.2 G230L 2376 2 2000 S PATTERN 1 2 -MAMA 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2011FE 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SN2011FE 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none 1 none 1 2295.0 S -MAMA SN2011FE 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none 2 none 2 3085 S -MAMA SN2011FE 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none 1 none 3 3085.0 S -MAMA SN2011FE 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none 2 none 4 3085 S -MAMA 12948( 2) - 25-Jun-2012 17:08:40 - [ 7] Visit: 03 Visit Requirements: BEFORE 03-OCT-2012:00:00:00 On Hold Comments: Additional Comments: Nebular UV STIS Spectroscopy of SN2011fe Visit 3 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2011FE STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 60 S ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2011FE STIS/CCD ACCUM 52X0.2E1 G430L 4300 CR-SPLIT=3 1 1236 S ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2011FE STIS/CCD ACCUM 52X0.2 G750L 7751 CR-SPLIT=3 1 660 S ------------------------------------------------------------------------------------------------------------------------------------ 4 CCDFLAT STIS/CCD ACCUM 0.3X0.09 G750L 7751 2 DEF ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2011FE 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SN2011FE 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 1 1 N/A SN2011FE 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 2 1 N/A SN2011FE 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 3 1 N/A SN2011FE 3 STIS/CCD ACCUM 52X0.2 G750L 7751 none none none 1 1 N/A SN2011FE 3 STIS/CCD ACCUM 52X0.2 G750L 7751 none none none 2 1 N/A SN2011FE 3 STIS/CCD ACCUM 52X0.2 G750L 7751 none none none 3 1 N/A CCDFLAT 4 STIS/CCD ACCUM 0.3X0.09 G750L 7751 none none 1 none 1 N/A CCDFLAT 4 STIS/CCD ACCUM 0.3X0.09 G750L 7751 none none 2 none 1 N/A 12948( 2) - 25-Jun-2012 17:08:40 - [ 8] Summary Form for Proposal 12948 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.3X0.09, 52X0.2, 52X0.2E1, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BEFORE 03-OCT-2012:00:00:00, PATTERN 1 2, PCS MODE FINE, SEQ 01, 02, 03 WITHIN 3 D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G230L, G430L, G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names CCDFLAT, SN2011FE ------------------------------------------------------------------------------------------------------------------------------------