13505( 3) - 07-Aug-2013 20:16:17 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13505 Version: 3 Check-in Time: 07-Aug-2013 20:16:17 STScI Edit Number: 0 Title SN 2012im/2013ek: A Supernova Double Take in NGC 6984 ------------------------------------------------------------------------------------ Type Cycle GO/DD 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Dan Milisavljevic Harvard University Y CoI: Prof. Alicia M. Soderberg Harvard University N CoI: Dr. Robert A. Fesen Dartmouth College N CoI: Maria Drout Harvard University N CoI: Dr. Raffaella Margutti Harvard University N CoI: Mr. Nathan Sanders Harvard University N CoI: Prof. Robert P. Kirshner Harvard University N ------------------------------------------------------------------------------------ Abstract An unprecedented transient event has just been detected in a spiral arm of NGC 6984. Two H-poor supernovae - SN 2012im and 2013ek - both originating from massive stripped-envelope progenitor stars have been found at virtually the same location (< 0.4 arcsec). Interpretations have varied widely. Chance alignment of two completely independent supernovae of the same Type Ib/c class exploding within one year of each other from the same stellar cluster is statistically improbable. Thus, the two explosions are most likely physically related, and this has important ramifications in areas of high-mass binary star evolution and explosion mechanisms of core-collapse supernovae. High resolution HST images are the only means by which to probe the stellar environment of the progenitor system. To this end, we request WFC3/UVIS imaging in F336W, F475W, F555W, and F814W of SN 2013ek in the next month while SN 2013ek is still bright to pin down its precise location within a nearby cluster of stars visible in an archival plate of NGC 6984. Complementary follow-up images will be requested during regular GO proposals in Cycle 22 when the fading supernova reveals what is left behind. The proposed suite of images will allow us to model the cluster's broadband colors to determine properties of the progenitor star system's environment (e.g., mass, age, luminosity, star formation rate, metallicity) that will be used to constrain possible explosion scenarios. We request Director's Discretionary time for these observations as a non-disruptive TOO. ------------------------------------------------------------------------------------ Observations Description ------------------------ We request two orbits to image the region of SN 2013ek and host galaxy NGC 6984 using WFC3/UVIS with the F336W, F475W, F555W, and F814W filters. Target is visible between August 7-22, for 57 mins per orbit. We estimate total integration times of ~25-30 mins per filter. Three- or four-point sub-pixel dithering will achieve the best resolution possible. NGC 6984 is at a distance of 65 Mpc. The 0.04" pixel scale of WFC3/UVIS will constrain the position of supernova and host cluster within ~12 pc. 13505( 3) - 07-Aug-2013 20:16:17 - [ 2] Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 13505( 3) - 07-Aug-2013 20:16:17 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2013EK EXT-STAR, SUPERNOVA RA=20H57M53.9000S +/- 1", J2000 V = 17.5 +/- 1 DEC=-51D52'24.50" +/- 1" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 13505( 3) - 07-Aug-2013 20:16:17 - [ 4] 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 ------------------------------------------------------------------------------------------------------------------------------------ 13505( 3) - 07-Aug-2013 20:16:17 - [ 5] Visit: 01 Visit Requirements: 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 SN2013EK WFC3/UVI ACCUM UVIS2 F336W FLASH=12 1 15 S (15 S S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2013EK WFC3/UVI ACCUM UVIS2 F336W FLASH=11 1 350 S PATTERN 1 2 S (1050 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2013EK WFC3/UVI ACCUM UVIS2 F555W 1 350 S PATTERN 1 3 S (1050 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 SN2013EK WFC3/UVI ACCUM UVIS2 F555W FLASH=12 1 10 S (10 S S) ------------------------------------------------------------------------------------------------------------------------------------ 5 SN2013EK WFC3/UVI ACCUM UVIS2 F438W FLASH=12 1 15 S (15 S S) ------------------------------------------------------------------------------------------------------------------------------------ 6 SN2013EK WFC3/UVI ACCUM UVIS2 F438W FLASH=9 1 350 S PATTERN 1 6 S (1050 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 SN2013EK WFC3/UVI ACCUM UVIS2 F814W FLASH=4 1 350 S PATTERN 1 7 S (1050 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 SN2013EK WFC3/UVI ACCUM UVIS2 F814W FLASH=12 1 15 S (15 S 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2013EK 1 WFC3/UVI ACCUM UVIS2 F336W none none none none 1 N/A S SN2013EK 2 WFC3/UVI ACCUM UVIS2 F336W 1 none none none 1 N/A S SN2013EK 2 WFC3/UVI ACCUM UVIS2 F336W 2 none none none 1 N/A S SN2013EK 2 WFC3/UVI ACCUM UVIS2 F336W 3 none none none 1 N/A S SN2013EK 3 WFC3/UVI ACCUM UVIS2 F555W 1 none none none 1 N/A S SN2013EK 3 WFC3/UVI ACCUM UVIS2 F555W 2 none none none 1 N/A S 13505( 3) - 07-Aug-2013 20:16:17 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2013EK 3 WFC3/UVI ACCUM UVIS2 F555W 3 none none none 1 N/A S SN2013EK 4 WFC3/UVI ACCUM UVIS2 F555W none none none none 1 N/A S SN2013EK 5 WFC3/UVI ACCUM UVIS2 F438W none none none none 2 N/A S SN2013EK 6 WFC3/UVI ACCUM UVIS2 F438W 1 none none none 2 N/A S SN2013EK 6 WFC3/UVI ACCUM UVIS2 F438W 2 none none none 2 N/A S SN2013EK 6 WFC3/UVI ACCUM UVIS2 F438W 3 none none none 2 N/A S SN2013EK 7 WFC3/UVI ACCUM UVIS2 F814W 1 none none none 2 N/A S SN2013EK 7 WFC3/UVI ACCUM UVIS2 F814W 2 none none none 2 N/A S SN2013EK 7 WFC3/UVI ACCUM UVIS2 F814W 3 none none none 2 N/A S SN2013EK 8 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 13505( 3) - 07-Aug-2013 20:16:17 - [ 7] Summary Form for Proposal 13505 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=11, FLASH=12, FLASH=4, FLASH=9 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 2, PATTERN 1 3, PATTERN 1 6, PATTERN 1 7 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F336W, F438W, F555W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN2013EK ------------------------------------------------------------------------------------------------------------------------------------