14607( 9) - 16-May-2018 13:29:31 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14607 Version: 9 Check-in Time: 16-May-2018 13:29:31 STScI Edit Number: 6 Title Identify the signature of neutron star mergers through rapid Hubble observations of a short GRB ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Eleonora Troja University of Maryland Y CoI: Dr. Stephen Bradley Cenko NASA Goddard Space Flight Center N CoI: Dr. Taka Sakamoto Aoyama Gakuin University N CoI: Dr. Neil Gehrels NASA Goddard Space Flight Center N CoI: Nobuyuki Kawai Tokyo Institute of Technology - TIT N CoI: Dr. Amy Lien NASA Goddard Space Flight Center N ------------------------------------------------------------------------------------ Abstract The afterglow of some short GRBs displays a late-time rebrightening, visible a few days after the gamma-ray burst. Recent HST observations provided tantalizing evidence that such late-time bump could be explained as the emergence of the underlying kilonova emission. This would represent the incontrovertible signature of a neutron star merger, and the first direct link between short GRBs and their progenitors. If the kilonova interpretation is correct, it would also confirm that neutron star mergers are significant and possibly dominant sources of the heaviest elements (e.g. gold, platinum, uranium) in the Universe. Here we ask for rapid HST follow-up observation of a nearby (z<0.4) short duration GRB in order to detect the expected kilonova bump, and to constrain the origin of the observed emission. Multi-color observations are critical to pin down the nature of the observed rebrightening, and to distinguish it from the standard afterglow. The proposed observations will provide the smoking gun evidence connecting short GRBs and neutron star mergers, and will serve as a powerful observational input in the forthcoming era of gravitational wave astronomy. ------------------------------------------------------------------------------------ Observations Description ------------------------ Below we provide an illustrative description of our observational strategy. Given the broad range of short GRB redshifts, afterglow and host properties, the exact details of the observations (response time, cadence, and filters) will be determined on a case by case basis. We request four epochs of observations, the exact times will be scaled according to the observed afterglow decay, the GRB distance scale, and the total time span of the ground-based data. We will plan our observations in order to require a reaction time >2 days. Each epoch will consist of three orbits in order to image the target in different colors. We remark that the choice of UVIS and IR filters reported in this observing form is preliminary, and the final selection will be made at the time of the ToO in order to match the best sampled light curves from the ground. ------------------------------------------------------------------------------------ 14607( 9) - 16-May-2018 13:29:31 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GW170817 STAR, GAMMA RAY BURSTER RA=13H09M48.0850S, J2000 V = 28 F606W~27 AB mag DEC=-23D22'53.34" Reference Frame: Other: SIMBAD Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 2 SHORTGRB STAR, GAMMA RAY RA=18H39M54.5600S, J2000 V = 25 BURSTER, NEUTRON STAR, DEC=+62D23'30.50" SUPERNOVA, X-RAY BURSTER, X-RAY TRANSIENT Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 14607( 9) - 16-May-2018 13:29:31 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.173 Line_Spacing 0.112 Coordinate_Frame POS-TARG Pattern_Orient 23.884 Angle_Between_Sides 81.785 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 14607( 9) - 16-May-2018 13:29:31 - [ 4] Visit: 01 (VISIT1) Visit Requirements: ORIENT 0D TO 90 D; ORIENT 130D TO 190 D; ORIENT 225D TO 285 D; ORIENT 335D TO 345 D; ON HOLD ; TOO RESPONSE TIME 25.0H On Hold Comments: nearby GRB Additional Comments: Our favorite time-window is between January 26 and February 1st, in coordination with scheduled Chandra, XMM-Newton and ATCA observations 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 GW170817 WFC3/UVI ACCUM UVIS F606W 1 500 S GS ACQ SCENARIO BASE1B3; S see below PATTERN 1 1 (2372 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 | ------------------------------------------------------------------------------------------------------------------------------------ GW170817 1 WFC3/UVI ACCUM UVIS F606W 1 none none none 1 593 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 2 none none none 1 593 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 3 none none none 1 593 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 4 none none none 1 593 S S 14607( 9) - 16-May-2018 13:29:31 - [ 5] Visit: 02 (VISIT2) Visit Requirements: ORIENT 0D TO 90 D; ORIENT 130D TO 190 D; ORIENT 225D TO 285 D; ORIENT 335D TO 345 D; AFTER 01 BY 30 D TO 45 D; ON HOLD ; TOO RESPONSE TIME 25.0H On Hold Comments: nearby GRB Additional Comments: Our favorite time-window is between February 28 and March 3rd. 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 GW170817 WFC3/UVI ACCUM UVIS F606W 1 500 S GS ACQ SCENARIO BASE1B3; S see below PATTERN 1 1 (2432 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 | ------------------------------------------------------------------------------------------------------------------------------------ GW170817 1 WFC3/UVI ACCUM UVIS F606W 1 none none none 1 608.0 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 2 none none none 1 608.0 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 3 none none none 1 608.0 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 4 none none none 1 608.0 S S 14607( 9) - 16-May-2018 13:29:31 - [ 6] Visit: 03 (VISIT3) Visit Requirements: ORIENT 0D TO 90 D; ORIENT 130D TO 190 D; ORIENT 225D TO 285 D; ORIENT 335D TO 345 D; AFTER 02 BY 75 D TO 90 D; ON HOLD ; TOO RESPONSE TIME 25.0H On Hold Comments: nearby GRB Additional Comments: Our favorite time-window is between May 15th and June 1st. 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 GW170817 WFC3/UVI ACCUM UVIS F606W 1 500 S GS ACQ SCENARIO BASE1B3; S see below PATTERN 1 1 (2432 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 | ------------------------------------------------------------------------------------------------------------------------------------ GW170817 1 WFC3/UVI ACCUM UVIS F606W 1 none none none 1 608.0 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 2 none none none 1 608.0 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 3 none none none 1 608.0 S S GW170817 1 WFC3/UVI ACCUM UVIS F606W 4 none none none 1 608.0 S S 14607( 9) - 16-May-2018 13:29:31 - [ 7] Visit: 04 (NEW VISIT3) Visit Requirements: ORIENT 50D TO 130 D On Hold Comments: Additional Comments: We'd like to keep the same orientation from previous visits of the same target. 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 SHORTGRB WFC3/IR MULTIAC IR F160W SAMP-SEQ=STEP100, NSAMP=13 1 DEF PATTERN 2 1 CUM (2796.93 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 | ------------------------------------------------------------------------------------------------------------------------------------ SHORTGRB 1 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM SHORTGRB 1 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM SHORTGRB 1 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM SHORTGRB 1 WFC3/IR MULTIAC IR F160W 4 none none none 1 N/A CUM 14607( 9) - 16-May-2018 13:29:31 - [ 8] Summary Form for Proposal 14607 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=13, SAMP-SEQ=STEP100 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 30 D TO 45 D, AFTER 02 BY 75 D TO 90 D, GS ACQ SCENARIO BASE1B3, ON HOLD , ORIENT 0D TO 90 D, ORIENT 130D TO 190 D, ORIENT 225D TO 285 D, ORIENT 335D TO 345 D, ORIENT 50D TO 130 D, PATTERN 1 1, PATTERN 2 1, TOO RESPONSE TIME 25.0H ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W, F606W ------------------------------------------------------------------------------------------------------------------------------------ Target Names GW170817, SHORTGRB ------------------------------------------------------------------------------------------------------------------------------------