11717( 2) - 02-Jul-2008 19:23:47 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11717 Version: 2 Check-in Time: 02-Jul-2008 19:23:47 STScI Edit Number: 0 Title Unraveling the Mysterious Origin of GRB 070125 ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Mr. S Bradley Cenko California Institute of Technology CoI: Dr. Derek B. Fox The Pennsylvania State University N CoI: Dr. Fiona A. Harrison California Institute of Technology N CoI: Prof. Shrinivas R. Kulkarni California Institute of Technology N CoI: Dr. Edo Berger Princeton University N CoI: Prof. Bryan E. Penprase Pomona College N CoI: Mr. Antonio Cucchiara The Pennsylvania State University N CoI: Dr. Eran O. Ofek California Institute of Technology N CoI: Dr. Arne Rau California Institute of Technology N CoI: Ms. Mansi Kasliwal California Institute of Technology N CoI: Dr. Alex V. Filippenko University of California - Berkeley N ------------------------------------------------------------------------------------ Abstract We propose a modest (2 WFC3 orbits) HST program to ascertain the origin of the mysterious gamma-ray burst GRB 070125. With a duration of 60 s and a high local (i.e. parsec scale) circum-burst density, GRB 070125 resembles a canonical (i.e. massive-star progenitor) long-duration event. However, we have strong evidence that GRB 070125 exploded in the halo of its host galaxy, far away from the bulk of massive star formation. The UV detection of a compact, star-forming cluster would confirm our original hypothesis that GRB 070125 exploded in a tidal tail formed by galaxy interactions (analogous to the Tadpole and Antenna galaxies) at z = 1.54. Alternatively, the absence of ongoing star formation and the presence of an old stellar population would require a novel explosion process unassociated with massive stars. While the former would open a new path to study star formation and galaxy interactions at high redshift, the latter would require a re-thinking of one of the fundamental tenets of GRB astronomy: the 1:1 mapping between duration and progenitor system. ------------------------------------------------------------------------------------ Observations Description ------------------------ One orbit of WFC3/UVIS (F336W) + one orbit of WFC3/IR (F110W) imaging. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments 11717( 2) - 02-Jul-2008 19:23:47 - [ 2] ------------------- ------------------------------------------------------------------------------------ 11717( 2) - 02-Jul-2008 19:23:47 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GRB070125 EXT-STAR, GAMMA RAY RA=07H51M17.7670S +/- 0.1", J2000 V = 27.0 +/- 2.0 BURSTER, HALO, TIDAL DEC=+31D09'4.11" +/- 0.1" TAIL Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 11717( 2) - 02-Jul-2008 19:23:47 - [ 4] 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 ------------------------------------------------------------------------------------------------------------------------------------ 11717( 2) - 02-Jul-2008 19:23:47 - [ 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GRB070125 WFC3/UVI ACCUM UVIS1 F336W CR-SPLIT=NO 1 630.0 S PATTERN 1 1 S ------------------------------------------------------------------------------------------------------------------------------------ 2 GRB070125 WFC3/IR MULTIAC IR F110W NSAMP=15, SAMP-SEQ=SPARS50 1 DEF PATTERN 2 2 CUM ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ GRB070125 1 WFC3/UVI ACCUM UVIS1 F336W 1 none none none 1 N/A S GRB070125 1 WFC3/UVI ACCUM UVIS1 F336W 2 none none none 1 N/A S GRB070125 1 WFC3/UVI ACCUM UVIS1 F336W 3 none none none 1 N/A S GRB070125 1 WFC3/UVI ACCUM UVIS1 F336W 4 none none none 1 N/A S GRB070125 2 WFC3/IR MULTIAC IR F110W 1 none none none 2 N/A CUM GRB070125 2 WFC3/IR MULTIAC IR F110W 2 none none none 2 N/A CUM GRB070125 2 WFC3/IR MULTIAC IR F110W 3 none none none 2 N/A CUM GRB070125 2 WFC3/IR MULTIAC IR F110W 4 none none none 2 N/A CUM 11717( 2) - 02-Jul-2008 19:23:47 - [ 6] Summary Form for Proposal 11717 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO, NSAMP=15, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, PATTERN 2 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F336W ------------------------------------------------------------------------------------------------------------------------------------ Target Names GRB070125 ------------------------------------------------------------------------------------------------------------------------------------