11782( 12) - 26-Aug-2009 13:18:27 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11782 Version: 12 Check-in Time: 26-Aug-2009 13:18:27 STScI Edit Number: 10 Title Measuring the Shape and Orientation of the Galactic Dark-Matter Halo using Hypervelocity Stars ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Oleg Y. Gnedin The Ohio State University Research Foundation CoI: Dr. Andrew Gould The Ohio State University Research N Foundation CoI: Mr. Jose Luis Prieto The Ohio State University Research N Foundation CoI: Dr. Krzysztof Stanek The Ohio State University Research N Foundation CoI: Dr. Howard E. Bond Space Telescope Science Institute N CoI: Dr. Mario Livio Space Telescope Science Institute N CoI: Dr. Edmund Nelan Space Telescope Science Institute N CoI: Dr. Warren R. Brown Smithsonian Institution Astrophysical N Observatory CoI: Dr. Margaret Geller Smithsonian Institution Astrophysical N Observatory CoI: Dr. Scott J. Kenyon Smithsonian Institution Astrophysical N Observatory CoI: Dr. Michael J. Kurtz Smithsonian Institution Astrophysical N Observatory CoI: Dr. Jay Anderson Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract We propose to obtain high-resolution images of five hypervelocity stars in the Galactic halo in order to establish the first-epoch astrometric frame for them, as a part of a long-term program to measure precise proper motions. The origin of these recently discovered stars, all with positive radial velocities above 540 km/s, is consistent only with being ejected from the deep potential well of the massive black hole at the Galactic center. The deviations of their space motions from purely radial trajectories probe the departures from spherical symmetry of the Galactic potential, mainly due to the triaxiality of the dark-matter halo. Reconstructing the full three-dimensional space motion of the hypervelocity stars, through astrometric proper motions, provides a unique opportunity to measure the shape and orientation of the dark halo. The hypervelocity stars allow measurement of the potential up to 75 kpc from the center, independently of and at larger distances than are afforded by tidal streams of satellite galaxies such as the Sagittarius dSph galaxy. HVS3 may be associated with the LMC, rather then the Galactic center, and would therefore present a case for a supermassive black hole at the center of the LMC. We request one orbit with ACS/WFC for each of the five hypervelocity stars to establish their current positions relative to background galaxies. We will request a repeated observation of these stars in Cycle 17, which will conclusively measure the astrometric proper motions. ------------------------------------------------------------------------------------ 11782( 12) - 26-Aug-2009 13:18:27 - [ 2] Observations Description ------------------------ In this program we are obtaining second-epoch images of 5 hypervelocity stars. The aim is to measure their proper motions against the reference frame of background galaxies. Each target will be centered either in the middle of WFC1, or for the brightest targets we will reduce overheads by using the subraster WFC1-2K. The targets will be observed either in F814W or F850LP, which appear to be better filters than the F606W mentioned in the original proposal. The reason is that the crucial background galaxies will give a better S/N at longer wavelengths, according to the ACS ETC. For each target we will take the maximum number of exposures possible in one orbit, with appropriate dithering. Exposures are chosen for each target to be no more than 70% of saturation on the target star. For these second-epoch observations, we are specifying the exact same ORIENT's that were used for the first-epoch observations in Cycle 15. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11782( 12) - 26-Aug-2009 13:18:27 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ090745. STAR, BP, HALO RA=09H07M44.9900S +/- 0.1", J2000 V = 19.96 +/- 0.2 0+024507 DEC=+02D45'6.40" +/- 0.1" Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ093320. STAR, BP, HALO RA=09H33M20.8800S +/- 0.1", J2000 V = 19 +/- 0.2 86+441705.4 DEC=+44D17'5.50" +/- 0.1" Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 3 HE0437-5439 STAR, BP, HALO RA=04H38M12.7700S +/- 0.1", J2000 V = 16.2 +/- 0.2 DEC=-54D33'11.80" +/- 0.1" Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSSJ091301. STAR, BP, HALO RA=09H13M1.0000S +/- 0.1", J2000 V = 18.59 +/- 0.2 0+305120 DEC=+30D51'20.20" +/- 0.1" Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 5 SDSSJ091759. STAR, BP, HALO RA=09H17M59.5500S +/- 0.1", J2000 V = 18.09 +/- 0.2 5+672238 DEC=+67D22'38.80" +/- 0.1" Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 11782( 12) - 26-Aug-2009 13:18:27 - [ 4] Visit: 01 Visit Requirements: ORIENT 279.7631D TO 279.7631 D; BEFORE 17-OCT-2009:00:00:00 On Hold Comments: Additional Comments: The ORIENT is chosen to exactly duplicate that used in the first-epoch observations made in Cycle 15. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ090745 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 540.0 S GS ACQ SCENARIO BASE1B3 .0+024507 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ090745 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 540.0 S POS TARG 0.25073, .0+024507 0.54151 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ090745 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 540.0 S POS TARG 0.52487, 0.7861 .0+024507 ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSSJ090745 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 540.0 S POS TARG 0.7713, 0.33176 .0+024507 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ090745.0+02450 1 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 7 SDSSJ090745.0+02450 2 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 7 SDSSJ090745.0+02450 3 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 7 SDSSJ090745.0+02450 4 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 7 11782( 12) - 26-Aug-2009 13:18:27 - [ 5] Visit: 02 Visit Requirements: ORIENT 303.7515D TO 303.7515 D; BEFORE 09-NOV-2009:00:00:00 On Hold Comments: Additional Comments: The ORIENT is chosen to exactly duplicate that used in the first-epoch observations made in Cycle 15. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ093320 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 560.0 S GS ACQ SCENARIO BASE1B3 .86+441705. 4 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ093320 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 560.0 S POS TARG 0.25073, .86+441705. 0.54151 4 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ093320 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 560.0 S POS TARG 0.52487, 0.7861 .86+441705. 4 ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSSJ093320 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 560.0 S POS TARG 0.7713, 0.33176 .86+441705. 4 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ093320.86+4417 1 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 05.4 SDSSJ093320.86+4417 2 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 05.4 SDSSJ093320.86+4417 3 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 05.4 SDSSJ093320.86+4417 4 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 05.4 11782( 12) - 26-Aug-2009 13:18:27 - [ 6] Visit: 03 Visit Requirements: ORIENT 34.9785D TO 34.9785 D; BEFORE 28-DEC-2009:00:00:00 On Hold Comments: Additional Comments: The ORIENT is chosen to exactly duplicate that used in the first-epoch observations made in Cycle 15. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HE0437-5439 ACS/WFC ACCUM WFC1-2K F850LP CR-SPLIT=NO 1 300 S ------------------------------------------------------------------------------------------------------------------------------------ 2 HE0437-5439 ACS/WFC ACCUM WFC1-2K F850LP CR-SPLIT=NO 1 300 S POS TARG 0.29815, 0.0473 ------------------------------------------------------------------------------------------------------------------------------------ 3 HE0437-5439 ACS/WFC ACCUM WFC1-2K F850LP CR-SPLIT=NO 1 300 S POS TARG 0.6127, 0.04604 ------------------------------------------------------------------------------------------------------------------------------------ 4 HE0437-5439 ACS/WFC ACCUM WFC1-2K F850LP CR-SPLIT=NO 1 300 S POS TARG 0.16794, 0.53528 ------------------------------------------------------------------------------------------------------------------------------------ 5 HE0437-5439 ACS/WFC ACCUM WFC1-2K F850LP CR-SPLIT=NO 1 300 S POS TARG 0.48231000000000007, 0.53404 ------------------------------------------------------------------------------------------------------------------------------------ 6 HE0437-5439 ACS/WFC ACCUM WFC1-2K F850LP CR-SPLIT=NO 1 300 S POS TARG 0.78064, 0.58136 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ HE0437-5439 1 ACS/WFC ACCUM WFC1-2K F850LP none none none none 1 N/A HE0437-5439 2 ACS/WFC ACCUM WFC1-2K F850LP none none none none 1 N/A HE0437-5439 3 ACS/WFC ACCUM WFC1-2K F850LP none none none none 1 N/A HE0437-5439 4 ACS/WFC ACCUM WFC1-2K F850LP none none none none 1 N/A HE0437-5439 5 ACS/WFC ACCUM WFC1-2K F850LP none none none none 1 N/A HE0437-5439 6 ACS/WFC ACCUM WFC1-2K F850LP none none none none 1 N/A 11782( 12) - 26-Aug-2009 13:18:27 - [ 7] Visit: 04 Visit Requirements: ORIENT 276.68D TO 277.9537 D; BEFORE 10-NOV-2009:00:00:00 On Hold Comments: Additional Comments: The ORIENT is chosen to exactly duplicate that used in the first-epoch observations made in Cycle 15. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ091301 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 410.0 S GS ACQ SCENARIO BASE1B3 .0+305120 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ091301 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 410.0 S POS TARG 0.26063, .0+305120 0.53727 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ091301 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 410.0 S POS TARG 0.5212, 1.07448 .0+305120 ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSSJ091301 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 410.0 S POS TARG 0.77839, .0+305120 0.81512 ------------------------------------------------------------------------------------------------------------------------------------ 5 SDSSJ091301 ACS/WFC ACCUM WFC1 F814W CR-SPLIT=NO 1 410.0 S POS TARG 1.03448, .0+305120 0.35651 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ091301.0+30512 1 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 0 SDSSJ091301.0+30512 2 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 0 SDSSJ091301.0+30512 3 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 0 SDSSJ091301.0+30512 4 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 0 SDSSJ091301.0+30512 5 ACS/WFC ACCUM WFC1 F814W none none none none 1 N/A 0 11782( 12) - 26-Aug-2009 13:18:27 - [ 8] Visit: 05 Visit Requirements: ORIENT 336.2947D TO 336.2947 D; BEFORE 06-SEP-2009:00:00:00 On Hold Comments: Additional Comments: The ORIENT is chosen to exactly duplicate that used in the first-epoch observations made in Cycle 15. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ091759 ACS/WFC ACCUM WFC1-2K F814W CR-SPLIT=NO 1 200.0 S .5+672238 ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ091759 ACS/WFC ACCUM WFC1-2K F814W CR-SPLIT=NO 1 200.0 S POS TARG 0.30527, .5+672238 0.05137 ------------------------------------------------------------------------------------------------------------------------------------ 3 SDSSJ091759 ACS/WFC ACCUM WFC1-2K F814W CR-SPLIT=NO 1 200.0 S POS TARG 0.6104, 0.05299 .5+672238 ------------------------------------------------------------------------------------------------------------------------------------ 4 SDSSJ091759 ACS/WFC ACCUM WFC1-2K F814W CR-SPLIT=NO 1 200.0 S POS TARG 0.1727, 0.5321 .5+672238 ------------------------------------------------------------------------------------------------------------------------------------ 5 SDSSJ091759 ACS/WFC ACCUM WFC1-2K F814W CR-SPLIT=NO 1 200.0 S POS TARG 0.47775, .5+672238 0.56923 ------------------------------------------------------------------------------------------------------------------------------------ 6 SDSSJ091759 ACS/WFC ACCUM WFC1-2K F814W CR-SPLIT=NO 1 200.0 S POS TARG 0.7831, 0.59932 .5+672238 ------------------------------------------------------------------------------------------------------------------------------------ 7 SDSSJ091759 ACS/WFC ACCUM WFC1-2K F814W CR-SPLIT=NO 1 200.0 S POS TARG 0.93792, .5+672238 0.33363 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ091759.5+67223 1 ACS/WFC ACCUM WFC1-2K F814W none none none none 1 N/A 8 SDSSJ091759.5+67223 2 ACS/WFC ACCUM WFC1-2K F814W none none none none 1 N/A 8 SDSSJ091759.5+67223 3 ACS/WFC ACCUM WFC1-2K F814W none none none none 1 N/A 8 SDSSJ091759.5+67223 4 ACS/WFC ACCUM WFC1-2K F814W none none none none 1 N/A 8 SDSSJ091759.5+67223 5 ACS/WFC ACCUM WFC1-2K F814W none none none none 1 N/A 8 SDSSJ091759.5+67223 6 ACS/WFC ACCUM WFC1-2K F814W none none none none 1 N/A 8 SDSSJ091759.5+67223 7 ACS/WFC ACCUM WFC1-2K F814W none none none none 1 N/A 8 11782( 12) - 26-Aug-2009 13:18:27 - [ 9] Summary Form for Proposal 11782 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1, WFC1-2K ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BEFORE 06-SEP-2009:00:00:00, BEFORE 09-NOV-2009:00:00:00, BEFORE 10-NOV-2009:00:00:00, BEFORE 17-OCT-2009:00:00:00, BEFORE 28-DEC-2009:00:00:00, GS ACQ SCENARIO BASE1B3, ORIENT 276.68D TO 277.9537 D, ORIENT 279.7631D TO 279.7631 D, ORIENT 303.7515D TO 303.7515 D, ORIENT 336.2947D TO 336.2947 D, ORIENT 34.9785D TO 34.9785 D, POS TARG 0.16794, 0.53528, POS TARG 0.1727, 0.5321, POS TARG 0.25073, 0.54151, POS TARG 0.26063, 0.53727, POS TARG 0.29815, 0.0473, POS TARG 0.30527, 0.05137, POS TARG 0.47775, 0.56923, POS TARG 0.48231000000000007, 0.53404, POS TARG 0.5212, 1.07448, POS TARG 0.52487, 0.7861, POS TARG 0.6104, 0.05299, POS TARG 0.6127, 0.04604, POS TARG 0.7713, 0.33176, POS TARG 0.77839, 0.81512, POS TARG 0.78064, 0.58136, POS TARG 0.7831, 0.59932, POS TARG 0.93792, 0.33363, POS TARG 1.03448, 0.35651 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W, F850LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names HE0437-5439, SDSSJ090745.0+024507, SDSSJ091301.0+305120, SDSSJ091759.5+672238, SDSSJ093320.86+441705.4 ------------------------------------------------------------------------------------------------------------------------------------