6756( 8) - 04/02/97 15:18 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6756 Version: 8 Check-in Date: 02-Apr-1997 14:58:47 1.Proposal Title: Measuring Proper Motions of Galactic Microlenses ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle STELLAR POPULATIONS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: DAVID BENNETT UNIVERSITY OF NOTRE DAME CoI: Matt Lehner U.C. San Diego N CoI: Bruce Peterson Mt. Stromlo and Siding Spring N Observatories CoI: Stuart Marshall U.C. Santa Barbara N CoI: Mark Pratt U.C. Santa Barbara N CoI: Peter Quinn European Southern Observatory N CoI: Alex Rodgers Mt. Stromlo and Siding Spring N Observatories CoI: Chris Stubbs University of Washington N CoI: Doug Welch McMaster University N CoI: Kem Cook Lawrence Livermore National Laboratory N CoI: Will Sutherland Oxford N CoI: Ken Freeman Mt. Stromlo and Siding Spring N Observatories CoI: Robyn Allsman Australian National University N CoI: Charles Alcock Lawrence Livermore National Laboratory N CoI: David Alves U.C., Davis N CoI: Tim Axelrod Mt. Stromlo and Siding Spring N Observatories CoI: Bob Becker U.C., Davis N CoI: Kim Griest U.C. San Diego N CoI: Jerry Guern U.C. San Diego N ------------------------------------------------------------------------------------ 6. Abstract Gravitational microlensing surveys have revealed an excess of lensing events over theoretical predictions toward both the Large Magellanic Cloud and the Galactic bulge. Only a small fraction of the LMC lensing events can be explained by known stellar populations in the Milky Way and LMC, suggesting that the bulk of the lenses belong to a new population of dark compact objects which contribute a significant fraction of the Galactic halo mass. Toward the Galactic bulge, most lenses are expected to be luminous stars in the Galactic bulge or disk, but the detected lensing rate is much higher than predicted. We propose to obtain high resolution images of 10 fields around some of our recently discovered gravitational microlensing events toward the bulge. These will be the first epoch images for comparison with later images to resolve the proper motion of the lensing objects which are luminous. We will observe 10 lens systems in the I band for one orbit per system. This will allow the measurement of proper motions for a large number of bulge lenses yielding a complete solution of the mass, distance, and velocity of the lenses. ------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 2] Observations Description ------------------------ We propose to image 10 fields in the Galactic bulge. We will collect F814W (I band) images as first epoch data to search for proper motion of (potentially) luminous lensing objects as faint as I = 25.5. All observations will have the target placed on the PC for maximum spacial resolution. They will also be dithered to increase the spacial resolution. Also, all exposures will be taken with clocks=YES to avoid bleeding problems and to reduce overhead time. All exposures will use a gain of 7 electrons per ADU to minimize digitization noise. The length of the exposures is limited by the requirement that the lensed star and its close neighbors not be saturated, and the exposures will be dithered to improve the spacial resolution. For 9 or the targets, we will take 6 F814W I band of 260 seconds each which just fill a single orbit. For the brightest source, STAR-1803-2942, which underwent a binary lensing event with a significant color shift due to blending, the F814W I band exposures will be 4* 160 seconds. Because of the detected chromaticity and blending in this event, we will also take two 400 second F555W V band exposures of this object in order to determine how much, if any, of the observed flux is coming from the lens. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- Because these observations are first epoch proper motion images it is highly desirable that they be scheduled as early as possible. The F555W V band exposures of star STAR-1803-2942 were included in the part (10 orbits) of the phase 1 proposal that was accepted, but the TAC also stated that only I band exposures should be taken. We believe that the resolution of these conflicting instructions from the TAC is clear: they clearly meant to exclude the deep V band images that were proposed in order to study the bulge luminosity function. (These added 2 more orbits to the bulge observations which were rejected by the TAC.) Forbiding the shallower V band images of the binary lens where the color information has already been demonstrated be important makes no scientific sence. ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: David Bennett*Physics Department*Nieuwland Science Hall*University of Notre Dame*Notre Dame, IN 46556 Ship Via: UPS Email: ------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1800- STAR RA=18H 00M 01.3S +/- 0.2S,DEC=- J2000 V = 19.7+/-0.3 2827 28D 27' 41.0" +/- 2" V-R = 1.1+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 2 STAR-1803- STAR RA=18H 03M 03.0S +/- 0.2S,DEC=- J2000 V = 19.5+/-0.3 3009 30D 09' 56.5" +/- 2" V-R = 0.7+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 3 STAR-1804- STAR RA=18H 04M 24.8S +/- 0.2S,DEC=- J2000 V = 19.7+/-0.3 3005 30D 05' 58.9" +/- 2" V-R = 1.1+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 4 STAR-1807- STAR RA=18H 07M 26.4S +/- 0.2S,DEC=- J2000 V = 20.8+/-0.3 2939 29D 39' 34.0" +/- 2" V-R = 0.7+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 5 STAR-1807- STAR RA=18H 07M 51.9S +/- 0.2S,DEC=- J2000 V = 20.0+/-0.3 3109 31D 09' 19.8" +/- 2" V-R = 0.7+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 6 STAR-1813- STAR RA=18H 13M 32.15S +/- 0.2S,DEC=- J2000 V = 20.1+/-0.3 2631 26D 31' 10.3" +/- 2" V-R = 0.9+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 7 STAR-1807- STAR RA=18H 07M 32.65S +/- 0.2S,DEC=- J2000 V = 19.5+/-0.3 2731 27D 31' 35.6" +/- 2" V-R = 0.8+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 8 STAR-1804- STAR RA=18H 04M 37.2S +/- 0.2S,DEC=- J2000 V = 19.9+/-0.3 3012 30D 12' 11.0" +/- 2" V-R = 1.0+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 9 STAR-1806- STAR RA=18H 06M 09.1S +/- 0.2S,DEC=- J2000 V = 19.9+/-0.3 2753 27D 53' 39.0" +/- 2" V-R = 0.6+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 10 STAR-1803- STAR RA=18H 03M 35.8S +/- 0.2S,DEC=- J2000 V = 19.0+/-0.3 2942 29D 42' 01.0" +/- 2" V-R = 0.9+/-0.2 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 0.0 0.0 0.0 6756( 8) - 04/02/97 15:18 - [ 4] Visit: 01 Visit Requirements: ORIENT 93d to 93d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1800-2 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 827 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 5] Visit: 02 Visit Requirements: ORIENT 93d to 93d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1803-3 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 009 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 6] Visit: 03 Visit Requirements: ORIENT 93d to 93d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1804-3 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 005 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 7] Visit: 04 Visit Requirements: ORIENT 89d to 89d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1807-2 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 939 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 8] Visit: 05 Visit Requirements: ORIENT 104d to 104d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1807-3 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 109 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 9] Visit: 06 Visit Requirements: ORIENT 90d to 90d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1813-2 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 631 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 10] Visit: 07 Visit Requirements: ORIENT 7d to 7d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1807-2 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 731 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 11] Visit: 08 Visit Requirements: ORIENT 84d to 84d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1804-3 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 012 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 12] Visit: 09 Visit Requirements: ORIENT 90d to 90d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1806-2 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=LINE, 1 260 S 753 DITHER-LINE-STEPS=6, DITHER-LINE-SPACING=0.4714 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 13] Visit: 10 Visit Requirements: ORIENT 80d to 80d On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-1803-2 WFPC2 IMAGE PC1 F814W CLOCKS=YES,DITHER-TYPE=BOX 1 160 S 942 ------------------------------------------------------------------------------------------------------------------------------------ 2 STAR-1803-2 WFPC2 IMAGE PC1 F555W CLOCKS=YES,DITHER-TYPE=LINE, 1 400 S 942 DITHER-LINE-STEPS=2, DITHER-LINE-SPACING=0.3535 ------------------------------------------------------------------------------------------------------------------------------------ 6756( 8) - 04/02/97 15:18 - [ 14] Summary Form for Proposal 6756 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CLOCKS=YES DITHER-TYPE=LINE DITHER-LINE-STEPS=6 DITHER-LINE-SPACING=0.4714 DITHER-TYPE=BOX DITHER-LINE-SPACING=0.3535 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR POPULATIONS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 93d to 93d ORIENT 89d to 89d ORIENT 104d to 104d ORIENT 90d to 90d ORIENT 7d to 7d ORIENT 84d to 84d ORIENT 80d to 80d ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names STAR-1800-2827 STAR-1803-3009 STAR-1804-3005 STAR-1807-2939 STAR-1807-3109 STAR-1813-2631 STAR-1807-2731 STAR-1804-3012 STAR-1806-2753 STAR-1803-2942 ------------------------------------------------------------------------------------------------------------------------------------