9977( 7) - 06/19/03 11:21 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9977 Version: 7 Check-in Date: 19-Jun-2003 11:18:10 1.Proposal Title: Gravitational Microlensing in the NGC 3314A-B Galaxy Pair ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 12 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: David Bennett University of Notre Dame CoI: Dr. Sun Hong Rhie University of Notre Dame N CoI: Dr. William Keel University of Alabama N CoI: Dr. Ian Bond University of Auckland N CoI: Dr. Philip Yock University of Auckland N ------------------------------------------------------------------------------------ 5. Abstract Determining the composition of the dark matter that dominates the masses of galaxies is an important unsolved problem, and the results of the MACHO Collaboration suggest that some of Milky Way's dark matter may be in the form of very old white dwarfs. However, some have argued that the excess of microlensing events seen by MACHO are due to a larger than expected microlensing rate for lens stars in the LMC itself or its tidal debris. We propose to address this question by detecting microlensing events in the line-of-sight galaxy pair NGC 3314 A & B. The large line-of-sight distance between these galaxies gives an optical depth that is 3-4 orders of magnitude larger than if the source stars and lenses were in the same galaxy, and the fact that the background galaxy is a spiral ensures that there will be a sufficient number of bright, non-variable source stars. Our proposed observations should have the sensitivity to detect microlensing by both ordinary stars and dark matter in NGC 3314A (the foreground galaxy). If there are dark matter microlensing events to be found, they can be clearly distinguished from stellar microlensing events because they will occur outside the visible disk of NGC 3314A. If baryonic dark matter is detected in NGC 3314A, we will be able to map its radial density variation. ------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 2] Observations Description ------------------------ We plan to use only single orbit visits so as to maximize number of visits and the the range of microlensing event time scales that we'll be sensitive to. We do not plan any filter changes during each visit, but we will get some color information by using the ACS WCF F606W filter in 1/4 to 1/3 of the visits. The majority of the visits will use the ACS WCF F475W filter since this offers the best sensitivity for our target stars which are typically highly magnified early B main sequence stars. In order to maximize our resolution, we plan to employ a 2* 2 square dither pattern of 0.5 pixel steps for each set of images (Lauer 1999). This will not give us the full Nyquist sampling in the F475W filter on the WFC, but a more complicated dither patter would cost too much observing time for our faint targets. We plan to use an image differencing technique similar to those proposed by Tomaney & Crotts (1996), Alard & Lupton (1998) and Lauer (1999) to analyze our data. (Our version has been developed by CoI Ian Bond.) One difficulty with this is that we will not be able to take all of the HST data with the same spacecraft orientation because the same orientation can only be maintained for a month or so. We plan to deal with this by ensuring that our data is taken at roll angles that are multiples of 30 degrees, so that there will be only 3 different orientations of the square pixels on this sky. We will also try to ensure that a large number of images over our two year program are taken at each orientation. This will result in relatively large data sets with each orientation that we can use to remove any orientation-specific systematic photometry errors. Finally, we also plan a time series of observations that will start with a slow tempo of observations every 2 weeks or so, and then increase toward the middle of the season to a rate of a couple visits per week. The tempo of observations will then decrease again in a mirror image of the first half of the observing season. There are several advantages of this plan. First it allows us to get reasonable sampling for events of different durations which is important because the durations are not well constrained in advance. It also allows us to schedule the bulk of the observations with telescope pointing far from the bright limb of the Earth which will decrease the background light levels and increase our photometric sensitivity. It is necessary to have two seasons of observations because the longest events are likely to last a year or so. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3314 GALAXY, SPIRAL RA=10H 37M 12.81S +/- 1", DEC=- J2000 B = 13.11 27D 41' 3.59" +/- 1" Coordinate Source: IMAGE_TIED_TO_GSC_FRAME 2 NGC3314-UP GALAXY, SPIRAL RA=10H 37M 12.81S +/- 1", DEC=- J2000 B = 13.11 27D 40' 40" +/- 1" Coordinate Source: IMAGE_TIED_TO_GSC_FRAME 3 NGC3314- GALAXY, SPIRAL RA=10H 37M 13.56S +/- 1", DEC=- J2000 B = 13.11 UPLEFT 27D 40' 54" +/- 1" Coordinate Source: IMAGE_TIED_TO_GSC_FRAME 9977( 7) - 06/19/03 11:21 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.265 Coordinate_Frame POS-TARG Pattern_Orient 20.67 Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 5] Visit: 01 Visit Priority: Visit Requirements: ORIENT 130D TO 130D BETWEEN 08-Jun-2003 AND 04-Jul-2003 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 6] Visit: 02 Visit Priority: Visit Requirements: ORIENT 130D TO 130D BETWEEN 30-Jun-2003 AND 12-Jul-2003 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 7] Visit: 03 Visit Priority: Visit Requirements: ORIENT 270D TO 270D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UP ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UP ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 8] Visit: 04 Visit Priority: Visit Requirements: ORIENT 315D TO 315D BETWEEN 18-Dec-2003 AND 26-Dec-2003 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 9] Visit: 05 Visit Priority: Visit Requirements: ORIENT 315D TO 315D AFTER 04 BY 7 D TO 15 D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 10] Visit: 06 Visit Priority: Visit Requirements: ORIENT 315D TO 315D BETWEEN 07-Jan-2004 AND 14-Jan-2004 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 11] Visit: 07 Visit Priority: Visit Requirements: ORIENT 315D TO 315D BETWEEN 13-Jan-2004 AND 20-Jan-2004 AFTER 06 BY 5 D TO 9 D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 12] Visit: 08 Visit Priority: Visit Requirements: ORIENT 315D TO 315D BETWEEN 20-Jan-2004 AND 27-Jan-2004 AFTER 07 BY 4 D TO 8 D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 13] Visit: 09 Visit Priority: Visit Requirements: ORIENT 315D TO 315D BETWEEN 27-Jan-2004 AND 02-Feb-2004 AFTER 08 BY 4 D TO 8 D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 14] Visit: 10 Visit Priority: Visit Requirements: ORIENT 315D TO 315D BETWEEN 02-Feb-2004 AND 10-Feb-2004 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UPL ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UPL ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 EFT C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 15] Visit: 11 Visit Priority: Visit Requirements: ORIENT 0D TO 0D BETWEEN 22-Feb-2004 AND 01-Mar-2004 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314 ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314 ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 16] Visit: 12 Visit Priority: Visit Requirements: ORIENT 0D TO 0D BETWEEN 03-Mar-2004 AND 10-Mar-2004 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314 ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314 ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 17] Visit: 13 Visit Priority: Visit Requirements: ORIENT 45D TO 45D BETWEEN 11-Mar-2004 AND 20-Mar-2004 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314 ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314 ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 18] Visit: 14 Visit Priority: Visit Requirements: ORIENT 45D TO 45D BETWEEN 22-Mar-2004 AND 05-Apr-2004 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314 ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314 ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 19] Visit: 15 Visit Priority: Visit Requirements: ORIENT 90D TO 90D BETWEEN 08-Apr-2004 AND 25-Apr-2004 AFTER 14 BY 15 D TO 30 D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UP ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UP ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 20] Visit: 16 Visit Priority: Visit Requirements: ORIENT 90D TO 90D AFTER 15 BY 33 D TO 50 D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC3314-UP ACS/WF ACCUM WFC2-FI F475W CR-SPLIT=NO 1 520 S PATTERN 1 10 C X ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC3314-UP ACS/WF ACCUM WFC2-FI F606W CR-SPLIT=NO 1 540 S PATTERN 1 20 C X ------------------------------------------------------------------------------------------------------------------------------------ 9977( 7) - 06/19/03 11:21 - [ 21] Summary Form for Proposal 9977 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC2-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 130D TO 130D BETWEEN 08-Jun-2003 AND 04-Jul-2003 PATTERN 1 10 PATTERN 1 20 ORIENT 130D TO 130D BETWEEN 30-Jun-2003 AND 12-Jul-2003 ORIENT 270D TO 270D ORIENT 315D TO 315D BETWEEN 18-Dec-2003 AND 26-Dec-2003 ORIENT 315D TO 315D AFTER 04 BY 7 D TO 15 D ORIENT 315D TO 315D BETWEEN 07-Jan-2004 AND 14-Jan-2004 ORIENT 315D TO 315D BETWEEN 13-Jan-2004 AND 20-Jan-2004 AFTER 06 BY 5 D TO 9 D ORIENT 315D TO 315D BETWEEN 20-Jan-2004 AND 27-Jan-2004 AFTER 07 BY 4 D TO 8 D ORIENT 315D TO 315D BETWEEN 27-Jan-2004 AND 02-Feb-2004 AFTER 08 BY 4 D TO 8 D ORIENT 315D TO 315D BETWEEN 02-Feb-2004 AND 10-Feb-2004 ORIENT 0D TO 0D BETWEEN 22-Feb-2004 AND 01-Mar-2004 ORIENT 0D TO 0D BETWEEN 03-Mar-2004 AND 10-Mar-2004 ORIENT 45D TO 45D BETWEEN 11-Mar-2004 AND 20-Mar-2004 ORIENT 45D TO 45D BETWEEN 22-Mar-2004 AND 05-Apr-2004 ORIENT 90D TO 90D BETWEEN 08-Apr-2004 AND 25-Apr-2004 AFTER 14 BY 15 D TO 30 D ORIENT 90D TO 90D AFTER 15 BY 33 D TO 50 D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W F606W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3314-UPLEFT NGC3314-UP NGC3314 ------------------------------------------------------------------------------------------------------------------------------------