10863( 3) - 06/02/06 13:32 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10863 Version: 3 Check-in Time: 02-Jun-2006 17:32:23 STScI Edit Number: Title Magnifying the High-z Universe with the Bullet Cluster 1E0657-56 ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 15 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Anthony H. Gonzalez University of Florida CoI: Dr. Marusa Bradac Stanford University N CoI: Dr. Douglas Clowe University of Arizona N CoI: Dr. Dennis Zaritsky University of Arizona N CoI: Dr. Christine Jones Smithsonian Institution Astrophysical N Observatory CoI: Dr. Maxim Markevitch Smithsonian Institution Astrophysical N Observatory CoI: Dr. William R. Forman Smithsonian Institution Astrophysical N Observatory CoI: Dr. Scott Randall Smithsonian Institution Astrophysical N Observatory ------------------------------------------------------------------------------------ Abstract We propose to use the bullet cluster 1E0657-56 (z=0.296) as a gravitational telescope to conduct a pencil beam survey of the galaxy population to z=7. The cluster 1E0657-56, one of the hottest and most X-ray luminous clusters known, is a highly efficient lens with critical curves comparable in size to Abell 1689. The proposed observations will yield a high-fidelity strong+weak lensing map of the cluster core, enabling identification of lensed, high-redshift sources and also providing a precision measurement of the cluster mass (good to 5% within 350 kpc). The mass measurement will also serve as a key input for numerical simulations designed to reconstruct the dynamical history of the cluster merger and provide a new constraint on the dark matter self-interaction cross-section. In the cluster core the requested imaging will reach (de-magnified) magnitudes comparable to the Hubble Ultra Deep Field for lensed sources, but with 2+ magnitudes of magnification facilitating spectroscopic follow-up. ------------------------------------------------------------------------------------ 10863( 3) - 06/02/06 13:32 - [ 2] Observations Description ------------------------ The goals of this program are to conduct a pencil-beam survey of high-z galaxies using 1E0657 as a gravitational telescope to probe to fainter magnitudes than would otherwise be possible, and to derive a detailed strong lensing map for the cluster core. The resolution of HST/ACS is critical to this program both for identification of counter-images that are used to refine the strong lensing map, and for identification of the high-z, lensed galaxies that are the focus of this program. Required area: Our program can be achieved with one ACS pointing covering the core of 1E0657. For the requested central pointing location all the arcs and multiple images associated with the cluster core (including two red arcs near the ICM peak) will lie within the ACS field of view for arbitrary roll angle. Required Filters: We require two filters, F850LP and F775W, for identification of counter images and constraining the redshifts of the high-z sources. F850LP is chosen rather than F814W because use of the redder band enables detection of background sources to z~7, which can have colors F814W-F850LP>2. For the bluer band we select F775W rather than F814W to provide a more extended color baseline when identifying counter-images of lower redshift sources. Required Depth: We will be observing for 5 orbits in F850LP and 4 in F775W. Our target sensitifity for this program is F850LP=25 mag per sq. arcsec (AB, 5 sigma) for typical arcs (equivalent to 26.2 mag 5-sigma detection for galaxies with r=0.3"), which we consider an optimal tradeoff between depth and practicality. At this limiting magnitude we would detect two images of the Kneib et al. arc at z~7, which is magnified by a factor of 25. We require comparable depth in F775W for color identification of counter images when constructing the strong lensing map. For star forming galaxies at z=2-6, F850LP-F775W~0-0.3 (AB0, and z>5 candidates are usually selected via F775W- F850LP>0.9. To enable comparable dropout selection in this work down to F850LP=26.2, we set the limiting magnitude to F775W=26.9 (3 sigma). To calculate the exposure times we assumed that the area for a typical arclet is equivalent to a circle of diameter 0.7" -- consistent with observed arclets in 1E0657 -- and require S/N=3 for 3x3 pixel resolution elements. For these requirements and the desired limiting surface brightness, the ACS ETC indicates nominal exposure times of 14 ks in F850LP and 9 ks in F775W. These estimates are also consistent with the Kneib et al. study, for which the authors had 5 orbits in F850LP. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 10863( 3) - 06/02/06 13:32 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 1E0657-56 CLUSTER OF GALAXIES, RA=06H58M34.0000S +/- 0.1", J2000 V = 25.0 GRAVITATIONAL LENS, DEC=-55D57'5.00" +/- 0.1" RICH CLUSTER Reference Frame: ICRS 10863( 3) - 06/02/06 13:32 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE ACS-WFC-DITHER-BOX Pattern_Purpose DITHER DITHER Number_Of_Points 2 4 Point_Spacing 3.011 0.265 Line_Spacing 0.187 Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 85.28 20.67 Angle_Between_Sides 69.05 Center_Pattern YES NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE ACS-WFC-DITHER-BOX Pattern_Purpose DITHER DITHER Number_Of_Points 3 4 Point_Spacing 3.011 0.265 Line_Spacing 0.187 Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 85.28 20.67 Angle_Between_Sides 69.05 Center_Pattern YES NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE ACS-WFC-DITHER-LINE Pattern_Purpose DITHER DITHER Number_Of_Points 2 2 Point_Spacing 3.011 0.15 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 85.28 34.13 Angle_Between_Sides Center_Pattern YES NO Pattern_Comments: Please verify that the subpattern is entered correctly. What I'm trying to do is use pattern 11 for the main pattern, with pattern 12 as the subpattern for dithering on small scales. I changed the point spacing and orientation by hand, but am not 100% sure that the subpatter is correctly implemented. Thanks. ------------------------------------------------------------------------------------------------------------------------------------ 10863( 3) - 06/02/06 13:32 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 4 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 3.011 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 85.28 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 5 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.265 Line_Spacing 0.187 Coordinate_Frame POS-TARG Pattern_Orient 20.67 Angle_Between_Sides 69.05 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 10863( 3) - 06/02/06 13:32 - [ 6] Visit: 01 Visit Priority: Visit Requirements: ORIENT 275.0D TO 300.0 D; GROUP 01, 02 WITHIN 14.0D 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 1E0657-56 ACS/WFC ACCUM WFC F775W CR-SPLIT=NO 1 1200 S PATTERN 1 1 see below ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 1E0657-56 1 ACS/WFC ACCUM WFC F775W 1 1 none none 1 1236.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F775W 1 2 none none 1 1236.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F775W 1 3 none none 2 1275.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F775W 1 4 none none 2 1275.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F775W 2 1 none none 3 1277.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F775W 2 2 none none 3 1277.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F775W 2 3 none none 4 1287.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F775W 2 4 none none 4 1287.0 S 10863( 3) - 06/02/06 13:32 - [ 7] Visit: 02 Visit Priority: Visit Requirements: SAME ORIENT AS 01 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 1E0657-56 ACS/WFC ACCUM WFC F850LP CR-SPLIT=NO 1 1200 S PATTERN 1 1 see below ------------------------------------------------------------------------------------------------------------------------------------ 2 1E0657-56 ACS/WFC ACCUM WFC F850LP CR-SPLIT=NO 1 1200 S POS TARG 0.494, 5.968; see below PATTERN 4 2 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 1E0657-56 1 ACS/WFC ACCUM WFC F850LP 1 1 none none 1 1236.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F850LP 1 2 none none 1 1236.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F850LP 1 3 none none 2 1275.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F850LP 1 4 none none 2 1275.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F850LP 2 1 none none 3 1277.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F850LP 2 2 none none 3 1277.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F850LP 2 3 none none 4 1274.0 S 1E0657-56 1 ACS/WFC ACCUM WFC F850LP 2 4 none none 4 1274.0 S 1E0657-56 2 ACS/WFC ACCUM WFC F850LP 1 none none none 5 1285.0 S 1E0657-56 2 ACS/WFC ACCUM WFC F850LP 2 none none none 5 1285.0 S 10863( 3) - 06/02/06 13:32 - [ 8] Summary Form for Proposal 10863 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 275.0D TO 300.0 D; GROUP 01, 02 WITHIN 14.0D; PATTERN 1 1; SAME ORIENT AS 01; POS TARG 0.494, 5.968; PATTERN 4 2; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F775W F850LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names 1E0657-56 ------------------------------------------------------------------------------------------------------------------------------------