12817( 6) - 21-Jun-2013 12:47:59 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12817 Version: 6 Check-in Time: 21-Jun-2013 12:47:59 STScI Edit Number: 1 Title Longevity of dark matter substructure in Abell 3827 ------------------------------------------------------------------------------------ Type Cycle GO 20 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Richard J. Massey University of Durham Y CoI: Prof. Douglas Clowe Ohio University Y CoI: Dr. Alastair C. Edge University of Durham N CoI: Mr. David R. Harvey University of Edinburgh, Institute for N Astronomy CoI: Dr. Thomas D. Kitching University of Edinburgh, Institute for N Astronomy CoI: Dr. Adrienne Leonard CEA/DSM/DAPNIA/Service d'Astrophysique N CoI: Dr. Julian Merten Jet Propulsion Laboratory N CoI: Prof. Daisuke Nagai Yale University N CoI: Dr. Prasenjit Saha Universitat Zurich, Theoretische Physik N CoI: Dr. Eric R. Tittley University of Edinburgh, Institute for N Astronomy CoI: Prof. Liliya L.R. Williams University of Minnesota - Twin Cities N ------------------------------------------------------------------------------------ Abstract We will investigate the interaction properties of dark matter, through the infall of substructure into a galaxy cluster with a rare dynamical history. Abell 3827 appears to have grown rapidly through several simultaneous mergers, and currently hosts the stellar remnants of five massive elliptical galaxies within 15 kpc of the core. Only one other well-studied cluster (Abell 2261) contains a distribution of baryonic matter that is even comparably corrugated - and a strong lens threaded through the core of Abell 3827 provides a unique gravitational handle on its distribution of dark matter. We will measure the late-stage dissipation of the dark matter halos that would have initially accompanied the infalling galaxies. The timescale for this dissipation is a key ingredient in models of structure formation. Most interestingly, our analysis of extant ground-based data also found dark matter offset from its stellar counterpart. This is predicted by numerical simulations if dark matter has (even a small) self-interaction cross section. If confirmed by a robust HST analysis, this result would achieve the same level of impact on fundamental physics as did HST confirmation of the Bullet Cluster offset between dark matter and gas. Constraints on both the tidal gravitational stripping and electroweak interactions of dark matter will be especially aided by the simultaneous measurement of multiple substructures within this single extended halo. This project will require UV, optical and NIR imaging, plus a combined strong-lensing, weak-lensing and flexion analysis. We request six orbits with WFC3/UVIS, ACS/WFC and WFC3/IR, and will also exploit new Chandra data already in the archive. ------------------------------------------------------------------------------------ 12817( 6) - 21-Jun-2013 12:47:59 - [ 2] Observations Description ------------------------ Multiband imaging with ACS/WFC, WFC3/UVIS and WFC3/IR of a single galaxy cluster. Real Time Justification ----------------------- None. Calibration Justification ------------------------- None. Additional Comments ------------------- There is a brightish (V=12.1) star nearby. The specified orients have been chosen to avoid that star. Different orients would also be acceptable; but if the orient changes, the POS TRAGs must also change. ------------------------------------------------------------------------------------ 12817( 6) - 21-Jun-2013 12:47:59 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 2 ACO3827-OFFS CLUSTER OF GALAXIES, RA=22H01M55.0446S +/- 0.1", J2000 V = 14 ET814 GRAVITATIONAL LENS, DEC=-59D57'14.85" +/- 0.1" MULTIPLE NUCLEI, RICH CLUSTER Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 ACO3827-OFFS CLUSTER OF GALAXIES, RA=22H01M57.9187S +/- 0.1", J2000 V = 14 ET606 GRAVITATIONAL LENS, DEC=-59D56'41.13" +/- 0.1" MULTIPLE NUCLEI, RICH CLUSTER Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 ACO3827-OFFS CLUSTER OF GALAXIES, RA=22H01M54.2069S +/- 0.1", J2000 V = 14 ET336 GRAVITATIONAL LENS, DEC=-59D56'58.66" +/- 0.1" MULTIPLE NUCLEI, RICH CLUSTER Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 5 ACO3827-OFFS CLUSTER OF GALAXIES, RA=22H01M54.5968S +/- 0.1", J2000 V = 14 ET160 GRAVITATIONAL LENS, DEC=-59D56'54.07" +/- 0.1" MULTIPLE NUCLEI, RICH CLUSTER Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 12817( 6) - 21-Jun-2013 12:47:59 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type LINE LINE Pattern_Purpose DITHER DITHER Number_Of_Points 2 2 Point_Spacing 6.10486 3.08553 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 91.16385 85.38987 Angle_Between_Sides Center_Pattern NO NO Pattern_Comments: Perform subpixel dithering, and ensure that there are at least 3 exposures across the ACS/WFC gap. ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BLOB WFC3-IR-DITHER-LINE Pattern_Purpose DITHER DITHER Number_Of_Points 2 2 Point_Spacing 5.183 0.636 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 41.859 131.788 Angle_Between_Sides Center_Pattern YES NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-MOS-DITH-LINE WFC3-UVIS-MOS-DITH-LINE Pattern_Purpose MOSAIC DITHER Number_Of_Points 3 2 Point_Spacing 2.4 0.119 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 85.754 33.606 Angle_Between_Sides Center_Pattern NO NO ------------------------------------------------------------------------------------------------------------------------------------ 12817( 6) - 21-Jun-2013 12:47:59 - [ 5] Visit: 01 Visit Requirements: SCHED 30%; ORIENT 31D TO 41 D On Hold Comments: Additional Comments: The F814W imaging should occur immediately after the F606W imaging and with the same orientation, to maximise thermal stability during the F814W exposures. To achieve full depth near the cluster core, one ACS/WFC detector covers it on both orbits; to enlarge the field of view, a different detector is centered for each orbit, with the other one covering an outlying region. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ACO3827-OFF ACS/WFC ACCUM WFCENTER F606W 1 610 S POS TARG 0, 0; PATTERN 1 SET606 see below 1 (2452 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ACO3827-OFF ACS/WFC ACCUM WFC2-FIX F814W 1 645 S POS TARG 0, 0; PATTERN 1 SET814 (2580 S) 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 ACO3827-OFF ACS/WFC ACCUM WFC1-FIX F814W 1 645 S POS TARG 1, -15; PATTERN SET814 see below 1 3 (2644 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACO3827-OFFSET606 1 ACS/WFC ACCUM WFCENTER F606W 1 1 none none 1 613.0 S ACO3827-OFFSET606 1 ACS/WFC ACCUM WFCENTER F606W 1 2 none none 1 613.0 S ACO3827-OFFSET606 1 ACS/WFC ACCUM WFCENTER F606W 2 1 none none 1 613.0 S ACO3827-OFFSET606 1 ACS/WFC ACCUM WFCENTER F606W 2 2 none none 1 613.0 S ACO3827-OFFSET814 2 ACS/WFC ACCUM WFC2-FIX F814W 1 1 none none 2 N/A ACO3827-OFFSET814 2 ACS/WFC ACCUM WFC2-FIX F814W 1 2 none none 2 N/A ACO3827-OFFSET814 2 ACS/WFC ACCUM WFC2-FIX F814W 2 1 none none 2 N/A ACO3827-OFFSET814 2 ACS/WFC ACCUM WFC2-FIX F814W 2 2 none none 2 N/A ACO3827-OFFSET814 3 ACS/WFC ACCUM WFC1-FIX F814W 1 1 none none 3 661.0 S ACO3827-OFFSET814 3 ACS/WFC ACCUM WFC1-FIX F814W 1 2 none none 3 661.0 S ACO3827-OFFSET814 3 ACS/WFC ACCUM WFC1-FIX F814W 2 1 none none 3 661.0 S ACO3827-OFFSET814 3 ACS/WFC ACCUM WFC1-FIX F814W 2 2 none none 3 661.0 S 12817( 6) - 21-Jun-2013 12:47:59 - [ 6] Visit: 02 Visit Requirements: SCHED 30%; ORIENT 10D TO 20 D 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ACO3827-OFF WFC3/IR MULTIAC IR-FIX F160W NSAMP=12, SAMP-SEQ=SPARS50 1 DEF LOW-SKY; PATTERN 3 1 SET160 CUM (2211.749 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACO3827-OFFSET160 1 WFC3/IR MULTIAC IR-FIX F160W 1 1 none none 1 N/A CUM ACO3827-OFFSET160 1 WFC3/IR MULTIAC IR-FIX F160W 1 2 none none 1 N/A CUM ACO3827-OFFSET160 1 WFC3/IR MULTIAC IR-FIX F160W 2 1 none none 1 N/A CUM ACO3827-OFFSET160 1 WFC3/IR MULTIAC IR-FIX F160W 2 2 none none 1 N/A CUM 12817( 6) - 21-Jun-2013 12:47:59 - [ 7] Visit: 03 Visit Requirements: SCHED 30%; ORIENT 0D TO 10 D 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ACO3827-OFF WFC3/UVI ACCUM UVIS-FIX F336W FLASH=9.0 1 940 S POS TARG 0, 0; PATTERN 2 SET336 S see below 1 (5871 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACO3827-OFFSET336 1 WFC3/UVI ACCUM UVIS-FIX F336W 1 1 none none 1 960.0 S S ACO3827-OFFSET336 1 WFC3/UVI ACCUM UVIS-FIX F336W 1 2 none none 1 960.0 S S ACO3827-OFFSET336 1 WFC3/UVI ACCUM UVIS-FIX F336W 2 1 none none 1 960.0 S S ACO3827-OFFSET336 1 WFC3/UVI ACCUM UVIS-FIX F336W 2 2 none none 2 997.0 S S ACO3827-OFFSET336 1 WFC3/UVI ACCUM UVIS-FIX F336W 3 1 none none 2 997.0 S S ACO3827-OFFSET336 1 WFC3/UVI ACCUM UVIS-FIX F336W 3 2 none none 2 997.0 S S 12817( 6) - 21-Jun-2013 12:47:59 - [ 8] Summary Form for Proposal 12817 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR-FIX, UVIS-FIX, WFC1-FIX, WFC2-FIX, WFCENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=9.0, NSAMP=12, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements LOW-SKY, ORIENT 0D TO 10 D, ORIENT 10D TO 20 D, ORIENT 31D TO 41 D, PATTERN 1 1, PATTERN 1 2, PATTERN 1 3, PATTERN 2 1, PATTERN 3 1, POS TARG 0, 0, POS TARG 1, -15, SCHED 30% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W, F336W, F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ACO3827-OFFSET160, ACO3827-OFFSET336, ACO3827-OFFSET606, ACO3827-OFFSET814 ------------------------------------------------------------------------------------------------------------------------------------