13756( 2) - 23-Jul-2014 19:54:25 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13756 Version: 2 Check-in Time: 23-Jul-2014 19:54:25 STScI Edit Number: 0 Title Rings within Rings: High Resolution Imaging of a Spectacular Gravitational Lens ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Saurabh W. Jha Rutgers the State University of New Jersey Y CoI: Dr. Armin Rest Space Telescope Science Institute N CoI: Mr. Peter Challis Harvard University N CoI: Prof. Robert P. Kirshner Harvard University N CoI: Dr. Ryan Foley University of Illinois at Urbana - N Champaign CoI: Dr. Thomas Matheson National Optical Astronomy Observatory, N AURA CoI: Prof. Felipe Menanteau University of Illinois at Urbana - N Champaign CoI: Dr. John P. Hughes Rutgers the State University of New Jersey N CoI: Prof. Charles R. Keeton Rutgers the State University of New Jersey N CoI: Mr. Amitpal Tagore Rutgers the State University of New Jersey N CoI: Mr. Curtis McCully Rutgers the State University of New Jersey N ------------------------------------------------------------------------------------ Abstract We propose WFC3 optical and infrared imaging of the largest, nearly-complete Einstein ring known. The ring has an extreme diameter, approximately 20 arcseconds, and is the result of gravitational lensing by a massive cluster elliptical galaxy at z = 0.36. This spectacular system shows two source galaxies (perhaps interacting), resulting in double arcs with striking differences in color. The proposed high resolution images will unveil detailed structure in the ring arcs (which exhibit a complex structure), allowing for the identification of multiply imaged regions in the source galaxies. Modelling the images over the full range of position angles around the rings will provide the best constraints on the lens mass distribution, and will connect observations and models from galaxy to cluster scales. These data will allow for the study of spatially resolved star-formation in the source galaxies, and enable additional followup through a more democratic window to the high-redshift Universe. ------------------------------------------------------------------------------------ Observations Description ------------------------ The ring features observed in the ground-based images range in surface brightness from 24 to 25 AB mag/arcsec^2 in Sloan g, and 23 to 24 AB mag/arcsec^2 in i. To achieve a S/N ~ 5 for the faintest of these in a 0.2 arcsec radius aperture requires ~1000 sec in F555W and F775W with WFC3/UVIS according to the WFC3 ETC; with overhead this corresponds to one orbit for the optical observations. We choose WFC3/UVIS rather than ACS/WFC to get the best possible spatial resolution (smaller pixels); to this end we will employ a standard dither pattern to subsample and eliminate pixel artifacts. 13756( 2) - 23-Jul-2014 19:54:25 - [ 2] We will also obtain one orbit of WFC3/IR F160W imaging to study at high resolution the red arcs that are bright in the IR and potentially find more distant lensed images. Coordinated parallel observations with ACS/WFC in F475W, F625W, and F775W will probe the lensing cluster environment, and a foreground cluster. ------------------------------------------------------------------------------------ 13756( 2) - 23-Jul-2014 19:54:25 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-CLUS-022 CLUSTER OF GALAXIES, RA=02H20M57.6870S, J2000 V = 19.5 +/- 0.5 058-38303 EINSTEIN RING, DEC=-38D33'3.47" GRAVITATIONAL LENS Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 13756( 2) - 23-Jul-2014 19:54:25 - [ 4] Visit: 01 Visit Requirements: 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 GAL-CLUS-02 WFC3/UVI ACCUM UVIS2 F555W 1 614 S (614 POS TARG -0.089, -1.203; 2058-38303 S S) PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 535 S (535 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-CLUS-02 WFC3/UVI ACCUM UVIS2 F555W 1 613 S (613 POS TARG 0.089, 1.203 2058-38303 S S) ------------------------------------------------------------------------------------------------------------------------------------ 4 GAL-CLUS-02 WFC3/UVI ACCUM UVIS2 F775W 1 670 S (670 POS TARG 0.089, 1.203; 2058-38303 S S) PAR 5 WITH 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 ANY ACS/WFC ACCUM WFC F475W 1 659 S (659 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 GAL-CLUS-02 WFC3/UVI ACCUM UVIS2 F775W 1 600 S (600 POS TARG -0.089, -1.203 2058-38303 S S) ------------------------------------------------------------------------------------------------------------------------------------ 7 GAL-CLUS-02 WFC3/IR MULTIAC IR F160W NSAMP=15, SAMP-SEQ=SPARS50 1 DEF POS TARG 0.000, 0.000; 2058-38303 CUM (702.939 PAR 8 WITH 7 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 ANY ACS/WFC ACCUM WFC F625W 1 577 S (577 S) ------------------------------------------------------------------------------------------------------------------------------------ 9 GAL-CLUS-02 WFC3/IR MULTIAC IR F160W NSAMP=15, SAMP-SEQ=SPARS50 1 DEF POS TARG 0.542, 0.182; 2058-38303 CUM (702.939 PAR 10 WITH 9 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 ANY ACS/WFC ACCUM WFC F625W 1 607 S (607 S) ------------------------------------------------------------------------------------------------------------------------------------ 11 GAL-CLUS-02 WFC3/IR MULTIAC IR F160W NSAMP=15, SAMP-SEQ=SPARS50 1 DEF POS TARG 0.339, 0.485; 2058-38303 CUM (702.939 PAR 12 WITH 11 S) ------------------------------------------------------------------------------------------------------------------------------------ 12 ANY ACS/WFC ACCUM WFC F775W 1 589 S (589 S) ------------------------------------------------------------------------------------------------------------------------------------ 13 GAL-CLUS-02 WFC3/IR MULTIAC IR F160W NSAMP=15, SAMP-SEQ=SPARS50 1 DEF POS TARG -0.203, 0.303; 2058-38303 CUM (702.939 PAR 14 WITH 13 S) 13756( 2) - 23-Jul-2014 19:54:25 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------------------------ 14 ANY ACS/WFC ACCUM WFC F775W 1 607 S (607 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 | ------------------------------------------------------------------------------------------------------------------------------------ GAL-CLUS-022058-383 1 WFC3/UVI ACCUM UVIS2 F555W none none none none 1 N/A 03 S ANY 2 ACS/WFC ACCUM WFC F475W none none none none 1 N/A GAL-CLUS-022058-383 3 WFC3/UVI ACCUM UVIS2 F555W none none none none 1 N/A 03 S GAL-CLUS-022058-383 4 WFC3/UVI ACCUM UVIS2 F775W none none none none 1 N/A 03 S ANY 5 ACS/WFC ACCUM WFC F475W none none none none 1 N/A GAL-CLUS-022058-383 6 WFC3/UVI ACCUM UVIS2 F775W none none none none 1 N/A 03 S GAL-CLUS-022058-383 7 WFC3/IR MULTIAC IR F160W none none none none 2 N/A 03 CUM ANY 8 ACS/WFC ACCUM WFC F625W none none none none 2 N/A GAL-CLUS-022058-383 9 WFC3/IR MULTIAC IR F160W none none none none 2 N/A 03 CUM ANY 10 ACS/WFC ACCUM WFC F625W none none none none 2 N/A GAL-CLUS-022058-383 11 WFC3/IR MULTIAC IR F160W none none none none 2 N/A 03 CUM ANY 12 ACS/WFC ACCUM WFC F775W none none none none 2 N/A GAL-CLUS-022058-383 13 WFC3/IR MULTIAC IR F160W none none none none 2 N/A 03 CUM ANY 14 ACS/WFC ACCUM WFC F775W none none none none 2 N/A 13756( 2) - 23-Jul-2014 19:54:25 - [ 6] Summary Form for Proposal 13756 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS2, WFC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=15, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PAR 10 WITH 9, PAR 12 WITH 11, PAR 14 WITH 13, PAR 2 WITH 1, PAR 5 WITH 4, PAR 8 WITH 7, POS TARG -0.089, -1.203, POS TARG -0.203, 0.303, POS TARG 0.000, 0.000, POS TARG 0.089, 1.203, POS TARG 0.339, 0.485, POS TARG 0.542, 0.182 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W, F475W, F555W, F625W, F775W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ANY, GAL-CLUS-022058-38303 ------------------------------------------------------------------------------------------------------------------------------------