14165( 13) - 27-Apr-2016 18:45:05 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14165 Version: 13 Check-in Time: 27-Apr-2016 18:45:05 STScI Edit Number: 6 Title Revealing the largest gravitational lens PLCK G287.0+32.9 ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Stella Seitz Universitats-Sternwarte Munchen Y CoI: Dr. Anna Monna Universitats-Sternwarte Munchen N CoI: Dr. Daniel Gruen Stanford University N CoI: Dr. Adi Zitrin California Institute of Technology N CoI: Dr. Johannes Koppenhoefer Max-Planck-Institut fur extraterrestrische N Physik CoI: Dr. Italo Balestra INAF, Osservatorio Astronomico di Trieste N CoI: Dr. Anton M. Koekemoer Space Telescope Science Institute Y CoI: Mario Nonino INAF, Osservatorio Astronomico di Trieste N CoI: Dr. Marisa Girardi Universita degli Studi di Trieste N CoI: Dr. Amata Mercurio INAF, Osservatorio Astronomico di N Capodimonte ------------------------------------------------------------------------------------ Abstract We propose to investigate the peculiar and extremely large gravitational lens PLCK G287.0+32.9, discovered as one of the most massive objects in SZ measurements by Planck. Our follow-up of the cluster with optical WFI ground based imaging shows evident strong lensing features in the cluster core. The outer arcs, confirmed at z=1.167 from our recent VIMOS observations, is at a distanceof ~85" from the brightest and centrally located galaxy of the cluster, which makes PLCK G287.0+32.9 a candidate for the largest strong lens in the sky. If confirmed, this would significantly add to the tension of observed Einstein radii with predictions from Lambda-CDM. To this end, we require high resolution spatial imaging of the cluster to verify its large lensing features and further investigate its properties. Our goal is to use the HST photometry with our recent VLT/VIMOS spectroscopic datasets to perform a robust and detailed strong lensing analysis of this cluster. We aim to trace the total mass distribution of PLCK G287.0+32.9 by combining the strong lensing features with our WFI weak lensing analysis. ------------------------------------------------------------------------------------ Observations Description ------------------------ According to our science project, we require observations of the core of the galaxy cluster PLCKG287.0+32.9 in 3 ACS/WFC filters (F475W, F606W and F814W) and 1 WFC3/IR filter (F110W). The rationale for using these filters is as follows. In order to detect arcs and their faint counter images we need filters with high throughput. Lensing is achromatic, which is why measuring at least one colour with good signal-to-noise ratio is essential for multiple images confirmation. Finally we want to be sensitive to lensed galaxies with various SED properties in a large redshift range. Having F110W band as the reddest filter, in addition allows us to detect F814W dropouts, which are candidate for magnified galaxies at redshift z > 7. 14165( 13) - 27-Apr-2016 18:45:05 - [ 2] The ACS/WFC filters F475W and F606W will be essential to photometrically select cluster members which we need to include in the strong lensing model to accurately trace the total mass distribution of the galaxy cluster. These two filters will be used to select candidate cluster members from the cluster red sequence, in combination with information from the sample of spectroscopically confirmed members from the VLT/VIMOS program. In addition, for the lens modelling of the galaxies in the cluster we need to relate the luminosity to the depth of their potential (using the Faber-Jackson and Fundamental Plane relations, see e.g. Faber et al. 1976, 1987, Bender et al. 1992). According to our previous experience, the F814W and F110W filters provide the smaller scatter estimate for the halo potential depth (i.e. velocity dispersion). Taking together, our set of 4 filters covers the entire wavelength range from 3800 to 14000 A. This will allow us to identify optical dropout candidates at z = [4:8; 6:8] robustly. If a multiply imaged galaxy is found only in the F110W filter, it could have a redshift up to 10. This could then be confirmed through the strong lensing model, following the procedure in Zitrin et al. (2014). In addition to allowing for the identification of multiply imaged objects and high redshift galaxies, the chosen filter set will help us to characterize the cluster galaxy population. For example, the F475W filter allows us to investigate whether galaxies which have elliptical morphology have undergone recent star formation triggered by the ongoing merger of the galaxy cluster. Exposure time estimations: Concerning the depths of the observations, the dithered pattern and cosmic rays split, we will follow our successful strategy from CLASH. Thus we require the following exposure time per filter: F475W 4x500s = 2000s (1700-2200s) "1 orbit" F606W 4x500s = 2000s (1700-2200s) "1 orbit" F814W 8x500s = 4000s (3900-4200s) "2 orbits" F110W 10x500s = 5000s (4900-5100s) "2 orbits". These exposures will give us the following depths (5 magnitude limits for a point source): F475W: 27.5 mag F606W: 27.6 mag F814W: 27.0 mag F110W: 28.2 mag For the mean cluster redshift in CLASH (zcl ~ 0:4) such a depth allowed for a robust identification of 10 to 20 multiply imaged systems over a broad redshift range per cluster, which is needed for a precise strong lensing model. We have already identified several strong lensing features spread over 160" in diameter. We can cover them with one pointing for the case of ACS/WFC, but need two pointings with the WFC3/IR. We have outlined roughly our pointing strategy in Fig. 3. By allowing the overlap of the WFC3/IR pointings in the central region of the cluster we will get even deeper there. This will help us to find central images for high-z lensed systems. Such a detection would make the case for high redshift galaxies even stronger, see Monna et al. (2014). The brightest star in the proposed pointings is comparable to the bright star in the core of the CLASH cluster MACS 0416, and still fainter than the brightest 14165( 13) - 27-Apr-2016 18:45:05 - [ 3] stars in the COSMOS field. Hence, it will not cause technical problems in the observations. ------------------------------------------------------------------------------------ 14165( 13) - 27-Apr-2016 18:45:05 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PLCKESZ-G287 CLUSTER OF GALAXIES, RA=11H50M51.2000S, J2000 V = 20 .0+32.9-CENT GRAVITATIONAL LENS DEC=-28D05'0.80" ER Reference Frame: Other: SIMBAD ------------------------------------------------------------------------------------------------------------------------------------ 3 PLCKESZ-G287 CLUSTER OF GALAXIES, RA=11H50M53.3000S, J2000 V = 20 .0+32.9-EAST GRAVITATIONAL LENS DEC=-28D05'9.60" Reference Frame: Other: SIMBAD ------------------------------------------------------------------------------------------------------------------------------------ 2 PLCKESZ-G287 CLUSTER OF GALAXIES, RA=11H50M46.8000S, J2000 V = 20 .0+32.9-WEST GRAVITATIONAL LENS DEC=-28D04'38.50" Reference Frame: Other: SIMBAD ------------------------------------------------------------------------------------------------------------------------------------ 14165( 13) - 27-Apr-2016 18:45:05 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 3.06806 Line_Spacing 6.06746 Coordinate_Frame POS-TARG Pattern_Orient 85.38230 Angle_Between_Sides 174.21599 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 5.183 Line_Spacing 0.365 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 14165( 13) - 27-Apr-2016 18:45:05 - [ 6] Visit: 01 Visit Requirements: ORIENT 133D TO 133 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 PLCKESZ-G28 ACS/WFC ACCUM WFCENTER F475W 1 540 S PATTERN 1 1 7.0+32.9-CE (2160 S) NTER ------------------------------------------------------------------------------------------------------------------------------------ 2 PLCKESZ-G28 ACS/WFC ACCUM WFCENTER F606W 1 580 S PATTERN 1 2 7.0+32.9-CE (2320 S) NTER ------------------------------------------------------------------------------------------------------------------------------------ 3 PLCKESZ-G28 ACS/WFC ACCUM WFCENTER F814W 1 580 S PATTERN 1 3 7.0+32.9-CE (2320 S) NTER ------------------------------------------------------------------------------------------------------------------------------------ 4 PLCKESZ-G28 ACS/WFC ACCUM WFCENTER F814W 1 590 S PATTERN 1 4 7.0+32.9-CE (2360 S) NTER ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ PLCKESZ-G287.0+32.9 1 ACS/WFC ACCUM WFCENTER F475W 1 none none none 1 N/A -CENTER PLCKESZ-G287.0+32.9 1 ACS/WFC ACCUM WFCENTER F475W 2 none none none 1 N/A -CENTER PLCKESZ-G287.0+32.9 1 ACS/WFC ACCUM WFCENTER F475W 3 none none none 1 N/A -CENTER PLCKESZ-G287.0+32.9 1 ACS/WFC ACCUM WFCENTER F475W 4 none none none 1 N/A -CENTER PLCKESZ-G287.0+32.9 2 ACS/WFC ACCUM WFCENTER F606W 1 none none none 2 N/A -CENTER PLCKESZ-G287.0+32.9 2 ACS/WFC ACCUM WFCENTER F606W 2 none none none 2 N/A -CENTER PLCKESZ-G287.0+32.9 2 ACS/WFC ACCUM WFCENTER F606W 3 none none none 2 N/A -CENTER PLCKESZ-G287.0+32.9 2 ACS/WFC ACCUM WFCENTER F606W 4 none none none 2 N/A -CENTER PLCKESZ-G287.0+32.9 3 ACS/WFC ACCUM WFCENTER F814W 1 none none none 3 N/A -CENTER PLCKESZ-G287.0+32.9 3 ACS/WFC ACCUM WFCENTER F814W 2 none none none 3 N/A -CENTER 14165( 13) - 27-Apr-2016 18:45:05 - [ 7] 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 | ------------------------------------------------------------------------------------------------------------------------------------ PLCKESZ-G287.0+32.9 3 ACS/WFC ACCUM WFCENTER F814W 3 none none none 3 N/A -CENTER PLCKESZ-G287.0+32.9 3 ACS/WFC ACCUM WFCENTER F814W 4 none none none 3 N/A -CENTER PLCKESZ-G287.0+32.9 4 ACS/WFC ACCUM WFCENTER F814W 1 none none none 4 N/A -CENTER PLCKESZ-G287.0+32.9 4 ACS/WFC ACCUM WFCENTER F814W 2 none none none 4 N/A -CENTER PLCKESZ-G287.0+32.9 4 ACS/WFC ACCUM WFCENTER F814W 3 none none none 4 N/A -CENTER PLCKESZ-G287.0+32.9 4 ACS/WFC ACCUM WFCENTER F814W 4 none none none 4 N/A -CENTER 14165( 13) - 27-Apr-2016 18:45:05 - [ 8] Visit: 02 Visit Requirements: ORIENT 110D TO 110 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 PLCKESZ-G28 WFC3/IR MULTIAC IR F110W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF GS ACQ SCENARIO BASE1B3; 7.0+32.9-WE CUM (2611.753 PATTERN 2 1 ST S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PLCKESZ-G28 WFC3/IR MULTIAC IR F110W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF PATTERN 2 2 7.0+32.9-WE CUM (2611.753 ST S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PLCKESZ-G28 WFC3/IR MULTIAC IR F110W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF PATTERN 2 3 7.0+32.9-EA CUM (2611.753 ST S) ------------------------------------------------------------------------------------------------------------------------------------ 4 PLCKESZ-G28 WFC3/IR MULTIAC IR F110W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF PATTERN 2 4 7.0+32.9-EA CUM (2611.753 ST 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 | ------------------------------------------------------------------------------------------------------------------------------------ PLCKESZ-G287.0+32.9 1 WFC3/IR MULTIAC IR F110W 1 none none none 1 N/A -WEST CUM PLCKESZ-G287.0+32.9 1 WFC3/IR MULTIAC IR F110W 2 none none none 1 N/A -WEST CUM PLCKESZ-G287.0+32.9 1 WFC3/IR MULTIAC IR F110W 3 none none none 1 N/A -WEST CUM PLCKESZ-G287.0+32.9 1 WFC3/IR MULTIAC IR F110W 4 none none none 1 N/A -WEST CUM PLCKESZ-G287.0+32.9 2 WFC3/IR MULTIAC IR F110W 1 none none none 2 N/A -WEST CUM PLCKESZ-G287.0+32.9 2 WFC3/IR MULTIAC IR F110W 2 none none none 2 N/A -WEST CUM PLCKESZ-G287.0+32.9 2 WFC3/IR MULTIAC IR F110W 3 none none none 2 N/A -WEST CUM PLCKESZ-G287.0+32.9 2 WFC3/IR MULTIAC IR F110W 4 none none none 2 N/A -WEST CUM PLCKESZ-G287.0+32.9 3 WFC3/IR MULTIAC IR F110W 1 none none none 3 N/A -EAST CUM PLCKESZ-G287.0+32.9 3 WFC3/IR MULTIAC IR F110W 2 none none none 3 N/A -EAST CUM 14165( 13) - 27-Apr-2016 18:45:05 - [ 9] 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 | ------------------------------------------------------------------------------------------------------------------------------------ PLCKESZ-G287.0+32.9 3 WFC3/IR MULTIAC IR F110W 3 none none none 3 N/A -EAST CUM PLCKESZ-G287.0+32.9 3 WFC3/IR MULTIAC IR F110W 4 none none none 3 N/A -EAST CUM PLCKESZ-G287.0+32.9 4 WFC3/IR MULTIAC IR F110W 1 none none none 4 N/A -EAST CUM PLCKESZ-G287.0+32.9 4 WFC3/IR MULTIAC IR F110W 2 none none none 4 N/A -EAST CUM PLCKESZ-G287.0+32.9 4 WFC3/IR MULTIAC IR F110W 3 none none none 4 N/A -EAST CUM PLCKESZ-G287.0+32.9 4 WFC3/IR MULTIAC IR F110W 4 none none none 4 N/A -EAST CUM 14165( 13) - 27-Apr-2016 18:45:05 - [ 10] Summary Form for Proposal 14165 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, WFCENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=14, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3, ORIENT 110D TO 110 D, ORIENT 133D TO 133 D, PATTERN 1 1, PATTERN 1 2, PATTERN 1 3, PATTERN 1 4, PATTERN 2 1, PATTERN 2 2, PATTERN 2 3, PATTERN 2 4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F475W, F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PLCKESZ-G287.0+32.9-CENTER, PLCKESZ-G287.0+32.9-EAST, PLCKESZ-G287.0+32.9-WEST ------------------------------------------------------------------------------------------------------------------------------------