! Proposal 5935, submission 1 ! PI: Ian Smail ! Received Fri Mar 31 15:50:41 EST 1995 ! From: lucas@stsci.edu ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5935,v 6.1 1995/12/20 18:54:04 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Ray Lucas ! Phone: 410 338-4716, E-mail: lucas@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Date generated: Sat Dec 17 10:51:32 EST 1994 ! Proposal_Information ! Section 4 Title: Gravitational Imaging in Well-Constrained Clusters: Absolute Masses and Faint Galaxy Redshifts Proposal_Category: GO Scientific_Category: Galaxies & Clusters Cycle: 5 Investigators PI_name: Ian Smail PI_Institution: OCIW CoI_Name: Richard Ellis CoI_Institution: Institute for Astronomy Contact: N ! Y or N (designate at most one contact) CoI_Name: Jean-Paul Kneib CoI_Institution: Institute for Astronomy Contact: N ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) The shear of faint galaxy images arising from gravitational lensing by foreground massive clusters provides important constraints on the distribution and total amount of mass in the clusters. Furthermore, in a few rare clusters, the lensing models may be sufficiently well-constrained by arcs and multiple images to yield robust redshift estimates for faint galaxies well beyond reach of current spectrographs. Ground- based telescopes suffer systematic degradations which reduce the detected shear by factors of ~2-3. Detecting the unadulterated shear pattern with HST will yield an absolute calibration of ground-based results and confirm or otherwise the high cluster mass/light ratios obtained so far. We propose deep WFPC-2 imaging of two of the most well-studied clusters for this purpose. Both have the rare distinction of having lensed features of known redshift which strongly constrain the absolute mass. When calibrated with the HST shear, not only will more reliable mass maps result, but the lensing equations can be inverted to provide statistical distances for large numbers of very faint field galaxies. These will be invaluable in studies of galaxy evolution and for subsequent lensing applications in other clusters. Questions ! Free format text (please update) Observing_Description: To fully exploit HST's unique capabilities for our proposed lensing study we require continous coverage of a sizeable area in the centre of each of our cluster. The area coverage must be contiguous and cover a field sufficient to adequately measure the morphology of the cluster mass to allow a robust inversion of the distribution in the redshift analysis. Moreover we require enough arclets in the outer regions to overcome noise in the weak shear pattern arising from the intrinsic orientations and shapes of faint galaxies. To accomplish this we have chosen four overlapping pointings. providing nearly complete coverage to a radius of 1.0-1.5 Mpc (H_o=50), and allowing for overlap, a ~20 arcmin^2 field. From ground-based images in sub-arcsecond seeing the induced shear at the 1.0 Mpc radius is 10--15% which determines the accuracy of the final mass reconstruction is the surface density of background galaxies. We propose to sample the mass map via a grid of 20 cells with 0.5 arcmin spacing. To get a signal/noise>3, we require an rms noise in the shear per cell of better than 3% an unfeasibly high surface density of background galaxies. However, the elimination of atmospheric seeing increases our shear sensitivity so that only 20--30 galaxies are required per cell using HST, corresponding to a surface density of ~50 galaxies arcmin^-2. We choose the F702W filter as it is the most efficient filter to reach a high surface density of background sources in the shortest time. Additionally, a long wavelength passband is the most appropriate for deep redshift surveys (c.f.\ Lilly 1993). A galaxy surface density of 50 arcmin^-2 is reached at a limiting magnitude of R_702=25.5. A deep limiting isophote is essential to ensure each faint image is sufficiently resolved for its shear to be reliably measured. We calculate that ~30 pixels above the 2 Sigma isophote in an R=25.5 galaxy will yield an orientation and ellipticity to the precision required from the considerations discussed above. Scaling from the deepest MDS blank field observations (available to RSE), this limiting isophote is found to be Mu_R = 30.2 mag pixel^-2. For a 2 Sigma detection of 30 pixels at this isophote, we calculate an exposure time of 17 ksec (6 orbits). With four pointings in the cluster and we are thus requesting a total of 24 orbits. We will additionally employ offsetting of each exposure by a small shift (1.0 arcsec) to further reduce the effects of flatfield errors. These deep exposures will provide high signal/noise mass maps in this cluster to ~1.5 Mpc with a resolution of 150-200 kpc in the outskirts and ~50 kpc in the core regions. The frames will also provide a sample of around 1000 field galaxies in the cluster for the redshift inversion. Real_Time_Justification: None. Calibration_Justification: None. Extensive ground-based imaging (UBVRIK) and spectroscopic data plus satellite X-ray images for the target have already been taken and analysed. Additional_Comments: According to the convention for WFPC2, coordinates as given in the FIXED TARGETS positions are shifted by POS TARG +10.0,+10.0 to bring the center to the apex of the pyramid. Exposures for a given field and are split into three groups with a shift introduced of +1.0 arcseconds in either X or Y, in order to displace objects situated on CCD defects or on the seams of the pyramid. Thus, POS TARG +11.0,+10.0 corresponds to the second group, POS TARG +10.0,+11.0 to the third. CR-SPLIT=NO for all observations since in all cases there are sufficient multiple exposures to perform cosmic ray rejection. Another very important factor is to to keep the ORIENT ANGLE the *SAME* for all exposures at POS1--POS4 in the cluster. This will simplify coadding the images and mosaicing the four different positions in the cluster together. Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: AC114-POS1 Alternate_Names: S1077-POS1 Description: CLUSTER OF GALAXIES, GRAVITATIONAL LENS, RICH CLUSTER Position: RA=22H 56M 01.91S +/- 0.1S, ! Most common specification format DEC=-35D 05' 05.4" +/- 2" ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 1950.0 RV_or_Z: Z=0.31 RA_PM: 0.0 ! Units are seconds of time per year Dec_PM: 0.0 ! Units are seconds of arc per year Epoch: 1950.0 Annual_Parallax: 0.0 Flux: R=25.5 V-R=1.5 ! Include at least V and B-V Comments: Fixed_Targets ! Section 5.1 Target_Number: 2 Target_Name: AC114-POS2 Alternate_Names: S1077-POS2 Description: CLUSTER OF GALAXIES, GRAVITATIONAL LENS, RICH CLUSTER Position: RA=22H 56M 01.96S +/- 0.1S, ! Most common specification format DEC=-35D 03' 16.5" +/- 2" ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 1950.0 RV_or_Z: Z=0.31 RA_PM: 0.0 ! Units are seconds of time per year Dec_PM: 0.0 ! Units are seconds of arc per year Epoch: 1950.0 Annual_Parallax: 0.0 Flux: R=25.5 V-R=1.5 ! Include at least V and B-V Comments: Exact position to be confirmed when roll-angle for AC114-POS1 is fixed in scheduling. Position may shift by +/-10 arcsec to retain chip alignment between the four pointings. Fixed_Targets ! Section 5.1 Target_Number: 3 Target_Name: AC114-POS3 Alternate_Names: S1077-POS3 Description: CLUSTER OF GALAXIES, GRAVITATIONAL LENS, RICH CLUSTER Position: RA=22H 56M 10.59S +/- 0.1S, ! Most common specification format DEC=-35D 05' 06.0" +/- 2" ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 1950.0 RV_or_Z: Z=0.31 RA_PM: 0.0 ! Units are seconds of time per year Dec_PM: 0.0 ! Units are seconds of arc per year Epoch: 1950.0 Annual_Parallax: 0.0 Flux: R=25.5 V-R=1.5 ! Include at least V and B-V Comments: Exact position to be confirmed when roll-angle for AC114-POS1 is fixed in scheduling. Position may shift by +/-10 arcsec to retain chip alignment between the four pointings. Fixed_Targets ! Section 5.1 Target_Number: 4 Target_Name: AC114-POS4 Alternate_Names: S1077-POS4 Description: CLUSTER OF GALAXIES, GRAVITATIONAL LENS, RICH CLUSTER Position: RA=22H 55M 53.17S +/- 0.1S, ! Most common specification format DEC=-35D 03' 16.1" +/- 2" ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: 1950.0 RV_or_Z: Z=0.31 RA_PM: 0.0 ! Units are seconds of time per year Dec_PM: 0.0 ! Units are seconds of arc per year Epoch: 1950.0 Annual_Parallax: 0.0 Flux: R=25.5 V-R=1.5 ! Include at least V and B-V Comments: Exact position to be confirmed when roll-angle for AC114-POS1 is fixed in scheduling. Position may shift by +/-10 arcsec to retain chip alignment between the four pointings. ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! Section 7.1 ORIENT 89.75D TO 90.25D GROUP 1-4 WITHIN 10D On_Hold_Comments: Visit_Comments: According to the convention for WFPC2 coordinates as given in the FIXED TARGETS positions are shifted by POS TARG +10.0,+10.0 to bring the center to the apex of the pyramid. Exposures for a given field and are split into three groups with a shift introduced of +1.0 arcseconds in either X or Y, in order to displace objects situated on CCD defects or on the seams of the pyramid. Thus, POS TARG +11.0,+10.0 corresponds to the second group, POS TARG +10.0,+11.0 to the third. CR-SPLIT=NO for all observations since in all cases there are sufficient multiple exposures to perform cosmic ray rejection. Another very important factor is to to keep the ORIENT ANGLE the *SAME* for all exposures at POS1--POS4 This will simplify coadding the images and mosaicing the four different positions in the cluster together. ORIENT range is 90 +10/-10 DEG due to bright stars outside the field. ( 90D +/- 10D = range of 80D to 100D as specified in the program's visit level requirements. ) NOTE: This was modified to a smaller range of 89.75D to 90.25D in order to help in generation of accurate plan windows after ORIENT was fixed at 90D in SOGS. This change and the subsequent re-PIPing was done at the request of the LRP Group. The actual period for scheduling at 90D is also only ~4 days long, from 3 January, 1996 - 7 January, 1996, but the LRP Group person said that the GROUP WITHIN 10D(ays) did not need to be changed to GROUP WITHIN 4D(ays), so that has been left "as is"... RAL - 11 October, 1995 Exposure_Number: 1 ! Section 6.5 Target_Name: AC114-POS1 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +10.0,+10.0 Comments: POS TARG +10,+10 PLACES TARGET COORDS AT APEX OF PYRAMID Exposure_Number: 2 ! Section 6.5 Target_Name: AC114-POS1 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +11.0,+10.0 Comments: SHIFTED BY 1.0,0.0 TO ALLOW REMOVAL OF CHIP DEFECTS Exposure_Number: 3 ! Section 6.5 Target_Name: AC114-POS1 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +10.0,+11.0 Comments: SHIFTED BY 0.0,1.0 TO ALLOW REMOVAL OF CHIP DEFECTS Visits ! Section 6 Visit_Number: 2 Visit_Requirements: ! Section 7.1 SAME ORIENT AS 1 On_Hold_Comments: Visit_Comments: Exposure_Number: 4 ! Section 6.5 Target_Name: AC114-POS2 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +10.0,+10.0 Comments: POS TARG +10,+10 PLACES TARGET COORDS AT APEX OF PYRAMID Exposure_Number: 5 ! Section 6.5 Target_Name: AC114-POS2 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +11.0,+10.0 Comments: SHIFTED BY 1.0,0.0 TO ALLOW REMOVAL OF CHIP DEFECTS Exposure_Number: 6 ! Section 6.5 Target_Name: AC114-POS2 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +10.0,+11.0 Comments: SHIFTED BY 0.0,1.0 TO ALLOW REMOVAL OF CHIP DEFECTS Visits ! Section 6 Visit_Number: 3 Visit_Requirements: ! Section 7.1 SAME ORIENT AS 1 On_Hold_Comments: Visit_Comments: Exposure_Number: 7 ! Section 6.5 Target_Name: AC114-POS3 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +10.0,+10.0 Comments: POS TARG +10,+10 PLACES TARGET COORDS AT APEX OF PYRAMID Exposure_Number: 8 ! Section 6.5 Target_Name: AC114-POS3 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +11.0,+10.0 Comments: SHIFTED BY 1.0,0.0 TO ALLOW REMOVAL OF CHIP DEFECTS Exposure_Number: 9 ! Section 6.5 Target_Name: AC114-POS3 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +10.0,+11.0 Comments: SHIFTED BY 0.0,1.0 TO ALLOW REMOVAL OF CHIP DEFECTS Visits ! Section 6 Visit_Number: 4 Visit_Requirements: ! Section 7.1 SAME ORIENT AS 1 On_Hold_Comments: Visit_Comments: Exposure_Number: 10 ! Section 6.5 Target_Name: AC114-POS4 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +10.0,+10.0 Comments: POS TARG +10,+10 PLACES TARGET COORDS AT APEX OF PYRAMID Exposure_Number: 11 ! Section 6.5 Target_Name: AC114-POS4 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +11.0,+10.0 Comments: SHIFTED BY 1.0,0.0 TO ALLOW REMOVAL OF CHIP DEFECTS Exposure_Number: 12 ! Section 6.5 Target_Name: AC114-POS4 Config: WFPC2 Opmode: IMAGE Aperture: WFALL-FIX Sp_Element: F702W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2300S Special_Requirements: ! Section 7.2 EXPAND POS TARG +10.0,+11.0 Comments: SHIFTED BY 0.0,1.0 TO ALLOW REMOVAL OF CHIP DEFECTS Data_Distribution ! Defaults indicated; change if desired Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 ! Only astronomers with very old 9- ! track tape drives should consider ! a blocking factor of 1 Ship_To: PI_address ! STSCI or PI_Address or ! ! ! Ship_Via: UPS ! UPS (2-day) or OVERNIGHT ! 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