6482( 4) - 02/17/97 11:41 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6482 Version: 4 Check-in Date: 17-Feb-1997 11:39:14 1.Proposal Title: Weak Lensing in the Field of Luminous Quasars. Masses of Groups of Galaxies and Magnification Bias. ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle COSMOLOGY GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Bernard Fort OBSERVATOIRE DE PARIS CoI: Peter Schneider Max-Planck-Institut fuer Astrophysik N CoI: Yannick Mellier Observatoire Midi-Pyrenees Y CoI: Matthias Bartelmann Max-Planck-Institut fuer Astrophysik N ------------------------------------------------------------------------------------ 6. Abstract Some relatively bright QSOs have long been suspected to be gravitationally magnified. We have found along the line of sight towards some of them a coherent shear pattern of faint distant galaxies. Moreover there appear to be overdensities of galaxies concentric with the shear patterns which are probably responsible for the weak lensing effect and the QSO magnifications. These concentrations seem to have sizes and masses comparable to those of groups or clusters of galaxies. Although the gravitational shear of the galaxies is easily seen from the ground, an accurate measurement of the mass and the M/L ratio of the concentration require observations with the WFPC2. , We have selected 3 QSOs from our ESO-CFHT survey for which a coherent shear pattern has been unambiguously detected. The proposed HST observations will determine the amount of dark matter in this new class of lensing masses first selected from their weak lensing effect. ------------------------------------------------------------------------------------ 6482( 4) - 02/17/97 11:41 - [ 2] Observations Description ------------------------ We want to measure the shear and the mass ditribution of the deflector responsible for the gravitational distortion with resolution of 30 arcsec. To overcome noise in the weak shear pattern arising from the intrinsic orientations and shapes of faint galaxies, we need to average these parameters from a large number of galaxies per cell. To get a signal/noise >3, we require an rms noise in the shear per cell better than 4%. This imposes to reach 80 galaxies per arcmin^-2, or I=24.5. We choose the F702W filter as it is the most efficient to go deep in the shortest time. To increase the detection level and the geometry of galaxies, we need low sky background and very good flat fields. Low sky visibility and small shifts between each exposures are important to meet our scientific goals. Real Time Justification ----------------------- None Calibration Justification ------------------------- None. Ground based imaging (VI) have been secured already and spectroscopic observations are scheduled for may 1996. Additional Comments ------------------- The target position is centered on the clump responsible for the shear. This is our initial position for the first exposure and from which shifts will be done. After the first exposure, we will shift of about 1 arcsec. according to POS TARG, in both X and Y directions to avoid simple shifts along the rows or the columns of the CCD. The position given in Target is our central initial position. We will keep the ORIENT unchanged for ALL the exposure, to minimize data processing before co-addition of images. Following the documentation we computed 48 mn for low sky visity at dec=-24 and 8mn overhead+3 mn CCD readout time for each new visit, or 6mn overhead+3mn CCD readout for subsequent orbits. This is why our exposure have 2400s. each. ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: ------------------------------------------------------------------------------------ 6482( 4) - 02/17/97 11:41 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PKS0135-247- GALAXY RA=1H 37M 35.4S +/- 0.1S, DEC=- J2000 Z=0.8310 V = 17.33 OFFSET 24D 31' 14.1" +/- 1.0" Comments: Target name and target position are our TRUE position, offsetted from the quasar position. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.0 0.0 0.0 0.0 6482( 4) - 02/17/97 11:41 - [ 4] Visit: 01 Visit Requirements: ORIENT 40D TO 50D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG +0.0, -OFFSET IX +0.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG +0.4, -OFFSET IX +0.2 ------------------------------------------------------------------------------------------------------------------------------------ 3 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG +0.8, -OFFSET IX +0.6 ------------------------------------------------------------------------------------------------------------------------------------ 4 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG -0.2, -OFFSET IX +0.4 ------------------------------------------------------------------------------------------------------------------------------------ 5 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG -0.6, -OFFSET IX +0.8 ------------------------------------------------------------------------------------------------------------------------------------ 6 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG -0.4, -OFFSET IX -0.2 ------------------------------------------------------------------------------------------------------------------------------------ 7 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG -0.8, -OFFSET IX -0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG +0.2, -OFFSET IX -0.4 ------------------------------------------------------------------------------------------------------------------------------------ 6482( 4) - 02/17/97 11:41 - [ 5] Visit: 02 Visit Requirements: SAME ORIENTation AS 1 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 9 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG +0.6, -OFFSET IX -0.8 ------------------------------------------------------------------------------------------------------------------------------------ 10 PKS0135-247 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2400 S LOW-SKY POS TARG -0.1, -OFFSET IX -0.7 ------------------------------------------------------------------------------------------------------------------------------------ 6482( 4) - 02/17/97 11:41 - [ 6] Summary Form for Proposal 6482 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COSMOLOGY ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 40D TO 50D LOW-SKY POS TARG +0.0,+0.0 LOW-SKY POS TARG +0.4,+0.2 LOW-SKY POS TARG +0.8,+0.6 LOW-SKY POS TARG -0.2,+0.4 LOW-SKY POS TARG -0.6,+0.8 LOW-SKY POS TARG -0.4,-0.2 LOW-SKY POS TARG -0.8,-0.6 LOW-SKY POS TARG +0.2,-0.4 SAME ORIENTation AS 1 LOW-SKY POS TARG +0.6,-0.8 LOW-SKY POS TARG -0.1,-0.7 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F702W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PKS0135-247-OFFSET ------------------------------------------------------------------------------------------------------------------------------------