8248( 4) - 06/21/99 14:55 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8248 Version: 4 Check-in Date: 05-Apr-1999 08:55:03 1.Proposal Title: WFPC2 observations of potential JVAS/CLASS gravitational lenses ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Peter Wilkinson University of Manchester CoI: Dr Ian Browne NRAL University of Manchester N CoI: Mr Daniel Marlow NRAL University of Manchester N CoI: Dr Neal Jackson Jodrell Bank, University of Manchester N CoI: Mr Chris Fassnacht California Institute of Technology N CoI: Dr Tony Readhead California Institute of Technology N CoI: Dr Tim Pearson California Institute of Technology N CoI: Prof Roger Blandford California Institute of Technology N CoI: Dr Steve Myers University of Pennsylvania N CoI: Dr Ger de Bruyn Netherlands Foundation for Radio Astronomy N CoI: Mr David Rusin University of Pennsylvania N CoI: Mr Leon Koopmans University of Groningen N ------------------------------------------------------------------------------------ 5. Abstract The JVAS/CLASS gravitational lens surveys have been the most successful so far at finding new arcsecond-scale gravitational lenses. A total of 17 confirmed systems have been discovered. One surprising result is the number of doubly-imaged lensed systems compared to ``quad'' configurations. The doubles are under-represented in the current JVAS/CLASS lens sample by a factor 5 based on conventional models of the lensing galaxies. This may be partly due to an observational selection bias that favours the discovery of quad lens sytems over doubles. It is essential to ensure that no doubly-imaged lensed systems are missed. Previous WFPC2 observations of candidate lens systems have proved remarkably successful at confirming new lensed systems by the detection of lensed images and the lensing galaxies. Recent Cycle 7 NICMOS observations of JVAS/CLASS candidate systems discovered three new lens systems. However, several ambiguous candidates from the first two phases of the CLASS survey remain and two very strong new candidates from the recently observed final phase of CLASS have also been uncovered. Based on the observed lensing rate in JVAS/CLASS (1:500) we expect that the majority of these candidates will turn out to be lenses. There is a companion proposal to this one which aims to examine confirmed cases of gravitational lensing in the JVAS/CLASS surveys in more detail. ------------------------------------------------------------------------------------ 8248( 4) - 06/21/99 14:55 - [ 2] Observations Description ------------------------ GALAXY, GRAVITATIONAL LENS The observations are aimed at detecting point objects of magnitude 20 (although J0935+073 is brighter) together with extended galaxies of integrated magnitudes down to about 20 to 21. In the 555 filter the point object will produce about 55 electrons per second. An extended galaxy of similar brightness will produce about 2 electrons per second in the central pixel assuming a redshift of about 0.6 and using the curve of figure 6.1. in the WFPC2 handbook. The figures for the 814 filter are roughly similar. We propose to take two exposures in each filter: one short (so as not to saturate on the point sources) and one long in order to search for any lensing galaxy. The available observing time per orbit is between 43 and 47 minutes, taking into account occultation and guide star acquisition. Allowing 16 minutes for exposure overheads (one CR-SPLIT=DEF and one NO-CR-SPLIT=DEF in each filter) this gives between 27 and 31 minutes for science exposures. In the deeper exposure in each filter we will therefore obtain about 12-15 minutes' integration. This will be enough to collect 1400 electrons in the central pixel of any lensing galaxy. The point sources will be easily detected in the short (~1 min) exposures. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: NO Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8248( 4) - 06/21/99 14:55 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J0307+105 GALAXY, GRAVITATIONAL RA=03H 7M 58.45S +/- 0.01S, 2000 V = 20 LENS DEC=10D 35' 50.85" +/- 0.05" 2 J0935+073 GALAXY, GRAVITATIONAL RA=09H 35M 1.07S +/- 0.01S, 2000 V = 20 LENS DEC=07D 19' 18.66" +/- 0.05" 3 B1152+199 GALAXY, GRAVITATIONAL RA=11H 55M 18.2971S +/- 0.01S, 2000 V = 20 LENS DEC=19D 39' 42.230" +/- 0.05" 4 J1546+082 GALAXY, GRAVITATIONAL RA=15H 46M .674S +/- 0.01S, 2000 V = 20 LENS DEC=08D 15' 3.10" +/- 0.05" 8248( 4) - 06/21/99 14:55 - [ 4] Visit: 01 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 J0307+105 WFPC2 IMAGE PC1 F555W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 15 J0307+105 WFPC2 IMAGE PC1 F814W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 8248( 4) - 06/21/99 14:55 - [ 5] Visit: 02 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 20 J0935+073 WFPC2 IMAGE PC1 F555W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 25 J0935+073 WFPC2 IMAGE PC1 F814W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 8248( 4) - 06/21/99 14:55 - [ 6] Visit: 03 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 30 B1152+199 WFPC2 IMAGE PC1 F555W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 35 B1152+199 WFPC2 IMAGE PC1 F814W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 8248( 4) - 06/21/99 14:55 - [ 7] Visit: 04 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 40 J1546+082 WFPC2 IMAGE PC1 F555W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 45 J1546+082 WFPC2 IMAGE PC1 F814W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 8248( 4) - 06/21/99 14:55 - [ 8] Summary Form for Proposal 8248 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters DITHER-TYPE=LINE CR-SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names J0307+105 J0935+073 B1152+199 J1546+082 ------------------------------------------------------------------------------------------------------------------------------------