6629( 3) - 02/20/96 10:51 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6629 Version: 3 Check-in Date: 20-Feb-1996 10:45:53 1.Proposal Title: Observations of a new sample of gravitational lens candidates ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle COSMOLOGY GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Neal Jackson Nuffield Radio Astronomy Laboratories, Jodrell Bank, University of Manchester CoI: Ian Browne NRAL Jodrell Bank N CoI: Peter Wilkinson NRAL Jodrell Bank N CoI: Sunita Nair NRAL Jodrell Bank N CoI: Steve Myers Caltech N CoI: Tony Readhead Caltech N CoI: Tim Pearson Caltech N CoI: Roger Blandford Caltech N CoI: George Miley Leiden Observatory N CoI: Chris Fassnacht Caltech N CoI: Ger de Bruyn Dwingeloo N CoI: Richard Schilizzi Dwingeloo N CoI: Malcolm Bremer Leiden Observatory N ------------------------------------------------------------------------------------ 6. Abstract gravitational lens candidates from the Cosmic Lens All-Sky Survey (CLASS) made with the VLA. The first phase of CLASS yielded two new gravitational lenses and two virtually certain candidates. All four are being followed up in Cycle 5. We now propose to investigate three more objects, two more from the first phase and one more from the recently completed second phase of CLASS. Statistically we would expect 14 lensed objects from the ~7000 targets already surveyed, based on our earlier survey which shows that 1 in 500 sources are lensed. All three new targets have multiple compact (<=30mas) flat radio spectrum components and have separations which make them difficult to study from the ground. Therefore they are uniquely suited to the capabilities of the HST. Our primary aims are to confirm the lens status by finding optical counterpatrs to the images and to identify ------------------------------------------------------------------------------------ 6629( 3) - 02/20/96 10:51 - [ 2] Observations Description ------------------------ The observations are aimed at detecting point objects of magnitude 20 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 and one NO-CR -SPLIT 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 (note that objects listed as magnitude >20 will almost certainly be <21.5 as they are flat spectrum radio sources). Real Time Justification ----------------------- We are conducting imaging and spectroscopic observations with the Keck and Palomar telescope for optical ground based followup of the lens candidates, and the wide--separation lens in figure 1 was confirmed using the William Herschel Telescope on La Palma. These ground based telescopes are not adequate for the investigation suggested here for the reasons presented above. MERLIN and VLBA will be used for radio followup of suspected lenses. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6629( 3) - 02/20/96 10:51 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 QSO- GALAXY RA=20H 47M 20.339S +/- 0.1S, J2000 V = 20+/-1 204720+26440 DEC=26D 44' 02.15" +/- 1" 2 2 QSO- GALAXY RA=10H 33M 34.025S +/- 0.1S, J2000 V = 20+/-1 103334+07112 DEC=07D 11' 26.12" +/- 1" 6 3 QSO- GALAXY RA=11H 30M 00.090S +/- 0.1S, J2000 V = 20+/-1 113000+38120 DEC=38D 12' 03.10" +/- 1" 3 6629( 3) - 02/20/96 10:51 - [ 4] Visit: 01 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 QSO- WFPC2 IMAGE PC1 F814W 1 1000S 204720+2644 02 ------------------------------------------------------------------------------------------------------------------------------------ 30 QSO- WFPC2 IMAGE PC1 F555W 1 1000S 204720+2644 02 ------------------------------------------------------------------------------------------------------------------------------------ 6629( 3) - 02/20/96 10:51 - [ 5] Visit: 02 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 ------------------------------------------------------------------------------------------------------------------------------------ 50 QSO- WFPC2 IMAGE PC1 F814W 1 1000S 103334+0711 26 ------------------------------------------------------------------------------------------------------------------------------------ 60 QSO- WFPC2 IMAGE PC1 F555W 1 1000S 103334+0711 26 ------------------------------------------------------------------------------------------------------------------------------------ 6629( 3) - 02/20/96 10:51 - [ 6] Visit: 03 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 ------------------------------------------------------------------------------------------------------------------------------------ 80 QSO- WFPC2 IMAGE PC1 F814W 1 1000S 113000+3812 03 ------------------------------------------------------------------------------------------------------------------------------------ 90 QSO- WFPC2 IMAGE PC1 F555W 1 1000S 113000+3812 03 ------------------------------------------------------------------------------------------------------------------------------------ 6629( 3) - 02/20/96 10:51 - [ 7] Summary Form for Proposal 6629 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COSMOLOGY ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names QSO-204720+264402 QSO-103334+071126 QSO-113000+381203 ------------------------------------------------------------------------------------------------------------------------------------