Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5352 Report Date: 18-Jul-95:17:13 Version: ********** Check-in Date: ********** 1.Proposal Title: GRAVITATIONAL LENSING STUDIES WITH HST: DARK MATTER AND HIGH REDSHIFT GALAXIES -- CYCLE4 HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO Sub Category CLUSTERS/LENSES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Bernard Fort 5474 FRANCE 011 - 33 - 613 ------------------------------------------------------------------------------------ 7. Abstract We propose deep multicolour WFC2 imaging of a sample of gravitationally-lensed `giant arcs' for which extensive ground-based data has already been secured. High resolution studies of these systems offer an unique probe of the dark matter distribution in the lensing clusters as well as of the nature of background field galaxies at redshifts above one. By resolving the arcs and their counter-images with HST, mass models that account for the lensing are much more highly constrained. This, in turn, will lead to an improved knowledge of the structure of the distant sources. Ground-based photometry indicates most arcs are intensely blue star-forming systems. Morphologies will provide important information on the ancestors of normal galaxies. Extrapolating the trends found in recent ground-based data, we also expect to identify many close image pairs in deep HST images. These pairs are probably highly magnified images of B=28-30 galaxies. The abundance of pairs will place a new constraint on the galaxy count turnover and hence the epoch of galaxy formation. Our program is uniquely suited to WFC2 and builds on a wealth of existing deep ground- based optical/infrared data. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 15.00 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5352 PI: Bernard Fort Proposal Title: GRAVITATIONAL LENSING STUDIES WITH HST: DARK MATTER AND HIGH REDSHIFT GALAXIES -- CYCLE4 HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Bernard Fort 5474 FRANCE X Yannick Mellier 5474 FRANCE X Genevieve Soucail 5474 FRANCE X Roser Pello 5474 FRANCE X Richard S Ellis 8014 UK X Alfonso Aragon-Salamanca 8014 UK X Jordi Miralda-Escude 2280 USA X Ian Smail 1590 USA Jean-Paul Kneib 5474 FRANCE X ------------------------------------------------------------------------------------ 3. Description of proposed observations. Our target list contains 2 lensing systems, each of which has been well-studied in previous ground-based campaigns. The selected clusters are : Cl2244-02 and Abell 2390. We require broad-band WFPC2 images using filters F555W and F814W. F814W samples the restframe light longward of 4000 A in the distant source galaxies at highest efficiency, while F555W samples the near uv restframe. This combination provides a direct comparison of the distribution of young stars with that of the entire population. We need individual exposures of 2300 sec to attain an optimal s/n ratio. For Cl2244-02 we require 4 exposures in filter F555W and 6 exposures in filter F814W. In the case of Abell 2390, the optimal number of exposures is 4 in filter F555W and 5 in filter F814W. A random shift of about 1 arcsec has to be introduced between successive frames, in order to correct for the presence of bad pixels and/or other geometrical features. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The largest ground-based telescopes have been pushed to their observational limits in the detection and analysis of gravitationally-lensed images. While considerable progress has been made, the fundamental limitation remains the inability to resolve fine detail in the giant arcs, as well as to unambiguously recognise further signatures of lensing such as the symmetry of close image pairs. The detail found in the case of AC114 has demonstrated that not only can these limitations be overcome with HST, but also that a new regime of lens models can be constructed. Specifically, in favourable cases such as those clusters selected in this proposal, it will become possible to distinguish between structure in the lensing cluster and that inherent in the distant source. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The main requirement is that the exposure time should be at least 2300 sec (1 orbit) in order to attain an optimal s/n. As the number of exposures is between 4 and 6 for each cluster + filter configuration, with a random shift between 2 successive exposures of about 1 arcsec, the exposures should not be splited into shorter subexposures. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Page 3 ------------------------------------------------------------------------------------ 9. Description of previous HST work. One of the Co-I, R. Ellis, has been involved in the following programs: No. 2269, 4298 ``Galaxy Populations in Intermediate Redshift Clusters'' (GO Cycles 1 and 3, WFC-1) as Co-I, and No. 4072 ``Star Formation Rates in Distant Cluster Galaxies'' (GTO Cycle 2, FOC) as PI. These are largely unrelated programs concerned with the morphology and star-formation characteristics of cluster member galaxies at z=0.3. Some gravitational lensing phenomena were found unexpectedly in AC114 (GO 2269) and the nature of the giant arc in Abell 370 is a secondary goal in the cycle 3 allocation GO 4298 (yet to be taken). However, the choice of clusters in these proposals was dictated entirely by the extensive ground-based spectroscopy of the cluster members and the lensing studies proposed here could not be carried out with these data. The publications resulting from these programs up to now are: Deep WFPC Imaging of the z=0.3 cluster AC114, Sharples, R.M., Smail, I., Ellis, R.S., Couch, W.J., Fitchett, M.J. eds. Benvenuti, P. & Schreier, E., ESO Conference and Workshop Proceedings 44, 119-126 (1993) and Morphological Studies of the Galaxy Populations in Distant `Butcher- Oemler' Clusters with HST, Couch, W.J., Ellis, R.S., Sharples, R.M. and Smail, I., in ``Observational Cosmology'', eds. Chincarini, G. et al., ASP Conference Series, in press. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Toulouse and Cambridge University have excellent computing facilities based on UNIX workstations running IRAF. In particular, Cambridge is a collaborator in the HST Medium Deep Survey Key Project for which dedicated reduction facilities have been provided. Additional resources for this collaboration have been provided by the European Economic Community. This will pay for postdoctoral assistants, computing costs and associated travel. ------------------------------------------------------------------------------------ 11. Address Information Name: Bernard Fort Category: PI Institution: 5474 Address: Observatoire Midi-Pyrenees 14, Avenue Edouard Belin City: TOULOUSE State: Zip Code: 31400 Country: FRANCE Telephone: 011-33-61-332-821 Telex (or e-mail): fort@obs-mip.fr ------------------------------------------------------------------------------------ Name: Category: CON Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5352 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 CL2244-02 F, RA= 22H 44M 38.3S +/- 0.1S, 1950.0 Z = 1 SURF(B)=24.5 +/- 0.5 411, DEC= -02D 21' 30" +/- 1.0" 0.329 2 B-V = 0.2 409 3 B-R = 0.9 ------------------------------------------------------------------------------------------------------------------------------------ 2 ABELL2390 F, RA= 21H 51M 14.3S +/- 0.1S, 1950.0 Z = 1 SURF(B)=25.3 +/- 0.5 411, DEC= +17D 27' 34.9" +/- 2.0" 0.231 2 B-R = 1.9 404 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5352 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 DEFINE # WFPC2 IMAGE # F814W 7940 CR-SPLIT=NO # 2100S 3.5 1 # CYCLE 4 SEQ1 11500S 2 ------------------------------------------------------------------------------------------------------------------------------------ 2 DEFINE # WFPC2 IMAGE # F555W 5407 CR-SPLIT=NO # 2100S 3.5 1 # CYCLE 4 SEQ2 6900S 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ1 10D POS TARG +5.0,-5.0 ------------------------------------------------------------------------------------------------------------------------------------ 4 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ1 10D POS TARG +6.0,-4.0 ------------------------------------------------------------------------------------------------------------------------------------ 5 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ1 10D POS TARG +7.0,-6.0 ------------------------------------------------------------------------------------------------------------------------------------ 6 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ1 10D POS TARG +4.0,-5.5 ------------------------------------------------------------------------------------------------------------------------------------ 7 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ1 10D POS TARG +5.5,-6.5 ------------------------------------------------------------------------------------------------------------------------------------ 8 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ1 10D POS TARG +3.5,-3.5 ------------------------------------------------------------------------------------------------------------------------------------ 9 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ2 10D POS TARG +5.0,-5.0 ------------------------------------------------------------------------------------------------------------------------------------ 10 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ2 10D POS TARG +6.0,-4.0 ------------------------------------------------------------------------------------------------------------------------------------ 11 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ2 10D POS TARG +7.0,-6.0 ------------------------------------------------------------------------------------------------------------------------------------ 12 USE CL2244-02 WF3 1 1 ORIENT 240D +/- SEQ2 10D POS TARG +5.0,-5.5 ------------------------------------------------------------------------------------------------------------------------------------ 13 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ1 POS TARG +10.3,- 20.5 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5352 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 14 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ1 POS TARG +11.3,- 19.5 ------------------------------------------------------------------------------------------------------------------------------------ 15 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ1 POS TARG +12.3,- 21.5 ------------------------------------------------------------------------------------------------------------------------------------ 16 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ1 POS TARG +9.3,- 21.0 ------------------------------------------------------------------------------------------------------------------------------------ 17 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ1 POS TARG +10.8,- 22.0 ------------------------------------------------------------------------------------------------------------------------------------ 18 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ2 POS TARG +10.3,- 20.5 ------------------------------------------------------------------------------------------------------------------------------------ 19 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ2 POS TARG +11.3,- 19.5 ------------------------------------------------------------------------------------------------------------------------------------ 20 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ2 POS TARG +12.3,- 21.5 ------------------------------------------------------------------------------------------------------------------------------------ 21 USE ABELL2390 WF2 1 1 ORIENT 85D +/- 20D SEQ2 POS TARG +9.3,- 21.0 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5352 [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 15.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category CLUSTERS/LENSES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; ORIENT 240D +/- 10D; POS TARG +5.0,-5.0 POS TARG +6.0,-4.0 POS TARG +7.0,-6.0; POS TARG +4.0,-5.5 POS TARG +5.5,-6.5 POS TARG +3.5,-3.5 POS TARG +7.0,-6.0 POS TARG +5.0,-5.5 ORIENT 85D +/- 20D; POS TARG +10.3,-20.5 POS TARG +11.3,-19.5 POS TARG +12.3,-21.5 POS TARG +9.3,-21.0 POS TARG +10.8,-22.0 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names CL2244-02 ABELL2390 ------------------------------------------------------------------------------------------------------------------------------------