Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5465 Report Date: 18-Jul-95:17:27 Version: ********** Check-in Date: ********** 1.Proposal Title: WFPC 2 IMAGING OF TWO GALAXY CLUSTERS AT Z=1.2 ------------------------------------------------------------------------------------ 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 Mark Dickinson 3470 USA 510 642 6110 ------------------------------------------------------------------------------------ 7. Abstract Using deep optical and infrared images taken at the KPNO 4m, we have identified two rich galaxy clusters around 3CR radio galaxies at z=1.2 These are perhaps the most distant clusters yet observed. The clusters appear to have a large population of extremely red members, contrary to naive expectations from an extrapolation of the Butcher-Oemler effect to large redshift. Both clusters apparently include galaxies as red as present day (z=0) ellipticals redshifted out to z=1.2. We propose to obtain deep HST images with WFPC 2 in order to examine the morphological types of these very red galaxies, and to study the properties of cluster galaxies in general at very large cosmic lookback times. We hope to investigate: whether the red galaxies are in fact relatively "unevolved" ellipticals; how their structural parameters compare to elliptical galaxies today; whether S0 galaxies exist at z=1.2; the frequency of interactions and mergers in very high redshift clusters; and the morphologies of cluster galaxies bluer than the "red envelope" galaxies. By imaging the radio galaxies themselves with the PC camera, we will obtain extremely deep images of these giant, morphologically peculiar objects. Finally, we will look for evidence of gravitational lensing of faint, extremely distant background sources by these high redshift clusters. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 17.50 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5465 PI: Mark Dickinson Proposal Title: WFPC 2 IMAGING OF TWO GALAXY CLUSTERS AT Z=1.2 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Mark Dickinson 3470 USA Hyron Spinrad 1500 USA Peter Eisenhardt 2370 USA S. Adam Stanford 2370 USA Stanislav Djorgovski 1590 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Deep WFPC2 imaging of the z=1.2 radio galaxy 3C324 and the extremely faint cluster companions in the surrounding field will be obtained through the F702W filter. The radio galaxy itself (whose coordinates are those specified in the target information section) will be placed onto the PC1 planetary camera CCD to obtain high spatial resolution images. We request a particular orientation with the ORIENT parameter to optimally position the other galaxies of interest from the surrounding cluster onto the other WFPC2 CCDs, and to keep them away from the interstices between the CCDs as much as is possible in order to avoid possible image degradation and light loss. The galaxies in the cluster are distributed out to the limits of the WFPC2 field of view. Thus the ORIENT angle we specify and the range of acceptable angles around it is fairly tightly constrained. An alternative ORIENT angle (approx. ORIENT=155D) is possible if the one we have specified proves to be too difficult to schedule; please contact the P.I. if this becomes necessary, as it may also require revisions to the POS TARG parameters. We have divided our total exposure time into many individual 2200s exposures, i.e. approximately the unocculted period of one orbit after allowing overhead time for guide star re-acquisition. We wish to maximize the per orbit exposure time in order to minimize the effects of readout noise; if during scheduling it becomes possible to increase this amount over 2200s, we would like to do so. Similarly, we hope that it will not be necessary to reduce the per orbit exposure time below approx. 2000s. We set CR-SPLIT=NO because many separate exposures will be obtained at each telescope pointing, facilitating cosmic ray removal without the need for CR-SPLIT. We have divided our observation into 4 groups of 7 exposures each. Within each group of 7, we will maintain the same FGS lock position. The telescope pointing is then offset between one group and the next by a small amount using a POS TARG command. This will result in the observations being taken in a small, square raster pattern in order to expose the objects to several portions of the WFPC2 CCDs and thus minimize the impact of any defects in the arrays. We request the same ORIENT angle for all of the exposures. Finally, we have included an "extra" 1400s exposure as LINENUM=5.0 in the exposure log sheet in order to fill out the allocated 21 hours of spacecraft time. Page 3 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. As for most WFPC-2 programs, the primary justification for observing with HST is its high angular resolution. At z=1.2, the linear scale corresponding to 1 arcsecond is 8.5 kpc for q0=0.5 and 12 kpc for q0=0 (H0=50 km/s/Mpc). It is essentially impossible to obtain useful morphological information with even the best ground-based seeing for any galaxies at this redshift except the giant radio galaxies. Without HST imaging, we can only measure global spectrophotometric properties for these galaxies. Their morphological types, the details of their structure, and their close interactions with other galaxies remain invisible from the ground. HST imaging of clusters at z=0.4 has provided a remarkably dynamic picture of activity: observations of spiral structure of many blue cluster members, evidence for frequent galaxy-galaxy interactions, and morphological/color correlations are permitting a thorough analysis of the evolutionary state of galaxies in clusters at modest lookback times. With the corrected optics of WFPC-2 we can now extend this work out to z > 1, where our ground--based images barely provide evidence for spatial extent, and give no clues as to the Hubble types of cluster members. In our two target clusters, the very red colors we observe for some of the galaxies lead us to infer that they are early type systems: HST will let us study their strucure at resolutions comparable to those achieved in ground--based observations the Coma Cluster. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. ------------------------------------------------------------------------------------ 9. Description of previous HST work. The PI has worked on reduction and analysis of WFPC-1 images of faint galaxies taken during HST Cycle 2. All of the co-investigators have been involved in other previous HST programs, and Stanford and Djorgovski in particular have been extensively involved in data reduction and analysis of HST imaging. Several papers have been published based on that work. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). The PI will be a fellowship postdoc at STScI for two to three years beginning this fall; this should provide an excellent opportunity for direct access to the expert human resources most important for processing, analyzing, and understanding HST data, as well as software and computing support. Two of the co -Is (Spinrad and Djorgovski) will have regular access to the Keck 10m telescope, now beginning scientific operation in Hawaii. Its merits are self-evident for ground-based followup observations. In particularly, spectroscopy of these cluster galaxies is only feasible with very large aperture telescopes such as Keck. We also hope to obtain very deep infrared imaging observations in with the best angular resolution that Mauna Kea can offer. Dickinson will receive year-round salary support from STScI, and thus is not requesting funds for that purpose. Academic year salaries for Spinrad and Djorgovski are provided by their respective institutions, and partial salary support is provided for Stanford and Eisenhardt by other grants to JPL. As this research program will be a primary occupation for Stanford during the period of the grant, we request several months of salary support for that purpose. In general, all of our institutions provide excellent computing resources, facilities, and administrative support. UC Berkeley and CalTech have excellent graduate students available for research assistance, and it is anticipated that one or more students will be invited to participate in data reduction and analysis at those institutions. ------------------------------------------------------------------------------------ 11. Address Information Page 4 Name: Mark Dickinson Category: PI Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5465 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 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 3C324 F,404,406,409, RA = 15H 47M 37.2S +/- 0.1S, 1950 Z = 1 V=21.5 +/- 0.5 E,303,309,315,325 DEC = +21D 34' 41.0" +/- 1.206 2 SURF(R)=25 1.0" Comments: OBJECTS OF INTEREST ARE VERY FAINT (21 < R < 25) GALAXIES IN A HIGH REDSHIFT CLUSTER. THE PRECISE SURFACE BRIGHTNESSES ARE UNKNOWN AND DEPEND ON GALAXY MORPHOLOGIES. SURF(R)=25 IS GIVEN AS A CHARAC- TERISTIC VALUE FOR USE IN THE S_TO_N CALCULATIONS BELOW IN THE EXPOSURE LOGSHEET; SPECIFIED S/N IS PER PC PIXEL AT SURF(R)=25. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5465 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1.1 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 1800S 1 2 1 CYCLE 4 15400S ORIENT 173D +/- 1D POS TARG -11.25,- 11.00 SEQ 1.1-1.2 NO GAP SAME ORIENT FOR Comments: FIRST OF 4 POINTINGS SEPARATED 1.2-4.4 AS 1.1 BY SMALL POS TARG SHIFTS. THE GROUP 1.1-1.4 ORIENT IS CHOSEN TO POSITION WITHIN 5D FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 1.2 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 2100S 1 2 1 CYCLE 4 15400S SAME POS FOR 1.2 AS 1.1 Comments: FIRST OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 1.3 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 1800S 1 2 1 CYCLE 4 15400S POS TARG -11.25,- 11.00 SEQ 1.3-1.4 NO GAP Comments: FIRST OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 1.4 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 2100S 1 2 1 CYCLE 4 15400S SAME POS FOR 1.4 AS 1.3 Comments: FIRST OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5465 [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 2.1 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 1800S 1 2 1 CYCLE 4 13200S POS TARG -11.00,- 10.50 SEQ 2.1-2.2 NO GAP GROUP 2.1-2.4 WITHIN 5D Comments: SECOND OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 2.2 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 2100S 1 2 1 CYCLE 4 13200S SAME POS FOR 2.2 AS 2.1 Comments: SECOND OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 2.3 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 1800S 1 2 1 CYCLE 4 13200S POS TARG -11.00,- 10.50 SEQ 2.3-2.4 NO GAP Comments: SECOND OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 2.4 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 2100S 1 2 1 CYCLE 4 13200S SAME POS FOR 2.4 AS 2.3 Comments: SECOND OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5465 [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 3.1 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 1800S 1 2 1 CYCLE 4 13200S POS TARG -10.50,- 10.75 SEQ 3.1-3.2 NO GAP GROUP 3.1-3.4 WITHIN 5D Comments: THIRD OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 3.2 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 2100S 1 2 1 CYCLE 4 13200S SAME POS FOR 3.2 AS 3.1 Comments: THIRD OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 3.3 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 1800S 1 2 1 CYCLE 4 13200S POS TARG -10.50,- 10.75 SEQ 3.3-3.4 NO GAP Comments: THIRD OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 3.4 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 2100S 1 2 1 CYCLE 4 13200S SAME POS FOR 3.4 AS 3.3 Comments: THIRD OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5465 [ 9] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 4.1 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 1800S 1 2 1 CYCLE 4 13200S POS TARG -10.75,- 11.25 SEQ 4.1-4.2 NO GAP GROUP 4.1-4.4 WITHIN 5D Comments: FOURTH OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 4.2 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 2100S 1 2 1 CYCLE 4 13200S SAME POS FOR 4.2 AS 4.1 Comments: FOURTH OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 4.3 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 1 1800S 1 2 1 CYCLE 4 13200S POS TARG -10.75,- 11.25 SEQ 4.3-4.4 NO GAP Comments: FOURTH OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ 4.4 3C324 WFPC2 IMAGE PC1-FIX F702W CR-SPLIT=NO 3 2100S 1 2 1 CYCLE 4 13200S SAME POS FOR 4.4 AS 4.3 Comments: FOURTH OF 4 POINTINGS SEPARATED BY SMALL POS TARG SHIFTS. THE ORIENT IS CHOSEN TO POSITION FAINT CLUSTER GALAXIES AWAY FROM CCD BORDERS. USE SAME ORIENT FOR ALL EXPOSURES ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5465 [ 10] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 17.50 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category CLUSTERS/LENSES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; ORIENT 173D +/- 1D; POS TARG -11.25,-11.00; SEQ 1.1-1.2 NO GAP; SAME ORIENT FOR 1.2-4.4 AS 1.1; GROUP 1.1-1.4 WITHIN 5D SAME POS FOR 1.2 AS 1.1 SEQ 1.3-1.4 NO GAP SAME POS FOR 1.4 AS 1.3 POS TARG -11.00,-10.50; SEQ 2.1-2.2 NO GAP; GROUP 2.1-2.4 WITHIN 5D SAME POS FOR 2.2 AS 2.1 SEQ 2.3-2.4 NO GAP SAME POS FOR 2.4 AS 2.3 POS TARG -10.50,-10.75; SEQ 3.1-3.2 NO GAP; GROUP 3.1-3.4 WITHIN 5D SAME POS FOR 3.2 AS 3.1 SEQ 3.3-3.4 NO GAP SAME POS FOR 3.4 AS 3.3 POS TARG -10.75,-11.25; SEQ 4.1-4.2 NO GAP; GROUP 4.1-4.4 WITHIN 5D SAME POS FOR 4.2 AS 4.1 SEQ 4.3-4.4 NO GAP SAME POS FOR 4.4 AS 4.3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F702W ------------------------------------------------------------------------------------------------------------------------------------ Target Names 3C324 ------------------------------------------------------------------------------------------------------------------------------------