Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5701 Report Date: 18-Jul-95:17:52 Version: ********** Check-in Date: ********** 1.Proposal Title: GALAXY POPULATIONS IN INTERMEDIATE REDSHIFT CLUSTERS: CYCLE 4 CARRY-OVER ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO/CAR 4298 Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. Warrick J Couch UNIVERSITY OF NEW SOUTH WALE AUSTRALIA 61-2-697-4578 LECTURER ------------------------------------------------------------------------------------ 7. Abstract We request WFC time to continue our program of high spatial resolution imagery of the members of southern rich galaxy clusters at intermediate redshifts (z ~ 0.3-0.4) which we have studied extensively at the AAT via fibre-optic spectroscopy and multi- colour photometry. Our comprehensive ground-based data have allowed us to measure precise line indices and colours for individual members in these clusters, thus allowing the construction of a unified picture for the various phenomena associated with the Butcher-Oemler effect whereby galaxies are seen at different stages of star -formation activity within a simple cycle. The WFC data will allow us to further our morphological classification of such galaxies, providing the information crucial to determining the physical phenomena which underlie the Butcher-Oemler effect. The superiority of our cluster samples in terms of the size and completeness of the spectroscopic and photometric coverage from theground makes them ideal targets for tackling this problem with HST. ------------------------------------------------------------------------------------ 8. Scientific Key Words: DISTANT GALAXY CLUSTERS, GALAXY EVOLUTION, GALAXY MORPHOLOGY ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 20.95 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5701 PI: Dr. Warrick J Couch Proposal Title: GALAXY POPULATIONS IN INTERMEDIATE REDSHIFT CLUSTERS: CYCLE 4 CARRY-OVER ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Dr. Warrick J Couch UNIVERSITY OF NEW SOUTH WALES AUSTRALIA Prof. Richard S Ellis DURHAM UNIVERSITY UK X Dr. Ray M Sharples DURHAM UNIVERSITY UK X Mr. Ian R Smail DURHAM UNIVERSITY UK X Page 3 ------------------------------------------------------------------------------------ 3. Description of proposed observations. We propose broad-band WFC imaging of the rich southern clusters AC118 and AC103 in F702W. The images will be exposed to depths required to provide morphological classifications of the bursting and post-starburst galaxies identified in our R < 20 spectroscopic and photometric ground-based samples. Morphological classification will proceed via quantitative surface photometry of the images obtained with the derivation of surface brightness profiles and disk/bulge ratios. Fourier deconvolution techniques will be employed to further enhance these processes. We propose additional F702W imaging of the cluster A2218. These observations will provide an important low redshift control sample to compare with the more distant Butcher-Oemler clusters. In addition we will obtain high resolution imaging of a wide variety of gravitationally lensed systems discovered in A2218. These include numerous arcs and arclets - several with spectroscopic redshifts and a unique optical Einstein ring. The F702W filter provides high throughput combined with rest wavelength coverage longward of the 4000A break in our two z=0.31 clusters. In A2218 because of the wide range of colours seen in the arcs F702W is a compromise choice to allow high signal to noise imaging of the widest range of gravitational arcs in the field. NOTE: The text ( above ) is from the original GF Q3 in Cycle 3 GO 4298. The remainder of GF Q3 pertains specifically to Cycle 4 Carry-Over. DESCRIPTION OF OBSERVATIONS: IMPLEMENTATION AND SCHEDULING NOTES FOR THE CYCLE 4 CARRY-OVER PROGRAM ( FORMERLY CYCLE 3 OBSERVATIONS ) The observations themselves should be performed as described here. All exposures are done with CR-SPLIT=NO to keep down read noise. For each target, there should be 3 exposures in F702W, all exposures per target being made together with NO GAPs, precluding intervention of any other activities. In each case, all three long exposures of a target should be made slightly shifted but at SAME ORIENTATION. The POS TARG positions are chosen to yield 3 pixel offsets in X and Y, thus POS TARG +10.0,+10.0, POS TARG +10.3,+10.0, and POS TARG +10.0,+10.3 are used. All exposures in this program should be made using the WFALL-FIX aperture in conjunction with the small shifts around POS TARG +10, +10 in order to place the Fixed Target List coords at ~ the apex of the pyramid. The Fixed Target List coords, POS TARGs, and ORIENT angles and tolerances have been chosen so as to avoid having objects of the greatest interest fall onto the apex of the pyramid or seams in between chips, etc., even though the FOV may be rotated slightly by STScI ( around the Fixed Target List coords at the apex, and within the tolerance range we have given for each specified ORIENT angle ) as needed for implementation and scheduling purposes. The details on a per-cluster basis are as follows: AC103 - IMPLEMENTATION AND SCHEDULING NOTES 3 exps in F702W, all done together at same time, with SAME ORIENT. NOTE: For purposes of overcoming hot pixels, do small shifts (3 pixels) around POS TARG +10,+10 ( i.e. at or near apex ) between each exposure. We will align the images post-observation to eliminate cosmic rays. Use ORIENT = 315D +/- 15D with field center ( FTL coords ): RA = 20h 52m 51.35s Dec = -64d 50' 26.5" Equinox: B1950 NOTE: Coords of the other two targets in this program are in J2000 Equinox, but this one is in B1950. AC118 - IMPLEMENTATION AND SCHEDULING NOTES 3 exps in F702W, all done together at same time, with SAME ORIENT. NOTE: For purposes of overcoming hot pixels, do small shifts (3 pixels) around POS TARG +10,+10 ( i.e. FTL coords at or near apex ) between each exposure. We will align images post-obs for cosmic ray removal. Use ORIENT = 37D +/- 5D ( preferred ) with field center coords: RA = 00h 14m 19.3s Dec = -30d 23' 18.2" Equinox: J2000 PLEASE INFORM US IF YOU NEED TO USE THE FOLLOWING OPTION: NOTE: If necessary for scheduling, may also use 217D +/- 5D with the SAME FTL coords at field center (FTL coords): RA = 00h 14m 19.3s Dec = -30d 23' 18.2" Equinox: J2000 A2218 - IMPLEMENTATION AND SCHEDULING NOTES 3 exps in F702W, all done together at same time, and at SAME ORIENT. NOTE: For purposes of overcoming hot pixels, do small shifts (3 pixels) around POS TARG +10,+10 (i.e. FTL coords at or near apex ) between exposures. We will align images post-obs for cosmic ray removal. Use ORIENT 95D +/- 5D (preferred) with field center ( FTL coords ): RA = 16h 35m 57.0s Dec = +66d 12' 38.0" Equinox: J2000 PLEASE INFORM US IF YOU NEED TO USE THE FOLLOWING OPTION: NOTE: May change ORIENT requirement to 45D +/- 5D or 225D +/- 5D if necessary for scheduling, provided you use this alternate field center ( FTL coords ): RA = 16h 35m 52.4s Dec = +66d 12' 38.0" Equinox: J2000 GENERAL NOTES ON THE PROGRAM STRUCTURE In this version of the program, each individual exposure of a given cluster has its own individual exposure log line, with special requirements SEQ NO GAP and SAME ORIENT tying the individual exposures together, and small offsets of 3 WF pixels in X and Y near POS TARG +10,+10 being applied to each line individually, while the ORIENT on one line is tied to all in a group by the aforementioned SAME ORIENT. It is also understood that in some cases the initial exposure may need to be slightly shorter, but hopefully not more than a few hundred seconds shorter at most, in order to accomodate the time for full guide star acquisition, etc. Please inform the observers and the STScI staff contact Ray Lucas if the program structure is changed, including any changes needed to ORIENT angles, target positions, exposure times, and special requirements, etc., so that they might have some input into the final structure if any decisions are required. In this WFPC2 carry-over program, we are using less time and therefore fewer exposures per target to achieve the same science. Both hot pixels and cosmic rays are a bigger problem with WFPC2, but the optimum solutions for each are in opposition. Since hot pixels are best identified and overcome by small shifts between exposures, but cosmic ray removal is facilitated and made more effective by having all the exposures of a given target aligned, we have decided to try and align the 3 exposures per target in the post-observation phase ( pointing accuracy is supposed to be good to 2-3 milliarcsec ) in order to remove cosmic rays and keep down the read noise, and the small offsets from +10,+10 in the 2nd and 3rd exposures will be used to provide a small shift of an integral number of pixels ( for detecting and overcoming the effects of hot pixels, etc. ) NOTE: Exposure time has been shortened to 1900s for the first orbit in the sequence of observations for each target. This was done in order to allow time for a full GS acquisition on the first orbit, and keeps the data set consistent for each object. This was done as a result of consultations between the PI and Ray Lucas at STScI. The observers wish the second and third orbits of each target to retain a full 2300s exposure time if possible. If this is never possible during the intended scheduling windows, please advise both the PI and Ray Lucas. - RAL 7/25/94 Page 4 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The largest 4-5m ground-based telescopes have been pushed to their observational limits in terms of detection, photometry and spectroscopy in investigations of the Butcher-Oemler effect. While there is now a much clearer understanding of the effect, the inability to spatially resolve the distant cluster galaxies from the ground remains the major barrier to resolving the key issues. None of the scientific objectives can be met from the ground because of atmospheric seeing limitations. Despite some progress with image enhancement techniques, such systems are not suitable for faint objects and do not reach the 0.1-0.2 arcsec resolution required for precise morphological work. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. Our main requirement is to obtain complete morphological information for the R<20 members in AC118 and AC103 identified and studied spectroscopically at the AAT. The R<20 limit corresponds to V < 21.0 and I < 19.3. Using our Cycle 1 GO observations of the z=0.3 cluster AC114 (the first target in this continuing project) we determine that a minimum of 5.8 hours (3 10**5 electrons in an R=20 source) in F702W on our AC118 and AC103 fields is required for us to pursue our morphological study of the galaxies in these clusters. A 5.7 hour exposure in F702W on A2218 will provide high signal to noise morphological information on the gravitational arcs and arclets to allow detailed modelling of their source galaxies. In order to correct for cosmic ray events, frame pairs are required, but to avoid charge defect problems associated with low background levels, ideally no individual sub-exposure should be less than 1 orbit. ( NOTE: The previous text in GF Q5 is from the original GO 4298. See GF Q3 for updated text on implementation of this carry-over program. ) ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Durham University and the University of New South Wales both have excellent computing facilities. In particular the facilities at Durham consist of a network of 12 SUN workstations served by a multi-processor server partly funded from HST grants and a cluster of 9 microVAXs. There is one STARLINK programmer dedicated to image processing requirements. ------------------------------------------------------------------------------------ 11. Address Information Name: WARRICK J COUCH Category: PI Institution: UNIVERSITY OF NEW SOUTH WALES Address: SCHOOL OF PHYSICS PO BOX 1 KENSINGTON City: SYDNEY, NSW State: Zip Code: 2033 Country: AUSTRALIA Telephone: 61-2-697-4578 Telex (or e-mail): AA26054 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5701 [ 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 AC103 F, RA = 20H 52M 51.35S +/- B1950 Z = 0.31 1 V = 21.1 +/- 0.2 404 0.2S, 2 I = 20.2 +/- 0.2 DEC = -64D 50' 26.5" +/- 4.5" Comments: NOTE: THE EQUINOX IS B1950 IN THIS CASE, UNLIKE THE OTHER 2 TARGETS, WHICH ARE J2000. ------------------------------------------------------------------------------------------------------------------------------------ 2 AC118 F, RA = 00H 14M 19.3S +/- 0.2S, J2000 Z = 0.31 1 V = 21.1 +/- 0.2 404 DEC = -30D 23' 18.2" +/- 2 I = 20.2 +/- 0.2 4.5" ------------------------------------------------------------------------------------------------------------------------------------ 3 A2218 F, RA = 16H 35M 57.0S +/- 0.2S, J2000 Z = 0.17 1 V = 21.1 +/- 0.2 404,411,412 DEC = +66D 12' 38.0" +/- 2 I = 20.2 +/- 0.2 4.5" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5701 [ 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 AC103 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 1900S 110 2 1 CYCLE 4 FIX 21000S POS TARG +10.0, +10.0 ORIENT 315D +/- 15D SAME ORIENT FOR Comments: ALL EXPOSURES OF THIS TARGET 1.1-1.2 AS 1.0 SHOULD BE TAKEN TOGETHER WITH SEQ 1.0-1.2 NO GAP NO GAPS IN BETWEEN, AND WITH THE EXACT SAME ORIENT. POS TARG +10,+10 PLACES FTL COORDS AT APEX. ------------------------------------------------------------------------------------------------------------------------------------ 1.1 AC103 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 2300S 110 2 1 CYCLE 4 FIX 21000S POS TARG +10.3, +10.0 Comments: EXPOSURE TIME IN FIRST ORBIT HAS BEEN CUT SLIGHTLY TO ALLOW TIME FOR FULL GS ACQ. SECOND AND THIRD EXPOSURES 2300s EACH. ------------------------------------------------------------------------------------------------------------------------------------ 1.2 AC103 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 2300S 110 2 1 CYCLE 4 FIX 21000S POS TARG +10.0, +10.3 Comments: NOTE: ALL S_TO_N_TIME VALUES FOR ALL TARGETS ARE FROM ORIGINAL PROGRAM AND ARE NOT VALID VALUES FOR THIS CARRY- OVER PROGRAM. ------------------------------------------------------------------------------------------------------------------------------------ 2 AC118 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 1900S 110 1 1 CYCLE 4 FIX 21000S POS TARG +10.0, +10.0 ORIENT 37D +/- 5D SAME ORIENT FOR 2.1-2.2 AS 2.0 Comments: ALL 3 EXPOSURES OF THIS TARGET SEQ 2.0-2.2 NO GAP SHOULD BE TAKEN TOGETHER WITH NO GAPS IN BETWEEN, AND WITH THE EXACT SAME ORIENT FOR ALL. POS TARG +10,+10 PLACES FTL COORDS AT APEX. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5701 [ 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 AC118 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 2300S 110 1 1 CYCLE 4 FIX 21000S POS TARG +10.3, +10.0 Comments: ORIENT 217D +/-5D ALSO OK FOR FTL COORDS LISTED, IF NECESSARY FOR FOR SCHEDULING, BUT ORIENT=37D +/-5D IS PREFERRED. EXP TIME IS SLIGHTLY LESS IN FIRST ORBIT FOR GS ACQ, BUT 2300S IN 2ND & 3RD. ------------------------------------------------------------------------------------------------------------------------------------ 2.2 AC118 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 2300S 110 1 1 CYCLE 4 FIX 21000S POS TARG +10.0, +10.3 Comments: NOTE: ALL S_TO_N_TIME VALUES FOR ALL TARGETS ARE FROM ORIGINAL PROGRAM AND ARE NOT VALID VALUES FOR THIS CARRY- OVER PROGRAM. ------------------------------------------------------------------------------------------------------------------------------------ 3 A2218 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 1900S 110 1 2 CYCLE 4 FIX 20600S POS TARG +10.0, +10.0 ORIENT 95D +/- 10D SAME ORIENT FOR 3.1-3.2 AS 3.0 Comments: ALL 3 EXPOSURES OF THIS TARGET SEQ 3.0-3.2 NO GAP SHOULD BE TAKEN TOGETHER WITH NO GAPS IN BETWEEN, AND WITH THE EXACT SAME ORIENT. POS TARG +10,+10 PLACES FTL COORDS AT APEX. ------------------------------------------------------------------------------------------------------------------------------------ 3.1 A2218 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 2300S 110 1 2 CYCLE 4 FIX 20600S POS TARG +10.3, +10.0 Comments: EXPOSURE TIME FOR FIRST ORBIT WAS CUT SLIGHTLY TO ALLOW FOR FULL GS ACQ. EXPOSURE TIME FOR 2ND & 3RD ORBITS SHOULD REMAIN AT 2300S FOR EACH, THOUGH. ------------------------------------------------------------------------------------------------------------------------------------ 3.2 A2218 WFPC2 IMAGE WFALL- F702W CR-SPLIT=NO 1 2300S 110 1 2 CYCLE 4 FIX 20600S POS TARG +10.0, +10.3 Comments: ALTERNATE ORIENTS 45D +/- 10D OR 225D +/- 10D MAY BE USED IF NECESSARY, PROVIDED THAT THESE COORDS ARE USED INSTEAD: RA=16H 35M 52.4S, DEC=+66D 12' 38.0", EQUINOX = J2000 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5701 [ 8] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO/CAR ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 20.95 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; POS TARG +10.0,+10.0; ORIENT 315D +/- 15D; SAME ORIENT FOR 1.1-1.2 AS 1.0; SEQ 1.0-1.2 NO GAP; POS TARG +10.3,+10.0; POS TARG +10.0,+10.3; ORIENT 37D +/- 5D; SAME ORIENT FOR 2.1-2.2 AS 2.0; SEQ 2.0-2.2 NO GAP; ORIENT 95D +/- 10D; SAME ORIENT FOR 3.1-3.2 AS 3.0; SEQ 3.0-3.2 NO GAP; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F702W ------------------------------------------------------------------------------------------------------------------------------------ Target Names AC103 AC118 A2218 ------------------------------------------------------------------------------------------------------------------------------------