Page   1
    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID 4298c
                                                       Report Date: 09-May-96:19:31
                                                       Version: **********
                                                       Check-in Date: **********

1.Proposal Title:
GALAXY POPULATIONS IN INTERMEDIATE REDSHIFT CLUSTERS  CYCLE3 HIGH
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2. Scientific Category   3. Proposal For  4. Proposal Type        5. Continuation ID
GALAXIES & CLUSTERS         GO                                       <none>
Sub Category

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6. Principal Investigator   Institution                    Country    Telephone
Dr. Warrick J Couch         UNIVERSITY OF NEW SOUTH WALE   AUSTRALIA  61-2-697-4578
LECTURER
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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.
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8. Scientific Key Words:   DISTANT GALAXY CLUSTERS, GALAXY EVOLUTION, GALAXY
MORPHOLOGY
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9. Est obs time (hours) pri: 20.95    par: 0       10. Num targs pri: 3      par: 0
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11. Instruments requested:  WF/PC
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                                                                  Page   2
I. GENERAL FORM    Proposal 4298c
PI: Dr. Warrick J Couch
Proposal Title:
GALAXY POPULATIONS IN INTERMEDIATE REDSHIFT CLUSTERS  CYCLE3 HIGH
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1. Proposers:
Proposers                        Institution                       Country       ESA
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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
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  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.
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  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.
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  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.
                                                                  Page   3
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  7. Data reduction and analysis plans.
  The WFC frames will be reduced on HST-funded SUN workstations using software
 proven for the analysis of extended galaxies (Couch and Newell 1984). All
 applicants have extensive experience in multicolour cluster photometry (Couch et
 al 1983) and in surface photometry of bright spheroidal and multi-component
 galaxies (Sharples, thesis).
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 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.
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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
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TARGET LIST    a) Fixed Targets                                                                    ID = 4298c            [  4]
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 1 |     2      |           3           |              4             |  5     |   6    |  7  |              8
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Tar|   Target   |         Target        |            Target          |Coord   | Radial |Acqui|FLX|     Flux data
No |    Name    |       Description     |           Position         |Eqnx    |  Vel.  |Prblm|REF|
   |            |                       |                            |        |        |     |   |
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1   AC103        GALAXY CLUSTER ;        RA = 20H 57M 09.4S +/- 0.2S, J2000    Z = 0.31       1   V = 21.1 +/- 0.2
                 DISTANT GALAXY CLUSTER  DEC = -64D 39' 18.7" +/-                             2   I = 20.2 +/- 0.2
                                         4.5"
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2   AC118        GALAXY CLUSTER ;        RA = 00H 14M 19.3S +/- 0.2S, J2000    Z = 0.31       1   V = 21.1 +/- 0.2
                 DISTANT GALAXY CLUSTER  DEC = -30D 23' 18.2" +/-                             2   I = 20.2 +/- 0.2
                                         4.5"
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3   A2218        GALAXY CLUSTER ;        RA = 16H 35M 52.9S +/- 0.2S, J2000    Z = 0.17       1   V = 21.1 +/- 0.2
                 NEARBY GALAXY CLUSTER   DEC = +66D 12' 19.6" +/-                             2   I = 20.2 +/- 0.2
                                         4.5"
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EXPOSURE LOGSHEET                                                                                  ID = 4298c            [  5]
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 1      |   2   |      3    |  4   |   5   |   6   |    7   |   8   |       9       |10 |   11  |   12    |13 |14|        15
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  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       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     1   1800S   110       2   1  CYCLE 3
                                                                     PRE-FLASH=NO                21000S           GROUP 1.0-1.1 NO
                                                                                                                  GAP
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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1.1              AC103       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     4   2300S   110       2   1  CYCLE 3
                                                                     PRE-FLASH=NO                21000S
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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1.5              AC103       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     1   1800S   110       2   1  CYCLE 3
                                                                     PRE-FLASH=NO                21000S           GROUP 1.5-1.6 NO
                                                                                                                  GAP
                                                                                                                  POS TARG 0.7, 0.7
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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1.6              AC103       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     4   2300S   110       2   1  CYCLE 3
                                                                     PRE-FLASH=NO                21000S           POS TARG 0.7, 0.7
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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2                AC118       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     1   1800S   110       1   1  CYCLE 3
                                                                     PRE-FLASH=NO                21000S           SEQ 2.0-2.2 NO GAP
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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EXPOSURE LOGSHEET                                                                                  ID = 4298c            [  6]
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 1      |   2   |      3    |  4   |   5   |   6   |    7   |   8   |       9       |10 |   11  |   12    |13 |14|        15
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  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
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2.2              AC118       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     4   2300S   110       1   1  CYCLE 3
                                                                     PRE-FLASH=NO                21000S
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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2.5              AC118       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     1   1800S   110       1   1  CYCLE 3
                                                                     PRE-FLASH=NO                21000S           POS TARG 0.7, 0.7
                                                                                                                  SEQ 2.5-2.6 NO GAP
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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2.6              AC118       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     4   2300S   110       1   1  CYCLE 3
                                                                     PRE-FLASH=NO                21000S           POS TARG 0.7, 0.7
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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3                A2218       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     1   1800S   110       1   2  CYCLE 3
                                                                     PRE-FLASH=NO                20600S           SEQ 3.0-3.1 NO GAP
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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3.1              A2218       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     4   2300S   110       1   2  CYCLE 3
                                                                     PRE-FLASH=NO                20600S
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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EXPOSURE LOGSHEET                                                                                  ID = 4298c            [  7]
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 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
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3.5              A2218       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     1   1800S   110       1   2  CYCLE 3
                                                                     PRE-FLASH=NO                20600S           SEQ 3.5-3.6 NO GAP
                                                                                                                  POS TARG 0.7, 0.7
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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3.6              A2218       WFC    IMAGE   WFALL   F702W            CR-SPLIT=NO     4   2300S   110       1   2  CYCLE 3
                                                                     PRE-FLASH=NO                20600S           POS TARG 0.7, 0.7
     Comments: MINIMUM USEFUL SUB-EXPOSURE IS
               2500S OR 1 ORBIT. SUB-EXPOSURES
               POSITIONS SHOULD BE RANDOMLY
               OFFSET FROM EACH OTHER BY 0.5-1
               ARCSEC TO ALLOW HOTSPOT
               REMOVAL.
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            Summary Form for Proposal 4298c                                                                              [  8]

  Item                          Used in this proposal
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  Configurations                WFC
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  Opmodes                       IMAGE
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  Optional Parameters           CR-SPLIT PRE-FLASH
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  Proposal for                  GO
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  S/C Hours                     20.95
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  Scientific Category           GALAXIES & CLUSTERS
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  Scientific Sub-category      <none>
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  Special Requirements          CYCLE 3; GROUP 1.0-1.1 NO GAP CYCLE 3 GROUP 1.5-1.6 NO GAP; POS TARG 0.7, 0.7 SEQ 2.0-2.2 NO GAP
                                POS TARG 0.7, 0.7; SEQ 2.5-2.6 NO GAP SEQ 3.0-3.1 NO GAP SEQ 3.5-3.6 NO GAP;
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  Spectral Elements             F702W
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  Target Names                  AC103 AC118 A2218
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