! Proposal 5991, submission 3
! PI: Garth Illingworth
! Received Fri Jul 14 12:55:28 EDT 1995
! From: kelson@ucolick.org
! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template
! $Id: 5991,v 8.1 1995/11/21 13:33:13 pepsa Exp $
!
! For help call your Program Coordinator: Giselle Sleiman
!             Phone: 410 338-4753    , E-mail: sleiman@stsci.edu

Proposal_Information                           ! Section 4
              Title:  The Fundamental Plane of Early-Type
                      Galaxies in X-Ray Clusters at z=0.3-0.6
  Proposal_Category:  GO
Scientific_Category:  Galaxies & Clusters
             Cycle:    5

Investigators
     PI_name:         Garth Illingworth
     PI_Institution:  Lick Observatory, University of California,
                      Santa Cruz

          CoI_Name:   Dan Fabricant
   CoI_Institution:   Smithsonian Astrophysical Observatory
           Contact:   

          CoI_Name:   Marijn Franx
   CoI_Institution:   Kapteyn Astronomical Institute, University of
                      Groningen
           Contact:  


Abstract: 
    We propose to utilize HST data for  quantitative studies that
    will allow a rigorous examination to be made of the
    evolutionary state of galaxies in intermediate redshift
    clusters. The Fundamental Plane (FP) of early-type galaxies is
    one of the most sensitive tests for galaxy evolution. This is
    because of its low intrinsic scatter for nearby cluster
    galaxies. It can be used to accurately measure the luminosity
    evolution of galaxies, and the change of M/L with time. We
    have started a program to determine internal velocity
    dispersions of galaxies in six rich, X-ray selected clusters
    at redshifts between 0.3-0.6 with the Keck telescope. We
    propose here for high resolution HST data on four X-ray
    selected clusters that span the full range in z (0.31<z<0.58)
    to determine very accurate scale lengths, surface
    brightnesses, color distributions and morphologies.  These
    results will be combined with Keck spectroscopic data for an
    FP analysis. The first Keck data on CL2053-04 and CL2137-23 is
    already in hand, and CL0302+16/17 are to be studied in a future
    Keck run. These, as well as the other clusters in our sample, are
    gravitational lensing clusters, some with a an abundance of
    arclets.  The WFPC2 images will be used to identify color
    dependent structures in the arcs or arclets.  Furthermore, while
    the galaxies are our highest priority, we plan to continue to use
    unassigned slitlets in the Keck slitmasks to determine redshifts
    and spectral characteristics of the arcs/arclets. 

Questions

     Observing_Description:
         We plan to image four clusters in two colors, F606W and
         F814W. We will image each cluster for two orbits. The first
         orbit in each case will be a CR-SPLIT F606W, with the second 
         orbit CR-SPLIT F814W. The total integration per cluster will
         be 5000 s (2400S (F606W) and 2400s (F814W) in the 
         consecutive orbits). The multiple images provide for good
         cosmic ray cleaning, and have suitable S/N for the fitting
         and modelling (based on experience with Cycle 4 images to
         I~21 from the HST Medium Deep Survey). Galaxies of I~21 can
         be measured at Keck to derive velocity dispersions in 1-2 
         nights.  CL2137-23 will be imaged in both filters to ensure 
         that we have the same  color information as for the other 
         three clusters.  We have decided to observe CL2053-04 in F702W
         to avoid the presence of the H/K break in the red end of the
         F606W bandpass. The color data from WFPC2 is important since 
         it provides quantitative diagnostics that cannot be obtained 
         from the ground (e.g., existence and location of star forming
         regions or starbursts,  blue nucleus indicative of possible
         activity, such as an AGN,  blue disk or bulge color
         indicative of large scale recent star formation).  All these
         effects can impact the use of relations such as the
         Fundamental Plane, yet they would be difficult or impossible
         to detect without color images from HST. Our objective is to
         establish if evolutionary differences exist compared to
         contemporary galaxies, and if so, to characterize them to
         high accuracy. The only way to do this is to carry out the
         analysis in a very consistent and thorough manner.
         Considerable interplay will occur with the results from the
         spectroscopic observations;  we expect to directly use the
         HST data with our unique Keck data in an internally
         consistent modelling approach.  We bring substantial combined
         experience on quantitative analysis of distant galaxies from
         HST WFPC data and from ground-based spectroscopic data.
         Furthermore, our considerable quantitative experience with
         nearby galaxies has been extended to fundamental plane work
         on distant galaxies (Franx), and to structural analyses of
         distant galaxies through the HST Medium Deep Survey
         (Illingworth). A graduate student, Dan Kelson will be deeply
         involved in this program as part of his thesis research.
         Kelson's considerable experience with HST imaging data also
         means that his ``learning curve'' will be minimal. As noted
         in the scientific justification, we also plan to obtain
         spectra of the gravitational arcs.  Given the difficulty of
         determining redshifts for these arcs, and of catagorizing
         their spectral characteristics, the Keck data should add
         substantially to the small number of redshifts that are
         currently available.

   Real_Time_Justification:
         We would prefer that the images from both filters on a given
         galaxy be taken at the same orientation.

	 We have specified ranges for useful orientations to prevent
	 contamination from bright stars and to prevent inappropriate
	 placement of the brightest gravitational arcs.

         We have already obtained extensive photometric and
         spectroscopic data on these clusters, as can be seen below in
         Table 2. Much, but not all, of this work is due to an ongoing
         effort by Fabricant and collaborators (see, e.g., Fort etal 
         1992, Fabricant etal  1994, Fabricant 1994). 
         Cluster        z     N_phot     N_spec    area (arcmin)
         CL0302+16    0.43      224       26        2.5x2.5   
         CL0302+17    0.42      326       43        2.5x2.5   
         CL2053-04    0.58      200       10        2.5x2.5   
         CL2137-23    0.31      200       25        2.5x2.5
         In addition, we are currently taking multi-aperture spectra
         of these clusters. A typical example of a high S/N spectrum
         obtained recently with the Keck telescope is shown in Figure
         5. Some  data were also obtained on CL2137-23  and on Cl2053-
         04. Further runs are scheduled for spring 1995, and planned
         for later in 1995.    This is to be a high priority program 
         on Keck for GDI.


Fixed_Targets
  Target_Number: 1
    Target_Name: GAL-CLUS-030533+171005
Alternate_Names: CL0302+1658
    Description: CLUSTER OF GALAXIES
       Position: RA=3H 2M 43.15S +/- 1.000S, DEC=16D 58' 26.2" +/- 1.000"
        Equinox: B1950
        RV_or_Z: Z = 0.43
           Flux: V = 21.70, V = 22.42, V = 23.60
       Comments: CLUSTER OF GALAXIES WITH GRAVITATIONAL ARCS

  Target_Number: 2
    Target_Name: GAL-CLUS-030518+172838
Alternate_Names: CL0302+1717
    Description: CLUSTER OF GALAXIES
       Position: RA=3H 2M 29.35S +/- 1.000S, DEC=17D 16' 47.6" +/- 1.000"
        Equinox: B1950
        RV_or_Z: Z = 0.42
           Flux: V = 21.0, R = 20.75
       Comments: RICH CLUSTER OF GALAXIES

  Target_Number: 3
    Target_Name: GAL-CLUS-205622-043744
Alternate_Names: MS2053.7-0449
    Description: CLUSTER OF GALAXIES,HIGH REDSHIFT CLUSTER (Z>0.5),RICH CLUSTER,GRAVITATIONAL LENS
       Position: RA=20H 56M 21.416S +/- 1.000S, DEC=-4D 37' 50.390" +/- 1.000"
        Equinox: J2000
        RV_or_Z: Z = 0.58
           Flux: V = 21.5, V = 22.4, V = 22.6, V = 23.3, V = 22.9, V = 23.6, R = 21.91
       Comments: RICH CLUSTER WITH PROMINENT GRAVITATIONAL ARCS 

  Target_Number: 4
    Target_Name: GAL-CLUS-214012-233927
Alternate_Names: MS2137.3-2328
    Description: CLUSTER OF GALAXIES,GRAVITATIONAL LENS
       Position: RA=21H 40M 14.97S +/- 1.000S, DEC=-23D 39' 37.94" +/- 1.000"
        Equinox: J2000
        RV_or_Z: Z = 0.31
           Flux: B = 22.04, V = 22.00, R = 21.55, I = 21.22
       Comments: CLUSTER OF GALAXIES WITH PROMINENT GRAVITATIONAL ARCS

Visits                                 
      Visit_Number: 1
Visit_Requirements:                   

          ORIENTation 234D TO 274D

  On_Hold_Comments:
    Visit_Comments:

     Exposure_Number: 1              
         Target_Name: GAL-CLUS-030533+171005
              Config: WFPC2
              Opmode: IMAGE
            Aperture: WFALL-FIX
          Sp_Element: F606W
 Optional_Parameters: CR-SPLIT=0.4761904762
Number_of_Iterations: 1
   Time_Per_Exposure: 2100S
Special_Requirements: POS TARG -12.0, -12.0

     Exposure_Number: 2                
         Target_Name: GAL-CLUS-030533+171005
              Config: WFPC2
              Opmode: IMAGE
            Aperture: WFALL-FIX
          Sp_Element: F814W
 Optional_Parameters: CR-SPLIT=0.5
Number_of_Iterations: 1
   Time_Per_Exposure: 2400S
Special_Requirements: POS TARG -12.0, -12.0


            Comments:

      Visit_Number: 2
Visit_Requirements:                 

          ORIENTation 234d TO 274d

  On_Hold_Comments:
    Visit_Comments:

     Exposure_Number: 1            
         Target_Name: GAL-CLUS-030518+172838
              Config: WFPC2
              Opmode: IMAGE
            Aperture: WFALL-FIX
          Sp_Element: F606W
 Optional_Parameters: CR-SPLIT=0.4761904762
Number_of_Iterations: 1
   Time_Per_Exposure: 2100S
Special_Requirements: POS TARG -12.0, -12.0

     Exposure_Number: 2                
         Target_Name: GAL-CLUS-030518+172838
              Config: WFPC2
              Opmode: IMAGE
            Aperture: WFALL-FIX
          Sp_Element: F814W
 Optional_Parameters: CR-SPLIT=0.5
Number_of_Iterations: 1
   Time_Per_Exposure: 2400S
Special_Requirements: POS TARG -12.0, -12.0


            Comments:

      Visit_Number: 3
Visit_Requirements:                     ! Section 7.1

          ORIENTation 50D TO 100D

  On_Hold_Comments:
    Visit_Comments:

     Exposure_Number: 1                 ! Section 6.5
         Target_Name: GAL-CLUS-205622-043744
              Config: WFPC2
              Opmode: IMAGE
            Aperture: WFALL-FIX
          Sp_Element: F702W
 Optional_Parameters: CR-SPLIT=0.5
Number_of_Iterations: 1
   Time_Per_Exposure: 2400S
Special_Requirements: POS TARG -15.0, -15.0
			EXPAND

     Exposure_Number: 2                
         Target_Name: GAL-CLUS-205622-043744
              Config: WFPC2
              Opmode: IMAGE
            Aperture: WFALL-FIX
          Sp_Element: F814W
          Wavelength:
 Optional_Parameters: CR-SPLIT=0.5
Number_of_Iterations: 1
   Time_Per_Exposure: 2400S
Special_Requirements: POS TARG -15.0, -15.0
			EXPAND

            Comments:

      Visit_Number: 4
Visit_Requirements:                     ! Section 7.1

          ORIENTation 60D TO 70D

  On_Hold_Comments:
    Visit_Comments:

     Exposure_Number: 1                
         Target_Name: GAL-CLUS-214012-233927
              Config: WFPC2
              Opmode: IMAGE
            Aperture: WFALL-FIX
          Sp_Element: F606W
 Optional_Parameters: CR-SPLIT=0.5
Number_of_Iterations: 1
   Time_Per_Exposure: 2400S
Special_Requirements: POS TARG -15.0, 0.0
			EXPAND

     Exposure_Number: 2                
         Target_Name: GAL-CLUS-214012-233927
              Config: WFPC2
              Opmode: IMAGE
            Aperture: WFALL-FIX
          Sp_Element: F814W
 Optional_Parameters: CR-SPLIT=0.5
Number_of_Iterations: 1
   Time_Per_Exposure: 2400S
Special_Requirements: POS TARG -15.0, 0.0
			EXPAND

            Comments:

Data_Distribution                     

         Medium:        8MM             
Blocking_Factor:        10             
                                      
        Ship_To:	PI_address
			
       Ship_Via:        UPS            
                                      

Recipient_Email: !       gdi@lick.ucsc.edu
                                    

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