! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /tmp_mnt/babbar/u1/med/d1/rps2/5967/5967.prop ! Generated by PREPROCESSOR, version 6.0e ! Date: Thu Apr 18 14:17:16 EDT 1996 Proposal_Information Title: Imaging Clusters of Galaxies at z > 1 Proposal_Category: GO Scientific_Category: Galaxies & Clusters Cycle: 5 Investigators PI_Name: Mark Dickinson PI_Institution: Space Telescope Science Institute CoI_Name: Hyron Spinrad CoI_Institution: Department of Astronomy,University of California, Berkeley Contact: CoI_Name: S. George Djorgovski CoI_Institution: California Institute of Technology Contact: CoI_Name: Peter Eisenhardt CoI_Institution: Jet Propulsion Laboratory Contact: CoI_Name: S. Adam Stanford CoI_Institution: Infrared Processing and Analysis Center/Jet Propulsion Laboratory Contact: Abstract: One of the most dramatic achievements of the refurbished HST is its capability for resolving the morphologies of galaxies at high redshift. In Cycle 4, we have obtained an extremely deep image of a rich cluster of galaxies at z=1.206 which surrounds the radio galaxy 3C 324. This observation offers a wealth of morphological data on ``normal'' galaxies at z > 1, many of which appear to be far from normal, at least by z=0 standards. At the same time, despite the early cosmic epoch (30\ is a population of apparently ordinary elliptical galaxies already in place, with colors and morphologies very similar to those of their z=0 counterparts. A substantial fraction of early--type cluster galaxies have existed throughout most of a Hubble Time, apparently unaffected by the processes which are driving strong evolution in the population of disk galaxies. We propose to continue this program, imaging two clusters at z=1.140 and 1.169 which span the range of high-z cluster properties. One cluster contains the numerous red galaxies also found around 3C 324, while the other appears to be dominated by blue, presumably star forming galaxies. In addition to extending our knowledge of ``ordinary'' galaxies at z > 1, these observations will provide high--quality data on the remarkably convoluted morphologies exhibited by the radio galaxies themselves at these redshifts. Questions Observing_Description: The observations we propose for Cycle 5 closely follow the approach we used in Cycle 4 for the 3C 324 cluster. The extremely long integration time (32 orbits) used for our observation of the 3C 324 cluster was motivated in part by our intent to unambiguously determine the nature of the ultra--red galaxies and compare them to present--day ellipticals. The combination of the very large k--correction for these galaxies and the strong cosmological surface brightness dimming ((1+z)^4 = 23.7 at z=1.2) necessitated the long integration time granted in Cycle 4. We consider this experiment a success, as Fig. 3 demonstrates. Having established this to our satisfaction, for Cycle 5 we choose to reduce our exposure times and to increase our sample size to include two new clusters. Our goal is to conduct as broad a survey of cluster properties at z ~gt 1 as possible. If galaxy and cluster evolution is not precisely synchronized throughout the universe, then differences between clusters should be accentuated at higher and higher redshifts, as small differences in age become larger and larger fractions of the age of the universe. Already this appears to be the case at z ~ 0.5, where ``red'' clusters like 0016+16 coexist with ``blue'' clusters like 0939+47. We have examined subsets of our data on 3C 324, reducing the signal to noise to that equivalent to a 10--orbit exposure through F814W. We conclude that these integrations are sufficient for determining basic morphologies for cluster galaxies down to at least R=25.5. Real_Time_Justification: None. Deep, ground--based optical and infrared imaging data are already in hand for our fields, and led to their selection as targets. As mentioned above, we have observed 3C 210 and 3C 324 with Rosat although only the latter was significantly detected. The most vital supporting data for this program is spectroscopy of the cluster galaxies in order to confirm their membership, determine their integrated spectral properties, and (if possible) measure cluster velocity dispersions. These clusters may represent the limit out to which this is possible with current telescopes and instrumentation: beyond z=1.2, the standard features used for redshift determination (e.g. OII, Ca H+K, the 4000Angstrom\\\\ break) move too far into the red where atmospheric emission bands are extremely strong, and LyAlpha (visible from the ground for z ~gt 1.6) is easily quenched by small amounts of dust in galaxies. Even at z=1.2, spectroscopy of these R ~ 25 galaxies provides a tremendous challenge. We plan to carry out a systematic program of multi--slit spectroscopy using the Keck 10m Telescope, to which two of the co-investigators (Spinrad and Djorgovski) have access. The multi--slit capabilities of the Keck LRIS spectrograph have only recently become functional, and no such observations were possible for the 3C 324 cluster during the spring 1994 observing season. A short (1 hour) single--slit observation of one of the ultra-- red galaxies in that field showed a spectrum consistent with that of a z=1.2 elliptical, but with insufficient signal--to- -noise to secure the redshift unambiguously. That observation is encouraging, however, and we believe that longer integrations in multi--object mode during the coming year will be capable of obtaining many redshifts within these clusters. Calibration_Justification: Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: 3C210 Alternate_Names: Description: GALAXY,RADIO GALAXY,HIGH Z GAL,BCM,CLUSTER OF GALAXIES,HIGH REDSHIFT CLUSTER (Z>0.5) Position: RA=8H 58M 10.58S +/- 1S,DEC=27D 50' 30.0" +/- 1" Equinox: J2000 RV_or_Z: Z = 1.169 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: R = 22 Comments: Target position is not for radio galaxy, but is a WF2-FIX center position designed to place radio galaxy + cluster in desired location on WFPC2. Target_Number: 2 Target_Name: 3C267 Alternate_Names: Description: CLUSTER OF GALAXIES,HIGH REDSHIFT CLUSTER,RICH CLUSTER,GALAXY,RADIO GALAXY,BCM,HIGH REDSHIFT GALAXY Position: RA=11H 49M 55.73S +/- 1S,DEC=12D 46' 49.2" +/- 1" Equinox: 2000 RV_or_Z: z=1.140 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: R = 22 Comments: Target position is not for radio galaxy, but is a WF2-FIX center position designed to place radio galaxy + cluster in desired location on WFPC2. Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: GROUP 1-2 WITHIN 7D ORIENT 99D TO 102D BEFORE 19-MAY-1996 On_Hold_Comments: Visit_Comments: BEFORE 19-MAY-1996 special requirement included to avoid bright background (zodiacal + possible scattered light). Please schedule as early as possible -- zodiacal background increases rapidly with time. Exposure_Number: 1 Target_Name: 3C210 Config: WFPC2 Opmode: IMAGE Aperture: WF2-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 5 Time_Per_Exposure: 2100S Special_Requirements: EXPAND Comments: Visit_Number: 02 Visit_Requirements: SAME ORIENT AS 01 GROUP 1-2 WITHIN 7D BEFORE 19-MAY-1996 On_Hold_Comments: Visit_Comments: BEFORE 19-MAY-1996 special requirement included to avoid bright background (zodiacal + possible scattered light). Please schedule as early as possible -- zodiacal background increases rapidly with time. Exposure_Number: 2 Target_Name: 3C210 Config: WFPC2 Opmode: IMAGE Aperture: WF2-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 5 Time_Per_Exposure: 2100S Special_Requirements: EXPAND POS TARG -0.95,-0.95 Comments: Visits Visit_Number: 03 Visit_Requirements: GROUP 3-4 WITHIN 14 D ORIENT 134.5D TO 135.5D On_Hold_Comments: Visit_Comments: Please schedule as early as possible -- zodiacal background increases rapidly with time. Exposure_Number: 1 Target_Name: 3C267 Config: WFPC2 Opmode: IMAGE Aperture: WF2-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 3 Time_Per_Exposure: 2100 S Special_Requirements: EXPAND Comments: Exposure_Number: 2 Target_Name: 3C267 Config: WFPC2 Opmode: IMAGE Aperture: WF2-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2100 S Special_Requirements: POS TARG -0.50,0.25 EXPAND Comments: Visit_Number: 04 Visit_Requirements: GROUP 3-4 WITHIN 14 D SAME ORIENT AS 03 On_Hold_Comments: Visit_Comments: Please schedule as early as possible -- zodiacal background increases rapidly with time. Exposure_Number: 1 Target_Name: 3C267 Config: WFPC2 Opmode: IMAGE Aperture: WFALL Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 3 Time_Per_Exposure: 2100 S Special_Requirements: POS TARG -0.75,0.75 EXPAND Comments: Exposure_Number: 2 Target_Name: 3C267 Config: WFPC2 Opmode: IMAGE Aperture: WFALL Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 2 Time_Per_Exposure: 2100 S Special_Requirements: POS TARG -0.25,0.50 EXPAND Comments: Data_Distribution ! Defaults indicated; change if desired Medium: 8MM Blocking_Factor: 10 Ship_To: PI_Address Ship_Via: UPS Recipient_Email: