6581( 5) - 04/17/97 11:52 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6581 Version: 5 Check-in Date: 08-Apr-1996 15:58:31 1.Proposal Title: Morphology and Photometry of Galaxies in Optically Selected High Redshift Clusters ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle GALAXIES & CLUSTERS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Marc Postman SPACE TELESCOPE SCIENCE INSTITUTE CoI: James E. Gunn Princeton University N CoI: John G. Hoessel University of Wisconsin N CoI: Lori Lubin Observatories of the Carnegie Institute of N Washington CoI: J. Beverley Oke Dominion Astrophysical Observatory N CoI: Donald Schneider Penn State University N ------------------------------------------------------------------------------------ 6. Abstract We are requesting deep, broad-band red WFPC2 images of eight distant clusters (0.55 < z ~less 1.1) to analyze the morphological characteristics of the cluster members. The high angular resolution imagery of HST, combined with our extensive ground based u,v,B,g,V,R,I,z photometry and spectroscopy, will allow the measurement of the morphological fractions in distant clusters as functions of redshift, color, spectral features, galaxy density, and global cluster properties such as core radius and ellipticity. We will study the spectral and rest-frame UV properties of the cluster galaxies as a function of morphological type in order to constrain the evolution of structural parameters of the cluster galaxies, the origin of the morphological segregation of galaxies, and the epoch of galaxy and cluster formation. The cluster sample has been selected objectively from large area optical/near IR ground based surveys. The proposal team has committed a significant amount of time on ground based telescopes for on--going spectroscopic data acquisition that will compliment the HST observations. We have developed and tested algorithms for performing objective measurements of galaxy morphology that will be applied to the data. ------------------------------------------------------------------------------------ 6581( 5) - 04/17/97 11:52 - [ 2] Observations Description ------------------------ def\\\\rt#1 #1 def\\\\lft#1#1 def #1 #1 def\\\\mid#1 -20pt plus 1000pt#1 -20pt plus 1000pt 20pt centerline #& #& #& # noalign\\\\medskip \\\\medskip Cluster & midz & HST Cycle & Exposures noalign\\\\medskip \\\\medskip CL0230+0036 & 0.75 & 6 & 16800 sec (7 orbits) CL0943+4805 & 0.70 & 6 & 16800 sec (7 orbits) CL1325+3009 & 1.06 & 6 & 16800 sec (7 orbits) CL2157+0348 & 0.69 & 6 & 16800 sec (7 orbits) CL0029+0509 & 0.55 & 7 & 14400 sec (6 orbits) CL0226+0118 & 0.80 & 7 & 16800 sec (7 orbits) CL0951+4741 & 0.65 & 7 & 16800 sec (7 orbits) CL1325+3024 & 0.60 & 7 & 14400 sec (6 orbits) noalign\\\\medskip \\\\medskip The F702W filter is the most efficient choice for imaging z > 0.6 clusters given the typical spectral energy distribution of the cluster galaxies combined with the relatively high QE and broad bandpass of this filter. We opt against using F814W because the sky background is slightly higher, the QE is slightly lower, and one does not gain a significant signal-to-noise ratio (S/N) improvement given a passively evolving elliptical spectral energy distribution (with significant color evolution or a high spiral fraction, the drive to observe much redward of 8000Angstrom\\\\ is negated). We will rely on our ground based data for integrated color information. Our exposure time estimates are based on a direct analysis of the WFPC2+F702W HST data of the z = 1.2 3C324 cluster observed by Dickinson (who kindly provided us access to these data). Our desire is to reach a S/N ratio of at least ~5 within the half-light radius of 0.50 L^* galaxies at z ~ 1.0. This requirement is based jointly on the desire to have quality data for a significant number of cluster members and on our estimates of the minimum signal needed to perform reliable measurement of basic morphological characteristics such as the effective radius, compactness parameter, asymmetry, and radial profile. After 16,800 seconds of exposure time, the relationship between S/N ratio and AB magnitude within the half-light radius of galaxies in the 3C324 WFC data is hboxlog_10( S/N)_0.5 ~ -0.413 hboxAB_0.5 + 10.827. Thus, galaxies with AB_0.5 <= 24.52 will typically have S/N >= 5 over their central 80 WFC pixels. This corresponds to the flux a passively evolving 0.50 L^* elliptical galaxy at z = 1.0 would have within its half-light radius (assuming an effective radius of 3h^-1 kpc). Color evolution aids S/N considerations but we want to be conservative to avoid biasing our results. We will, thus, require 7 orbits to perform our analysis on our most distant clusters; 6 orbits for the clusters at z ~less 0.7. These S/N computations are relatively independent of the assumed Hubble constant. We will request offsets of a few WFC-pixels after every 2 orbits to improve rejection of residual hot pixels and other CCD defects. We propose to split our observations over two HST cycles given the expected shorter duration of cycle 6. Real Time Justification ----------------------- No special requirements needed. We have acquired and reduced multiband photometry ( u,v,B, g,V,R,I, z) for the clusters in our HST target list. The photometric data were obtained using the Hale 5m and Keck 10m telescopes. Spectroscopic data for galaxies the clusters are being obtained with the Low- Resolution Imaging Spectrograph at the Keck 10m telescope (Oke & Postman have already had 8 nights of Keck time for this survey). Slit masks are used to obtain between 70 - 100 spectra per cluster field. Schneider and Hoessel will commit significant blocks of their GTO time on the Hobby-Eberly 8m telescope and on the WIYN telescope, respectively, for additional spectroscopic data acquisition. All members of the proposal team have expertise in the fields of galaxy and cluster formation and evolution. Postman and Gunn have developed and tested software for measuring structural parameters and performing morphological classification of galaxies. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6581( 5) - 04/17/97 11:52 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: ------------------------------------------------------------------------------------ 6581( 5) - 04/17/97 11:52 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-CLUS- CLUSTER OF GALAXIES RA=09H 43M 38.57S +/- 1",DEC=48D J2000 Z = 0.70 V = 23 094339+48044 04' 45.5" +/- 1",PLATE-ID=00T8 6 Comments: Gunn, Hoessel, Oke Cluster 2 GAL-CLUS- CLUSTER OF GALAXIES RA=21H 57M 52.22S +/- 1",DEC=03D J2000 Z = 0.70 V = 23 215752+03480 48' 06.3" +/- 1",PLATE-ID=0511 6 Comments: Gunn, Hoessel, Oke Cluster 3 GAL-CLUS- CLUSTER OF GALAXIES RA=16H 04M 29.45S +/- 1",DEC=43D J2000 Z = 0.90 V = 23.5 160429+43213 21' 35.4" +/- 1",PLATE-ID=01RZ 5 Comments: Gunn, Hoessel, Oke cluster 4 GAL-CLUS- CLUSTER OF GALAXIES RA=13H 25M 18.22S +/- 1",DEC=30D J2000 Z = 1.06 V = 23.8 132518+30093 09' 38.5" +/- 1",PLATE-ID=009L 9 Comments: Gunn, Hoessel, Oke Cluster 6581( 5) - 04/17/97 11:52 - [ 5] Visit: 01 Visit Requirements: ORIENT 185D TO 10D On Hold Comments: Additional Comments: Rotate U3 axis between 185D and 10D east of north Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 101 GAL-CLUS-09 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2800 S 4339+480446 IX ------------------------------------------------------------------------------------------------------------------------------------ 102 GAL-CLUS-09 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 3 2900 S 4339+480446 IX ------------------------------------------------------------------------------------------------------------------------------------ 103 GAL-CLUS-09 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 3 2900 S POS TARG 0.50,0.50 4339+480446 IX ------------------------------------------------------------------------------------------------------------------------------------ 6581( 5) - 04/17/97 11:52 - [ 6] Visit: 02 Visit Requirements: ORIENT 215D TO 275D On Hold Comments: Additional Comments: Rotate U3 axis between 215D and 275D east of north Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 201 GAL-CLUS-21 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2600 S 5752+034806 IX ------------------------------------------------------------------------------------------------------------------------------------ 202 GAL-CLUS-21 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 3 2700 S 5752+034806 IX ------------------------------------------------------------------------------------------------------------------------------------ 203 GAL-CLUS-21 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 3 2700 S POS TARG 0.50,0.50 5752+034806 IX ------------------------------------------------------------------------------------------------------------------------------------ 6581( 5) - 04/17/97 11:52 - [ 7] Visit: 03 Visit Requirements: ORIENT 200D TO 20D On Hold Comments: Additional Comments: Rotate U3 axis between 200D and 20D east of north Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 301 GAL-CLUS-16 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 1 2700 S 0429+432135 IX ------------------------------------------------------------------------------------------------------------------------------------ 302 GAL-CLUS-16 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 3 2800 S 0429+432135 IX ------------------------------------------------------------------------------------------------------------------------------------ 303 GAL-CLUS-16 WFPC2 IMAGE WFALL-F F702W CR-SPLIT=NO 3 2800 S POS TARG 0.50,0.50 0429+432135 IX ------------------------------------------------------------------------------------------------------------------------------------ 6581( 5) - 04/17/97 11:52 - [ 8] Visit: 04 Visit Requirements: ORIENT 295D TO 340D On Hold Comments: Additional Comments: Rotate U3 axis between 295D and 340D east of north Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 401 GAL-CLUS-13 WFPC2 IMAGE WFALL-F F814W CR-SPLIT=NO 1 2600 S 2518+300939 IX ------------------------------------------------------------------------------------------------------------------------------------ 402 GAL-CLUS-13 WFPC2 IMAGE WFALL-F F814W CR-SPLIT=NO 3 2700 S 2518+300939 IX ------------------------------------------------------------------------------------------------------------------------------------ 403 GAL-CLUS-13 WFPC2 IMAGE WFALL-F F814W CR-SPLIT=NO 3 2700 S POS TARG 0.50,0.50 2518+300939 IX ------------------------------------------------------------------------------------------------------------------------------------ 6581( 5) - 04/17/97 11:52 - [ 9] Summary Form for Proposal 6581 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 185D TO 10D POS TARG 0.50,0.50 ORIENT 215D TO 275D ORIENT 200D TO 20D ORIENT 295D TO 340D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F702W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names GAL-CLUS-094339+480446 GAL-CLUS-215752+034806 GAL-CLUS-160429+432135 GAL-CLUS-132518+300939 ------------------------------------------------------------------------------------------------------------------------------------