5995( 0) - 07/18/95 19:08 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5995 Version: ********** Check-in Date: ********** 1.Proposal Title: Morphology of galaxies in very high redshift clusters: 3C265 (z=0.811), and 3C184 (z=0.996) ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Galaxies & Clusters GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Olivier Le Fevre Observatoire de Paris-Meudon ------------------------------------------------------------------------------------ 6. Abstract We are proposing to obtain morphological information on galaxies in two of the highest redshift clusters known at present. The environments of 3C265 (z=0.811) and 3C184 (z=0.996) have been shown by us to contain rich clusters: deep imaging and spectroscopy from the ground show an excess of galaxies, several of them subsequently identified at the same redshift as the radio-galaxy in spectroscopy. The morphological state of galaxies in high redshift clusters should give us important clues about the formation and evolution of galaxies in dense environments and the formation of clusters. The role played by mergers into the observed raise in the blue active fraction of galaxies with redshift (the Butcher-Oemler effect), the location of star forming regions, and the shape of "normal" elliptical and spiral galaxies, and their differences with galaxies in present day clusters, can be ideally assessed from HST imaging with WFPC2. Only a handful of clusters are known at z>0.8, these observations are expected to bring unique clues on the evolution of galaxies in clusters when the universe was 40% of its present age. ------------------------------------------------------------------------------------ 5995( 0) - 07/18/95 19:08 - [ 2] Observations Description ------------------------ Observations will be performed in the F606W and F814W filters, in the WF. For typical cluster galaxies at z=0.8 and z=1, A S/N>1 for mu_V=26.5 will probe I=19-22 galaxies at least 3 magnitudes fainter than the central surface brightness of "disc" galaxies (a disc has mu_I=21+10log(1+z) at z=0.8). 8 consecutive orbits will be needed on 3C184 to obtain a total integration time of 9510 sec. in F606W, and 12690 sec. in F814W, which will yield a S/N=3 for mu_V=25.3 mag/arcsec^2 and mu_I=24.6 mag/arcsec^2 respectively. The calcultations are as follows:, beginitemize item F606W: From the WFPC2 handbook pp.56-58 the sky brightness with mu_V=23.3 mag/arcsec^2, and an efficiency of 0.04485, will give 0.0485 e^-/sec/pixel; a galaxy at mu_V=25.3 mag/arcsec^2 will give 0.00851 e^-/sec/pixel, and the dark current at -77^degreesC is 0.016 e^-/sec/pixel. The S/N in 9510 sec will then be, fracSN=\frac0.00851*9510SQRT(5.2^2+(0.00851+0.0485+0.016)*951 0) = 3 item F814W: for AB_Nu=-0.5 and an efficiency of 0.01822, the sky will give 0.03618 e^-/sec/pixel; a galaxy at mu_I=24.6 will give 0.0104 e^-/sec/pixel. The S/N in 12690 sec. will be, fracSN=\frac0.0104*12690SQRT(5.2^2+(0.0104+0.0485+0.016)*1269 0)= 3 enditemize Seven consecutive orbits will be necessary on 3C265 to obtain exposure times of 7020 sec and 9720 sec in F606W and F814W respectively. Similar calculations as shown above indicate that a S/N=3 will be reached for mu_V=25.1 and mu_I=24.4 in F606W and F814W respectively. Small shifts between each exposure (on order 20 min) and a minimum of 6 exposures per filter will be obtained to best remove cosmic rays and low level flat field defects. A total of 15 orbits is then requested for this program. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- The TAC has recommended to observe 3C184 only, for 4 orbits. ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5995( 0) - 07/18/95 19:08 - [ 3] 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 = 07H33M59.01S +/-0.19S, DEC 1950 Z=0.994 V=21.5 B-V=0.52 V-R=0.11 073924+70231 HIGH REDSHIFT CLUSTER = +70D30' 1.1" +/-1.0" 1 (Z>0.5) Comments: Flux is for radio-galaxy, cluster galaxies have fluxes from V=22.0 down to the computed HST plate limit. 5995( 0) - 07/18/95 19:08 - [ 4] Visit: 01 Visit Requirements: PCS MODE F CVZ On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GAL-CLUS- WFPC2 IMAGE WF3 F814W CR- 1 2250S POS TARG 0.0,0.0 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 2 GAL-CLUS- WFPC2 IMAGE WF3 F814W CR- 1 2250S POS TARG 0.5,0.0 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 3 GAL-CLUS- WFPC2 IMAGE WF3 F814W CR- 1 2250S POS TARG 0.0,0.5 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 4 GAL-CLUS- WFPC2 IMAGE WF3 F814W CR- 1 2250S POS TARG -0.5,0.0 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 5 GAL-CLUS- WFPC2 IMAGE WF3 F814W CR- 1 2250S POS TARG 0.0,-0.5 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 6 GAL-CLUS- WFPC2 IMAGE WF3 F606W CR- 1 1550S POS TARG 0.0,0.0 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 7 GAL-CLUS- WFPC2 IMAGE WF3 F606W CR- 1 1550S POS TARG 0.5,0.0 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 8 GAL-CLUS- WFPC2 IMAGE WF3 F606W CR- 1 1550S POS TARG 0.0,0.5 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 9 GAL-CLUS- WFPC2 IMAGE WF3 F606W CR- 1 1350S POS TARG -0.5,0.0 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 10 GAL-CLUS- WFPC2 IMAGE WF3 F606W CR- 1 1350S POS TARG 0.0,-0.5 073924+7023 TOLERANCE=0.0 11 ------------------------------------------------------------------------------------------------------------------------------------ 5995( 0) - 07/18/95 19:08 - [ 5] Summary Form for Proposal 5995 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Galaxies & Clusters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE F CVZ POS TARG 0.0,0.0 POS TARG 0.5,0.0 POS TARG 0.0,0.5 POS TARG -0.5,0.0 POS TARG 0.0,-0.5 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F606W ------------------------------------------------------------------------------------------------------------------------------------ Target Names GAL-CLUS-073924+702311 ------------------------------------------------------------------------------------------------------------------------------------