6439( 32) - 05/22/97 10:34 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6439 Version: 32 Check-in Date: 22-May-1997 10:33:26 1.Proposal Title: Using a Cepheid based Distance to Test the Large Peculiar Motions Inferred in the Centaurus Region ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle COSMOLOGY GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: STEPHEN ZEPF University of California, Berkeley CoI: Marc Davis University of California N CoI: Barry Madore NASA/IPAC Extragalactic Database N CoI: Wendy Freedman Carnegie Institution of Washington N ------------------------------------------------------------------------------------ 6. Abstract We propose to use the HST and WFPC2 to obtain periods and luminosities for Cepheids in a spiral galaxy in the Centaurus cluster in order to determine its distance. A Cepheid distance to Centaurus is possible with HST and will be a major step in the comparison of observed peculiar velocities with the predictions based on reconstructions of the density field from the spatial distribution of galaxies. The Centaurus region is critical for such tests. Secondary distance indicators (SBFs, Tully-Fisher, and D_n - Sigma) place this galaxy and others in the ``Cen30'' cluster at a distance of only about 2,300 - 2,700 kms, whereas the cluster has a redshift of 3,300 kms\ in the CMB frame. Such a high peculiar velocity is not predicted for this cluster by reconstructions of the density field based on IRAS or optical galaxy distributions. This cluster is the nearest and one of the clearest cases of disagreement between the peculiar motions inferred from secondary distance indicators and those predicted by the density fields. A great deal of theoretical and observational effort has gone into programs to determine Omega in this way. The major obstacle to progress has been discrepancies like those for the Centaurus cluster. To resolve this discrepancy, there is no substitute for directly obtaining Cepheid distances. ------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 2] Observations Description ------------------------ The scientific goals require an observing program in which the target is visited nine times, the first eight in optimized time intervals covering a 50- day window, and the ninth a year later to guard against aliasing for long period objects. The time sequence of the 8 visits is critical to the project. The first six visits will consist of observations in the F55W filter for three orbits in each visit. Each orbit is defined as one exposure which is CR-split into two. Between orbits, the pointing is shifted by 2.5,2.5 WF pixels. The last three visits will consist of two orbits. In this case, we will utilize an integer shift bewteen orbits. In all cases, the F55W filter will be used. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: ------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS1 galaxy,spiral RA=12H 40M 58.77S +/- 5", DEC=- 2000 V = 2562 SURF(V) = 24 40D 58' 02.5" +/- 5" 6439( 32) - 05/22/97 10:34 - [ 4] Visit: 01 Visit Requirements: ORIENTation 95.0D TO 105.0D SCHEDulability 50% On Hold Comments: Additional Comments: The orientation must be 99D +/- 0.5D for all visits. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.25,+0.25 1 Comments: Dithering pattern equal to an offset of 2.5, 2.5 WF pixels is put in by hand because dither-line step etc would not produce an acceptable phase 2 proposal ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.5,+0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 5] Visit: 02 Visit Requirements: SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 4.8D TO 5.8D On Hold Comments: Additional Comments: Orientation of all visits must be the same as visit 1. Visit 2 must occur from 4.8 to 5.8 days after visit 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.25,+0.25 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.5,+0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 6] Visit: 03 Visit Requirements: SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 10.6D TO 11.8D On Hold Comments: Additional Comments: Orientation of all visits must be the same as visit 1. Visit 3 must occur from 10.6 to 11.8 days after visit 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.25,+0.25 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.5,+0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 7] Visit: 04 Visit Requirements: SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 17.0D TO 18.2D On Hold Comments: Additional Comments: Orientation of all visits must be the same as visit 1. Visit 4 must occur from 17.0 to 18.2 days after visit 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.25,+0.25 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.5,+0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 8] Visit: 05 Visit Requirements: SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 24.0D TO 25.2D On Hold Comments: Additional Comments: Orientation of all visits must be the same as visit 1. Visit 5 must occur from 24.0 to 25.2 days after visit 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.25,+0.25 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.5,+0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 9] Visit: 06 Visit Requirements: SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 31.5D TO 32.9D On Hold Comments: Additional Comments: Orientation of all visits must be the same as visit 1. Visit 6 must occur from 31.5 to 32.9 days after visit 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.25,+0.25 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.5,+0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 10] Visit: 07 Visit Requirements: SAME ORIENT AS 1 SCHEDulability 50% On Hold Comments: Additional Comments: Orientation of all visits must be the same as visit 1. Visit 7 must occur from 39.9 to 41.5 days after visit 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG 0.5, 0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 11] Visit: 08 Visit Requirements: ORIENT 99D TO 99D SCHED 50% BETWEEN 16-JUN-1997 AND 19-JUN-1997 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 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG 0.5, 0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 12] Visit: 09 Visit Requirements: ORIENT 99D TO 99D SCHEDulability 50% AFTER 08 BY 29.7D TO 31.7D On Hold Comments: Additional Comments: Original Comment: Orientation of all visits must be the same as visit 1. Visit 9 must occur from 364.0 to 366.0 days after visit 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2200 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4603-POS WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=0.5,CR-TOLERANCE=0.1 1 2700 S POS TARG +0.5, +0.5 1 ------------------------------------------------------------------------------------------------------------------------------------ 6439( 32) - 05/22/97 10:34 - [ 13] Summary Form for Proposal 6439 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 CR-TOLERANCE=0.1 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COSMOLOGY ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENTation 95.0D TO 105.0D SCHEDulability 50% POS TARG +0.25,+0.25 POS TARG +0.5,+0.5 SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 4.8D TO 5.8D SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 10.6D TO 11.8D SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 17.0D TO 18.2D SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 24.0D TO 25.2D SAME ORIENT AS 1 SCHEDulability 50% AFTER 1 BY 31.5D TO 32.9D SAME ORIENT AS 1 SCHEDulability 50% POS TARG 0.5, 0.5 ORIENT 99D TO 99D SCHED 50% BETWEEN 16-JUN-1997 AND 19-JUN-1997 ORIENT 99D TO 99D SCHEDulability 50% AFTER 08 BY 29.7D TO 31.7D POS TARG +0.5, +0.5 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC4603-POS1 ------------------------------------------------------------------------------------------------------------------------------------