5914( 0) - 07/18/95 18:38 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5914 Version: ********** Check-in Date: ********** 1.Proposal Title: The Formation History of Globular Clusters in M33 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Stellar Populations GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Ata Sarajedini Kitt Peak National Observatory CoI: Doug Geisler Cerro Tololo Inter-American Obs. N CoI: Robert Schommer Cerro Tololo Inter-American Obs. N CoI: Paul Harding Steward Observatory N ------------------------------------------------------------------------------------ 6. Abstract We propose to study the early formation history of M33 by investigating the nature of the ``second parameter'' phenomenon among its globular star clusters. Discovered among the globular clusters of the Milky Way more than 30 years ago, the ``second parameter'' effect describes the degeneracy in the behavior of horizontal branch morphology with metal abundance. This degeneracy implies the existence of a second parameter, which, in addition to metal abundance, influences the morphology of the horizontal branch. Our approach involves the construction of (V,V-I) color-magnitude diagrams for a number of M33 clusters selected to be analogs of globular clusters in the Galaxy. From these diagrams, we will measure the cluster metallicity and horizontal branch morphology in order to look for a range of horizontal branch types at a given metal abundance and thus determine the presence and nature of any second parameter effect. A knowledge of both the metallicities and HB morphologies of the globulars in M33 will provide important constraints on their formation and evolution as well as that of the galaxy. Furthermore, when these data are combined with similar data for the globular clusters in M31, the Large and Small Magellanic Clouds, and the Fornax dwarf spheroidal galaxy, we will have the opportunity to probe the evolutionary history of these galaxies and how it varies with mass and morphological type. ------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 2] Observations Description ------------------------ M33 is at (m-M)_V ~ 24.8 implying that the horizontal branch (HB) stars of a typical M33 cluster are at V ~ 25.6. The following signal-to-noise calculations are based on information provided in the WFPC2 manual. With the F555W filter, a 5000 sec. exposure will yield signal-to-noise (S/N) ~ 25 at V=25.6. With the F814W filter, 5000 sec. will yield S/N~20 at I=25.6. The stars that comprise the target clusters are on average ~ 1 magnitude brighter in the I filter as compared with the V filter, so an exposure time of 5000 sec. will yield S/N~28 at I=24.6. Given its declination, M33 will be observable for 53 minutes during each HST orbit. Thus, for each visit, the first orbit will consist of 720 sec for guide star acquisition + 2200 sec CR-SPLIT F555W exposure + 120 sec CR- SPLIT overhead. A small offset will occur during Earth occultation. The next orbit will consist of 360 sec for guide star re-acquisition + 2700s F555W exposure + 120 sec CR-SPLIT overhead, with the small offset again occurring during Earth occultation. The third orbit and fourth orbit are identical to the second. Thus, each target cluster requires 4 orbits. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC598-U49 EXT-CLUSTER RA=01H 33M 45.01S +/- 0.013S, J2000 V = 16.25 DEC=+30D 47' 46.8" +/- 0.15" B-V = 0.68 2 NGC598-C20 EXT-CLUSTER RA=01H 34M 44.19S +/- 0.013S, J2000 V = 17.67 DEC=+30D 52' 18.9" +/- 0.15" B-V = 0.77 3 NGC598-M9 EXT-CLUSTER RA=01H 34M 30.21S +/- 0.013S, J2000 V = 17.12 DEC=+30D 38' 13.0" +/- 0.15" B-V = 0.69 4 NGC598-U137 EXT-CLUSTER RA=01H 33M 14.28S +/- 0.013S, J2000 V = 18.30 DEC=+30D 28' 23.1" +/- 0.15" B-V = 0.83 5 NGC598-U77 EXT-CLUSTER RA=01H 33M 28.68S +/- 0.013S, J2000 V = 17.19 DEC=+30D 41' 35.2" +/- 0.15" B-V = 0.67 6 NGC598-R14 EXT-CLUSTER RA=01H 34M 02.45S +/- 0.013S, J2000 V = 16.48 DEC=+30D 40' 40.7" +/- 0.15" B-V = 0.98 7 NGC598-H38 EXT-CLUSTER RA=01H 33M 52.11S +/- 0.013S, J2000 V = 17.25 DEC=+30D 29' 04.0" +/- 0.15" B-V = 0.73 8 NGC598-H10 EXT-CLUSTER RA=01H 33M 35.08S +/- 0.013S, J2000 V = 18.23 DEC=+30D 49' 00.2" +/- 0.15" B-V = 0.96 9 NGC598-C38 EXT-CLUSTER RA=01H 33M 30.65S +/- 0.013S, J2000 V = 18.10 DEC=+30D 22' 21.6" +/- 0.15" B-V = 0.73 10 NGC598-R12 EXT-CLUSTER RA=01H 34M 08.01S +/- 0.013S, J2000 V = 16.38 DEC=+30D 38' 38.3" +/- 0.15" B-V = 1.03 5914( 0) - 07/18/95 18:38 - [ 4] Visit: 01 Visit Requirements: ORIENT 135.0D TO 270.0D On Hold Comments: Additional Comments: Orientation to get bright star ~1 arcmin SSW off field. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC598-U49 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC598-U49 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC598-U49 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC598-U49 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 5] Visit: 02 Visit Requirements: ORIENT 140.0D TO 315.0D On Hold Comments: Additional Comments: Orientation to avoid two bright nearby stars Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC598-C20 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC598-C20 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC598-C20 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC598-C20 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 6] Visit: 03 Visit Requirements: ORIENT 250.0D TO 270.0D On Hold Comments: Additional Comments: Orientation to put PH1224 in WF3 chip. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 9 NGC598-M9 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC598-M9 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 11 NGC598-M9 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC598-M9 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 7] Visit: 04 Visit Requirements: ORIENT 160.0D TO 200.0D On Hold Comments: Additional Comments: Orientation to avoid one bright nearby star Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 13 NGC598-U137 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 14 NGC598-U137 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 15 NGC598-U137 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 16 NGC598-U137 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 8] Visit: 05 Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 17 NGC598-U77 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 18 NGC598-U77 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 19 NGC598-U77 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC598-U77 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 9] Visit: 06 Visit Requirements: ORIENT 315.0D TO 25.0D On Hold Comments: Additional Comments: Orientation will place R13 in WF3 chip and bright star in WF2. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 NGC598-R14 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 22 NGC598-R14 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 23 NGC598-R14 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 24 NGC598-R14 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 10] Visit: 07 Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 25 NGC598-H38 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 26 NGC598-H38 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 27 NGC598-H38 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 28 NGC598-H38 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 11] Visit: 08 Visit Requirements: ORIENT 90.0D TO 120.0D On Hold Comments: Additional Comments: Orientation will place PH1164, PH1163, and PH1162 in WF chips. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 29 NGC598-H10 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC598-H10 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 31 NGC598-H10 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC598-H10 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 12] Visit: 09 Visit Requirements: ORIENT 25.0D TO 65.0D On Hold Comments: Additional Comments: Orientation to get bright star 2 arcmin NE off field. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 33 NGC598-C38 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 34 NGC598-C38 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 35 NGC598-C38 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 36 NGC598-C38 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 13] Visit: 10 Visit Requirements: ORIENT 90.0D TO 130.0D On Hold Comments: Additional Comments: Orientation will place R13 in WF3 chip. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 37 NGC598-R12 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2200S EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 38 NGC598-R12 WFPC2 IMAGE PC1-FIX F555W CLOCKS=YES 1 2700S POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 39 NGC598-R12 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC598-R12 WFPC2 IMAGE PC1-FIX F814W CLOCKS=YES 1 2700S POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 5914( 0) - 07/18/95 18:38 - [ 14] Summary Form for Proposal 5914 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CLOCKS=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Stellar Populations ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 135.0D TO 270.0D EXPAND; END ORBIT; MAX DUR POS TARG +0.223, 0.000; EXPAND; END ORBIT; MAX DUR POS TARG 0.000, +0.223; EXPAND; END ORBIT; MAX DUR POS TARG -0.223, 0.000; EXPAND; END ORBIT; MAX DUR ORIENT 140.0D TO 315.0D ORIENT 250.0D TO 270.0D ORIENT 160.0D TO 200.0D ORIENT 315.0D TO 25.0D ORIENT 90.0D TO 120.0D ORIENT 25.0D TO 65.0D ORIENT 90.0D TO 130.0D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC598-U49 NGC598-C20 NGC598-M9 NGC598-U137 NGC598-U77 NGC598-R14 NGC598-H38 NGC598-H10 NGC598-C38 NGC598-R12 ------------------------------------------------------------------------------------------------------------------------------------