6101( 10) - 02/23/96 11:44 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6101 Version: 10 Check-in Date: 23-Feb-1996 11:25:16 1.Proposal Title: The young double cluster NGC 1850 in the Large Magellanic Cloud ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Stellar Populations GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Roberto Gilmozzi European Southern Observatory CoI: Nino Panagia Space Telescope Science Institute N CoI: Shawn Ewald California Institute of Technology N CoI: Ellyne Kinney Space Telescope Science Institute Y CoI: Salvatore Scuderi Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract We propose to study the stellar population of the young double cluster NGC 1850 in the LMC. Our plan includes WFPC2 imaging both in broad band filters (to study the general properties of stars) and THE narrow band filter HAlpha to identify PMS stars. Previous observations have shown that both subclusters, NGC 1850A and NGC1850B, are quite young (50 and 4 Myr, respectively) while the field stars have ages between 500 Myr and 6 Gyr, at least. In addition, the two clusters are distinct not only in age but also in their IMFs (the younger has a steeper slope) and in their spatial distributions (the younger one is more widely spread). Therefore, NGC 1850 and its surrounding field represent an ideal astrophysical laboratory where to study different stellar populations and many aspects of stellar evolution. In particular, in the younger cluster we expect to detect hundreds of PMS stars. ------------------------------------------------------------------------------------ 6101( 10) - 02/23/96 11:44 - [ 2] Observations Description ------------------------ noindent Imaging with WFPC2 2mm We plan to complement the observations made in Cycle 4 (i.e. imaging with UV(1700Angstrom) 2000s, B 1000s, V 200s and I 1000s) by obtaining new images in R (F675W, 30+500s). All long exposures will be CR- split. To isolate the PMS stars we will also take narrow band images in H Alpha (F656N, 1000s). The grand total for the imaging part of the proposal is 5 CVZ orbits, including overheads and CR-splits. Exposure times for broad band imaging were calculated using SYNPHOT (after adjustments based on the Cycle 4 observations) to reach mag at least 26 in each filter (absolute magnitude about 7.5, or 0.7). The H Alpha filter exposure time was chosen to yield a S/N ~ 7Sigma for a R=23 T Tau star with W_eq ~ 20Angstrom so that discrimination against other stars of similar magnitude can be done at the 5 Sigma level. 2mm noindent Control Observations 2mm We plan to obtain images of three control fields with a comparable set of filters and exposure times as done for the main field. In particular, we will expose the 170, B, V, R, I and H Alpha filters for 2000s, 1000s, 200s, 500s, 1000s, 1130s. Real Time Justification ----------------------- We wish to take these observation in the CVZ because it uses spacecraft time most efficiently. The maximum CVZ duration of a CVZ interval at the position of NGC 1850 is 28 hours (for a total of about 58 hours in a year). Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6101( 10) - 02/23/96 11:44 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1850 STELLAR CLUSTER, OPEN RA = 05H 08M 59S +/- 1.0S, DEC = 1950 SURF(V) = 9.3 CLUSTER -68D 49' 24" +/- 5.0" 2 NGC1850- STELLAR CLUSTER, OPEN RA = 05H 08M 52S +/- 1.0S, DEC = 1950 SURF-BKG(V) = 24.5+/-0.5 FIELD-1 CLUSTER -68D 45' 54" +/- 5.0" Comments: Control field for NGC1850 3 NGC1850- STELLAR CLUSTER, OPEN RA = 05H 08M 54S +/- 1.0S, DEC = 1950 SURF-BKG(V) = 24.5+/-0.5 FIELD-2 CLUSTER -68D 51' 39" +/- 5.0" Comments: Control field for NGC1850 6101( 10) - 02/23/96 11:44 - [ 4] Visit: 01 Visit Requirements: 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 NGC1850 WFPC2 IMAGE WFALL F656N ATD-GAIN = 1 2000S 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1850 WFPC2 IMAGE WFALL F656N ATD-GAIN = 1 1000S 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1850 WFPC2 IMAGE WFALL F656N ATD-GAIN = 15 1 90S ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC1850 WFPC2 IMAGE WFALL F675W ATD-GAIN = 15 1 30S ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC1850 WFPC2 IMAGE WFALL F675W ATD-GAIN = 1 500S 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 6101( 10) - 02/23/96 11:44 - [ 5] Visit: 02 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 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC1850- WFPC2 IMAGE WFALL F170W ATD-GAIN = 1 2000S FIELD-1 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC1850- WFPC2 IMAGE WFALL F791W ATD-GAIN = 1 1000S FIELD-1 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 9 NGC1850- WFPC2 IMAGE WFALL F439W ATD-GAIN = 1 1000S FIELD-1 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC1850- WFPC2 IMAGE WFALL F675W ATD-GAIN = 1 500S FIELD-1 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 11 NGC1850- WFPC2 IMAGE WFALL F656N ATD-GAIN = 1 1000S FIELD-1 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC1850- WFPC2 IMAGE WFALL F569W ATD-GAIN = 1 200S FIELD-1 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 13 NGC1850- WFPC2 IMAGE WFALL F675W ATD-GAIN = 15 1 30S FIELD-1 ------------------------------------------------------------------------------------------------------------------------------------ 14 NGC1850- WFPC2 IMAGE WFALL F656N ATD-GAIN = 1 2000S FIELD-1 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC1850- WFPC2 IMAGE WFALL F170W ATD-GAIN = 15 1 60S FIELD-1 ------------------------------------------------------------------------------------------------------------------------------------ 31 NGC1850- WFPC2 IMAGE WFALL F791W ATD-GAIN = 15 1 30S FIELD-1 ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC1850- WFPC2 IMAGE WFALL F439W ATD-GAIN = 15 1 30S FIELD-1 ------------------------------------------------------------------------------------------------------------------------------------ 6101( 10) - 02/23/96 11:44 - [ 6] Visit: 03 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 NGC1850- WFPC2 IMAGE WFALL F170W ATD-GAIN = 1 2000S FIELD-2 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 18 NGC1850- WFPC2 IMAGE WFALL F439W ATD-GAIN = 1 1000S FIELD-2 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 19 NGC1850- WFPC2 IMAGE WFALL F569W ATD-GAIN = 1 200S FIELD-2 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC1850- WFPC2 IMAGE WFALL F675W ATD-GAIN = 1 500S FIELD-2 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 22 NGC1850- WFPC2 IMAGE WFALL F675W ATD-GAIN = 15 1 30S FIELD-2 ------------------------------------------------------------------------------------------------------------------------------------ 23 NGC1850- WFPC2 IMAGE WFALL F791W ATD-GAIN = 1 1000S FIELD-2 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 25 NGC1850- WFPC2 IMAGE WFALL F656N ATD-GAIN = 1 1000S FIELD-2 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 26 NGC1850- WFPC2 IMAGE WFALL F656N ATD-GAIN = 1 2000S FIELD-2 15,CR-SPLIT = 0.7,CR- TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC1850- WFPC2 IMAGE WFALL F170W ATD-GAIN = 15 1 60S FIELD-2 ------------------------------------------------------------------------------------------------------------------------------------ 31 NGC1850- WFPC2 IMAGE WFALL F791W ATD-GAIN = 15 1 30S FIELD-2 ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC1850- WFPC2 IMAGE WFALL F439W ATD-GAIN = 15 1 30S FIELD-2 ------------------------------------------------------------------------------------------------------------------------------------ 6101( 10) - 02/23/96 11:44 - [ 7] Summary Form for Proposal 6101 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ATD-GAIN = 15 CR-SPLIT = 0.7 CR-TOLERANCE = 0.0 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Stellar Populations ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F656N F675W F170W F791W F439W F569W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1850 NGC1850-FIELD-1 NGC1850-FIELD-2 ------------------------------------------------------------------------------------------------------------------------------------