6678( 7) - 04/11/96 20:04 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6678 Version: 7 Check-in Date: 11-Apr-1996 19:58:48 1.Proposal Title: Nearby young dwarf galaxies and their Lyman Alpha emission ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle COSMOLOGY GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Trinh X. Thuan University of Virginia CoI: Yuri Izotov Main Astronomical Observatory N CoI: Valentin Lipovetsky Special Astrophysical Observatory N ------------------------------------------------------------------------------------ 6. Abstract We wish to obtain GHRS UV spectra of 3 and WFPC2 V and I images of 2 of the most metal-deficient ( Zsun/41 <=sssim Z <=sssim Zsun/21) blue compact galaxies (BCGs) known. These BCGs are the best candidates for nearby young primeval galaxies where massive star formation can be studied and constraints put on theories of gas collapse and fragmentation in a nearly pristine environment. Color-magnitude diagrams will constrain ages. The high resolution imaging will allow to determine the sizes, luminosities and colors of the ionizing star clusters. The absence or presence of an underlying low-surface-brightness old stellar population will tell us whether the BCG is genuinely young or not. The UV spectra will allow to examine the Ly-alpha/H Beta--O/H correlation. For galaxies with Z >~ 0.1 Zsun, there appears to be a correlation of increasing Ly-alpha emission with decreasing metallicity. HST has found the surprising result that the most metal-deficient BCG known, IZw18, does not have Ly-alpha emission. Is the latter suppressed in nearly primordial objects? If this is the case, Ly-alpha searches for high-redshift primeval galaxies will have to be rethought entirely. ------------------------------------------------------------------------------------ 6678( 7) - 04/11/96 20:04 - [ 2] Observations Description ------------------------ We wish to carry out an imaging program with the WFPC2 and a spectroscopic program with the GHRS. 1. Imaging. The WFPC2 will be used to obtain V(F555W) and I(F814W) images of the 2 BCGs T1214-277 and Tol 65. We shall use 2 orbits for each object. We shall split each orbit into two, spending 13 mn for the V exposure and 25 mn for the I exposure. Thus 2x13 mn will be spent with F555W and 2x25 mn will be spent with F814W. The same position and orientation angle are to be maintained for the 2 orbits, so it is desirable that they are consecutive. 2. Spectra. The GHRS will be used to obtain UV spectra of 3 BCGs: SBS0335-052, T1214-277 and Tol65. We shall use the grating G140L with the LSA (1.75" diameter) to obtain spectra in the wavelength range 1150 to 1450 A. We shall spend 3 orbits on SBS0335-052 with 1 orbit used for acquisition and 2 orbits for collecting data, and 2 orbits each for T1214-277 and Tol65, with 1 orbit for acquisition and 1 orbit for collecting data. Real Time Justification ----------------------- None Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6678( 7) - 04/11/96 20:04 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SBS0335-052 GALAXY,DWARF COMPACT, RA=03H 37M 43.99S +/- 0.02S,DEC= J2000 Z = V = 16.30+/-0.31 -05D 02' 39.0" +/- 0.3",PLATE- 0.0137 F-CONT(1300)=7.5+/-1.0e-15 ID=044L 2 T1214-277 GALAXY,DWARF COMPACT, RA=12H 17M 17.08S +/- 0.03S,DEC= J2000 Z = V = 17.50+/-0.50 -28D 02' 32.4" +/- 0.5",PLATE- 0.026 F-CONT(1300)=2.5+/-1.0e-15 ID=01C8 3 TOL65 GALAXY,DWARF COMPACT, RA=12H 25M 46.47S +/- 0.03S,DEC= J2000 Z = V = 17.70+/-0.50 -36D 14' 02.3" +/- 0.5",PLATE- 0.0094 F-CONT(1300)=2.0+/-1.0e-15 ID=04HG 6678( 7) - 04/11/96 20:04 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: HRS Spectrum of SBS0335-052 at Ly-alpha Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SBS0335-052 FOS/BL ACQ/PEA 4.3 MIRROR SCAN-STEP- 1 10.0S ONBOARD ACQ FOR 2 K Y=1.23,SEARCH- SIZE-X=1,SEARCH -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SBS0335-052 FOS/BL ACQ/PEA 1.0 MIRROR SCAN-STEP- 1 11.0S ONBOARD ACQ FOR 3 K X=0.61,SCAN- STEP- Y=0.61,SEARCH- SIZE-X=6,SEARCH Comments: -SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 3 SBS0335-052 FOS/BL ACQ/PEA 0.5 MIRROR SCAN-STEP- 1 12.0S ONBOARD ACQ FOR 4-6 K X=0.29,SCAN- STEP- Y=0.29,SEARCH- SIZE-X=3,SEARCH Comments: Three stage ACQ followed by GHRS exposures -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 4 SBS0335-052 HRS ACCUM 2.0 G140L 1162- 1 326.4S 1448 ------------------------------------------------------------------------------------------------------------------------------------ 5 SBS0335-052 HRS ACCUM 2.0 G140L 1162- 1 2720.0S 1448 ------------------------------------------------------------------------------------------------------------------------------------ 6 SBS0335-052 HRS ACCUM 2.0 G140L 1162- 1 2692.8S 1448 ------------------------------------------------------------------------------------------------------------------------------------ 6678( 7) - 04/11/96 20:04 - [ 5] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: HRS Spectrum of T1214-277 at Ly-alpha Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 7 T1214-277 FOS/BL ACQ/PEA 4.3 MIRROR SCAN-STEP- 1 10.0S ONBOARD ACQ FOR 8 K Y=1.23,SEARCH- SIZE-X=1,SEARCH -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 8 T1214-277 FOS/BL ACQ/PEA 1.0 MIRROR SCAN-STEP- 1 11.0S ONBOARD ACQ FOR 9 K X=0.61,SCAN- STEP- Y=0.61,SEARCH- SIZE-X=6,SEARCH Comments: -SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 9 T1214-277 FOS/BL ACQ/PEA 0.5 MIRROR SCAN-STEP- 1 12.0S ONBOARD ACQ FOR 10-11 K X=0.29,SCAN- STEP- Y=0.29,SEARCH- SIZE-X=3,SEARCH Comments: Three stage ACQ followed by GHRS exposures -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 10 T1214-277 HRS ACCUM 2.0 G140L 1177- 1 353.6S 1463 ------------------------------------------------------------------------------------------------------------------------------------ 11 T1214-277 HRS ACCUM 2.0 G140L 1177- 1 2720.0S 1463 ------------------------------------------------------------------------------------------------------------------------------------ 6678( 7) - 04/11/96 20:04 - [ 6] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: HRS Spectrum of TOL65 at Ly-alpha Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 12 TOL65 FOS/BL ACQ/PEA 4.3 MIRROR SCAN-STEP- 1 10.0S ONBOARD ACQ FOR 13 K Y=1.23,SEARCH- SIZE-X=1,SEARCH -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 13 TOL65 FOS/BL ACQ/PEA 1.0 MIRROR SCAN-STEP- 1 11.0S ONBOARD ACQ FOR 14 K X=0.61,SCAN- STEP- Y=0.61,SEARCH- SIZE-X=6,SEARCH Comments: -SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 14 TOL65 FOS/BL ACQ/PEA 0.5 MIRROR SCAN-STEP- 1 12.0S ONBOARD ACQ FOR 15-16 K X=0.29,SCAN- STEP- Y=0.29,SEARCH- SIZE-X=3,SEARCH Comments: Three stage ACQ followed by GHRS exposures -SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 15 TOL65 HRS ACCUM 2.0 G140L 1157- 1 408.0S 1443 ------------------------------------------------------------------------------------------------------------------------------------ 16 TOL65 HRS ACCUM 2.0 G140L 1157- 1 2774.4S 1443 ------------------------------------------------------------------------------------------------------------------------------------ 6678( 7) - 04/11/96 20:04 - [ 7] Visit: 04 Visit Requirements: On Hold Comments: Additional Comments: WFC Images in V and I of T1214-277 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 17 T1214-277 WFPC2 IMAGE WF3 F555W 5398 CR-SPLIT=NO,CR- 1 800S TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 18 T1214-277 WFPC2 IMAGE WF3 F814W 7921 CR-SPLIT=NO,CR- 1 1600S SAME POS AS 17 TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 19 T1214-277 WFPC2 IMAGE WF3 F555W 5398 CR-SPLIT=NO,CR- 1 800S SAME POS AS 17 TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 20 T1214-277 WFPC2 IMAGE WF3 F814W 7921 CR-SPLIT=NO,CR- 1 1600S SAME POS AS 17 TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 6678( 7) - 04/11/96 20:04 - [ 8] Visit: 05 Visit Requirements: On Hold Comments: Additional Comments: WFC Images in V and I of TOL65 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 TOL65 WFPC2 IMAGE WF3 F555W 5398 CR-SPLIT=NO,CR- 1 800S TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 22 TOL65 WFPC2 IMAGE WF3 F814W 7921 CR-SPLIT=NO,CR- 1 1700S SAME POS AS 21 TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 23 TOL65 WFPC2 IMAGE WF3 F555W 5398 CR-SPLIT=NO,CR- 1 800S SAME POS AS 21 TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 24 TOL65 WFPC2 IMAGE WF3 F814W 7921 CR-SPLIT=NO,CR- 1 1700S SAME POS AS 21 TOLERANCE=0.0 ------------------------------------------------------------------------------------------------------------------------------------ 6678( 7) - 04/11/96 20:04 - [ 9] Summary Form for Proposal 6678 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL HRS WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SCAN-STEP-Y=1.23 SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SEARCH-SIZE-Y=2 SEARCH-SIZE-X=3 SEARCH-SIZE-X=6 SCAN-STEP-Y=0.29 SCAN-STEP-Y=0.61 SCAN-STEP-X=0.29 CR-TOLERANCE=0.0 CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COSMOLOGY ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4-6 ONBOARD ACQ FOR 8 ONBOARD ACQ FOR 9 ONBOARD ACQ FOR 10-11 ONBOARD ACQ FOR 13 ONBOARD ACQ FOR 14 ONBOARD ACQ FOR 15-16 SAME POS AS 17 SAME POS AS 21 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SBS0335-052 T1214-277 TOL65 ------------------------------------------------------------------------------------------------------------------------------------