9165( 2) - 02/22/01 10:19 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9165 Version: 2 Check-in Date: 22-Feb-2001 10:18:50 1.Proposal Title: A Damped LyAlpha System in a Close Separation Lens ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Lutz Wisotzki Universitat Hamburg, Hamburger Sternwarte CoI: Dr. Jose Maza Universidad de Chile N CoI: Dr. Dieter Reimers Hamburger Sternwarte N CoI: Dr. Paul Schechter Massachusetts Institute of Technology N CoI: Dr. Richard White Space Telescope Science Institute N CoI: Dr. Robert Becker University of California, Davis N CoI: Dr. Michael Gregg University of California, Davis N CoI: Dr. Sebastian Lopez Universidad de Chile N ------------------------------------------------------------------------------------ 5. Abstract Damped LyAlpha absorption systems hold key information about galaxy formation and chemical evolution of the universe. We propose to conduct spatially resolved absorption line spectroscopy in the only presently known DLA system with two independent lines of sight. This object was discovered recently by us in the course of an ongoing HST snapshot survey as a double QSO at z=1.57 with an image separation of only 0.63 arcsec, almost certainly due to gravitational lensing. The ground-based composite optical spectrum shows an exceptionally strong Mg II+ Fe II absorption system at z=0.93, which clearly indicates the presence of a damped LyAlpha absorber (DLA) in the line of sight. Here we propose to obtain direct imaging and medium- resolution spectra in the wavelength range 1700-5700 Angstrom , with the following principal aims: (1) Confirm the gravitational lens (vs. physical binary) hypothesis. (2) Estimate hydrogen column densities N(H I) along both lines of sight, and test competing DLA models. (3) In combination with already granted ESO-VLT observations, measure absolute metal abundances and compare the variation of metallicities between the two lines of sight. (4) Derive the extinction curve and dust properties of the z=0.93 lensing/absorbing galaxy. ------------------------------------------------------------------------------------ 9165( 2) - 02/22/01 10:19 - [ 2] Observations Description ------------------------ Optical imaging: To detect the lensing/absorbing galaxy, to study the distribution of its luminous matter, and to obtain the inclination angle, we need a high-quality optical image. Falco et al. (priv. comm.) report to have marginally detected the lensing galaxy in a 700 s WFPC2 F814W exposure. We intend to go much deeper by having a longer exposure time (>~ 2000 s) and by using STIS with its LP filter. This band is much broader than the F814W band, while it cuts out all light below 5500A and enhances the galaxy over the QSO. Optical spectroscopy: We need G430L + CCD to obtain optical spectra of both QSO components. The two components have V magnitudes of 17.7 and 18.0, respectively. We can achieve a S/N ratio of >~ 25 for both components in 1800 s, thus requiring one orbit for this setting. UV spectroscopy: Using the G230L + NUV-MAMA, we plan to obtain 3 Angstrom resolution (FWHM) spectra of the near UV down to ~1700 Angstrom. We demand a S/N of at least 20 at 1980 Angstrom in both components. Assuming a standard QSO spectrum, this S/N can be achieved with 14340 seconds integration, or 6 orbits. The S/N would be 35 at LyAlpha which is well suited for modeling the line wings, and ~ 10 at the Lyman limit, just sufficient to detect an optically thin Lyman limit system similar to that in HE 1104-1805B. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9165( 2) - 02/22/01 10:19 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HE0512-3329 Galaxy, QSO RA = 05H 14M 10.7833S +/- 0.05", J2000 Z = V = 17.7+/-0.1 DEC = -33D 26' 22.504" +/- 1.565 B-V = 0.7+/-0.1 0.05", PLATE-ID=029U Coordinate Source: HST_IMAGE 9165( 2) - 02/22/01 10:19 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-CCD-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 1.9875 Coordinate_Frame POS-TARG Pattern_Orient 26.6 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 1.54666 Coordinate_Frame POS-TARG Pattern_Orient 90 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9165( 2) - 02/22/01 10:19 - [ 5] Visit: 01 Visit Priority: Visit Requirements: PCS MODE FINE ORIENT 146.5D TO 156.5D ORIENT 326.5D TO 336.5D 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 HE0512-3329 STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 616 S PATTERN 1 EXPAND CD P ------------------------------------------------------------------------------------------------------------------------------------ 9165( 2) - 02/22/01 10:19 - [ 6] Visit: 02 Visit Priority: Visit Requirements: GROUP 2-4 WITHIN 30D PCS MODE FINE ORIENT 61.9D TO 61.9D ORIENT 241.9D TO 241.9D 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 HE0512-3329 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 4 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 HE0512-3329 STIS/C ACCUM 52X0.5E G430L 4300 CR-SPLIT=NO 1 750 S PATTERN 2 EXPAND CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 9165( 2) - 02/22/01 10:19 - [ 7] Visit: 03 Visit Priority: Visit Requirements: GROUP 2-4 WITHIN 30D PCS MODE FINE ORIENT 61.5D TO 61.5D ORIENT 241.5D TO 241.5D 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 HE0512-3329 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 4 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 HE0512-3329 STIS/N ACCUM 52X0.2 G230L 2376 1 40 M EXPAND UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HE0512-3329 STIS/N ACCUM 52X0.2 G230L 2376 1 48 M POS TARG 0.0, +1.54666 UV-MAM EXPAND A ------------------------------------------------------------------------------------------------------------------------------------ 4 HE0512-3329 STIS/N ACCUM 52X0.2 G230L 2376 1 48 M POS TARG 0.0, -1.54666 UV-MAM EXPAND A ------------------------------------------------------------------------------------------------------------------------------------ 9165( 2) - 02/22/01 10:19 - [ 8] Visit: 04 Visit Priority: Visit Requirements: GROUP 2-4 WITHIN 30D PCS MODE FINE ORIENT 61.5D TO 61.5D ORIENT 241.5D TO 241.5D 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 HE0512-3329 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 4 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 HE0512-3329 STIS/N ACCUM 52X0.2 G230L 2376 1 40 M EXPAND UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HE0512-3329 STIS/N ACCUM 52X0.2 G230L 2376 1 48 M POS TARG 0.0, +1.54666 UV-MAM EXPAND A ------------------------------------------------------------------------------------------------------------------------------------ 4 HE0512-3329 STIS/N ACCUM 52X0.2 G230L 2376 1 48 M POS TARG 0.0, -1.54666 UV-MAM EXPAND A ------------------------------------------------------------------------------------------------------------------------------------ 9165( 2) - 02/22/01 10:19 - [ 9] Summary Form for Proposal 9165 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.5E1 52X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=2 ACQTYPE=POINT CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE FINE ORIENT 146.5D TO 156.5D ORIENT 326.5D TO 336.5D PATTERN 1 EXPAND GROUP 2-4 WITHIN 30D PCS MODE FINE ORIENT 61.9D TO 61.9D ORIENT 241.9D TO 241.9D PATTERN 2 EXPAND GROUP 2-4 WITHIN 30D PCS MODE FINE ORIENT 61.5D TO 61.5D ORIENT 241.5D TO 241.5D EXPAND POS TARG 0.0, +1.54666 EXPAND POS TARG 0.0, -1.54666 EXPAND ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430L G230L ------------------------------------------------------------------------------------------------------------------------------------ Target Names HE0512-3329 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 4300 2376 ------------------------------------------------------------------------------------------------------------------------------------