7475( 5) - 10/10/97 07:53 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7475 Version: 5 Check-in Date: 10-Oct-1997 07:51:13 1.Proposal Title: The Chemical Content of the Universe at z< 1.6 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: KENNETH LANZETTA SUNY CoI: David Meyer Northwestern University N CoI: James Lattimer State University of New York at Stony N Brook CoI: James Truran University of Chicago N CoI: Noriaki Yahata State University of New York at Stony N Brook CoI: Arthur M. Wolfe University of California, San Diego N ------------------------------------------------------------------------------------ 5. Abstract Damped Ly-alpha\ absorption systems provide a means of directly probing the chemical content of the universe to redshifts approaching z = 5. Previous observations have concentrated on redshifts z = 2 - 3.5, because there are very few damped Ly-alpha\ absorption systems known at redshifts z < 1.6. But based on an exhaustive survey at ultraviolet wavelengths, we have constructed a statistically unbiased sample of damped Ly-alpha\ absorption systems with neutral hydrogen column densities satisfying \log N > 19.5 \cmjj\ at redshifts z < 1.6. This sample provides the first means of systematically measuring the chemical content of the universe at redshifts z < 1.6. Here we propose an intensive investigation of moderate-redshift damped Ly- alpha\ absorption systems. We plan to target weak transitions of S II, Zn II, and Cr II for seven absorption systems and to obtain high- resolution WFPC2 images of the galaxies responsible for four damped Ly-alpha\ absorption systems. The proposed observations will provide the first chemical abundance measurements at redshifts z < 0.5, will establish the S/Si ratio as an indicator of dust content, and will probe nucleosynthetic processes by targeting undepleted elements of different nucleosynthetic origin. The proposed observations will furthermore establish the luminosities, morphological types, and impact geometries of the galaxies responsible for the absorption systems, which is essential for interpreting the abundance measurements in the context of specific galactic chemical evolution models. ------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 2] Observations Description ------------------------ Spectroscopic observations of S II: We will use STIS with the G230M or G230MB gratings to target the weak S II transitions of five damped Ly-alpha\\ absorption systems at redshifts z ~ 1. To determine the required exposure times, for each absorber we calculated the STIS signal-to-noise ratio required to obtain a 3 Sigma detection of the strongest S II transition assuming both 10\\ hydrogen column density and assuming that the absorption lines are unsaturated. We then used the STIS exposure time calculator to determine the corresponding exposure times, adopting ultraviolet fluxes measured from existing HST spectra. In some cases, the 10\\ of several orbits, which in other cases only the 20\\ Allowing for instrumental overheads, the proposed observations require between 2 and 9 orbits each. Spectroscopic observations of Zn II and Cr II: We will use STIS with the G230MB grating to target the weak Zn II and Cr II transitions of two damped Ly- alpha\\ absorption systems at redshifts z ~ 0.5. We have examined existing FOS spectra of the proposed targets and have identified plausible, 2 Sigma detections of Zn II (but not Cr II) in both cases. These tentative FOS results must be verified with appreciably better data. To determine the required exposure times, for each absorber we calculated the STIS signal-to-noise ratio required to obtain a detection threshold three times more sensitive than the existing FOS data. We then used the STIS exposure time calculator to determine the corresponding exposure times, adopting ultraviolet fluxes measured from existing HST spectra. Allowing for instrumental overheads, the proposed observations require 8 orbits on each target. Imaging observations: To determine the feasibility of the proposed observations and to estimate the required exposure times, we considered existing images of fields targeted by WFPC2 in previous cycles. We find that WFPC2 with the F702W reaches reaches a limiting magnitude of R ~ 25.0 in two orbits and that even without sophisticated modeling of the QSO profiles objects of R \\apl 24.0 can be detected to within ~ 1 arcsec of bright QSOs. (One of the images that we considered detects a pair of galaxies of R = 23.0 and R = 23.9 only ~ 1.4 arcsec from a very bright QSO, which we identify as the absorbing galaxies.) We therefore require two orbits per field, or eight orbits to complete all four fields. Our experience with other WFPC2 images indicates that these images will be sufficient to determine the morphological types of the absorbing galaxies (i.e.\\ to distinguish late- type from early-type galaxies and to distinguish low luminosity or low surface brightness from high luminosity or high surface brightness galaxies) and to assess the geometry of the impacts of the lines of sight through the absorbing galaxies (i.e.\\ to determine the impact parameters, inclinations, and orientations of the absorbing galaxies). We will adopt an integration time of 600 s per exposure (with three exposures per orbit), which will saturate only the central ~ 5 pixels of the QSO profiles. We will also dither the image by n + 1/2 pixel steps between orbits in order to increase the spatial sampling of the final images. Real Time Justification ----------------------- Not applicable. Calibration Justification ------------------------- Not applicable. Additional Comments ------------------- ------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Department of Earth and Space Sciences*State University of New York at Stony Brook*Stony Brook, NY 11794- 2100 Ship Via: Email: ------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 Q0302-2223 GALAXY,QSO RA = 03H 04M 49.82S +/- 0.07S, 2000 Z = V = 16.0+/-0.5 DEC = -22D 11' 51.8" +/- 1.0", 1.400 B-V = 0.0+/-0.1 PLATE-ID = 014E 2 Q0454-2203 GALAXY,QSO RA = 04H 56M 08.91S +/- 0.07S, 2000 Z = V = 15.51+/-0.5 DEC = -21D 59' 09.3" +/- 1.0", 0.534 B-V = 0.06+/-0.1 PLATE-ID = 029V 3 FIELD-Q0454- GALAXY,QSO RA = 04H 56M 08.91S +/- 0.07S, 2000 Z = V = 15.51+/-0.5 2203 DEC = -21D 59' 09.3" +/- 1.0", 0.534 B-V = 0.06+/-0.1 PLATE-ID = 029V 4 Q0454+0356 GALAXY,QSO RA = 04H 56M 47.17S +/- 0.07S, 2000 Z = V = 16.53+/-0.5 DEC = +04D 00' 53.1" +/- 1.0", 1.345 B-V = 0.23+/-0.1 PLATE-ID = 02V3 5 Q0935+4143 GALAXY,QSO RA = 09H 38M 57.03S +/- 0.07S, 2000 Z = V = 16.25+/-0.5 DEC = +41D 28' 21.8" +/- 1.0", 1.980 PLATE-ID = 01BS 6 FIELD- GALAXY,QSO RA = 09H 38M 57.03S +/- 0.07S, 2000 Z = V = 16.25+/-0.5 Q0935+4143 DEC = +41D 28' 21.8" +/- 1.0", 1.980 PLATE-ID = 01BS 7 Q0957+5608 GALAXY,QSO RA = 10H 01M 20.71S +/- 0.07S, 2000 Z = V = 17.25+/-0.5 DEC = +55D 53' 53.8" +/- 1.0", 1.405 PLATE-ID = 01RP Comments: POSITION REFERS TO THE B IMAGE 8 Q1229-0207 GALAXY,QSO RA = 12H 32M 00.03S +/- 0.07S, 2000 Z = V = 16.72+/-0.5 DEC = -02D 24' 04.8" +/- 1.0", 1.038 B-V = 0.48+/-0.1 PLATE-ID = 00BB 9 FIELD- GALAXY,QSO RA = 12H 50M 05.73S +/- 0.07S, 2000 Z = V = 15.80+/-0.5 1247+2647 DEC = +26D 31' 07.6" +/- 1.0", 2.038 PLATE-ID = 01PM 10 Q1328+3045 GALAXY,QSO RA = 13H 31M 08.30S +/- 0.07S, 2000 Z = V = 17.25+/-0.5 DEC = +30D 30' 32.7" +/- 1.0", 0.849 B-V = 0.26 PLATE-ID = 009L 11 FIELD- GALAXY,QSO RA = 13H 54M 05.42S +/- 0.07S, 2000 Z = V = 17.40+/-0.5 1351+3153 DEC = +31D 39' 02.5" +/- 1.0", 1.326 PLATE-ID = 019J 7475( 5) - 10/10/97 07:53 - [ 5] Visit: 01 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 Q0302-2223 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 5.0 S ONBOARD ACQ FOR 12-13 CD P ------------------------------------------------------------------------------------------------------------------------------------ 12 Q0302-2223 STIS/C ACCUM 52X0.2 G230MB 2557 CR-SPLIT = NO 2 1000.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 13 Q0302-2223 STIS/C ACCUM 52X0.2 G230MB 2557 CR-SPLIT = NO 12 1200.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 6] Visit: 02 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 20 Q0454-2203 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 5.0 S ONBOARD ACQ FOR 22-23 CD P ------------------------------------------------------------------------------------------------------------------------------------ 22 Q0454-2203 STIS/C ACCUM 52X0.2 G230MB 2976 CR-SPLIT = NO 2 1000.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 23 Q0454-2203 STIS/C ACCUM 52X0.2 G230MB 2976 CR-SPLIT = NO 14 1200.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 7] Visit: 03 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 30 FIELD-Q0454 WFPC2 IMAGE WFALL-F F702W 7020 ATD-GAIN = 7,CLOCKS = YES, 3 800 S -2203 IX CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ 31 FIELD-Q0454 WFPC2 IMAGE WFALL-F F702W 7020 ATD-GAIN = 7,CLOCKS = YES, 3 800 S POS TARG 0.25, 0.25 -2203 IX CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 8] Visit: 04 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 40 Q0454+0356 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 7.0 S ONBOARD ACQ FOR 42-43 CD P ------------------------------------------------------------------------------------------------------------------------------------ 42 Q0454+0356 STIS/N ACCUM 52X0.2 G230M 2338 CR-SPLIT = NO 2 860.0 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 43 Q0454+0356 STIS/N ACCUM 52X0.2 G230M 2338 CR-SPLIT = NO 6 1100.0 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 9] Visit: 05 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 50 Q0935+4143 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 5.0 S ONBOARD ACQ FOR 52-53 CD P ------------------------------------------------------------------------------------------------------------------------------------ 52 Q0935+4143 STIS/C ACCUM 52X0.2 G230MB 2976 CR-SPLIT = NO 2 1000.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 53 Q0935+4143 STIS/C ACCUM 52X0.2 G230MB 2976 CR-SPLIT = NO 4 1200.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 10] Visit: 06 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 60 FIELD-Q0935 WFPC2 IMAGE WFALL-F F702W 7020 ATD-GAIN = 7,CLOCKS = YES, 3 800 S +4143 IX CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ 61 FIELD-Q0935 WFPC2 IMAGE WFALL-F F702W 7020 ATD-GAIN = 7,CLOCKS = YES, 3 800 S POS TARG 0.25, 0.25 +4143 IX CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 11] Visit: 07 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 70 Q0957+5608 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 72-73 CD P ------------------------------------------------------------------------------------------------------------------------------------ 72 Q0957+5608 STIS/C ACCUM 52X0.2 G230MB 2976 CR-SPLIT = NO 2 1000.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 73 Q0957+5608 STIS/C ACCUM 52X0.2 G230MB 2976 CR-SPLIT = NO 10 1400.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 12] Visit: 08 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 80 Q1229-0207 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 7.0 S ONBOARD ACQ FOR 82-83 CD P ------------------------------------------------------------------------------------------------------------------------------------ 82 Q1229-0207 STIS/C ACCUM 52X0.2 G230MB 2836 CR-SPLIT = NO 2 1000.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 83 Q1229-0207 STIS/C ACCUM 52X0.2 G230MB 2836 CR-SPLIT = NO 14 1200.0 CD ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 13] Visit: 09 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 90 FIELD-1247+ WFPC2 IMAGE WFALL-F F702W 7020 ATD-GAIN = 7,CLOCKS = YES, 3 800 S 2647 IX CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ 91 FIELD-1247+ WFPC2 IMAGE WFALL-F F702W 7020 ATD-GAIN = 7,CLOCKS = YES, 3 800 S POS TARG 0.25, 0.25 2647 IX CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 14] Visit: 10 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 100 Q1328+3045 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 102-103 CD P ------------------------------------------------------------------------------------------------------------------------------------ 102 Q1328+3045 STIS/N ACCUM 52X0.2 G230M 2095 CR-SPLIT = NO 2 860.0 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 103 Q1328+3045 STIS/N ACCUM 52X0.2 G230M 2095 CR-SPLIT = NO 8 1100.0 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 15] Visit: 11 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 110 FIELD-1351+ WFPC2 IMAGE WFALL-F F702W 7020 ATD-GAIN = 7,CLOCKS = YES, 3 800 S 3153 IX CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ 111 FIELD-1351+ WFPC2 IMAGE WFALL-F F702W 7020 ATD-GAIN = 7,CLOCKS = YES, 3 800 S POS TARG 0.25, 0.25 3153 IX CR-SPLIT = NO ------------------------------------------------------------------------------------------------------------------------------------ 7475( 5) - 10/10/97 07:53 - [ 16] Summary Form for Proposal 7475 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD WFPC2 STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT CR-SPLIT = NO CLOCKS = YES ATD-GAIN = 7 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 12-13 ONBOARD ACQ FOR 22-23 POS TARG 0.25, 0.25 ONBOARD ACQ FOR 42-43 ONBOARD ACQ FOR 52-53 ONBOARD ACQ FOR 72-73 ONBOARD ACQ FOR 82-83 ONBOARD ACQ FOR 102-103 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G230MB F702W G230M ------------------------------------------------------------------------------------------------------------------------------------ Target Names Q0302-2223 Q0454-2203 FIELD-Q0454-2203 Q0454+0356 Q0935+4143 FIELD-Q0935+4143 Q0957+5608 Q1229-0207 FIELD-1247+2647 Q1328+3045 FIELD-1351+3153 ------------------------------------------------------------------------------------------------------------------------------------