6222( 0) - 07/18/95 21:12 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6222 Version: ********** Check-in Date: ********** 1.Proposal Title: Spectra of the Gravitationally Lensed QSO PG 1115+080 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle QUASARS GTO/FOS 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: E. MARGARET BURBIDGE UNIVERSITY OF CALIFORNIA, SAN DIEGO CoI: GEORGE F. HARTIG SPACE TELESCOPE SCIENCE INSTITUTE N CoI: BRUCE H. MARGON UNIVERSITY OF WASHINGTON N CoI: RICHARD J. HARMS APPLIED RESEARCH CORPORATION N CoI: J. ROGER P. ANGEL UNIVERSITY OF ARIZONA N CoI: FRANK BARTKO UNAFFILIATED N CoI: EDWARD BEAVER UNIVERSITY OF CALIFORNIA, SAN DIEGO N CoI: RALPH C. BOHLIN SPACE TELESCOPE SCIENCE INSTITUTE N CoI: ARTHUR F. DAVIDSEN JOHNS HOPKINS UNIVERSITY N CoI: HOLLAND C. FORD SPACE TELESCOPE SCIENCE INSTITUTE N ------------------------------------------------------------------------------------ 6. Abstract Variations in the velocity and column density of Lyman alpha forest clouds and associated absorption systems on small scales will be studied with observations of a closely spaced pair of QSOs. Accurate measurements of Lyman alpha and beta lines and CIV lines in the two brightest components of PG1115+080 will be made using FOS spectra with the G270H and G400H gratings. ------------------------------------------------------------------------------------ 6222( 0) - 07/18/95 21:12 - [ 2] Observations Description ------------------------ A specially designed series of peak-ups will be performed to center the brightest object to +/-0.04" and G270H and G400H ACCUM observations performed with the 0.3" aperture and red detector. The observations are designed to achieve a signal-to-noise per diode of 33 in the region of lowest sensitivity for each grating. A blind offset of 0.485" will be made to the second brightest object and another pair of ACCUM observations will be made. Because the two targets are separated by only 0.485", a conventional peakup beginning with the 4.3" aperture would not work, while starting with a binary search places restrictions on the orientation and still requires a complex peakup because of the relatively large positional uncertainty following BSTA. Likewise for an interactive target acquisition. The errors in the measurements of offset stars and possible proper motion are too large to allow any simple scheme of offsets followed by peakups. The error budget is very small because the separation of the two brightest components is 0.48" so the maximum error that can be tolerated is 0.24" which means the one sigma error along the line connecting the two brightest components should not exceed 0.08". There are no WF images of the PG1115+080 field and the PC images of PG 1115+080 do not include the best offset stars. Ground based images (from CFHT) include the best offset stars but appear rotated relative to the PC images by 1.35 degrees. The error in the correction of the CCD rotation combined with centering and offset errors plus plausible proper motion (over 5 years) exceed the error budget allowable for acquisition of one of the fainter gravitational lens images and completely rule out direct offsets to either of the two brightest components from the best offset star about 51" away. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: ROSS COHEN*CASS 0111*9500 GILMAN DRIVE*LA JOLLA, CA 92093-0111 Ship Via: UPS Email: ross@cassfos03.ucsd.edu , ------------------------------------------------------------------------------------ 6222( 0) - 07/18/95 21:12 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PG1115+080A1 GALAXY,QSO,GRAVITATIONA RA=11H 18M 16.934S +/- 0.067S, J2000 Z = V = 17.0 +/- 1.0 L LENS,BLR,EXT- DEC= 7D 45' 58.53" +/- 1.00", 1.722 F(2500.0) = 1.5 +/- 0.3 E-15 MEDIUM,ABSORPTION LINE PLATE-ID=00ZW SYSTEM,IGM Comments: These are the coordinates of the blended image measured from the guide star plates. 2 PG1115+080A2 GALAXY,QSO,GRAVITATIONA R=0.485", PA=18.4D, FROM 1, J2000 Z = V = 17.3 +/- 1.0 L LENS,BLR,EXT- PLATE-ID=00ZW 1.722 F(2500.0) = 1.1 +/- 0.3 E-15 MEDIUM,ABSORPTION LINE SYSTEM,IGM Comments: Offsets were measured from PC and ground based images. 6222( 0) - 07/18/95 21:12 - [ 4] Visit: 01 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 PG1115+080A FOS/RD ACQ/PEA 1.0 MIRROR SEARCH-SIZE- 1 1.39S ONBOARD ACQ FOR 15 1 K Y=5, SCAN-STEP- Y=0.602, SEARCH -SIZE-X=5, SCAN -STEP-X=0.602 Comments: This step is desgned to find the 1" region containing the brightest (or both) target(s) ------------------------------------------------------------------------------------------------------------------------------------ 15 PG1115+080A FOS/RD ACQ/PEA 0.5 MIRROR SEARCH-SIZE-Y=4 1 1.5S ONBOARD ACQ FOR 20 1 K SCAN-STEP-Y=0.3 SEARCH-SIZE-X=4 SCAN-STEP-X=0.3 ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1115+080A FOS/RD ACQ/PEA 0.3 MIRROR SEARCH-SIZE- 1 1.58S ONBOARD ACQ FOR 25 1 K Y=5, SCAN-STEP- Y=0.17, SEARCH- SIZE-X=5, SCAN- STEP-X=0.17 Comments: Searches a 1" region for the brightest target. Accurate to 0.12 ------------------------------------------------------------------------------------------------------------------------------------ 25 PG1115+080A FOS/RD ACQ/PEA 0.3 MIRROR SEARCH-SIZE- 1 15.8S ONBOARD ACQ FOR 30-31 1 K Y=5, SCAN-STEP- Y=0.057, SEARCH -SIZE-X=5, SCAN -STEP-X=0.057 Comments: Accurate to 0.04" ------------------------------------------------------------------------------------------------------------------------------------ 30 PG1115+080A FOS/RD ACCUM 0.3 G400H 4000.0 1 1590S 1 ------------------------------------------------------------------------------------------------------------------------------------ 31 PG1115+080A FOS/RD ACCUM 0.3 G270H 2700.0 1 6190S 1 ------------------------------------------------------------------------------------------------------------------------------------ 6222( 0) - 07/18/95 21:12 - [ 5] Visit: 02 Visit Requirements: AFTER 01 BY 2D to 9D On Hold Comments: Additional Comments: This visit should reuse the target offset from the first visit. The centering in the 0.3" aperture must be accurate, so the time between visits should be minimized. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 40 PG1115+080A FOS/RD ACCUM 0.3 G400H 4000.0 1 1810S 2 ------------------------------------------------------------------------------------------------------------------------------------ 41 PG1115+080A FOS/RD ACCUM 0.3 G270H 2700.0 1 7080S 2 ------------------------------------------------------------------------------------------------------------------------------------ 6222( 0) - 07/18/95 21:12 - [ 6] Summary Form for Proposal 6222 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE-Y=5 SCAN-STEP-Y=0.602 SEARCH-SIZE-X=5 SCAN-STEP-X=0.602 SEARCH-SIZE-Y=4 SCAN-STEP-Y=0.3 SEARCH-SIZE-X=4 SCAN-STEP-X=0.3 SCAN-STEP-X=0.17 SCAN-STEP-X=0.057 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GTO/FOS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category QUASARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 15 ONBOARD ACQ FOR 20 ONBOARD ACQ FOR 25 ONBOARD ACQ FOR 30-31 AFTER 01 BY 2D to 9D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G400H G270H ------------------------------------------------------------------------------------------------------------------------------------ Target Names PG1115+080A1 PG1115+080A2 ------------------------------------------------------------------------------------------------------------------------------------