6707( 7) - 08/28/96 17:33 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6707 Version: 7 Check-in Date: 28-Aug-1996 18:29:22 1.Proposal Title: M33: An archetypal QSO absorption line galaxy? ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Galaxies & clusters GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: David V. Bowen ROYAL OBSERVATORY, EDINBURGH CoI: Colin Norman Johns Hopkins University N CoI: Laura Danly Space Telescope Science Institute N CoI: J. Chris Blades Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract We propose using the G140L grating of the GHRS to observe C IV, Si IV, & Si II absorption lines towards 7 QSOs & AGNs whose sightlines pass through the outer disk and halo of M33. These multiple probes of a single galaxy give us one of the few opportunities to directly probe how the distribution of interstellar gas varies across a galaxy. Our data will measure the total extent of the halo, its shape, and covering factor; variations in line equivalent width with radius will establish how the gas density falls across the galaxy, and whether the halo is sharply truncated due to ionization by the UV background. In particular, our probes are selected to test whether absorption occurs in the disk of M33, or whether it arises in an extended spherical halo. Characterising the absorption through M33 will provide an important comparison with higher-redshift metal absorption lines. By observing many lines of sight through a single galaxy, we can test whether the variation in the absorption lines seen along different lines of sight through M33 in any way replicates the range of variations seen in different absorption line systems at high redshifts. If normal spiral galaxies like M33 are indeed responsible for higher redshift systems, our results should show similarities to those obtained from ground -based QSO absorption line surveys. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose observing 7 QSOs & AGNs with the G140L grating of the GHRS, covering the wavelength range at which Si IV, C IV and and Si II absorption will be expected from M33. Exposure times are shown in Table 1, and are estimated either from known UV fluxes, or from V magnitudes extrapolated to 1400 Angstrom\\ assuming the object flux follows a power law of the form F_Nu \\propto nu^Alpha where Alpha=-1 if Alpha is not available. The Seyfert 1 galaxies are compact and at low redshift, which has the advantage that no higher redshift Lyman limit system will cut off the UV flux. Exposure times are calculated to give a S/N of 18 per pixel for half-stepped data from the G140L grating, assuming a background count rate of 36 counts diode^-1 hr^-1. A S/N of 18 then gives a 3Sigma equivalent width limit of 0.1 Angstrom\\ for a resolving power of 2150 with the G140L at Si IV and 0.15 Angstrom\\ at C IV. These limits are smaller or comparable to the equivalent widths of absorption lines through our own Galactic halo, ~ 0.2 Angstrom , ~ 0.3 Angstrom . A synthetic spectrum showing absorption by Si IV with W(Lambda 1393)=0.23 Angstrom\\ is shown in Figure 2 assuming a resolution of 139 kms\\ FWHM for the G140L. A S/N of 18 ensures that absorption from M33 is clearly resolved from local Milky Way lines and provides accurate determination of line centers and equivalent widths. Real Time Justification ----------------------- We plan to obtain spectra of the optical absorption lines of Ca II and Na I toward Q0131+3039 using the WHT on La Palma in October 1995. The H I column density of interstellar gas is expected to be high toward this sightline since it passes close to the center of the galaxy, and Ca II and Na I absorption should be detectable. These data will provide important information on the kinematics and substructure of the absorbing gas which will be used to help interpret the HST data. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Dr. David V. Bowen*Royal Observatory, Edinburgh (R.O.E.)*Blackford Hill*Edinburgh EH9 3HJ*United Kingdom Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6707( 7) - 08/28/96 17:33 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 Q0116+3146 Galaxy,Seyfert;EXT- RA=01H 19M 22.15S +/-0.03S, 2000.0 z=0.058 V = 16.4 MEDIUM,absorption line DEC=32D 02' 38.0" +/- 0.5", F-CONT(1400)=0.2e-14 system PLATE-ID=00DV Comments: Faint UV-excess galaxy, but F-CONT calc. assuming alpha=-1.5. 2 Q0121+3154 Galaxy,Seyfert;EXT- RA=01H 24M 45.08S +/- 0.03S, 2000.0 z=0.036 V = 14.27 MEDIUM,absorption line DEC=32D 09' 55.6" +/- 0.5", B-V = 0.79 system PLATE-ID=00DV U-B = 0.18 F-CONT(1400)=0.1e-13 Comments: UV-excess galaxy, but F-CONT calculated assuming alpha=-1.5. 3 Q0122+3152 Galaxy,Seyfert;EXT- RA=01H 25M 31.46S+/-0.03S, 2000.0 z=0.017 V = 13.96 MEDIUM,absorption line DEC=32D 08' 10.5" +/-0.5", PLATE B-V = 1.05 system -ID=00DV U-B = 0.27 F-CONT(1400)=0.2e-13 Comments: UV-excess galaxy, but F-CONT calculated assuming alpha=-1.5 4 Q0123+3121 Galaxy,Seyfert;EXT- RA=01H 26M 33.65S +/-0.03S, 2000 z=0.042 V = 15.23 MEDIUM,absorption line DEC=31D 36' 58.2" +/-0.5", PLATE B-V = 0.79 system -ID=00DV U-B = -0.32 F-CONT(1400)=0.6e-14 Comments: UV-excess galaxy, but F-CONT calculated assuming alpha=-1.5 5 Q0137+3159 Galaxy,Seyfert;EXT- RA=01H 40M 27.09S+/-0.03S, 2000 z=0.065 V = 15.8 MEDIUM,absorption line DEC=32D 14' 46.9" +/-0.5", PLATE F-CONT(1400)=0.3e-14 system -ID=037O Comments: F-CONT known from IUE flux: agrees with alpha=-1.5 6 Q0134+3254 Galaxy,Seyfert RA=01H 37M 41.25S +/-0.03S, 2000.0 z=0.367 V = 16.20 DEC=33D 09' 33.4" +/-0.05", B-V = 0.42 PLATE-ID=00DV U-B = -0.58 F-CONT(1400)=0.1e-14 Comments: F-CONT calculated assumming alpha=-1.5 6707( 7) - 08/28/96 17:33 - [ 2] 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 Q0116+3146 HRS ACQ 2.0 MIRROR-N2 bright=return,search-size=3 1 99 S ONBOARD ACQ for 20-50 Comments: step-time=11s ------------------------------------------------------------------------------------------------------------------------------------ 20 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 30 ------------------------------------------------------------------------------------------------------------------------------------ 30 Q0116+3146 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 15 435.2 S Comments: FIRST set ------------------------------------------------------------------------------------------------------------------------------------ 40 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 50; really to set SPYBAL again ------------------------------------------------------------------------------------------------------------------------------------ 50 Q0116+3146 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 14 435.2 S Comments: SECOND set ------------------------------------------------------------------------------------------------------------------------------------ 52 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 54; really to set SPYBAL again ------------------------------------------------------------------------------------------------------------------------------------ 54 Q0116+3146 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 14 435.2 S Comments: THIRD set ------------------------------------------------------------------------------------------------------------------------------------ 6707( 7) - 08/28/96 17:33 - [ 3] 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 ------------------------------------------------------------------------------------------------------------------------------------ 80 Q0121+3154 HRS ACQ 2.0 MIRROR-N1 bright=return,search-size=3 1 108 S ONBOARD ACQ for 90-100 Comments: step-time=12s ------------------------------------------------------------------------------------------------------------------------------------ 90 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 100 ------------------------------------------------------------------------------------------------------------------------------------ 100 Q0121+3154 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 7 435.2 S Comments: ONLY set ------------------------------------------------------------------------------------------------------------------------------------ 6707( 7) - 08/28/96 17:33 - [ 4] Visit: 04 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 Q0122+3152 HRS ACQ 2.0 MIRROR-N1 bright=return,search-size=3 1 108 S ONBOARD ACQ for 120-130 Comments: step-time=12s ------------------------------------------------------------------------------------------------------------------------------------ 120 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 130 ------------------------------------------------------------------------------------------------------------------------------------ 130 Q0122+3152 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 7 435.2 S Comments: ONLY set ------------------------------------------------------------------------------------------------------------------------------------ 6707( 7) - 08/28/96 17:33 - [ 5] Visit: 05 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 ------------------------------------------------------------------------------------------------------------------------------------ 140 Q0123+3121 HRS ACQ 2.0 MIRROR-N1 bright=return,search-size=3 1 108 S ONBOARD ACQ for 150-160 Comments: step-time=12s ------------------------------------------------------------------------------------------------------------------------------------ 150 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 160 ------------------------------------------------------------------------------------------------------------------------------------ 160 Q0123+3121 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 13 435.2 S Comments: ONLY set ------------------------------------------------------------------------------------------------------------------------------------ 6707( 7) - 08/28/96 17:33 - [ 6] Visit: 06 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 ------------------------------------------------------------------------------------------------------------------------------------ 160 Q0137+3159 HRS ACQ 2.0 MIRROR-N1 bright=return,search-size=3 1 108 S ONBOARD ACQ for 170-200 Comments: step-time=12s ------------------------------------------------------------------------------------------------------------------------------------ 170 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 180 ------------------------------------------------------------------------------------------------------------------------------------ 180 Q0137+3159 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 16 435.2 S Comments: FIRST set ------------------------------------------------------------------------------------------------------------------------------------ 190 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 200; really to set SPYBAL again ------------------------------------------------------------------------------------------------------------------------------------ 200 Q0137+3159 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 17 435.2 S Comments: SECOND set ------------------------------------------------------------------------------------------------------------------------------------ 6707( 7) - 08/28/96 17:33 - [ 7] Visit: 07 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 ------------------------------------------------------------------------------------------------------------------------------------ 210 Q0134+3254 HRS ACQ 2.0 MIRROR-N2 bright=return,search-size=3 1 99 S ONBOARD ACQ for 220-250 Comments: step-time=11s ------------------------------------------------------------------------------------------------------------------------------------ 220 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 230 ------------------------------------------------------------------------------------------------------------------------------------ 230 Q0134+3254 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 17 435.2 S Comments: FIRST set ------------------------------------------------------------------------------------------------------------------------------------ 240 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 250; really to set SPYBAL again ------------------------------------------------------------------------------------------------------------------------------------ 250 Q0134+3254 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 17 435.2 S Comments: SECOND set ------------------------------------------------------------------------------------------------------------------------------------ 260 WAVE HRS ACCUM SC2 G140L 1437 1 DEF Comments: Wave calib for 270; really to set SPYBAL again ------------------------------------------------------------------------------------------------------------------------------------ 270 Q0134+3254 HRS ACCUM 2.0 G140L 1437 fp-split=no,step-patt=5,spybal=no 16 435.2 S Comments: THIRD set ------------------------------------------------------------------------------------------------------------------------------------ 6707( 7) - 08/28/96 17:33 - [ 8] Summary Form for Proposal 6707 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters bright=return search-size=3 spybal=no step-patt=5 fp-split=no ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Galaxies & clusters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ for 20-50 ONBOARD ACQ for 90-100 ONBOARD ACQ for 120-130 ONBOARD ACQ for 150-160 ONBOARD ACQ for 170-200 ONBOARD ACQ for 220-250 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G140L MIRROR-N1 ------------------------------------------------------------------------------------------------------------------------------------ Target Names Q0116+3146 WAVE Q0121+3154 Q0122+3152 Q0123+3121 Q0137+3159 Q0134+3254 ------------------------------------------------------------------------------------------------------------------------------------