5984( 7) - 09/15/95 16:15 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5984 Version: 7 Check-in Date: ********** 1.Proposal Title: High Resolution Imaging of Intermediate Redshift Absorption-Selected Galaxies ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Quasars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Charles Steidel California Institute of Technology CoI: Mark Dickinson Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract We propose to use WFPC2 to obtain high resolution images of 0.4 <= z <= 1.0 galaxies taken from a large survey where the selection criterion is diffuse gas cross-section rather than apparent magnitude. The implications of our survey are that large, roughly spherical gaseous halos are a generic property of all relatively massive (L_K > 0.05L_K^*) galaxies, and that the nature of these envelopes is more closely related to galaxy mass than to current star formation rate or spectroscopic type. The aim of our proposed observations is to use a carefully chosen, representative subset of our sample in order 1) to test directly whether the absorbers represent the full range in normal Hubble sequence morphological types (as suggested by the ground--based spectra and colors), 2) to confirm whether the statistical inference of roughly spherical gas distributions is correct by examining whether, e.g., galaxy inclination angle is related to the nature of the absorption, 3) to verify that the galaxies identified as the absorbers are indeed the most likely candidates by searching for previously undetected faint companions very near the QSO line of sight, and 4) to obtain crucial morphological and sky- -orientation information that can be combined with our existing ground--based data and with planned high resolution spectroscopy of the background QSOs to obtain a complete picture of the interrelationship between morphological type, impact parameter, star formation rate, and the gas--phase kinematics, physical conditions, and chemical abundances. ------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 2] Observations Description ------------------------ For reasons stated in the justification, we will use the filter F702W for all of the observations. The apparent ($AB_{\nu}$) magnitudes of the galaxies of interest, at the wavelength of F702W, range from 20.0 to 22.8. We have estimated the necessary exposure times by examining actual WFC and PC data (also through F702W) obtained by one or both of the investigators during Cycle 4. By combining subsets of frames from these Cycle~4 exposures, and taking care to include the added readout noise appropriate for CR--SPLIT observations, we have replicated exposures similar to those we propose here. Examining field galaxies with similar apparent magnitudes to those of the absorbers and spanning a large range of morphology, we find that 2 orbits per field should be adequate for our scientific goals, offering reliable morphological classification down to $R=22.8$ (the limit of our sample), and revealing subtler structural details (e.g. distortions, tidal features, etc.) at the typical magnitudes of our absorbers. The QSOs in each field range in magnitude from 16.0 to 17.7; these will saturate the CCD in a typical individual exposure of $\sim 1200$ seconds, and produce moderate blooming (several pixels) on the WFC CCDs; however, the typical galaxy separation from the QSO is $\sim $4 arcsec, so that this will not adversely affect the objects of interest. Nevertheless, it will in some cases be important to have a well-defined PSF with which to model the QSO light profile, so we have planned to place the QSO in the same position (WF3-FIX) for each of the 12 fields; absolute ORIENT ranges have been specified which guarantee that objects of primary interest will not fall beneath diffraction spikes from the QSO, and so as to place absorbing galaxies evenly throughout the 4 azimuthal ``quadrants'' of the PSF. This will allow us to produce a very good PSF at exactly the position of interest on the chip, using all of the observations together. We have chosen not to use the PC because of the substantial penalty in read noise and the larger amount of scattered light in the PSF wings. Our general approach for each field is to obtain 2 separate CR-split exposures (typical integration of 1200-1300s per actual read--out), with the second one being at a position dithered by a fractional pixel (+ an integer number of pixels) relative to the first, thereby allowing us to achieve slightly better sampling of the data. There is a total of 18 absorbing galaxies in the 12 fields proposed; these have been carefully selected to span the full range in absolute magnitude, impact parameter, and spectroscopic type from our ground--based survey. A reasonably large number of fields is required in order to make general statements about the nature of the galaxy halos as a function of other observed galaxy properties. As stated below, these images will also complement a comprehensive extension of our ground--based survey to include wider-ranging multi--object faint galaxy spectroscopy and high--resolution QSO spectroscopy in the same fields. Real Time Justification ----------------------- none Calibration Justification ------------------------- none Additional Comments ------------------- ------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 UM18-FIELD GALAXY RA=0H 05M 20.2S +/- 0.1 S, J2000 Z= 0.851 R=22.8 DEC=05D 24' 11.0" +/- 1" Comments: Three high redshift galaxies producing absorption in the spectrum of the background QSO. 2 PG1222+228- GALAXY RA=12H 25M 27.4S +/- 0.1 S, J2000 Z= 0.668 R=22.5 FIELD DEC=22D 35' 12.3" +/- 1" Comments: High redshift galaxy producing absorption in the spectrum of the background QSO. 3 Q0450-1310- GALAXY RA=04H 53M 13.51S +/- 0.1S, DEC= J2000 Z= 0.451 R=21.0 FIELD -13D 05' 56.0" +/- 1" Comments: Two high redshift galaxies producing absorption in the spectrum of the background QSO. 4 Q1548+0917- GALAXY,quasar,high z RA=15H 51M 03.4S +/- 0.1S, J2000 Z= 0.771 R=23.0 FIELD gal DEC=09D 08' 50.0" +/- 1" Comments: A high redshift galaxy producing absorption in the spectrum of the background QSO. 5 B20827+24- GALAXY,quasar,high z RA=08H 30M 52.1S +/- 0.05S, J2000 Z= 0.525 R=21.0 FIELD gal DEC=24D 11' 00.0" +/- 1" Comments: A high redshift galaxy producing absorption in the spectrum of the background QSO. 6 4C06.41- GALAXY,quasar RA=10H 41M 17.2S +/- 0.05S, J2000 Z= 0.443 R=21.0 FIELD DEC=06D 10' 17.0" +/- 1" Comments: A high redshift galaxy producing absorption in the spectrum of the background QSO. 7 B21148+38- GALAXY,quasar RA=11H 51M 29.3S +/- 0.05S, J2000 Z= 0.551 R=21.6 FIELD DEC=38D 25' 53.0" +/- 1" Comments: A high redshift galaxy producing absorption in the spectrum of the background QSO. 8 Q1246-057- GALAXY,qso RA=12H 49M 13.84S +/- 0.02S, J2000 Z= 0.640 R=22.8 FIELD DEC=-05D 59' 19.3" +/- 1" Comments: A high redshift galaxy producing absorption in the spectrum of the background QSO. 9 TON153-FIELD GALAXY,qso RA=13H 19M 56.3S +/- 0.05S, J2000 Z= 0.660 R=21.3 DEC=27D 28' 08.0" +/- 1" Comments: A high redshift galaxy producing absorption in the spectrum of the background QSO. 10 PG1329+412- GALAXY,qso RA=13H 31M 41.1S +/- 0.05S, J2000 Z= 0.504 R=22.2 FIELD DEC=41D 01' 58.0" +/- 1" Comments: A high redshift galaxy producing absorption in the spectrum of the background QSO. 11 PKS1354+19- GALAXY,quasar RA=13H 57M 04.47S +/- 0.02S, J2000 Z= 0.457 R=22.0 FIELD DEC=19D 19' 06.5" +/- 1" Comments: High redshift galaxies producing absorption in the spectrum of the background QSO. 12 Q2342+089- GALAXY,qso RA=23H 45M 31.1S +/- 0.05S, J2000 Z= 0.738 R=22.5 FIELD DEC=09D 09' 6.0" +/- 1" Comments: High redshift galaxies producing absorption in the spectrum of the background QSO. 5984( 7) - 09/15/95 16:15 - [ 5] Visit: 01 Visit Requirements: ORIENT 45D TO 90D 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 UM18-FIELD WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND ------------------------------------------------------------------------------------------------------------------------------------ 2 UM18-FIELD WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 6] Visit: 02 Visit Requirements: ORIENT 83D TO 115D 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 PG1222+228- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 2 PG1222+228- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 7] Visit: 03 Visit Requirements: ORIENT 70D TO 90D 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 ------------------------------------------------------------------------------------------------------------------------------------ 9 Q0450-1310- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 11 Q0450-1310- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 8] Visit: 04 Visit Requirements: ORIENT 60D to 103D 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 ------------------------------------------------------------------------------------------------------------------------------------ 41 Q1548+0917- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 42 Q1548+0917- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 9] Visit: 05 Visit Requirements: ORIENT 90D TO 135D 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 ------------------------------------------------------------------------------------------------------------------------------------ 51 B20827+24- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 52 B20827+24- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 10] Visit: 06 Visit Requirements: ORIENT 90D TO 135D 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 ------------------------------------------------------------------------------------------------------------------------------------ 61 4C06.41- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 62 4C06.41- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 11] Visit: 07 Visit Requirements: ORIENT 105D TO 130D 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 ------------------------------------------------------------------------------------------------------------------------------------ 71 B21148+38- WFPC2 IMAGE WF3-FIX F702W 1 2200S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 72 B21148+38- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 12] Visit: 08 Visit Requirements: ORIENT 80D TO 100D 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 ------------------------------------------------------------------------------------------------------------------------------------ 81 Q1246-057- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 82 Q1246-057- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 13] Visit: 09 Visit Requirements: ORIENT 135D TO 175D 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 ------------------------------------------------------------------------------------------------------------------------------------ 91 TON153- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 92 TON153- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 14] Visit: 10 Visit Requirements: ORIENT 125D TO 145D 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 ------------------------------------------------------------------------------------------------------------------------------------ 101 PG1329+412- WFPC2 IMAGE WF3-FIX F702W 1 2200S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 102 PG1329+412- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 15] Visit: 11 Visit Requirements: ORIENT 135D TO 155D 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 ------------------------------------------------------------------------------------------------------------------------------------ 111 PKS1354+19- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 112 PKS1354+19- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 16] Visit: 12 Visit Requirements: ORIENT 90D TO 110D 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 ------------------------------------------------------------------------------------------------------------------------------------ 121 Q2342+089- WFPC2 IMAGE WF3-FIX F702W 1 2000S EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 122 Q2342+089- WFPC2 IMAGE WF3-FIX F702W 1 2400S POS TARG -1.25,+1.25 EXPAND FIELD ------------------------------------------------------------------------------------------------------------------------------------ 5984( 7) - 09/15/95 16:15 - [ 17] Summary Form for Proposal 5984 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Quasars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 45D TO 90D EXPAND POS TARG -1.25,+1.25 EXPAND ORIENT 83D TO 115D ORIENT 70D TO 90D ORIENT 60D to 103D ORIENT 90D TO 135D ORIENT 105D TO 130D ORIENT 80D TO 100D ORIENT 135D TO 175D ORIENT 125D TO 145D ORIENT 135D TO 155D ORIENT 90D TO 110D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F702W ------------------------------------------------------------------------------------------------------------------------------------ Target Names UM18-FIELD PG1222+228-FIELD Q0450-1310-FIELD Q1548+0917-FIELD B20827+24-FIELD 4C06.41-FIELD B21148+38-FIELD Q1246-057-FIELD TON153-FIELD PG1329+412-FIELD PKS1354+19-FIELD Q2342+089-FIELD ------------------------------------------------------------------------------------------------------------------------------------