6712( 11) - 08/14/96 18:21 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6712 Version: 11 Check-in Date: 14-Aug-1996 18:17:37 1.Proposal Title: The Gaseous Extent of Galaxies: How Far is Too Far? ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle QSO ABSORPTION LINES GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: John Webb UNIVERSITY OF NEW SOUTH WALES CoI: Kenneth M. Lanzetta State University of New York at Stony N Brook CoI: Robert F. Carswell Institute of Astronomy N CoI: Xavier Barcons Instituto de Fisica de Cantabria N ------------------------------------------------------------------------------------ 6. Abstract The origin of the Lyman-Alpha clouds has been a subject of intense recent activity. The launch of HST made it possible for the first time to make direct identification of objects at low/intermediate redshift which give rise to Lyman-Alpha absorption towards a bright background QSO. Using a combination of HST QSO spectra and ground- based multi-slit spectroscopy, we have shown that many Lyman-Alpha clouds arise in gigantic gaseous envelopes around galaxies. Our analysis so far has been based on HST FOS QSO spectra, where the weakest absorption systems typically detected are ~ 0.3Angstrom, which can arise around galaxies at impact parameters of out to 160 h^-1 kpc. In order to properly understand the nature of gas in and around galaxies we must now explore how far out from the galaxy centre this incredibly tenuous gas extends. To do this, we wish to obtain GHRS spectra of two particularly interesting QSOs, centred on fields where we have already carried out extensive multi-slit redshift surveys, to search for weak Lyman-Alpha absorption associated with the galaxies. Detections or non-detections of absorption associated with galaxies greater than 160 h^-1 kpc will both place fundamental new constraints on the nature of these gigantic gaseous envelopes around galaxies. ------------------------------------------------------------------------------------ Observations Description ------------------------ The appropriate gratings are the G160M up to 1700A, and the G200M thereafter. Note that there is a group of redshifts very close together towards 0405-12 (1731 to 1736 Angstrom). Also, the z=0.5170 galaxy towards 0405-12 has a reasonably convenient redshift from the point of view of the G200M efficiency. We thus choose 4 spectral ranges to cover, 3 towards 0405-12 and one towards 1001+291. These spectral regions are centred on 1556, 1721 and 1856 Angstrom towards 0405-12 and 1564 towards 1001+291. We have computed the required exposure times using the Case 2 equation on page 34 of the GHRS Handbook version 6.0. Both QSO fluxes are measured to be ~ 2.0 e -14 ergs s^-1 cm^-2 AA^ -1. The 1856Angstrom region requires an integration time of 7700s and the other three wavelength regions all approximately 13,600s. Allowing for the relevent overheads, acquisitions etc, we will require a total of 21 orbits to complete the project as described. Real Time Justification ----------------------- We have in hand and are scheduled to obtain a large amount of ground-based supporting observations, which will complement the proposed HST observations. First, we are obtaining more ground-based spectroscopy of galaxies in the fields. Second, we are obtaining ground-based optical (B, V, R, and I) and infrared (K) images of galaxies in the fields, which we will use to measure accurate spectral energy distributions and luminosities of the galaxies. Finally, we are obtaining ground-based high-resolution spectroscopy of the brighter galaxies in the fields, which we will use to measure accurate redshifts and rotational velocities. The proposed HST observations will be used together with these ground-based observations to develop a comprehensive picture of how properties of the absorbers depend on properties of the galaxies. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6712( 11) - 08/14/96 18:21 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 01 Q0405-1219 GALAXY, QSO RA = 04H 07M 48.420S +/- 0.03S, J2000 Z=0.574 V = 15.4+/-0.3 DEC = -12D 11' 36.00" +/- 0.04", B-V = 0.18+/-0.1 PLATE-ID=0238 U-B = -0.60+/-0.1 F(1600)=2.5+/-0.1e-14 02 Q1001+2910 GALAXY,QSO RA= 10H 04M 02.627S +/- 0.01S, J2000 Z=0.329 V = 15.5+/-0.3 DEC= +28D 55' 35.14" +/- 0.2", B-V = 0.12+/-0.1 PLATE-ID=021H U-B = -0.90+/-0.1 F(1600)=2.5+/-0.1e-14 6712( 11) - 08/14/96 18:21 - [ 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 Q0405-1219 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,SEARCH-SIZE=3 1 27 S ONBOARD ACQUISITION FOR 20-70 ------------------------------------------------------------------------------------------------------------------------------------ 20 WAVE HRS ACCUM SC2 G160M 1556.0 SPYBAL=YES 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 30 Q0405-1219 HRS ACCUM 2.0 G160M 1556.0 STEP-PATT=DEF,FP-SPLIT=NO, 9 598.4 S COMB=FOUR,SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 40 Q0405-1219 HRS ACCUM 2.0 G160M 1556.0 STEP-PATT=DEF,FP-SPLIT=NO, 8 598.4 S COMB=FOUR,SPYBAL=YES ------------------------------------------------------------------------------------------------------------------------------------ 50 Q0405-1219 HRS ACCUM 2.0 G160M 1556.0 STEP-PATT=DEF,FP-SPLIT=NO, 8 598.4 S COMB=FOUR,SPYBAL=YES ------------------------------------------------------------------------------------------------------------------------------------ 60 WAVE HRS ACCUM SC2 G200M 1721.0 SPYBAL=YES 1 27.2 S ------------------------------------------------------------------------------------------------------------------------------------ 70 Q0405-1219 HRS ACCUM 2.0 G200M 1721.0 STEP-PATT=DEF,FP-SPLIT=NO, 9 598.4 S COMB=FOUR,SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 6712( 11) - 08/14/96 18:21 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 Q1001+2910 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,SEARCH-SIZE=3 1 27 S ONBOARD ACQUISITION FOR 20-50 ------------------------------------------------------------------------------------------------------------------------------------ 20 WAVE HRS ACCUM SC2 G160M 1564.0 SPYBAL=YES 1 54.4 S ------------------------------------------------------------------------------------------------------------------------------------ 30 Q1001+2910 HRS ACCUM 2.0 G160M 1564.0 STEP-PATT=DEF,FP-SPLIT=NO, 9 625.6 S COMB=FOUR,SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 40 Q1001+2910 HRS ACCUM 2.0 G160M 1564.0 STEP-PATT=DEF,FP-SPLIT=NO, 8 598.4 S COMB=FOUR,SPYBAL=YES ------------------------------------------------------------------------------------------------------------------------------------ 50 Q1001+2910 HRS ACCUM 2.0 G160M 1564.0 STEP-PATT=DEF,FP-SPLIT=NO, 8 598.4 S COMB=FOUR,SPYBAL=YES ------------------------------------------------------------------------------------------------------------------------------------ 6712( 11) - 08/14/96 18:21 - [ 4] Visit: 03 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 Q0405-1219 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,SEARCH-SIZE=3 1 27 S ONBOARD ACQUISITION FOR 60-110 ------------------------------------------------------------------------------------------------------------------------------------ 60 WAVE HRS ACCUM SC2 G200M 1721.0 SPYBAL=YES 1 27.2 S ------------------------------------------------------------------------------------------------------------------------------------ 80 Q0405-1219 HRS ACCUM 2.0 G200M 1721.0 STEP-PATT=DEF,FP-SPLIT=NO, 8 598.4 S COMB=FOUR,SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 90 Q0405-1219 HRS ACCUM 2.0 G200M 1721.0 STEP-PATT=DEF,FP-SPLIT=NO, 8 598.4 S COMB=FOUR,SPYBAL=YES ------------------------------------------------------------------------------------------------------------------------------------ 95 WAVE HRS ACCUM SC2 G200M 1856.0 SPYBAL=YES 1 27.2 S ------------------------------------------------------------------------------------------------------------------------------------ 100 Q0405-1219 HRS ACCUM 2.0 G200M 1856.0 STEP-PATT=DEF,FP-SPLIT=NO, 7 571.2 S COMB=FOUR,SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 110 Q0405-1219 HRS ACCUM 2.0 G200M 1856.0 STEP-PATT=DEF,FP-SPLIT=NO, 7 571.2 S COMB=FOUR,SPYBAL=YES ------------------------------------------------------------------------------------------------------------------------------------ 6712( 11) - 08/14/96 18:21 - [ 5] Summary Form for Proposal 6712 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 SPYBAL=YES SPYBAL=NO COMB=FOUR FP-SPLIT=NO STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category QSO ABSORPTION LINES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQUISITION FOR 20-70 ONBOARD ACQUISITION FOR 20-50 ONBOARD ACQUISITION FOR 60-110 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M G200M ------------------------------------------------------------------------------------------------------------------------------------ Target Names Q0405-1219 WAVE Q1001+2910 ------------------------------------------------------------------------------------------------------------------------------------