8695( 2) - 03/01/00 10:08 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8695 Version: 2 Check-in Date: 01-Mar-2000 10:06:30 1.Proposal Title: The Nature and Distribution of O VI Absorbers in the Vicinity of Galaxies ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Todd Tripp Princeton University CoI: Dr. Edward Jenkins Princeton University Observatory N CoI: Dr. Blair Savage University of Wisconsin-Madison N CoI: Dr. David Bowen Princeton University Observatory N ------------------------------------------------------------------------------------ 5. Abstract Hydrodynamic cosmological simulations predict that at z ~ 0, up to 50\ of the baryons are in a shock-heated gaseous phase at 10^5 -- 10^7 \ ^degreesK. Such gas may be easiest to detect via O VI absorption lines in the spectrum of a background QSO. We have recently discovered several low redshift O VI absorption line systems in the vicinity of groups of galaxies. In some cases these absorbers are highly ionized, and the O VI lines can be quite weak. In one case, low and intermediate ionization stages are detected, as well as O VI, with complex velocity structure. Here we propose to study PG1259+593 (z_ Q = 0.472) with the STIS E140M echelle mode to substantially improve the statistical base of observed O VI absorbers (including weak lines) for comparison with the cosmological models and to constrain the physical conditions and abundances in these systems and their relationships with galaxies. We will also obtain follow-up observations of PG0953+415. With these observations we will (1) measure the number of O VI absorbers per unit redshift (dN/dz) with a limiting equivalent width of W_Lambda ~25 mAngstrom , (2) examine whether the O VI absorption arises in photoionized, collisionally ionized, or multiphase gas, (3) estimate the absorber metallicities, and (4) study the dependence of the absorber properties on the proximity of luminous galaxies. These observations will be useful for testing predictions from the cosmological models. ------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 2] Observations Description ------------------------ We have proposed STIS observations to search for O VI in galaxy groups to improve the statistics on this type of absorber, which may be an important reservoir of baryons. We will also study the physical conditions and metallicity of these absorbers and their relationship with galaxies. To achieve these goals, we plan to obtain an FUV E140M echelle observation of PG1259+593 (z_ QSO = 0.472). This will cover all O VI lines from z_ abs ~ 0.11 to z_ abs = z_ QSO, and will cover most of the H I LyAlpha and LyBeta lines and a variety of metals (e.g., Si II, Si III, C II, N V) which might accompany the O VI. We have also requested first-order grating observations of PG0953+415 in the G140M and G230M modes to enhance echelle E140M observations of this QSO already obtained. A summary of the proposed observations is provided in Table 1 along with signal-to-noise estimates calculated with the WWW STIS Spectroscopic Exposure Time Calculator. We will use the supported narrow slits (e.g., 0.2*0.06'' for E140M) to maintain the full spectroscopic resolution of the data. The S/N requirements in Table 1 are set to achieve limiting equivalent widths which are similar to those of the other QSOs we are observing in Cycle 8. Real Time Justification ----------------------- To search for all O VI doublets at 0.11 < z_ abs < z_ QSO in the direction of PG1259+593, we must use the multiplexing advantage of the STIS echelle mode. We will also benefit from the better resolution of this mode compared to first- order grating observations. Consequently, the PG1259+593 observation requires a long exposure time to achieve the needed S/N, and we request that the target be observed in the CVZ to complete the program in a reasonable number of orbits. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PG0953+415 GALAXY, QSO, EXT- RA=09H 56M 52.35S +/- 1.0", J2000 Z = V = 14.5 MEDIUM, ABSORPTION LINE DEC=41D 15' 22.5" +/- 1.0", 0.234 F(1189)=2.5+/-0.5e-14 SYSTEM - EXTRAGALACTIC PLATE-ID=00XW F(1780)=1.3+/-0.5e-14 E(B-V) = 0.021 2 PG1259+593 GALAXY, QSO, EXT- RA=13H 1M 12.94S +/- 1.0", J2000 Z = V = 15.84 MEDIUM, ABSORPTION LINE DEC=59D 2' 6.76" +/- 1.0", PLATE 0.472 B = 15.60 SYSTEM - EXTRAGALACTIC -ID=01R2 F(1400)=1.0+/-0.3e-14 F(1250)=1.0+/-0.3e-14 E(B-V) = 0.029 8695( 2) - 03/01/00 10:08 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 222 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.10 Coordinate_Frame POS-TARG Pattern_Orient 90 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 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 PG0953+415 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.7 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG0953+415 STIS/C ACQ/PEA 52X0.1 MIRROR 1 1.7 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 30 PG0953+415 STIS/F ACCUM 52X0.1 G140M 1173 1 35.0 M EXPAND UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG0953+415 STIS/F ACCUM 52X0.1 G140M 1173 1 45.0 M EXPAND PATTERN 222 40 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 PG0953+415 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.7 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG0953+415 STIS/C ACQ/PEA 52X0.1 MIRROR 1 1.7 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 30 PG0953+415 STIS/F ACCUM 52X0.1 G140M 1173 1 35.0 M EXPAND PATTERN 222 30 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 PG0953+415 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.7 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG0953+415 STIS/C ACQ/PEA 52X0.1 MIRROR 1 1.7 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 30 PG0953+415 STIS/N ACCUM 52X0.1 G230M 1769 1 35.0 M EXPAND UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG0953+415 STIS/N ACCUM 52X0.1 G230M 1769 1 45.0 M EXPAND PATTERN 222 40 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 PG0953+415 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.7 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG0953+415 STIS/C ACQ/PEA 52X0.1 MIRROR 1 1.7 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 30 PG0953+415 STIS/N ACCUM 52X0.1 G230M 1769 1 35.0 M EXPAND PATTERN 222 30 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 9] Visit: 05 Visit Priority: Visit Requirements: CVZ 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 PG1259+593 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.5 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1259+593 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 3.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 30 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 41 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 42 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 43 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 44 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2440.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 10] Visit: 06 Visit Priority: Visit Requirements: CVZ 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 PG1259+593 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.5 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1259+593 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 3.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 30 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 41 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 42 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 43 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 44 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2440.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 11] Visit: 07 Visit Priority: Visit Requirements: CVZ 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 PG1259+593 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.5 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1259+593 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 3.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 30 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 41 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 42 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 43 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 44 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2440.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 12] Visit: 08 Visit Priority: Visit Requirements: CVZ 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 PG1259+593 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.5 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1259+593 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 3.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 30 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 41 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 42 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 43 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 44 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2440.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 13] Visit: 09 Visit Priority: Visit Requirements: CVZ 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 PG1259+593 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.5 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1259+593 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 3.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 30 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 41 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 42 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 43 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 44 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2440.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 14] Visit: 10 Visit Priority: Visit Requirements: CVZ 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 PG1259+593 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.5 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1259+593 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 3.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 30 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 41 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 42 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 43 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 40.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 44 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2440.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 15] Visit: 11 Visit Priority: Visit Requirements: CVZ 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 PG1259+593 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.5 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1259+593 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 3.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 30 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 38.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 40 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 38.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 41 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 38.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 42 PG1259+593 STIS/F ACCUM 0.2X0.0 E140M 1425 1 38.0 M UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 8695( 2) - 03/01/00 10:08 - [ 16] Summary Form for Proposal 8695 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.1 0.2X0.06 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements EXPAND EXPAND PATTERN 222 40 EXPAND PATTERN 222 30 CVZ ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140M G230M E140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names PG0953+415 PG1259+593 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1173 1769 1425 ------------------------------------------------------------------------------------------------------------------------------------