9172( 2) - 02/14/01 08:38 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9172 Version: 2 Check-in Date: 14-Feb-2001 08:37:20 1.Proposal Title: Molecular Hydrogen in the Damped LyAlpha Absorber of Q1331+170 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Jill Bechtold University of Arizona CoI: Dr. David Meyer Northwestern University N CoI: Dr. Jian Ge Penn State N ------------------------------------------------------------------------------------ 5. Abstract We wish to search for the Lyman and Werner absorption lines of molecular hydrogen (rest LambdaLambda = 1104 to 911 Angstrom) associated with the well-studied damped LyAlpha and 21-cm absorber at z=1.776 in Q1331+170. The rare detection of C I absorption in this system make this a promising candidate for a search. After detecting H_2, we plan to measure the relative population in the individual rotation states. The J = 0, 1, 2, 3 states will yield the kinetic temperature of the gas, while the weak J = 4 and higher states will measure (or limit) the local UV radiation field and hydrogen density. The detection of C I^* has been used to measure the cosmic microwave background temperature at z=1.776, and test the validity of the Big Bang model. The observed population of the fine structure levels of C I can be explained entirely by the expected CMB radiation, with surprisingly strong limits on local sources of excitation. The H_2 spectrum will enable us to check this result, by allowing us to make an independent estimate of the rate of UV and collisional pumping of the C I^* levels. ------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 2] Observations Description ------------------------ For estimating exposure times we use the STIS ETC, and the flux as measured with STIS during our previous observations. They agree well with the IUE flux. We have fLambda (3100 Angstrom) = 1* 10^-15 ergs s^-1 cm^-2 AA^-1. The optical and UV continuum of Q1331+17 has not varied in the many years it has been observed (e.g. O'Brien et al. 1988). We simulated spectra using the output tables from the STIS ETC, so we have proper signal-to-noise as a function of wavelength. Q1331+17 has an orbit visibility of 52 minutes per orbit. We use the 0.2 arcsecond slit, in order to obtain high spectral resolution while minimizing overhead for acquisition. With guide star acquisition and instrument overhead, we calculate that we get 12, 240 seconds of exposure per 5 orbit visit. beginfigureht plotfiddleh2f.ps4.truein-906060-240400 captionSimulated STIS E230M Spectrum of Q1331+170. Expected molecular hydrogen and Lyman series spectrum, at the resolution and sampling of the STIS E230M grating. Positions of other lines from known redshift systems are shown: (squares: z=1.3284, triangles: z=0.7443, 0.7454, circles: z=1.7765). Upper panel shows f_H_2=3times10^-7, with the barely detectable H_2 lines indicated by arrows. If f=5times10^-6, H_2 will be easy to detect. For larger f, the individual J- levels will be measured. In each case we chose the J-level populations to match observed ISM lines-of-sight at the f given, to most realistically match the expected spectrum (>~mmaVel, RhoLeo, EpsilonPer for f=3times10^-7, 5times10^-6, 0.04, respectively). endfigure We request 20 orbits, which, when added to our existing data, will yield spectra with S/N~9.3 at 2700Angstrom. Figure 2 shows the expected Lyman series of H I and Lyman and Werner bands of H_2 at the R~30, 000 resolution and sampling of the STIS E230M grating and NUV MAMA, for several values of f_H_2. We show the expected spectrum obtained in with 20 more orbits, with the expected position of absorption lines associated with known metal-line absorbers marked. Although we expect numerous lines from other systems, the high resolution and distinctive spectrum of H_2 will enable us to recognize it easily, especially after we apply standard cross-correlation techniques. We have included a simulated LyAlpha forest spectrum for 1.09~mma, etc. forest associated with higher redshift LyAlpha) will not be an insurmountable problem. We plot also the expected positions of Lyman and metal lines for the known metal absorbers (z_abs = 1.7765, 1.3284, 0.7443, 0.7454). Figure 2 shows that we will easily detect H_2 if f=5times10^- 6, and marginally detect it if f=3times10^-7. This lower value is the lowest f seen in the ISM (>~mma Vel, 41). Note that because self- shielding plays an important role in H_2 production, it is observed in the ISM that either f<<10^- 3 or f~ 0.1-0.5 41. If f~0.1 for the Q1331+170 system, we will detect many bands, and be able to model the effects of saturation in order to accuratedly measure the column density of molecular hydrogen, N(H_2), through standard curve-of-growth techniques. Our simulations have assumed typical ISM values for temperature, density and UV field. If the density for the Q1331+170 system is as low as the Songaila et al. results imply, then collisional de-excitation will not be as important, and the J=4 lines will be relatively stronger. They will also be stronger if the UV radiation field is higher than in the ISM. Finally, we can co-add the regions around several bands to improve our limits on the J=4 lines. Therefore with 20 more orbits we have a good chance of detecting the J=4 lines if the f_H_2 is high, and will put an excellent limit on f_H_2 if it is low. Real Time Justification ----------------------- None. None. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 Q1331+170 Galaxy, QUASAR RA=13H 33M 35.84S +/- 0S, J2000.0 V = 16.71 DEC=16D 49' 03.07" +/- 0", PLATE B-V = 0.13 -ID=01TF Coordinate Source: GSC_SURVEY_PLATE 9172( 2) - 02/14/01 08:38 - [ 4] 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 Q1331+170 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.0 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 Q1331+170 STIS/C ACQ/PEA 0.2X0.2 MIRROR 1 1.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 1 32.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 2 42.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 5] 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 Q1331+170 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.0 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 Q1331+170 STIS/C ACQ/PEA 0.2X0.2 MIRROR 1 1.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 1 32.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 2 42.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 6] 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 Q1331+170 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.0 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 Q1331+170 STIS/C ACQ/PEA 0.2X0.2 MIRROR 1 1.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 1 32.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 2 42.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 7] 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 Q1331+170 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.0 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 Q1331+170 STIS/C ACQ/PEA 0.2X0.2 MIRROR 1 1.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 1 32.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 2 42.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 8] Visit: 05 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 Q1331+170 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.0 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 Q1331+170 STIS/C ACQ/PEA 0.2X0.2 MIRROR 1 1.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 1 32.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 2 42.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 9] Visit: 06 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 Q1331+170 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.0 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 Q1331+170 STIS/C ACQ/PEA 0.2X0.2 MIRROR 1 1.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 1 32.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 2 42.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 10] Visit: 07 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 Q1331+170 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.0 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 Q1331+170 STIS/C ACQ/PEA 0.2X0.2 MIRROR 1 1.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 1 32.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 Q1331+170 STIS/N ACCUM 0.2X0.2 E230M 2707 1 42.0 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9172( 2) - 02/14/01 08:38 - [ 11] Summary Form for Proposal 9172 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 0.2X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E230M ------------------------------------------------------------------------------------------------------------------------------------ Target Names Q1331+170 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 2707 ------------------------------------------------------------------------------------------------------------------------------------