8316( 4) - 04/14/99 07:57 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8316 Version: 4 Check-in Date: 14-Apr-1999 07:56:19 1.Proposal Title: The Lyman-alpha Absorption Cross-Section of Nearby Galaxies ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: David Bowen Royal Observatory, Edinburgh CoI: Dr. Max Pettini Royal Greenwich Observatory N CoI: Dr. Chris Blades Space Telescope Science Institute N ------------------------------------------------------------------------------------ 5. Abstract We propose to determine the size of Ly-alpha\ absorbing halos around nearby, relatively isolated galaxies, by searching for Ly-alpha\ absorption in STIS spectra of 12 UV-bright, background QSOs and AGNs. The galaxies selected cover a range of luminosities, from M_B = -16.1 to -19.9, and are probed at distances of 4-160 \h\ from their centers. We aim to settle the question of whether galaxies possess extended, gaseous envelopes with radii of several hundred kpc, and whether the presence of Ly-alpha -absorbing gas around a galaxy depends on its luminosity, morphology, or inclination. We wish to obtain spectra with the G140M grating to measure precise column densities of the absorbing gas and thereby map the decline in H I column density with galactocentric radius. The high resolution of the spectra will allow us to accurately determine the velocity of the gas, which can be compared to the systemic velocity of the galaxy, and to the velocity field determined from 21 cm H I emi ss ion measurements, when available, enabling us to determine if or how the gas is kinematically tied to the galaxy. ------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 2] Observations Description ------------------------ Fluxes at 1220 Angstrom , F_Lambda(1220), are known for our QSO/AGN from either IUE or HST spectra in several cases. For the remaining probes, we use U-band (preferably) or V-band magnitudes, and calculate F_Lambda(1220) assuming the object has a power law continuum with F_Nu \propto nu^Alpha, and adopting the conservative value of Alpha = -0.5 and an extimated amount of Galactic reddening. We aim to achieve a signal-to-noise of 6 per pixel in the continuum, giving a 3Sigma equivalent width limit of W = 50 mAngstrom\ with the G140M, allowing us to search for very weak Ly-alpha\ lines from nearby galaxies. We note that Ly-alpha\ absorption from galaxies with low velocities is expected to be blended with the damped Ly-alpha\ absorption profile of the Milky Way. Most of the galaxies in our sample have v > 1500 kms , but a few have 1450 < v < 2000 kms . We have simulated the expected line profiles using a conservative limit to N(H I) in the Milky Way of \log N(H I)=20.7 \log N (H I) >= 20.7 for Galactic latitudes of b <= 40degrees, and find that our expected signal-to- noise, combined with the high resolution of the G140M, is the most efficient method of detecting Ly- alpha\ from the intervening galaxy. Our simulations show that given the same exposure time with, e.g., the G140L, although the signal-to-noise is considerably higher, the resolution of 250-300 kms\ is inadequate to reveal the absorption at ~\:1500 kms . All QSO/AGN have emission redshifts cz > 6000 kms\ of the intervening galaxy, so that any absorption lines from the galaxy will not lie near the Ly-alpha\ emission line of the probe; conversely, the QSO/AGN all have z < 0.4, so higher redshift optically thick absorption systems will not cut off the UV flux where we wish to observe. Real Time Justification ----------------------- Two of our targets would be observed in the CVZ. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 TON730 GALAXY, QUASAR, LYMAN RA=13H 43M 56.72S +/- 1.5", J2000 Z = U = 15.6 ALPHA CLOUD, HALO DEC=25D 38' 47.5" +/- 1.5", 0.087 F-CONT(2800)=3e-15 PLATE-ID=01GF F-CONT(1220)=4+/-3e-15 V = 15.6 Comments: A(1200)=0.18 mags; V is not real and included for ACQ 2 MCG10.16.111 GALAXY, QUASAR, LYMAN RA=11H 18M 57.71S +/- 1.5", J2000 Z = V = 15.7 ALPHA CLOUD, HALO DEC=58D 3' 23.9" +/- 1.5", PLATE 0.027 B = 16.5 -ID=01OJ F-CONT(1220)=4+/-2e-15 Comments: A(1220)=0.14 mags 3 PKS1004+130 GALAXY, QUASAR, LYMAN RA=10H 7M 26.09S +/- 1.5", J2000 Z = 0.24 U = 14.5 ALPHA CLOUD, HALO DEC=12D 48' 56.2" +/- 1.5", F-CONT(1400)=1e-14 PLATE-ID=028W V = 14.5 Comments: A(1220)=0.65 mags; Flux from GHRS spectra; V not real, included for ACQ 4 SBS1127+575 GALAXY, QUASAR, LYMAN RA=11H 30M 3.47S +/- 1.5", J2000 Z = V = 16 ALPHA CLOUD, HALO DEC=57D 18' 29.6" +/- 1.5", 0.036 F-CONT(1220)=3+/-2e-15 PLATE-ID=01OJ Comments: A(1200)=0.16mags 5 PG1149-110 GALAXY, QSO, LYMAN RA=11H 52M 3.45S +/- 1.5", DEC=- J2000 Z = V = 15.5 ALPHA CLOUD, HALO 11D 22' 24.4" +/- 1.5", PLATE- 0.049 F-CONT(1220)=6e-15 ID=02N8 Comments: A(1220)=0.6 mags 6 ES438-G009 GALAXY, SEYFERT, LYMAN RA=11H 10M 48.01S +/- 1.5", DEC= J2000 Z = V = 14.1 ALPHA CLOUD, HALO -28D 30' 3.7" +/- 1.5", PLATE- 0.025 B-V = 0.58 ID=04JC U-B = -0.4 V-R = 0.5 V-I = 0.95 F-CONT(1220)=1e-14 Comments: A(1220)=1.0 mags 7 ISO1475+3554 GALAXY, SEYFERT, LYMAN RA=1H 50M 32.74S +/- 1.5", J2000 Z = 0.08 V = 15.3 ALPHA CLOUD, HALO DEC=36D 9' 25.8" +/- 1.5", PLATE F-CONT(1220)=4+/-2e-15 -ID=02S4 Comments: A(1220)=0.93 mags; Sy 2 8 MS10473+35 GALAXY, SEYFERT, LYMAN RA=10H 50M 10.86S +/- 1.5", J2000 Z = 0.04 V = 15.6 ALPHA CLOUD, HALO DEC=35D 2' 1.6" +/- 1.5", PLATE- F-CONT(1220)=5e-15 ID=01R8 Comments: A(1220)=0.37 mags 9 Q1831+731 GALAXY, ULTRALUMINOUS RA=18H 30M 23.09S +/- 1.5", J2000 Z = V = 15.5 IR GAL, LYMAN ALPHA DEC=73D 13' 10.0" +/- 1.5", 0.123 F-CONT(1220)=1e-14 CLOUD, HALO PLATE-ID=01L8 Comments: A(1220)=0.98 mags Flux from IUE spectra 8316( 4) - 04/14/99 07:57 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 TON730 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 TON730 STIS/F ACCUM 52X0.2 G140M 1222 NUM-POS=3,STEP-SIZE=0.025, 1 45 M EXPAND UV-MAM PATTERN-DIRECTION=PLUS, A PATTERN=ALONG-SLIT ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 5] Visit: 02 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 MCG10.16.11 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 20 1 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 MCG10.16.11 STIS/F ACCUM 52X0.2 G140M 1222 PATTERN=ALONG-SLIT,NUM-POS=5, 1 65 M 1 UV-MAM STEP-SIZE=.025, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 PKS1004+130 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 5.0 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PKS1004+130 STIS/F ACCUM 52X0.2 G140M 1222 PATTERN=ALONG-SLIT,NUM-POS=2, 1 45 M EXPAND UV-MAM STEP-SIZE=0.025, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 7] Visit: 04 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 SBS1127+575 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 SBS1127+575 STIS/F ACCUM 52X0.2 G140M 1222 PATTERN=ALONG-SLIT,NUM-POS=5, 1 65 M UV-MAM STEP-SIZE=0.025, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 PG1149-110 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PG1149-110 STIS/F ACCUM 52X0.2 G140M 1222 PATTERN=ALONG-SLIT,NUM-POS=3, 1 40 M EXPAND UV-MAM STEP-SIZE=0.025, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 ES438-G009 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 3.0 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 ES438-G009 STIS/F ACCUM 52X0.2 G140M 1222 PATTERN=ALONG-SLIT,NUM-POS=4, 1 45 M EXPAND UV-MAM STEP-SIZE=0.025, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 ISO1475+355 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 20 4 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 ISO1475+355 STIS/F ACCUM 52X0.2 G140M 1222 PATTERN=ALONG-SLIT,NUM-POS=2, 1 45 M EXPAND 4 UV-MAM STEP-SIZE=0.025, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 11] Visit: 08 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 MS10473+35 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 MS10473+35 STIS/F ACCUM 52X0.2 G140M 1222 PATTERN=ALONG-SLIT,NUM-POS=3, 1 45 M EXPAND UV-MAM STEP-SIZE=0.025, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 12] Visit: 09 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 Q1831+731 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10.0 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 Q1831+731 STIS/F ACCUM 52X0.2 G140M 1222 PATTERN=ALONG-SLIT,NUM-POS=2, 1 45 M EXPAND UV-MAM STEP-SIZE=0.025, A PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8316( 4) - 04/14/99 07:57 - [ 13] Summary Form for Proposal 8316 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT PATTERN=ALONG-SLIT PATTERN-DIRECTION=PLUS STEP-SIZE=0.025 NUM-POS=5 NUM-POS=3 NUM-POS=4 NUM-POS=2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 20 EXPAND CVZ ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names TON730 MCG10.16.111 PKS1004+130 SBS1127+575 PG1149-110 ES438-G009 ISO1475+3554 MS10473+35 Q1831+731 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1222 ------------------------------------------------------------------------------------------------------------------------------------