! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 6237,v 6.1 1995/12/13 16:58:32 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Karla Peterson, ! Phone: 410/338-4774, E-mail: peterson@stsci.edu ! Proposal_Information ! Section 4 Title: Evolution of the Molecular Fraction of Damped Lyman-alpha Absorption Systems Proposal_Category: GTO/HRS Scientific_Category: Quasars Cycle: 5 Investigators PI_Name: EDWARD A. BEAVER PI_Institution: UNIVERSITY OF CALIFORNIA, SAN DIEGO CoI_Name: ROSS D. COHEN ! Repeat as often as necessary CoI_Institution: UNIVERSITY OF CALIFORNIA, SAN DIEGO Contact:Y ! Y or N (designate at most one contact) CoI_Name: VESA T. JUNKKARINEN ! Repeat as often as necessary CoI_Institution: UNIVERSITY OF CALIFORNIA, SAN DIEGO CoI_Name: ATHANASSIOS DIPLAS ! Repeat as often as necessary CoI_Institution: UNIVERSITY OF CALIFORNIA, SAN DIEGO Abstract: Molecular hydrogen measurements are unique diagnostics of the physical conditions in the gas, including temperature, density, and ionizing background. The formation of molecular hydrogen depends as well on dust content. We will use the FOS to measure the column density and excitation of molecular hydrogen in a bright, moderate redshift damped Lyman-alpha absorption system. The very accurate H I column densty determined from the same spectrum will be combined with very high resolution, high signal-to-noise optical spectra to measure metal abundances and dust content. Additional indicators of metallicity, ionization, and dust content will come from metal absorption lines measured in the HST spectrum. The molecular fraction will be compared with the high redshift damped Lyman-alpha systems to study the evolution of these systems. Thus our measurements will provide clues to the nature of the damped Lyman-alpha absorption systems. Questions ! Free format text (clear and concise) Observing_Description:This observation is designed to measure the column density and excitation of molecular hydrogen in relatively low resolution FOS data. In order to achieve this we will attain a signal-to-nose of greater than 50 per diode over the entire spectrum and greater than 65 over most of the region of interest. Our simulations show that this is adequate to make these measurements. Another observation of this target which is part of a different program uses less than one quarter of the integration time used for this observation and will not attain high enough signal-to-noise to study molecular hydrogen. That program is designed to study lines of the Lyman-alpha forest. We will use a binary search followed by two stages of peak-up in the 0.3" aperture. This is designed to use the same centering as the flat field observations (accurate to 0.04") in order to achieve highest possible accuracy in flat fielding. Following target acquisition, an 8750s integration will be obtained with the FOS, red detector, G270H grating and 0.3" aperture. Real_Time_Justification: Calibration_Justification: Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: PG0935+417 Description: GALAXY,QSO,EXT-MEDIUM,ABSORPTION LINE SYSTEM,IGM Position: RA = 9H 38M 57.03S +/- 0.04S, DEC = 41D 28' 21.5" +/- 0.5", PLATE-ID = 01BS Equinox: J2000 Rv_or_z: Z = 1.9657 Flux: V = 16.25 +/- 0.2, F(2500.0) = 2.0 +/- 0.25 E-15 Comments: Coordinates are from an inventory GASP measurement by Karla; Absorption redshift z(a)=1.379; Emission redshift from Tytler and Fan 1992 Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_number: 10 Target_Name: PG0935+417 Config: FOS/RD Opmode: ACQ/BINARY Aperture: 4.3 Sp_Element: MIRROR Optional_Parameters: BRIGHT=700000 Number_of_iterations:1 Time_Per_Exposure: 10.0S Special_Requirements:ONBOARD ACQ FOR 20 Comments: calculated time was 4.53S Exposure_number: 20 Target_Name: PG0935+417 Config: FOS/RD Opmode: ACQ/PEAK Aperture: 0.3 Sp_Element: MIRROR Optional_Parameters: SEARCH-SIZE-Y=5, SCAN-STEP-Y=0.17, SEARCH-SIZE-X=5, SCAN-STEP-X=0.17 Number_of_iterations:1 Time_Per_Exposure: 1S Special_Requirements:ONBOARD ACQ FOR 30 Exposure_number: 30 Target_Name: PG0935+417 Config: FOS/RD Opmode: ACQ/PEAK Aperture: 0.3 Sp_Element: MIRROR Optional_Parameters: SEARCH-SIZE-Y=5, SCAN-STEP-Y=0.05, SEARCH-SIZE-X=5, SCAN-STEP-X=0.05 Number_of_iterations:1 Time_Per_Exposure: 10S Special_Requirements:ONBOARD ACQ FOR 40 Exposure_number: 40 Target_Name: PG0935+417 Config: FOS/RD Opmode: ACCUM Aperture: 0.3 Sp_Element: G270H Wavelength: Number_of_iterations:1 Time_Per_Exposure: 8750S Comments: Data_Distribution Medium: 8MM Blocking_Factor: 10 Ship_To: PI_Address Ship_Via: UPS Recipient_Email: