! Proposal 6612, submission 1
! PI: Kenneth M. Lanzetta
! Received Wed Feb 21 12:10:48 EST 1996
! From: lanzetta@sbast3.ess.sunysb.edu
Proposal_Information
Title: Damped Lyman-alpha Absorption Lines from
Moderate-Redshift Galaxies
Proposal_Category: GO
Scientific_Category: QSO Absorption Lines
Cycle: 6
Investigators
PI_name: Kenneth M. Lanzetta
PI_Institution: State University of New York at Stony Brook
CoI_Name: Arthur M. Wolfe
CoI_Institution: University of California, San Diego
Contact: N
Abstract:
We propose to obtain intermediate-resolution spectroscopy of
eight moderate-redshift (0.05 < z < 0.8) candidate damped Ly-
alpha\ absorption features that were detected toward higher-
redshift background QSOs in an exhaustive search of the HST
archival data base. This search forms a systematic, unbiased
survey for moderate-redshift damped Ly-alpha\ absorbers.
Accurate spectra of the candidate features will allow us to
confirm (or otherwise) the damped nature of the absorption
profiles and to determine the neutral hydrogen column
densities. By combining the results of this ultraviolet survey
with those derived from existing optical surveys we will
determine the redshift evolution of the rate of incidence,
cosmological mass density, and column density distribution of
damped Ly-alpha\ absorbers over a redshift baseline spanning
0.05 < z < 4.0. We will furthermore secure a sample of
moderate-redshift damped Ly-alpha\ absorbers for further
detailed study. These results will constrain theories of
galaxy formation and evolution and will help to determine the
type or types of galaxies responsible for the absorption.
Questions
Observing_Description:
We require observations of eight candidate damped LyAlpha
absorption features toward six background QSOs in order to
generate a statistically complete sample of absorption
systems. Based on our experience with similar spectra
obtained at optical wavelengths and on simulations of the
planned HST observations, we estimate that in order to
unambiguously confirm (or otherwise) the damped nature of the
candidate damped LyAlpha absorption features and to determine
accurate neutral hydrogen column densities we require signal-
to-noise ratios (in the continuum) of S/N ~ 15 per diode
with the GHRS and grating G140L or the FOS and grating G190H.
To estimate the exposure times required to obtain these
signal-to-noise ratios, we determined actual ultraviolet
fluxes from the HST spectra and used the sensitivity curves
and aperture throughputs quoted in the Faint Object
Spectrograph Instrument Handbook, Version 6.0 and the
Instrument Handbook for the Goddard High Resolution
Spectrograph (GHRS), Version 6.0. At the wavelengths of
interest, ultraviolet fluxes of the background QSOs in our
sample range from 0.15 * 10^-14 through 1.0 * 10^-14 erg s^-1
cm^-2 AA^-1, with 0.3 * 10^-14 erg s^-1 cm^-2 AA^-1 being
typical. As an example, consider an object observed at Lambda
= 1850 Angstrom\ with f_Lambda = 0.3 * 10^-14 erg s^-1 cm^-2
AA^-1 using the FOS with G190H and the red detector. From
Table 1--7 of the Faint Object Spectrograph Instrument
Handbook, the count rate is found to be 0.2 count s^-1 diode^
-1. This count rate greatly exceeds the dark count rate of
0.01 count s^-1 diode^-1, and the background is negligible,
so dark and background counts may be neglected. A total of
225 counts per diode (i.e. a signal-to-noise ratio of S/N =
15 per diode) may therefore be obtained in an exposure time
of 1125 s. We will adopt FOS-assisted target acquisition for
the GHRS exposures and PEAKUP target acquisition for the FOS
exposures. In most cases we can easily fit the guide star
acquisition, the target acquisition, and the science exposure
into two orbits, although in one case we require one orbit
and in one case we require three orbits. (We will pad, or in
a few cases trim, exposure times as necessary to fill
orbits.)
Real_Time_Justification:
Calibration_Justification:
Additional_Comments:
Fixed_Targets
Target_Number: 1
Target_Name: UM301
Description: GALAXY,QSO
Position: RA = 01H 03M 12.960S +/- 0.07S,
DEC = +02D 21' 10.70" +/- 0.1",
PLATE-ID=04YD
Equinox: 2000
RV_or_Z: Z=0.39
Flux: V = 17.7 +/- 0.5
Target_Number: 2
Target_Name: 3C95
Description: GALAXY,QSO
Position: RA = 03H 51M 28.55S +/- 0.07S,
DEC = -14D 29' 09.0" +/- 0.1",
PLATE-ID=029R
Equinox: 2000
RV_or_Z: Z=0.616
Flux: V = 16.22 +/- 0.5,
B-V = 0.33 +/- 0.1,
U-B = -0.56 +/- 0.1
Target_Number: 3
Target_Name: US1867
Description: GALAXY,QSO
Position: RA = 08H 53M 34.20S +/- 0.07S,
DEC = +43D 49' 0.20" +/- 0.1",
PLATE-ID=00XV
Equinox: 2000
RV_or_Z: Z=0.513
Flux: V = 16.4 +/- 0.5
Target_Number: 4
Target_Name: PG1338+416
Description: GALAXY,QSO
Position: RA = 13H 41M 0.770S +/- 0.07S,
DEC = +41D 23' 13.50" +/- 0.1",
PLATE-ID=00XY
Equinox: 2000
RV_or_Z: Z=1.219
Flux: V = 16.08 +/- 0.5
Target_Number: 5
Target_Name: PG1352+011
Description: GALAXY,QSO
Position: RA = 13H 54M 58.670S +/- 0.07S,
DEC = +00D 52' 10.10" +/- 0.1",
PLATE-ID=014F
Equinox: 2000
RV_or_Z: Z=1.121
Flux: V = 16.03 +/- 0.5
Target_Number: 6
Target_Name: 4C11.72
Description: GALAXY,QSO
Position: RA = 22H 54M 10.43S +/- 0.07S,
DEC = +11D 36' 39.00" +/- 0.1",
PLATE-ID=00JD
Equinox: 2000
RV_or_Z: Z=0.323
Flux: V = 15.77 +/- 0.5,
B-V = 0.17 +/- 0.1,
U-B = -0.87 +/- 0.1
Visits
Visit_Number: 1
Exposure_Number: 1
Target_Name: UM301
Config: FOS/BL
Opmode: ACQ/PEAK
Aperture: 4.3
Sp_Element: MIRROR
Optional_Parameters: SCAN-STEP-Y=1.204,
SEARCH-SIZE-X=1,
SEARCH-SIZE-Y=3
Number_of_Iterations: 1
Time_Per_Exposure: 2.34s
Special_Requirements: ONBOARD ACQUISITION FOR 2
Comments:
Exposure_Number: 2
Target_Name: UM301
Config: FOS/BL
Opmode: ACQ/PEAK
Aperture: 1.0
Sp_Element: MIRROR
Optional_Parameters: SCAN-STEP-X=0.602,
SCAN-STEP-Y=0.602,
SEARCH-SIZE-X=6,
SEARCH-SIZE-Y=2
Number_of_Iterations: 1
Time_Per_Exposure: 2.34S
Special_Requirements: ONBOARD ACQUISITION FOR 3
Comments:
Exposure_Number: 3
Target_Name: UM301
Config: FOS/BL
Opmode: ACQ/PEAK
Aperture: 0.5
Sp_Element: MIRROR
Optional_Parameters: SCAN-STEP-X=0.29,
SCAN-STEP-Y=0.29,
SEARCH-SIZE-X=3,
SEARCH-SIZE-Y=3
Number_of_Iterations: 1
Time_Per_Exposure: 2.34S
Special_Requirements: ONBOARD ACQUISITION FOR 4
Comments:
Exposure_Number: 4
Target_Name: UM301
Config: FOS/BL
Opmode: ACQ/PEAK
Aperture: 0.3
Sp_Element: MIRROR
Optional_Parameters: SCAN-STEP-X=0.172,
SCAN-STEP-Y=0.172,
SEARCH-SIZE-X=3,
SEARCH-SIZE-Y=3
Number_of_Iterations: 1
Time_Per_Exposure: 10S
Special_Requirements: ONBOARD ACQUISITION FOR 5-7
Comments:
Exposure_Number: 5
Target_Name: UM301
Config: FOS/BL
Opmode: ACCUM
Aperture: 1.0
Sp_Element: G190H
Wavelength: 1628.8
Number_of_Iterations: 1
Time_Per_Exposure: 180.0S
Special_Requirements: MIN DUR 80%; MAX DUR 1000%
Comments:
Exposure_Number: 6
Target_Name: UM301
Config: FOS/BL
Opmode: ACCUM
Aperture: 1.0
Sp_Element: G190H
Wavelength: 1628.8
Number_of_Iterations: 1
Time_Per_Exposure: 2400.0S
Special_Requirements: MIN DUR 80%; MAX DUR 1000%
Comments:
Exposure_Number: 7
Target_Name: UM301
Config: FOS/BL
Opmode: ACCUM
Aperture: 1.0
Sp_Element: G190H
Wavelength: 1628.8
Number_of_Iterations: 1
Time_Per_Exposure: 2401.0S
Special_Requirements: MIN DUR 80%; MAX DUR 1000%
Comments:
Visit_Number: 2
Exposure_Number: 1
Target_Name: 3C95
Config: FOS/BL
Opmode: ACQ/BINARY
Aperture: 4.3
Sp_Element: MIRROR
Number_of_Iterations: 1
Time_Per_Exposure: 8.9S
Special_Requirements: ONBOARD ACQUISITION FOR 2
Comments:
Exposure_Number: 2
Target_Name: 3C95
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1303.8
Optional_Parameters: STEP-PATT=DEF, FP-SPLIT=NO, COMB=FOUR
Number_of_Iterations: 15
Time_Per_Exposure: 299.2S
Comments:
Visit_Number: 3
Exposure_Number: 1
Target_Name: US1867
Config: FOS/BL
Opmode: ACQ/BINARY
Aperture: 4.3
Sp_Element: MIRROR
Number_of_Iterations: 1
Time_Per_Exposure: 13.1S
Special_Requirements: ONBOARD ACQUISITION FOR 2
Comments:
Exposure_Number: 2
Target_Name: US1867
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1409.7
Optional_Parameters: STEP-PATT=DEF, FP-SPLIT=NO, COMB=FOUR
Number_of_Iterations: 16
Time_Per_Exposure: 299.2S
Comments:
Visit_Number: 4
Exposure_Number: 1
Target_Name: PG1338+416
Config: FOS/RD
Opmode: ACQ/BINARY
Aperture: 4.3
Sp_Element: MIRROR
Number_of_Iterations: 1
Time_Per_Exposure: 3.4S
Special_Requirements: ONBOARD ACQUISITION FOR 2
Comments:
Exposure_Number: 2
Target_Name: PG1338+416
Config: FOS/RD
Opmode: ACCUM
Aperture: 1.0
Sp_Element: G190H
Wavelength: 1945.0
Number_of_Iterations: 1
Time_Per_Exposure: 1690.0S
Special_Requirements: MIN DUR 80%; MAX DUR 1000%
Comments:
Exposure_Number: 3
Target_Name: PG1338+416
Config: FOS/RD
Opmode: ACCUM
Aperture: 1.0
Sp_Element: G190H
Wavelength: 1945.0
Number_of_Iterations: 1
Time_Per_Exposure: 2500.0S
Special_Requirements: MIN DUR 80%; MAX DUR 1000%
Comments:
Visit_Number: 5
Exposure_Number: 1
Target_Name: PG1352+011
Config: FOS/RD
Opmode: ACQ/BINARY
Aperture: 4.3
Sp_Element: MIRROR
Number_of_Iterations: 1
Time_Per_Exposure: 3.3S
Special_Requirements: ONBOARD ACQUISITION FOR 2
Comments:
Exposure_Number: 2
Target_Name: PG1352+011
Config: FOS/RD
Opmode: ACCUM
Aperture: 1.0
Sp_Element: G190H
Wavelength: 1852.3
Number_of_Iterations: 1
Time_Per_Exposure: 1580.0S
Special_Requirements: MIN DUR 80%; MAX DUR 1000%
Comments:
Visit_Number: 6
Exposure_Number: 1
Target_Name: 4C11.72
Config: FOS/BL
Opmode: ACQ/PEAK
Aperture: 4.3
Sp_Element: MIRROR
Optional_Parameters: SCAN-STEP-Y=1.204,
SEARCH-SIZE-X=1,
SEARCH-SIZE-Y=3
Number_of_Iterations: 1
Time_Per_Exposure: 1S
Special_Requirements: ONBOARD ACQUISITION FOR 2
Comments:
Exposure_Number: 2
Target_Name: 4C11.72
Config: FOS/BL
Opmode: ACQ/PEAK
Aperture: 1.0
Sp_Element: MIRROR
Optional_Parameters: SCAN-STEP-X=0.602,
SCAN-STEP-Y=0.602,
SEARCH-SIZE-X=6,
SEARCH-SIZE-Y=2
Number_of_Iterations: 1
Time_Per_Exposure: 1S
Special_Requirements: ONBOARD ACQUISITION FOR 3
Comments:
Exposure_Number: 3
Target_Name: 4C11.72
Config: FOS/BL
Opmode: ACQ/PEAK
Aperture: 0.5
Sp_Element: MIRROR
Optional_Parameters: SCAN-STEP-X=0.29,
SCAN-STEP-Y=0.29,
SEARCH-SIZE-X=3,
SEARCH-SIZE-Y=3
Number_of_Iterations: 1
Time_Per_Exposure: 10s
Special_Requirements: ONBOARD ACQUISITION FOR 4
Comments:
Exposure_Number: 4
Target_Name: 4C11.72
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1313.0
Number_of_Iterations: 10
Time_Per_Exposure: 299.2S
Comments:
Data_Distribution
Medium: 8MM
Blocking_Factor: 10
Ship_To: Kenneth M. Lanzetta
Department of Earth and Space Sciences
State University of New York at Stony Brook
Stony Brook, NY 11794-2100
Ship_Via: UPS
Recipient_Email: lanzetta@sbastc.ess.sunysb.edu