! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /antares/data1/tex/cycle6/lyman/6705.prop ! Generated by PREPROCESSOR, version 6.0e ! Date: Wed Jan 17 14:50:43 EST 1996 Proposal_Information Title: Below the Lyman Edge: UV Polarimetry of Quasars Proposal_Category: GO Scientific_Category: AGN Cycle: 6 Investigators PI_Name: Anuradha Koratkar PI_Institution: Space Telescope Science Institute CoI_Name: Robert Goodrich CoI_Institution: Space Telescope Science Institute Contact: CoI_Name: Robert Antonucci CoI_Institution: University of California, Santa Barbara Contact: Abstract: The Lyman edge at 912 Angstrom is an important diagnostic region for studying quasi-stellar objects (QSOs). In particular, it reveals a great deal about the physical conditions within the atmospheres of accretion disks, a ubiquitous component of QSO theories. A fairly robust prediction of accretion disk theory is a high polarization just longward (in wavelength) of the edge. Observations of the Lyman edge regions of QSOs have shown scant evidence for the predicted features---few QSOs show the broad, partial Lyman edges expected to be common according to most theories, and none show the high polarizations expected longward of the Lyman edge. Still, polarization spectra of a small number of QSOs have shown a rising polarization (up to 20\%) at wavelengths shortward of the Lyman edge. The cause for this rise is not well understood, mostly because only one object, PG 1630+377, has been studied in enough detail to determine some characteristics of the polarization feature. We propose to observe four bright QSOs, chosen for having strong UV flux at rest wavelengths shorter than 800 Angstrom, to search for evidence of this highly polarized component and to better define its character. As a byproduct we will also accumulate more information on the polarization properties of QSOs longward of the Lyman edge. Cycle 6 will be the last chance for this type of study for the foreseeable future, with the impending removal of the FOS and HST's spectropolarimetric capability. Questions Observing_Description: We will use the FOS with the G190H and G270H gratings and the polarimetry optics. We have used archival spectra from both IUE and HST to estimate continuum fluxes of our targets at various wavelengths, and the tables in the FOS Instrument Handbook to calculate count rates for each target at those wavelengths. To account for the throughput of the polarimetry optics and the inefficiencies of the wave plate (caused by its retardance not being exactly 180degrees at all wavelengths) we multiply these count rates by ~ 0.35. Using the empirical formula for converting total counts to the polarization uncertainty (section 1.6 of the FOS Instrument Handbook), we calculated exposure times which would yield a polarization uncertainty of 1\\\\\\\\% or less in 100 Angstrom bins. def\\\\\\\\flamerg cm^-2 s^-1 AA^-1 We use as an example PG 1522+101, which has continuum fluxes of 7 * 10^-15 \\\\\\\\flam in the G190H grating and 5 * 10^-15 \\\\\\\\flam in the G270H grating. The inverse sensitivities are roughly 4 * 10^-14 \\\\\\\\flam counts^-1 s diode in the G190H and 4 * 10^-15 \\\\\\\\flam counts^-1 s diode in the G270H. The count rates are hence 0.175 and 1.25 count s^-1 diode^-1 in G190H and G270H respectively. Note that dark count is not significant. Multiplying these by the polarimetry efficiency of 0.35 and also by the number of diodes per 100 Angstrom bin (68 for the G190H and 48 for the G270H) we get 4.16 and 21 count s^-1. The polarization uncertainty is given by Sigma(P) = 4.16% (1600/N)^1/2 where N is the total number of counts for an entire set of polarimetry observations. To achieve Sigma(P) = 1\\\\\\\\% we require 28,000 total counts, implying exposure times of 6700 s and 1400 s in G190H and G270H, respectively. We hence require 3 orbits for the G190H data and a single orbit for the G270H data. Using a binary acquisition with the FOS we can fit the G270H easily into the end of the first orbit. These targets are not known to vary, have well-measured V magnitudes, and are bright enough for the binary acquisition strategy. Real_Time_Justification: None. Calibration_Justification: None. Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: UM18 Alternate_Names: Description: GALAXY,QSO,QUASAR, Position: RA=00H 05M 20.22S +/- 0.5",DEC=05D 24' 11.08" +/- 0.5",PLATE-ID=026E Equinox: J2000 RV_or_Z: Z = 1.887 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 16.21 F(2200)=1.7+/-0.2e-15 F(3250)=1.85+/-0.2e-15 Comments: Lyman edge at 2633 angstrom. Coordinates determined from gasp images. The previous FOS observations have a failed ACQ/BIN. Target_Number: 2 Target_Name: 1247+267 Alternate_Names: PG1247+267 Description: GALAXY,QSO,QUASAR, Position: RA=12H 50M 05.727S +/- 0.5",DEC=26D 31' 07.53" +/- 0.5",PLATE-ID=01PM Equinox: J2000 RV_or_Z: Z = 2.038 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 15.8 F(2300)=3.2+/-0.4e-15 F(3100)=3.0+/-0.3e-15 Comments: Lyman edge at 2770 angstrom. Coordinates determined from gasp images and previous FOS observations. Pervious ACQ/BIN successful. Target_Number: 3 Target_Name: 1522+101 Alternate_Names: PG1522+101 Description: GALAXY,QSO,QUASAR, Position: RA=15H 24M 24.527S +/- 0.6",DEC=09D 58' 29.406" +/- 0.6",PLATE-ID=0291 Equinox: J2000 RV_or_Z: Z = 1.321 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 15.74 F(1570)=5.5+/-0.4e-15 F(1700)=6.2+/-0.5e-15 F(1800)=8.0+/-0.6e-15 F(2000)=6.6+/-0.6e-15 F(2300)=6.0+/-0.7e-15 F(2700)=5.0+/-0.4e-15 Comments: Lyman edge at 2120 angstrom. Coordinates determined from gasp images and previous FOS observations. ACQ/BIN previous was successful Target_Number: 4 Target_Name: 1718+481 Alternate_Names: PG1718+481 Description: GALAXY,QSO,QUASAR, Position: RA=17H 19M 38.23S +/- 1.0",DEC=48D 04' 13.01" +/- 1.0",PLATE-ID=02D4 Equinox: J2000 RV_or_Z: Z = 1.084 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 15.33 F(1600)=18.5+/-3e-15 F(2400)=15.2+/-3e-15 Comments: Lyman edge at 1900 angstrom, intervening edge at 1550. Coordinates determined from gasp images. Coordinates of previous FOS observations not used since ACQ/BIN unsucessful Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: UM18 Config: FOS/BL Opmode: ACQ/BINARY Aperture: 4.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 13S Special_Requirements: ONBOARD ACQ FOR 2-8 Comments: Exposure_Number: 2 Target_Name: UM18 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G270H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 1430S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 3 Target_Name: UM18 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G270H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2210S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 4 Target_Name: UM18 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2090S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 5 Target_Name: UM18 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2210S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 6 Target_Name: UM18 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2230S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 7 Target_Name: UM18 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2220S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 8 Target_Name: UM18 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2200S Special_Requirements: MAX DUR 200% Comments: Visit_Number: 02 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: 1247+267 Config: FOS/BL Opmode: ACQ/BINARY Aperture: 4.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 7S Special_Requirements: ONBOARD ACQ FOR 2-3 Comments: Exposure_Number: 2 Target_Name: 1247+267 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G270H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 1420S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 3 Target_Name: 1247+267 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G270H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2220S Special_Requirements: MAX DUR 200% Comments: Visit_Number: 03 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: 1522+101 Config: FOS/BL Opmode: ACQ/BINARY Aperture: 4.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 6S Special_Requirements: ONBOARD ACQ FOR 2-5 Comments: Exposure_Number: 2 Target_Name: 1522+101 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G270H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 1200S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 3 Target_Name: 1522+101 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2200S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 4 Target_Name: 1522+101 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2220S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 5 Target_Name: 1522+101 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2210S Special_Requirements: MAX DUR 200% Comments: Visit_Number: 04 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: 1718+481 Config: FOS/BL Opmode: ACQ/BINARY Aperture: 4.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2S Special_Requirements: ONBOARD ACQ FOR 2-4 Comments: Exposure_Number: 2 Target_Name: 1718+481 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G270H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 1640S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 3 Target_Name: 1718+481 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2320S Special_Requirements: MAX DUR 200% Comments: Exposure_Number: 4 Target_Name: 1718+481 Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: POLSCAN=8B Number_of_Iterations: 1 Time_Per_Exposure: 2340S Special_Requirements: MAX DUR 200% Comments: Data_Distribution ! 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