! Proposal 5894, submission 1
! PI: Bart Wakker
! Received Fri Feb 24 17:11:07 EST 1995
! From: wakker@astro.uiuc.edu
! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template
! $Id: 5894,v 13.1 1995/12/18 16:01:25 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: Alice Berman
!             Phone: 410 338-4462    , E-mail: aberman@stsci.edu
!
! This partially completed template was generated from a Phase I proposal.
!

Proposal_Information                           ! Section 4
              Title:  The hot gaseous halo of the Large
                      Magellanic Cloud
  Proposal_Category:  GO
Scientific_Category:  Interstellar Medium
             Cycle:    5

Investigators
     PI_name:         Bart Wakker
     PI_Institution:  University of Wisconsin

          CoI_Name:   You-Hua Chu
   CoI_Institution:   University of Illinois
           Contact:   Y         ! Y or N (designate at most one contact)

          CoI_Name:   Sean Points
   CoI_Institution:   University of Illinois
           Contact:             ! Y or N (designate at most one contact)

          CoI_Name:   Dominik Bomans
   CoI_Institution:   Universitaet Bonn
           Contact:             ! Y or N (designate at most one contact)


Abstract:                                ! Free format text (please update)
    We request observing time with the GHRS on HST to help
    determine the structure and physical parameters of the hot
    gaseous halo of the Large Magellanic Cloud (LMC). The SMC and
    LMC are the only galaxies in which such a determination can be
    done in detail, as confusion along the line-of-sight is much
    less than in the Milky Way. They are also the only other
    galaxies near enough to be able to obtain high-resolution
    spectra of individual stars. Gas at 10^5 K can be detected in
    the C IV LambdaLambda1548, 1550 UV absorption lines. From such
    data it is also possible to obtain information on velocities
    and the depth structure of the halo. Previous work with IUE
    has shown that 10^5 K gas is present around very hot stars,
    in some H II regions, in superbubbles and in supergiant
    shells. However, with IUE it is not possible to determine the
    existence of a continuous halo surrounding the LMC, since the
    required probes are too faint. We request observing time for
    eight probes selected to take into account the distribution
    10^6 K gas mapped by ROSAT, while avoiding areas known to
    produce 10^5 K gas locally. We request a total of ten orbits
    and plan to use the G160M grating of GHRS, which allows us to
    reach a signal-to-noise ratio of 20 or higher. This
    corresponds to a detection limit for N(C IV) of 2x10^13  ,
    within the range of values detected in the Milky Way.

Questions                       ! Free format text (please update)

     Observing_Description:
         We plan to observe six stars in X-ray dim areas of the LMC,
         and two in X-ray bright areas. These targets have been
         selected avoid bright H Alpha emission and supergiant
         shells. For each target we intend to use the G160M grating
         over the wavelength range 1533-1566 Angstrom. Standard comb-
         addition and FP-split will be used to reduce the effects of
         fixed pattern noise. The spectra will be sampled with 2 sub-
         steps per diode (Step Pattern 4).   We will use the large
         aperture during our observations. The small loss of
         resolution relative to the use of the small aperture does not
         outweigh the loss of a factor two in light.   Exposure times
         are estimated using the description in the post-COSTAR HST
         GHRS Instrument Handbook (v5.0, May 1994). To determine the
         stellar fluxes, we constructed a table of unreddened flux
         ratios f(1550)/f(5500) for several different stellar types,
         and we determined the reddening for each target.   To
         determine flux ratios, we used IUE Newsletter No. 22, and
         measured reddened flux ratios for stars of spectral types
         between O9 and B1, of all luminosity classes. These values
         were dereddened using the value of E(B-V) given in the
         Newsletter and the UV extinction model described in the GHRS
         handbook (Seaton 1979, MNRAS 187, 73p). Since stars of
         spectral type B0 and especially B1 also have a broad stellar
         absorption, we used half of the continuum flux to obtain the
         flux ratios to make sure that we do not underestimate the
         flux at the wavelength of interest.   The reddening of each
         target was found by subtracting the intrinsic color given by
         Fitzgerald (1970, AA 4, 234) from the value of \bmv\ given by
         Rousseau et al. We used E(B-V)=0.12 for the one target with
         unknown color (Sk-70 69).   Given the flux ratio, reddening
         and visual magnitude, we find the flux at 1550 Angstrom. The
         table below gives the result. The count rate then follows
         from the sensitivities in the Handbook. Column 7 gives the
         resulting integration time to reach a S/N of 20, the minimum
         value we need to obtain results that can be unambiguously
         interpreted.   The acquisition overhead is substantial (12
         minutes for the guide star, 11 minutes for the target), and
         only 36 out of each 59 minutes in an orbit are available for
         the actual integration. In one orbit we can reach the desired
         S/N only for Sk-69 59 and Sk-69 110. For Sk-68 28 and Sk-67
         46, the missing time is only 4 and 6 minutes, and the
         resulting S/N of 19 will still be sufficient. For Sk-67 45
         and Sk-69 68 on the other hand, the noise increases by 25%.
         Scheduling three consecutive orbits, we can combine the two
         longest integrations with the third and fourth longest and we
         can achieve the desired S/N for all four stars in two groups
         of three consecutive orbits. We would then acquire one of the
         objects midway through the second orbit, and we would need
         two 6-minute re-acquisitions. The total acquisition overhead
         in the three orbits would be 2*(23+6) or 58 minutes, leaving
         118 minutes of integration time, just what we need. We
         therefore request one orbit each for four probes, and two
         combinations of three orbits for the other four probes, for a
         grand total of 10 orbits.   We note that the right ascension
         and declination of the LMC place it within the Continuous
         Viewing Zone (CVZ) of HST four times each year. We may use
         the CVZ to increase the efficiency of our program from 40% to
         91%. The sum of the required integration times is 363 minutes.
         The total required overhead for each star is 26 minutes (12 for
         guide-star acquisition, 11 for target acquisition, 3 for internal
         wavelength calibration) or a total of 208 minutes. Within the
         CVZ, the total required time of 571 minutes can fit in 6
         orbits.

         In the case that our program is scheduled during CVZ time,
         we can adjust the description of the observation accordingly.

          Name       & type &   V   &E(B-V)&  f_1550    &ct/s/d &T(20)&SN(36)
          (1)        & (2)  &  (3)  & (4)  &    (5)     &  (6)  &(7) &(8)
           Priority-1 probes
           Sk-67 46  & B1   & 12.34 & 0.12 & 3.5x10^-13 & 0.173 & 40 & 19
           Sk-67 76  & B0   & 12.42 & 0.17 & 3.1x10^-13 & 0.151 & 46 & 18
           Sk-69 59  & B0   & 12.13 & 0.18 & 3.8x10^-13 & 0.183 & 38 & 20
           Sk-69 110 & B1   & 11.65 & 0.18 & 4.3x10^-13 & 0.210 & 33 & 21
           Sk-70 96  & B1   & 12.67 & 0.12 & 3.1x10^-13 & 0.152 & 45 & 18
           Priority-2 probes (only if CVZ time scheduled)
           Sk-67 28  & B1   & 12.4  & 0.12 & 3.4x10^-13 & 0.164 & 42 & 19
           Sk-67 45  & B1   & 12.97 & 0.09 & 2.3x10^-13 & 0.112 & 62 & 15
           Sk-69 68  & B0.5 & 12.6  & 0.21 & 2.5x10^-13 & 0.122 & 57 & 16


   Real_Time_Justification:

Calibration_Justification:              ! Move appropriate text from Real_Time_Justification

      Additional_Comments:
         If scheduling permits we may increase the efficiency of our
         program from 40% to 64%.
         IUE observing time has been awarded to re-observe the three
         stars for which we found tentative non-detections. These
         stars have the following magnitudes and spectral types: 10.6
         (a composite spectrum of main type B2Ia), 11.2 (type O9Ib)
         and 12.4 (type O7Ib). The IUE proposal also includes the
         brightest two stars known that are not obviously connected
         with regions containing hot material. These are of magnitude
         11.5 (type B0) and 11.9 (type O9). For all five probes we
         calculated that at least two IUE shifts (16 hours) are needed
         to obtain a useful spectrum. A total of 10 US1 shifts in the
         18th episode were awarded to us.   Observing time has been
         awarded to start a ROSAT HRI survey of the LMC, with Chu as
         P.I. The HRI observations are more sensitive to point
         sources. The results will help the removal of point sources
         from the PSPC images, and improve the diffuse X-ray
         measurements.

Fixed_Targets                           ! Section 5.1
  Target_Number: 1
    Target_Name: Sk-67.46
Alternate_Names: GSC9161-00960
    Description: EXT-STAR, B0-B2 III-I, EXT-MEDIUM, Coronal Gas
! 3/29/95 - Added temporary RA and DEC uncertainties TO ALL 5 TARGETS; deleted Plate IDs
       Position: RA = 05H 07M 1.63S +/- 0.03S,
                 DEC = -67D 37' 29.7" +/- 0.2",
                 PLATE-ID = 06B0
        Equinox: J2000
        RV_or_Z:
          RA_PM:                        ! Units are seconds of time per year
         Dec_PM:                        ! Units are seconds of arc per year
          Epoch: 1979.193
Annual_Parallax:
           Flux: TYPE=B1I,  V=12.34,  B-V=-0.06, E(B-V)=0.12, F(1550)=3.5E-13
       Comments: Coordinates are from GSC


Fixed_Targets                           ! Section 5.1
  Target_Number: 2
    Target_Name: Sk-67.76
Alternate_Names: GSC8890-00822
    Description: EXT-STAR, B0-B2 III-I, EXT-MEDIUM, Coronal Gas
       Position: RA = 05H 20M 5.81S +/- 0.03S,
                 DEC = -67D 21' 8.9" +/- 0.2",
                 PLATE-ID = 06B0
        Equinox: J2000
        RV_or_Z:
          RA_PM:                        ! Units are seconds of time per year
         Dec_PM:                        ! Units are seconds of arc per year
          Epoch: 1979.193
Annual_Parallax:
           Flux: TYPE=B0I,  V=12.42,  B-V=-0.13,  E(B-V)=0.17,  F(1550)=3.1E-13
       Comments: Coordinates are from GSC


Fixed_Targets                           ! Section 5.1
  Target_Number: 3
    Target_Name: Sk-69.59
Alternate_Names: HDE268960,GSC9161-01130 
    Description: EXT-STAR, B0-B2 III-I, EXT-MEDIUM, Coronal Gas
       Position: RA = 05H 03M 12.79S +/- 0.04S,
                 DEC = -69D 01' 37.2" +/- 0.2",
                 PLATE-ID = 05ZW
        Equinox: J2000
        RV_or_Z:
          RA_PM:                        ! Units are seconds of time per year
         Dec_PM:                        ! Units are seconds of arc per year
          Epoch: 1987.064
Annual_Parallax:
           Flux: TYPE=B0I,  V=12.13,  B-V=-0.12,  E(B-V)=0.10,  F(1550)=6.8E-13
       Comments: Coordinates are from GSC


Fixed_Targets                           ! Section 5.1
  Target_Number: 4
    Target_Name: Sk-69.110
Alternate_Names: HDE269399, GSC9166-00238
    Description: EXT-STAR, B0-B2 III-I, EXT-MEDIUM, Coronal Gas
       Position: RA = 05H 20M 33.85S +/- 0.04S,
                 DEC = -69D 32' 35.5" +/- 0.2",
                 PLATE-ID = 05ZW
        Equinox: J2000
        RV_or_Z:
          RA_PM:                        ! Units are seconds of time per year
         Dec_PM:                        ! Units are seconds of arc per year
          Epoch: 1987.064
Annual_Parallax:
           Flux: TYPE=B1,  V=11.65,  B-V=0.08,  E(B-V)=0.16,  F(1550)=5.0E-13
       Comments: Coordinates are from GSC


Fixed_Targets                           ! Section 5.1
  Target_Number: 5
    Target_Name: Sk-70.96
Alternate_Names: GSC9166-00139
    Description: EXT-STAR, B0-B2 III-I, EXT-MEDIUM, Coronal Gas
       Position: RA = 05H 29M 23.90S +/- 0.04S,
                 DEC = -70D 14' 0.9" +/- 0.2",
                 PLATE-ID = 05ZW
        Equinox: J2000   
        RV_or_Z:
          RA_PM:                        ! Units are seconds of time per year
         Dec_PM:                        ! Units are seconds of arc per year
          Epoch: 1987.064
Annual_Parallax:
           Flux: TYPE=B1Ib,  V=12.67,  E(B-V)=0.10,  F(1550)=3.6E-13
       COMMENTS: Coordinates are from GSC

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! Sk-67.46
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Visits                                  ! Section 6
      Visit_Number: 1
Visit_Requirements:                     ! Section 7.1
        ! CVZ

     Exposure_Number: 1
         Target_Name: Sk-67.46
              Config: HRS
              Opmode: ACQ
            Aperture: 2.0
          Sp_Element: MIRROR-N2
          Wavelength: 
 Optional_Parameters: MAP=DEF, SEARCH-SIZE=3
Number_of_Iterations: 1
   Time_Per_Exposure: 1.8S
Special_Requirements: ONBOARD ACQ FOR 2
            Comments: STEP-TIME=0.2S

! template kept just in case we decide to change our minds
!     Exposure_Number: 2
!         Target_Name: WAVE
!              Config: HRS
!              Opmode: ACCUM
!            Aperture: SC2
!          Sp_Element: G160M
!          Wavelength: 1539
! Optional_Parameters: FP-SPLIT=STD, STEP-PATT=4
!Number_of_Iterations: 1
!   Time_Per_Exposure: DEF
!Special_Requirements:

     Exposure_Number: 2
         Target_Name: Sk-67.46
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G160M
          Wavelength: 1539
 Optional_Parameters: STEP-PATT=4, COMB=FOUR, FP-SPLIT=STD, DOPPLER=ON
Number_of_Iterations: 5
   Time_Per_Exposure: 403.2s
Special_Requirements:                   ! Section 7.2
            Comments: STEP-TIME=0.2S; Changes required if scheduled in CVZ


!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! Sk-67.76
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Visits                                  ! Section 6
      Visit_Number: 2
Visit_Requirements:                     ! Section 7.1
        ! CVZ

     Exposure_Number: 1
         Target_Name: Sk-67.76
              Config: HRS
              Opmode: ACQ
            Aperture: 2.0
          Sp_Element: MIRROR-N2
          Wavelength: 
 Optional_Parameters: MAP=DEF, SEARCH-SIZE=3
Number_of_Iterations: 1
   Time_Per_Exposure: 1.8S
Special_Requirements: ONBOARD ACQ FOR 2
            Comments: STEP-TIME=0.2S

! template kept just in case we decide to change our minds
!     Exposure_Number: 2
!         Target_Name: WAVE
!              Config: HRS
!              Opmode: ACCUM
!            Aperture: SC2
!          Sp_Element: G160M
!          Wavelength: 1539
! Optional_Parameters: FP-SPLIT=STD STEP-PATT=4
!Number_of_Iterations: 1
!   Time_Per_Exposure: DEF
!Special_Requirements:

     Exposure_Number: 2
         Target_Name: Sk-67.76
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G160M
          Wavelength: 1539
 Optional_Parameters: STEP-PATT=4, COMB=FOUR, FP-SPLIT=STD, DOPPLER=ON
Number_of_Iterations: 5
   Time_Per_Exposure: 403.2s
Special_Requirements:                   ! Section 7.2
            Comments: STEP-TIME=0.2S; Changes required if scheduled in CVZ


!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! Sk-69.59
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Visits                                  ! Section 6
      Visit_Number: 3
Visit_Requirements:                     ! Section 7.1
        ! CVZ

     Exposure_Number: 1
         Target_Name: Sk-69.59
              Config: HRS
              Opmode: ACQ
            Aperture: 2.0
          Sp_Element: MIRROR-N2
          Wavelength: 
 Optional_Parameters: MAP=DEF, SEARCH-SIZE=3
Number_of_Iterations: 1
   Time_Per_Exposure: 1.8S
Special_Requirements: ONBOARD ACQ FOR 2
            Comments: STEP-TIME=0.2S

! template kept just in case we decide to change our minds
!     Exposure_Number: 2
!         Target_Name: WAVE
!              Config: HRS
!              Opmode: ACCUM
!            Aperture: SC2
!          Sp_Element: G160M
!          Wavelength: 1539
! Optional_Parameters: FP-SPLIT=STD STEP-PATT=4
!Number_of_Iterations: 1
!   Time_Per_Exposure: DEF
!Special_Requirements:

     Exposure_Number: 2
         Target_Name: Sk-69.59
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G160M
          Wavelength: 1539
 Optional_Parameters: STEP-PATT=4, COMB=FOUR, FP-SPLIT=STD, DOPPLER=ON
Number_of_Iterations: 5
   Time_Per_Exposure: 403.2s
Special_Requirements:                   ! Section 7.2
            Comments: STEP-TIME=0.2S; Changes required if scheduled in CVZ


!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! Sk-69.110
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Visits                                  ! Section 6
      Visit_Number: 4
Visit_Requirements:                     ! Section 7.1
        ! CVZ

     Exposure_Number: 1
         Target_Name: Sk-69.110
              Config: HRS
              Opmode: ACQ
            Aperture: 2.0
          Sp_Element: MIRROR-N2
          Wavelength: 
 Optional_Parameters: MAP=DEF, SEARCH-SIZE=3
Number_of_Iterations: 1
   Time_Per_Exposure: 1.8S
Special_Requirements: ONBOARD ACQ FOR 2
            Comments: STEP-TIME=0.2S

! template kept just in case we decide to change our minds
!     Exposure_Number: 2
!         Target_Name: WAVE
!              Config: HRS
!              Opmode: ACCUM
!            Aperture: SC2
!          Sp_Element: G160M
!          Wavelength: 1539
! Optional_Parameters: FP-SPLIT=STD STEP-PATT=4
!Number_of_Iterations: 1
!   Time_Per_Exposure: DEF
!Special_Requirements:

     Exposure_Number: 2
         Target_Name: Sk-69.110
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G160M
          Wavelength: 1539
 Optional_Parameters: STEP-PATT=4, COMB=FOUR, FP-SPLIT=STD, DOPPLER=ON
Number_of_Iterations: 5
   Time_Per_Exposure: 403.2s
Special_Requirements:                   ! Section 7.2
            Comments: STEP-TIME=0.2S; Changes required if scheduled in CVZ


!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! Sk-70.96
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Visits                                  ! Section 6
      Visit_Number: 5
Visit_Requirements:                     ! Section 7.1
        ! CVZ

     Exposure_Number: 1
         Target_Name: Sk-70.96
              Config: HRS
              Opmode: ACQ
            Aperture: 2.0
          Sp_Element: MIRROR-N2
          Wavelength: 
 Optional_Parameters: MAP=DEF, SEARCH-SIZE=3
Number_of_Iterations: 1
   Time_Per_Exposure: 1.8S
Special_Requirements: ONBOARD ACQ FOR 2
            Comments: STEP-TIME=0.2S

! template kept just in case we decide to change our minds
!     Exposure_Number: 2
!         Target_Name: WAVE
!              Config: HRS
!              Opmode: ACCUM
!            Aperture: SC2
!          Sp_Element: G160M
!          Wavelength: 1539
! Optional_Parameters: FP-SPLIT=STD STEP-PATT=4
!Number_of_Iterations: 1
!   Time_Per_Exposure: DEF
!Special_Requirements:

     Exposure_Number: 2
         Target_Name: Sk-70.96
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G160M
          Wavelength: 1539
 Optional_Parameters: STEP-PATT=4, COMB=FOUR, FP-SPLIT=STD, DOPPLER=ON
Number_of_Iterations: 5
   Time_Per_Exposure: 403.2s
Special_Requirements:                   ! Section 7.2
            Comments: STEP-TIME=0.2S; Changes required if scheduled in CVZ


Data_Distribution                       ! Defaults indicated; change if desired

         Medium:        8MM             ! 8MM or 6250BPI or 1600BPI
Blocking_Factor:        10              ! 10 or 1
                                        ! Only astronomers with very old 9-
                                        ! track tape drives should consider
                                        ! a blocking factor of 1

        Ship_To:        Dr. Bart Wakker
			University of Wisconsin
			Astronomy Department! STSCI or PI_Address or <free-text>
                        475 N Charter St    ! PI Address from Phase I is:
                        WI 53706            !
                                        !
                                        !
       Ship_Via:        UPS             ! UPS (2-day) or OVERNIGHT
                                        ! Overnight shipping done at PI expense

Recipient_Email:                        ! Needed if Ship_To: is not PI_Address
                                        ! <free-text>

! Let us know what you think of this template and software!
! Please send a list of your likes and dislikes to your Program Coordinator