! Proposal 6516, submission 1
! PI: Brian Schmidt
! Received Sat Feb 10 07:52:05 EST 1996
! From: brian@merlin.anu.edu.au
!  +====================+
!  | PED OUTPUT PRODUCT |
!  +====================+
!
!  /priv/magician5/brian/proposals/HST/91T/phase2/6516.prop
!  Generated by PREPROCESSOR, version 6.0e
!  Date: Thu Feb  8 12:01:35 EST 1996

Proposal_Information
              Title: SN 1991T: Reflections of Past Glory
  Proposal_Category: GO
Scientific_Category: Interstellar Medium
              Cycle: 6


Investigators

            PI_Name: Brian Schmidt
     PI_Institution: Mount Stromlo and Siding Spring Observatories


           CoI_Name: Peter Garnavich
    CoI_Institution: Harvard
            Contact: N


Abstract:
We propose to image SN~1991T (host galaxy, NGC 4527) with the FOC to
resolve a light echo inferred from ground based measurements. These
observations will conclusively demonstrate  (or repudiate)
the presence of a light echo around SN~1991T. If demonstrated, measurements
of the light echo's size and shape will enable us to map out the position and
structure of dust in NGC~4527's disk, and combined with ground based velocity
measurements, gain  unique insight into the kinematics of the disk of a spiral
galaxy other than the Milky Way. The light echo observations will also be
helpful for determining the scale height of the SNe~Ia population ---
a useful tool for understanding their progenitors. If a light echo
is not seen, strong constraints as to the nature of SNe Ia explosions
and their progenitors would be gained.


Questions


    Observing_Description:
We propose to image the area around SN~1991T using the FOC with the F430W
filter. Ground observations have demonstrated that the light echo is quite
bright, mB=21, peaks in flux at about 400nm, and has an apparent size less
than 1 arcsec. A 1 orbit exposure approx 2200s should supply
sufficient signal so as to determine the size and morphology of the ring,
regardless of its size. The light echo has a precise position measured, and
should be easily  acquired within the 7 arcsec field of the FOC.
One problem is that there will not be any bright stars in the field to
determine the PSF (there may be some very faint stars in NGC 4527 which we
resolve). Will use FOC images taken near the time of our observations to get
a good estimate of the PSF.

  Real_Time_Justification:
None

Calibration_Justification:
Internal Flat during occultation time would be useful to accurately measure
the geometric distortion in the FOC as suggested in "Status Update
for Science Instruments: Faint Object Camera"

      Additional_Comments:



Fixed_Targets

  Target_Number: 1
    Target_Name: NGC4527-SN1991T
Alternate_Names: NGC4527-123137+025628
    Description: EXT-STAR,SUPERNOVA TYPE IA,GALAXY,SPIRAL
       Position: RA=12H 31M 36.89S +/- 0.3",DEC=2D 56' 28.7" +/- 0.3"
        Equinox: B1950
        RV_or_Z: 
          RA_PM: 
         Dec_PM: 
          Epoch: 
Annual_Parallax: 
           Flux: 
                V = 21.4+/-0.3
                B-V = 0.0+/-0.3
       Comments: The source is extended by an unknown amount - it is less than
0.8" in diameter.


Solar_System_Targets


Generic_Targets


Scan_Data


Visits

      Visit_Number: 01
Visit_Requirements: 
  On_Hold_Comments: 
    Visit_Comments: 

     Exposure_Number: 1
         Target_Name: NGC4527-SN1991T
              Config: FOC/96
              Opmode: IMAGE
            Aperture: 512X512
          Sp_Element: F430W
          Wavelength: 
 Optional_Parameters: 
Number_of_Iterations: 1
   Time_Per_Exposure: 2563S
Special_Requirements: 
            Comments: 

Data_Distribution         ! Defaults indicated; change if desired

         Medium: 8MM
Blocking_Factor: 10
        Ship_To: PI_Address
       Ship_Via: UPS
Recipient_Email: 

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