6052( 17) - 03/21/96 15:46  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      6052
                                                       Version: 17
                                                       Check-in Date: 21-Mar-1996
                                                                      15:43:51

1.Proposal Title:
Excitation Mechanisms and Abundances in the O-rich SNR E0102.2--7219 in the SMC
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2. Scientific Category   3. Proposal For  4. Cycle
Interstellar Medium         GO               5
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5. Investigators
                                                                                     Contact?
    PI: Jon A. Morse                      Space Telescope Science Institute
   CoI: Michael A. Dopita                 Mt. Stromlo & Siding Spring Obs.              N
   CoI: William P. Blair                  Johns Hopkins University                      N
   CoI: John C. Raymond                   Harvard-Smithsonian CfA                       N
   CoI: John P. Hughes                    Harvard-Smithsonian CfA                       N
   CoI: Robert P. Kirshner                Harvard University                            N
   CoI: Knox S. Long                      Space Telscope Science Institute              N
   CoI: Ralph Sutherland                  Univ. of Colorado -- Boulder / JILA           N
   CoI: P. Frank Winkler                  Middlebury College                            N

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6. Abstract

We propose to obtain WFPC2 images and FOS spectra of the young, oxygen-rich
supernova remnant E0102.2--7219 in the Small Magellanic Cloud. The images will be
used to study the fine-scale spatial and ionization structures within the knotty
filaments, and also provide EARLY ACQ exposures for the spectroscopy. The FOS
spectra will provide relative intensities of UV and optical emission lines in
isolated knots. Only HST has the resolving power necessary to study individual knots
in the remnant. We will compare the observed line ratios to predictions made by
theoretical models in order to determine the excitation mechanisms and to derive
reliable elemental abundances. E0102.2--7219 is one of only two O-rich supernova
remnants that can be studied effectively at UV wavelengths, and the HST data will
provide important tests for theories of nucleosynthesis in massive stars as well as
improve our understanding of the dynamics of supernova explosions and mixing in the
ejecta. We will compare these data to our HST Cycle 4 observations of N132D in the
LMC to investigate differences between these SNRs apparent in the IUE spectra.
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                                                6052( 17) - 03/21/96 15:46  - [  2]

  Observations Description
  ------------------------

     WFPC2 Imaging: We request WFPC2 F502N (O IIILambda5007), F375N (O IILambda3727)
     and F547M (continuum) exposures of E0102 with the Wide Field Camera (WFC) to
     study small scale spatial and ionization structure in the O-rich filaments.
     Achieving 0.''1 resolution in E0102 will resolve structure similar to a 2''
     ground-based image of Cas A, sufficient to identify excitation variations in
     individual filaments. The WFPC2 images will also be used as EARLY ACQ exposures
     to verify that the filaments selected for spectroscopy are appropriate and to
     set up the FOS blind offset acquisitions. The total velocity range in E0102 is
     larger than the F502N and F375N filter widths, so we will concentrate on those
     filaments in the SE rim (see Fig. 1) that the velocity maps of Tuohy & Dopita
     (1983) show will be included in the bandpasses. The SE rim is also where we
     placed the IUE aperture. To estimate the expected count rates, we used the
     formula N_el = 2.28 * 10^12,Lambda T_max F, where N_el is the number of
     electrons detected per second, T_max is the throughput at the wavelength Lambda
     (in Angstrom) from the WFPC2 handbook, and F is the observed integrated line
     flux (in ergs cm^-2 s^-1) per unit area on the sky being considered. Table 2
     gives N_el per 0.''1 WFC pixel using the fluxes of Blair Etal\\ (1989) and
     assuming an enhancement of the count rate in the filaments by a factor of 3 due
     to the clumpiness of the emission. centerline
     figure=tab2.ps,height=1.9in,width= A 1000 s continuum image through the broader
     F547M filter will be sufficient to distinguish stars from ``stellar-appearing"
     emission knots. We thus request a total of 6 orbits (including acquisition and
     instrument overheads) for the WFPC2 imaging: 1.5 orbits for F502N, 0.5 orbits
     for F547M, and 4 orbits for F375N. FOS Spectroscopy: The large body of optical
     and IUE data for E0102 that we have published can be used to estimate the
     feasibility of HST observations. The UV/optical line fluxes listed in Blair
     Etal\\ (1989) are integrated over roughly a 100 arcsec^2 region in the SE rim
     of E0102. We will obtain spectra at two positions in the SE rim since our
     optical spectra show that significant variations in the excitation exist over
     scales sampled by the large IUE aperture (Dopita & Tuohy 1984). Although the
     total velocity range in E0102 is large, the velocity dispersion within
     individual knots is small enough that the total flux from each emission line
     will fall within ~ 1 diode. Table 3 lists emission-line flux estimates for
     observations made through the FOS 0.''9 circular aperture. Using the formula
     for monochromatic fluxes from Table 1.2.1 of the Version 5.0 FOS handbook and
     the integration times shown, one obtains the total counts per diode listed in
     the last column. These are conservative estimates because the peak surface
     brightness in individual knots will be several times higher than the average
     over the IUE aperture that the fluxes listed represent. Note that the O I
     (Lambda1356/Lambda7774) line ratio has a theoretical value of 5.9, and will
     provide an excellent baseline for reddening corrections. centerline
     figure=tab3.ps,height=4.5in,width= From the WFPC2 EARLY ACQ images, we will use
     Binary Search mode for acquiring an offset star and then perform blind offsets
     to the two knot positions. Each position will require 6 orbits (including
     acquisition and instrument overheads) for a total FOS program of 12 orbits.

  Real Time Justification
  -----------------------

     We have computed the required number of orbits for our observing program
     assuming the normal visibility of 59 minutes per orbit. However, there are two
     CVZ opportunities for the RA and Dec of our target during Cycle 5, though
     totaling only ~ 50 hours. Assuming two windows of 25 hours each (~ 16 CVZ
     orbits) separated by several months, we could accomplish our WFPC2 imaging
     during the first CVZ opportunity and our FOS spectroscopy during the second.
     With the ~ 50\\ increased viewing time, our WFPC2 images could be obtained in 4
     CVZ orbits and our FOS spectra in 8 CVZ orbits, for a total of 12 CVZ orbits
     instead of 18 normal viewing orbits. We have worked hard with IUE to obtain the
     existing UV data on E0102. The spectra shown in Fig. 3 involved lengthy double
     -shift IUE exposures, but IUE simply cannot resolve individual filaments.
     Hence, blending of material with different physical conditions and abundances
     hampers an accurate comparison with models. We have optical observations (CCD
     images in a number of optical lines, and spectra) as well as the most recent
     ROSAT and ASCA data. Collectively, these data will provide important additional
     support for and comparison with the HST data.

  Calibration Justification
  -------------------------


  Additional Comments
  -------------------

     Please ensure that WFPC-2 EARLY/ACQ imaging is scheduled well in advance of FOS
     spectroscopy.
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                                                6052( 17) - 03/21/96 15:46  - [  3]

  Data Distribution

  Media:           8MM
  Blocking Factor: 10
  Ship To:         Dr. Jon Morse*CASA*University of
                   Colorado*Campus Box 389*Boulder, CO
                   80309
  Ship Via:        UPS
  Email:                                                              ,
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                                                6052( 17) - 03/21/96 15:46  - [  4]

TARGET LIST    a) Fixed Targets
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Tar|   Target   |         Target        |            Target              |Coord   | Radial |             Flux data
No |    Name    |       Description     |           Position             |Eqnx    |  Vel.  |
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1   E0102-7219   ISM, SNR                RA=01H04M01.50S +/- 0.1S, DEC=-  2000     V=+200   SURF(V) = 25.3+/-1
                                         72D01'55.7" +/- 1", PLATE-                         SURF-LINE(5007)=3+/-1e-15
                                         ID=015Q

2   E0102-OFFSET STAR                    RA=01H04M00.96S +/- 0.05S, DEC=- 2000              V = 18.35+/-0.2
                                         72D01'57.2" +/- 0.3"
    Comments: WFPC2 coords using METRIC, V_mag from F547M exposure.

3   E0102-POS1   ISM, SNR, KNOT          R=6.31", PA=175.32D, FROM 2      2000     V=+200   SURF(V) = 25.3+/-1
                                                                                            SURF-LINE(5007)=3+/-1e-15
    Comments: Knot selection from WFPC2 F502N image.

                                                6052( 17) - 03/21/96 15:46  - [  5]

Visit: 01
     Visit Requirements:  ORIENT 150D TO 240D
     On Hold Comments:    <none>
     Additional Comments: EARLY ACQ images to identify target for FOS spectroscopy. Best ORIENT is
                          210D. Try to schedule as early as possible. Put target in middle of PC1 and
                          orient so that at WF chips cover regions N and E of target.


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        E0102-7219  WFPC2  IMAGE   PC1-FIX F547M                            1   900S
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2        E0102-7219  WFPC2  IMAGE   PC1-FIX F502N            CR-SPLIT=NO     1   1400S   EXPAND
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3        E0102-7219  WFPC2  IMAGE   PC1-FIX F502N                            1   2800S
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4        E0102-7219  WFPC2  IMAGE   PC1-FIX F502N                            1   2800S
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                                                6052( 17) - 03/21/96 15:46  - [  6]

Visit: 02
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: Acquire offset star with 2x6 ACQ/PEAK (1.0), then ACQ/BIN (4.3) and
                          ACQ/PEAK (0.3), offset to SNR knot, and run through exposures.


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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101      E0102-      FOS/RD ACQ/PEA 4.3     MIRROR           SEARCH-SIZE-    1   15S     ONBOARD ACQ FOR 102
         OFFSET             K                                X=2,SEARCH-SIZE
                                                             -Y=6,SCAN-STEP-
                                                             X=3.3,SCAN-STEP
                                                             -Y=1.23
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102      E0102-      FOS/RD ACQ/BIN 4.3     MIRROR           FAINT=330       1   100S    ONBOARD ACQ FOR 103
         OFFSET             ARY
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103      E0102-      FOS/RD ACQ/PEA 0.25-   MIRROR           SEARCH-SIZE-    1   25S     ONBOARD ACQ FOR 104-108
         OFFSET             K       PAIR-A                   X=4,SEARCH-SIZE
                                                             -Y=4,SCAN-STEP-
                                                             X=.172,SCAN-
                                                             STEP-Y=.172
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104      E0102-POS1  FOS/RD ACCUM   1.0-    G780H            STEP-           1   2400S   NO SPLIT
                                    PAIR-A                   PATT=SINGLE
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105      E0102-POS1  FOS/RD ACCUM   1.0-    G570H            STEP-           1   1200S   NO SPLIT
                                    PAIR-A                   PATT=SINGLE
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106      E0102-POS1  FOS/RD ACCUM   1.0-    G400H            STEP-           1   1250S   NO SPLIT
                                    PAIR-A                   PATT=SINGLE
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107      E0102-POS1  FOS/RD ACCUM   1.0-    G270H            STEP-           1   2600S   NO SPLIT
                                    PAIR-A                   PATT=SINGLE
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108      E0102-POS1  FOS/BL ACCUM   1.0-    G160L            STEP-           1   7600S
                                    PAIR-A                   PATT=SINGLE
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                                                6052( 17) - 03/21/96 15:46  - [  7]

            Summary Form for Proposal  6052

  Item                         Used in this proposal
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  Configurations               WFPC2 FOS/RD FOS/BL
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  Opmodes                      IMAGE ACQ/PEAK ACQ/BINARY ACCUM
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  Optional Parameters          CR-SPLIT=NO SCAN-STEP-Y=1.23 FAINT=330 SCAN-STEP-Y=.172 STEP-PATT=SINGLE
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  Proposal Category            GO
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  Scientific Category          Interstellar Medium
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  Special Requirements         ORIENT 150D TO 240D EXPAND ONBOARD ACQ FOR 102 ONBOARD ACQ FOR 103 ONBOARD ACQ FOR 104-108 NO SPLIT
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  Spectral Elements            F547M F502N MIRROR G780H G570H G400H G270H G160L
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  Target Names                 E0102-7219 E0102-OFFSET E0102-POS1
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