Proposal_Information ! Section 4 Title: Excitation Mechanisms and Abundances in the O-rich SNR E0102.2--7219 in the SMC Proposal_Category: GO Scientific_Category: Interstellar Medium Cycle: 5 Investigators PI_name: Jon A. Morse PI_Institution: Space Telescope Science Institute CoI_Name: Michael A. Dopita CoI_Institution: Mt. Stromlo & Siding Spring Obs. Contact: ! Y or N (designate at most one contact) CoI_Name: William P. Blair CoI_Institution: Johns Hopkins University Contact: ! Y or N (designate at most one contact) CoI_Name: John C. Raymond CoI_Institution: Harvard-Smithsonian CfA Contact: ! Y or N (designate at most one contact) CoI_Name: John P. Hughes CoI_Institution: Harvard-Smithsonian CfA Contact: ! Y or N (designate at most one contact) CoI_Name: Robert P. Kirshner CoI_Institution: Harvard University Contact: ! Y or N (designate at most one contact) CoI_Name: Knox S. Long CoI_Institution: Space Telscope Science Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Ralph Sutherland CoI_Institution: Univ. of Colorado -- Boulder / JILA Contact: ! Y or N (designate at most one contact) CoI_Name: P. Frank Winkler CoI_Institution: Middlebury College Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) 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. Questions ! Free format text (please update) Observing_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: ! Move appropriate text from Real_Time_Justification Additional_Comments: Please ensure that WFPC-2 EARLY/ACQ imaging is scheduled well in advance of FOS spectroscopy. Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: E0102-7219 Alternate_Names: Description: ISM, SNR Position: RA=01H04M01.50S +/- 0.1S, DEC=-72D01'55.7" +/- 1", PLATE-ID=015Q Equinox: 2000 RV_or_Z: V=+200 Flux: SURF(V)=25.3 +/- 1, SURF-LINE(5007)=3+/-1 E-15 Comments: Target_Number: 2 Target_Name: E0102-OFFSET Alternate_Names: Description: STAR Position: RA=01H04M00.96S +/- 0.05S, DEC=-72D01'57.2" +/- 0.3", ! PLATE-ID=015Q Equinox: 2000 Flux: V=18.35+/-0.2 Comments: WFPC2 coords using METRIC, V_mag from F547M exposure. Target_Number: 3 Target_Name: E0102-POS1 Alternate_Names: Description: ISM, SNR, KNOT Position: R=6.31", PA=175.32D, FROM 2 Equinox: 2000 RV_or_Z: V=+200 Flux: SURF(V)=25.3 +/- 1, SURF-LINE(5007)=3+/-1 E-15 Comments: Knot selection from WFPC2 F502N image. ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ORIENT 150D TO 240D ! Section 7.1 Visit_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. Exposure_Number: 1 ! Section 6.5 Target_Name: E0102-7219 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F547M Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 900S Special_Requirements: ! Section 7.2 Exposure_Number: 2 ! Section 6.5 Target_Name: E0102-7219 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F502N Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1400S Special_Requirements: EXPAND ! Section 7.2 Exposure_Number: 3 ! Section 6.5 Target_Name: E0102-7219 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F502N Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2800S Special_Requirements: ! Section 7.2 Exposure_Number: 4 ! Section 6.5 Target_Name: E0102-7219 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F502N Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2800S Special_Requirements: ! Section 7.2 Visit_Number: 2 Visit_Requirements: ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN