9080( 3) - 03/25/02 08:13 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9080 Version: 3 Check-in Date: 25-Mar-2002 08:12:25 1.Proposal Title: Transition from Non-radiative to Radiative Shocks in the Cygnus Loop ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: William Blair The Johns Hopkins University CoI: Dr. Ravi Sankrit The Johns Hopkins University N CoI: Dr. John C. Raymond Smithsonian Astrophysical Observatory N ------------------------------------------------------------------------------------ 5. Abstract We request WFPC2 narrow band HAlpha and O III imaging of faint filaments in the northeastern Cygnus Loop that represent the location of the primary shock front as it first encounters the ISM. The primary character of these filaments is non- radiative, but certain filaments are poised at the onset of becoming radiative, providing a unique laboratory for testing shock model predictions of the development and evolution of astrophysical shock waves. We also request a STIS/MAMA far-UV spectrum cutting across one of the transition filaments that has a clean geometry (selected from the requested imagery) to study the physical scale over which the strong far-UV resonance lines of N V, C IV and He II ramp up in the post- shock flow. Reobservation of a set of HAlpha filaments first observed with HST/WFPC2 in 1997 will permit an accurate proper motion measurement which, in conjunction with existing ground- based measurements, will permit us to assess directly whether the filament has decelerated over the last 50 years. ------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 2] Observations Description ------------------------ The WFPC2 imagery we request can best be summarized as shown in Figure 2 of the Phase I proposal. F656N and F502N exposures for each of the two fields indicated will sample two regions with the best examples of transition-to- radiative filaments. Inspection of these images will allow us to understand the detailed geometry and study the widths and positions of the O III and HAlpha filaments, as well as to select the best region for the crosscut with STIS/MAMA and the G140L grating. Our cycle 7 program data provide a measure of `ground truth' to our exposure requests. The filament surface brightnesses in regions 1 and 2 are comparable, and as Hester et al (1994) show, the peak HAlpha and O III surface brightnesses are roughly the same. (Note added, Ph II, 2/15/01; the field orientation for imaging will be roughly 180 degrees different than shown in Figure 1. This is because we need to get the images in fall 2001 to support STIS spectra in spring 2002 when the orientation is correct. See details below.) Our cycle 7 3-orbit F656N exposure (7600 s), shown in Figure 1 of the Phase I proposal, shows peak counts of about 40 per pixel above the background in the WF chips. While this is none too luxurious, it is certainly sufficient for the task (and makes a marvelous picture). Since the WFPC2 QE at 5000 Angstroms is only about half that at 6500 Angstroms, we need twice the time to reach a comparable result, or 6 orbits. Hence, 9 orbits are required each for regions 1 and 2. Our cycle 7 STIS data also provide ground truth for the spectral data requested here. A 3-orbit crosscut of one of the non-radiative filaments in region 1 with the same set up requested here provided rather low (but adequate) S/N data on the spatial distributions of N V, C IV, and He II at the 0.1" level (see Figures 4 and 5 of the Phase I proposal). The somewhat higher expected UV line fluxes for the `transition-to-radiative' filaments combined with a 4-orbit integration should provide an excellent data set with which to pursue the spatial variations of different emission lines. Our total orbit request is thus 22 orbits. Scheduling at the time when the FOV orientation is approximately as shown in Figure 2 of the Phase I proposal is requested to maximize the field coverage of the filaments of interest and to approximately align the filaments along the CCD rows/columns. However, flexibility at the ~15degrees level is allowable for scheduling, which is not stringent. In Figure 1, for instance, the filaments are not strictly aligned along rows and columns, but the result is acceptable. Notes added in Phase II, Feb. 2001; Visits 1-8 are for the imaging part of the program. We have selected an ORIENT for this visit that provides as much scheduling flexibility as possible while keeping the timing right so the data can be analyzed and revised Phase II information entered to support visit 2. THE EXACT POSITION AND ORIENTATION FOR VISIT 10 IS DEPENDENT ON INSPECTION OF DATA FROM VISITS 1-8. The ORIENT for Visit 1-4 provides a scheduling window from early October though mid November. The ORIENT for Visits 5-8 provides a window from late September through mid-November. The orientation of the STIS long slit will be approximately correct in the May timeframe, so the timing should be manageable within the constraints of Cycle 10. A revised Phase II for visit 10 will have to be submitted after visits 1-8 are complete, but enough is known now to enter placeholder observations for visit 10 in this version of the Phase II. Note also that a placeholder offset star has been included as target 3. This star was used for earlier STIS offset acq work. However, the choice of best offset star will have to be revisited when the actual STIS slit position is selected from inspection of the Visit 1-8 WFPC2 image data. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- Additional Phase II sumission comments from Feb. 2001-- Per Web page instructions about keeping visits short, we have broken out what we consider to a a single `visit' to field 1 and a single `visit' to field 2 into 4 visits each. (1-3 orbit visit for F656N plus 3-2 orbit visits for the F502N images, for each field). However, we maintain 1-4 orbit STIS/MAMA visit for the spectra because it is important to the science to get these data all in one chunk. Positions--the position for field 1 is exactly the same coordinate, aperture choice, and POS targ combination that was used in our Cy7 proposal for this field. We want to duplicate that field position as close as reasonably possible. For field 2, the strategy is somewhat different. We specify the position for the WFALL-FIX aperture and then use much smaller POS TARG offsets. In both cases, since multiple orbits are being expended per filter, the POS TARGs are used to make small (10 pixels or 1 arcsec each in X and Y) offsets, which enhances the flatness of the background in the final coadded images. ------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 CYGLOOP- ISM, SNR RA=20H 56M 2.7S +/- 0.1S, J2000 SURF-LINE(6563)=6.2+/-0.5e-16 NENR1 DEC=31D 56' 39.2" +/- 2.0", PLATE-ID=01ZM Coordinate Source: HST_IMAGE Comments: Position for WFPC2 Field 1 F656N and F502N images. Long, narrow SNR filament. 2 CYGLOOP- ISM, SNR RA=20H 55M 48.53S +/- 0.1S, J2000 SURF-LINE(6563)=6.2+/-0.5e-16 NENR2 DEC=31D 59' 14.7" +/- 2.0", PLATE-ID=01ZM Coordinate Source: IMAGE_TIED_TO_GSC_FRAME Comments: Position for WFPC2 Field 2 F656N and F502N images. Long, narrow SNR filament. 3 CYGLOOP-NENR STAR, A4-A9 V-IV RA=20H 55M 48.82S +/- 0.05S, J2000 V = 13.1+/-0.4 -OFFSET1 DEC=31D 57' 21.3" +/- 0.2", PLATE-ID=01ZM Coordinate Source: HST_IMAGE Comments: Acquisition star, to be used prior to offsetting to SNR spectral position. Selected from DSS to be nearest HST Guide Star to the desired position. GSCID=026923341. Spectral type is only a guesstimate. 4 CYGLOOP- ISM, SNR RA=20H 55M 46.40S +/- 0.02S, J2000 SURF-LINE(6563)=6.2+/-0.5e-16 NENRS DEC=31D 58' 53.8" +/- 0.2" Coordinate Source: OTHER_SOURCE Comments: Position for STIS Spectral crosscut of supernova remnant filament selected from WFPC2 EARLY ACQ images. This position was selected after inspection of the WFPC2 data from visits 1-8. 9080( 3) - 03/25/02 08:13 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 70D TO 80D On Hold Comments: Additional Comments: WFPC2 EARLY ACQ for 21-23. The SNR filaments are nearly linear on the sky, with PA= -45 to -50 degrees (SE to NW). The intent is to roughly align the filament along the rows or columns of the WFC CCDs across any two chips. Exact orientation is not crucial, and is modulo 90 degrees. The ORIENT above places filament along the y-direction of the WF2-3 chips (+U3 pointing roughly east) and corresponds to a window from late Sept. to mid-Nov. (approximately). This leaves time to analyze images and finalize information for visit 10 (STIS), which will occur the following May. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 CYGLOOP-NEN WFPC2 IMAGE WF3-FIX F656N 6564 1 2200 S POS TARG 0, 15 R1 ------------------------------------------------------------------------------------------------------------------------------------ 2 CYGLOOP-NEN WFPC2 IMAGE WF3-FIX F656N 6564 1 2600 S POS TARG -1, 14 R1 Comments: Slightly different POS TARG is intentional. ------------------------------------------------------------------------------------------------------------------------------------ 3 CYGLOOP-NEN WFPC2 IMAGE WF3-FIX F656N 6564 1 2600 S POS TARG -2, 13 R1 Comments: Slightly different POS TARG is intentional. ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 5] Visit: 02 Visit Priority: Visit Requirements: ORIENT 70D TO 80D; SAME ORIENT AS 1 On Hold Comments: Additional Comments: WFPC2 EARLY ACQ for 21-23. The SNR filaments are nearly linear on the sky, with PA= -45 to -50 degrees (SE to NW). The intent is to roughly align the filament along the rows or columns of the WFC CCDs across any two chips. Exact orientation is not crucial, and is modulo 90 degrees. The ORIENT above places filament along the y-direction of the WF2-3 chips (+U3 pointing roughly east) and corresponds to a window from late Sept. to mid-Nov. (approximately). This leaves time to analyze images and finalize information for visit 10 (STIS), which will occur the following May. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 4 CYGLOOP-NEN WFPC2 IMAGE WF3-FIX F502N 5010 2 2600 S POS TARG 0, 15 R1 ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 6] Visit: 03 Visit Priority: Visit Requirements: ORIENT 70D TO 80D; SAME ORIENT AS 1 On Hold Comments: Additional Comments: WFPC2 EARLY ACQ for 21-23. The SNR filaments are nearly linear on the sky, with PA= -45 to -50 degrees (SE to NW). The intent is to roughly align the filament along the rows or columns of the WFC CCDs across any two chips. Exact orientation is not crucial, and is modulo 90 degrees. The ORIENT above places filament along the y-direction of the WF2-3 chips (+U3 pointing roughly east) and corresponds to a window from late Sept. to mid-Nov. (approximately). This leaves time to analyze images and finalize information for visit 10 (STIS), which will occur the following May. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 5 CYGLOOP-NEN WFPC2 IMAGE WF3-FIX F502N 5010 2 2600 S POS TARG -1, 14 R1 Comments: Slightly different POS TARG is intentional. ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 7] Visit: 04 Visit Priority: Visit Requirements: ORIENT 70D TO 80D; SAME ORIENT AS 1 On Hold Comments: Additional Comments: WFPC2 EARLY ACQ for 21-23. The SNR filaments are nearly linear on the sky, with PA= -45 to -50 degrees (SE to NW). The intent is to roughly align the filament along the rows or columns of the WFC CCDs across any two chips. Exact orientation is not crucial, and is modulo 90 degrees. The ORIENT above places filament along the y-direction of the WF2-3 chips (+U3 pointing roughly east) and corresponds to a window from late Sept. to mid-Nov. (approximately). This leaves time to analyze images and finalize information for visit 10 (STIS), which will occur the following May. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 6 CYGLOOP-NEN WFPC2 IMAGE WF3-FIX F502N 5010 2 2600 S POS TARG -2, 13 R1 Comments: Slightly different POS TARG is intentional. ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 8] Visit: 05 Visit Priority: Visit Requirements: ORIENT 80D TO 100D On Hold Comments: Additional Comments: WFPC2 EARLY ACQ for 21-23. The SNR filaments are nearly linear on the sky, with PA= -45 to -50 degrees (SE to NW). The intent is to roughly align the filament along the rows or columns of the WFC CCDs across any two chips. Exact orientation is not crucial, and is modulo 90 degrees. The ORIENT above places filament along the y-direction of the WF2-3 chips (+U3 pointing roughly east) and corresponds to a window from late Sept. to mid-Nov. (approximately). This leaves time to analyze images and finalize information for visit 10 (STIS), which will occur the following May. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 CYGLOOP-NEN WFPC2 IMAGE WFALL-F F656N 6564 1 2200 S R2 IX ------------------------------------------------------------------------------------------------------------------------------------ 11 CYGLOOP-NEN WFPC2 IMAGE WFALL-F F656N 6564 1 2600 S POS TARG -1,-1 R2 IX Comments: Slightly different POS TARG is intentional. ------------------------------------------------------------------------------------------------------------------------------------ 12 CYGLOOP-NEN WFPC2 IMAGE WFALL-F F656N 6564 1 2600 S POS TARG -2,-2 R2 IX Comments: Slightly different POS TARG is intentional. ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 9] Visit: 06 Visit Priority: Visit Requirements: ORIENT 80D TO 100D; SAME ORIENT AS 5 On Hold Comments: Additional Comments: WFPC2 EARLY ACQ for 21-23. The SNR filaments are nearly linear on the sky, with PA= -45 to -50 degrees (SE to NW). The intent is to roughly align the filament along the rows or columns of the WFC CCDs across any two chips. Exact orientation is not crucial, and is modulo 90 degrees. The ORIENT above places filament along the y-direction of the WF2-3 chips (+U3 pointing roughly east) and corresponds to a window from late Sept. to mid-Nov. (approximately). This leaves time to analyze images and finalize information for visit 10 (STIS), which will occur the following May. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 13 CYGLOOP-NEN WFPC2 IMAGE WFALL-F F502N 5010 2 2600 S R2 IX ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 10] Visit: 07 Visit Priority: Visit Requirements: ORIENT 80D TO 100D; SAME ORIENT AS 5 On Hold Comments: Additional Comments: WFPC2 EARLY ACQ for 21-23. The SNR filaments are nearly linear on the sky, with PA= -45 to -50 degrees (SE to NW). The intent is to roughly align the filament along the rows or columns of the WFC CCDs across any two chips. Exact orientation is not crucial, and is modulo 90 degrees. The ORIENT above places filament along the y-direction of the WF2-3 chips (+U3 pointing roughly east) and corresponds to a window from late Sept. to mid-Nov. (approximately). This leaves time to analyze images and finalize information for visit 10 (STIS), which will occur the following May. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 14 CYGLOOP-NEN WFPC2 IMAGE WFALL-F F502N 5010 2 2600 S POS TARG -1,-1 R2 IX Comments: Slightly different POS TARG is intentional. ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 11] Visit: 08 Visit Priority: Visit Requirements: ORIENT 80D TO 100D; SAME ORIENT AS 5 On Hold Comments: Additional Comments: WFPC2 EARLY ACQ for 21-23. The SNR filaments are nearly linear on the sky, with PA= -45 to -50 degrees (SE to NW). The intent is to roughly align the filament along the rows or columns of the WFC CCDs across any two chips. Exact orientation is not crucial, and is modulo 90 degrees. The ORIENT above places filament along the y-direction of the WF2-3 chips (+U3 pointing roughly east) and corresponds to a window from late Sept. to mid-Nov. (approximately). This leaves time to analyze images and finalize information for visit 10 (STIS), which will occur the following May. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 15 CYGLOOP-NEN WFPC2 IMAGE WFALL-F F502N 5010 2 2600 S POS TARG -2,-2 R2 IX Comments: Slightly different POS TARG is intentional. ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 12] Visit: 10 Visit Priority: Visit Requirements: ORIENT 256D TO 271D On Hold Comments: Additional Comments: The ORIENT shown above covers the range expected for placing the STIS long slit perpendicular to the filaments in this region of the supernova remnant. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 CYGLOOP-NEN STIS/C ACQ F28X50L MIRROR 1 1.0 S R-OFFSET1 CD P Comments: Acquire this star prior to offsetting to SNR spectral position. ------------------------------------------------------------------------------------------------------------------------------------ 22 CYGLOOP-NEN STIS/F ACCUM 52X0.5 G140L 1425 1 2000 S EXPAND RS UV-MAM A Comments: Fills out first orbit after acq. ------------------------------------------------------------------------------------------------------------------------------------ 23 CYGLOOP-NEN STIS/F ACCUM 52X0.5 G140L 1425 3 2600 S EXPAND RS UV-MAM A Comments: Three additional full orbits of STIS exposure. ------------------------------------------------------------------------------------------------------------------------------------ 9080( 3) - 03/25/02 08:13 - [ 13] Summary Form for Proposal 9080 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WF3-FIX WFALL-FIX F28X50LP 52X0.5 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 70D TO 80D POS TARG 0, 15 POS TARG -1, 14 POS TARG -2, 13 ORIENT 70D TO 80D; SAME ORIENT AS 1 ORIENT 80D TO 100D POS TARG -1,-1 POS TARG -2,-2 ORIENT 80D TO 100D; SAME ORIENT AS 5 ORIENT 256D TO 271D EXPAND ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F656N F502N MIRROR G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names CYGLOOP-NENR1 CYGLOOP-NENR2 CYGLOOP-NENR-OFFSET1 CYGLOOP-NENRS ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 6564 5010 1425 ------------------------------------------------------------------------------------------------------------------------------------