7299( 6) - 11/13/98 14:14 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7299 Version: 6 Check-in Date: 13-Nov-1998 14:13:47 1.Proposal Title: Interfaces Between Hot and Cold Gas: The Superbubble N51D in the LMC ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Dominik J. Bomans Astronomishces Institut CoI: You-Hua Chu University of Illinois at Urbana-Champaign N CoI: Bram Boroson Center for Astrophysics N CoI: Bart Wakker University of Wisconsin N CoI: Klaas de Boer Sternwarte Universitaet Bonn N CoI: Sally Oey Institute of Astrophysics, Cambridge N ------------------------------------------------------------------------------------ 5. Abstract We request STIS E140M echelle spectra for four probes of the X-ray bright superbubble N 51 D in the LMC. We further request WFPC2 images of the H Alpha\ and S II emission in this region to be taken in parallel with the STIS spectra. The combination of absorption and emission information will allow a study of the transition between hot (10^6 K) shocked gas and warm (10^4 K) gas in the interface of a superbubble around an OB association. Such a study can best be done for a superbubble in the LMC because this minimizes the confusion with intervening interstellar absorption. N51D provide a well- defined closed environment with known distance, size, and kinetic energy. The 10 km/s resolution of the spectra will resolve the N V, C IV and Si IV lines, which we will use as a thermometer. Further, by studying lines of different ionization stages we can determine the ionization structure of the shell as well as study the reaction of dust to the harsh conditions inside the shell. Combined with our supporting X- ray, radio and optical data the STIS observations will enable us to determine the density, pressure and ionization of the different gas phases in N51D. The parallel WFPC2 HAlpha and SII images will trace the impact of supernova shocks on the shell. ------------------------------------------------------------------------------------ 7299( 6) - 11/13/98 14:14 - [ 2] Observations Description ------------------------ The four target stars were selected to sample the superbubble at four different projected distances from the shell center. We plan to use STIS with the E140M grating to obtain high- dispersion, high quality spectra over the spectral range of 1150--1735 Angstrom\ for each of these four stars. Exposure times and S/N ratios are listed in Table 1 and were calculated using the STIS Exposure Time Calculator and UV fluxes determined from low-dispersion IUE spectra of these stars. At the declination of N51D, the orbital visibility lasts 57 min per orbit. During the first orbit there are the following overhead times: guide star acquisition - 9 min, target acquisition - 8 min, and target peak-up - 10 min. Thus, only 30 min is available for science exposure during the first orbit. During the second orbit, 6 min re- acquisition and 2 min STIS overhead are needed, leaving 49 min of on-source integration time. To reach a S/N of ~25, the two fainter stars each require two orbits, while only one orbit is needed for the two brighter stars. In all cases, we reach the highest S/N ratio currently guaranteed for STIS. A S/N of 25 corresponds to a limiting 3-Sigma optical depth of about 0.12. For N V, this gives a limiting column density of 4* dex12 cm^-2. This is a factor of 6 lower than the N V column density of the conduction front in the wind-blown bubble around the WR star HD 50896 (Boroson et al. 1996), and a factor of >10 lower than that detected toward Sk-67 104, one of our targets previously observed by de Boer & Nash (1982). Thus, if any N V is present, we expect to find it also in the other stars. Real Time Justification ----------------------- None. Calibration Justification ------------------------- Move appropriate text from Real_Time_Justification Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7299( 6) - 11/13/98 14:14 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SK-67.101 EXT-MEDIUM, Ring RA=5H 25M 56.33S +/- 0.1S, DEC=- J2000 V=+300 V = 12.63 Nebula, Coronal Gas, 67D 30' 28.7" +/- 0.3", PLATE- F(1300)=1.5+/-0.1e-12 Absorption Line System, ID=06B0 F(1500)=1.0+/-0.1e-12 EXT-STAR, B0-B2 III-I Comments: Star in LMC 2 SK-67.104 EXT-MEDIUM, Ring RA=5H 26M 04.13S +/- 0.1S, DEC=- J2000 V=+300 V = 11.28 Nebula, Coronal Gas, 67D 29' 57.1" +/- 0.3", PLATE- F(1300)=3.8+/-0.1e-12 Absorption Line System, ID=06B0 F(1500)=2.8+/-0.1e-12 EXT-STAR, Wolf Rayet - Comments: Star in LMC, brightest star in tight group 3 SK-67.106 EXT-MEDIUM, Ring RA=5H 26M 15.20S +/- 0.1S, DEC=- J2000 V=+300 V = 11.78 Nebula, Coronal Gas, 67D 29' 58.3" +/- 0.3", PLATE- F(1300)=2.5+/-0.1e-12 Absorption Line System, ID=06B0 F(1500)=2.1+/-0.1e-12 EXT-STAR, B0-B2 III-I Comments: Star in LMC, brightest star in tight group 4 SK-67.107 EXT-MEDIUM, Ring RA=5H 26M 20.67S +/- 0.1S, DEC=- J2000 V=+300 V = 12.50 Nebula, Coronal Gas, 67D 29' 55.4" +/- 0.3", PLATE- F(1300)=1.2+/-0.1e-12 Absorption Line System, ID=06B0 F(1500)=0.9+/-0.1e-12 EXT-STAR, B0-B2 III-I Comments: Star in LMC, brightest star in tight group 7299( 6) - 11/13/98 14:14 - [ 4] Visit: 01 Visit Priority: Visit Requirements: PCS MODE Fine On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SK-67.101 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.1 S ONBOARD ACQuisition FOR CD P 2-3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SK-67.101 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.3 S ONBOARD ACQuisition FOR 3 CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 3 SK-67.101 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2300.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 4 SK-67.101 STIS/F ACCUM 0.2X0.0 E140M 1425 1 3000.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 7299( 6) - 11/13/98 14:14 - [ 5] Visit: 02 Visit Priority: Visit Requirements: PCS MODE Fine On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SK-67.104 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.1 S ONBOARD ACQuisition FOR CD P 2-3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SK-67.104 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.3 S ONBOARD ACQuisition FOR 3 CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 3 SK-67.104 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2300.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 7299( 6) - 11/13/98 14:14 - [ 6] Visit: 03 Visit Priority: Visit Requirements: PCS MODE Fine On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SK-67.106 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.1 S ONBOARD ACQuisition FOR CD P 2-3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SK-67.106 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.3 S ONBOARD ACQuisition FOR 3 CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 3 SK-67.106 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2300.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 7299( 6) - 11/13/98 14:14 - [ 7] Visit: 04 Visit Priority: Visit Requirements: PCS MODE Fine On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SK-67.107 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.1 S ONBOARD ACQuisition FOR CD P 2-3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SK-67.107 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.3 S ONBOARD ACQuisition FOR 3 CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 3 SK-67.107 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2300.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 4 SK-67.107 STIS/F ACCUM 0.2X0.0 E140M 1425 1 3000.0 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 7299( 6) - 11/13/98 14:14 - [ 8] Summary Form for Proposal 7299 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 0.2X0.06 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE Fine ONBOARD ACQuisition FOR 2-3 ONBOARD ACQuisition FOR 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names SK-67.101 SK-67.104 SK-67.106 SK-67.107 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 ------------------------------------------------------------------------------------------------------------------------------------