Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4359c Report Date: 09-May-96:19:34 Version: ********** Check-in Date: ********** 1.Proposal Title: PROBING THE HOT INTERSTELLAR MEDIUM OF THE LARGEST LMC SUPERGIANT SHELL CYC3-MED ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GO Sub Category ABSORPTION LINES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Klaas S. De boer UNIVERSITAT BONN GERMANY ------------------------------------------------------------------------------------ 7. Abstract We will measure absorptions due to interstellar CIV, OI and SiII on 4 lines of sight to stars located inside supershell LMC4 in the Large Magellanic Cloud. The equivalent widths and line profiles of the CIV absorptions are excellent probes for the determination of the temperature and structure of the coronal gas inside the LMC4 cavity, and thus of the energy content of the region. In addition, these measurements will determine the extent to which hot gas from the bubble flows into the LMC halo. We know that the bubble also contains neutral and low ionization species, and the proposed measurements of SiII and OI are essential to derive the relative importance of the hot versus the cool interstellar phases in supporting the LMC4 bubble. With these data we aim to test and calibrate existing models for the expansion of LMC4, improve insight in the disk-halo connection in (irregular) galaxies, and test scenarios for the creation of quasar absorption lines. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 5.00 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4359c PI: Klaas S. De boer Proposal Title: PROBING THE HOT INTERSTELLAR MEDIUM OF THE LARGEST LMC SUPERGIANT SHELL CYC3-MED ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Klaas S. De Boer UNIVERSITAT BONN GERMANY X Dominik J. Bomans UNIVERSITAT BONN GERMANY X Eva K. Grebel UNIVERSITAT BONN GERMANY X Jan Koornneef STSCI USA X ------------------------------------------------------------------------------------ 3. Description of proposed observations. The table below contains the relevant data for our target stars. The positions of our stars over the face of LMC4 ist shown in Fig. 1. Star V Spec Typ F1300 F1550 grat. time(s) 130nm 155nm Sk-66 118 11.81 B2 Iab 2.4e-12 1.6e-12 G160M 600 3000 Sk-67 169 12.18 B0 I 1.1e-12 6.1e-13 G160M 1400 7000 F [erg* cm e-2*s e-1*A e-1] For each star we plan to obtain two spectra: 1. A spectrum with the G160M grating centered on 130.3 nm trough the LSA to aquire data with the high spectral resolution (through convolution techniques, e.g. Wahlgren et al. 1991) and modest S/N for the O I 130.2 nm and Si II 130.4 nm absorption lines. This provides information on the velocity structure of the neutral gas. Furthermore, comparison of the O I with 21 -cm HI allows a direct interpretation of the depth structure. As substructures are already indicated in the IUE spectra, the velocity resolution with the G160M grating is sufficient to fully resolve them. The velocity range covered is -917 to 6649 km/s for Si II 130.4 nm and -459 to 7119 km/s for O I 130.2. As this exposure covers a wavelength range of 130.0 nm to 133.4 nm, we might get additional lines which provide information on cold and warm gas, namely Ni II 130.8 nm, Ni II 131.7 nm, C I 132.8 nm, Si II* 130.9 nm, and O I* 130.48 nm. These lines are weak, but will be useful in combination with the two lines we are actually aiming at. The second spectrum with the G160M grating and LSA is centered on 155.0 nm to analyze the CIV doublet at 154.8 and 155.0 nm with the highest S/N possible; this will show the ubiquitousness of the hot gas and the velocity structure in the hot gas. Our spectrum covers a velocity range of -2510 to 3283 km/s for C IV 154.8nm and a range of -2893 to 2893 km/s for C IV 155.0 nm. For all observations we want to use the FP-SPLIT exposure mode with substepping by 1/4 diode steps to get spectra as well-sampled as possible. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The absorption lines of the hot ISM are only observable in the UV. This is also true for lines with intrinsically large optical depth originating in the neutral ISM. Our experience with IUE shows that the absorption profiles in the direction to the center of supershell LMC4 usually are weak and often are heavily blended. The velocity resolution of the IUE satellite is incapable of resolving the LMC absorption in all its components. Faint lines cannot be resolved at all, and fine structure in stronger lines is only indicated. We can achieve a sufficiently high resolution and a high enough S/N for the detailed analysis of these components within an acceptable amount of observing time with the GHRS using its G160M grating. As G160M is situated at Side 2 of the GHRS, it is not affected by the current instrument problems. Page 3 ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The data reduction will be carried out on the VMS and Ultrix clusters of the Astronomical Institutes of the University of Bonn and at the STScI. We will use STSDAS and MIDAS to perform the basic reduction steps. We will use the profile fitting packages of IRAF/STSDAS and/or MIDAS to produce cloud models to measure equivalent widths and central velocities of the lines. The data will provide us with detailed information on the velocities and temperatures of the gas clouds of LMC4, particularly in order to map the proposed outflow of gas into the halo of the LMC. We have ample experience in analyzing high dispersion UV spectra; two members of our group (KSdB and JK) have been working with the IUE since 1978, and on the ISM of the LMC in particular (see de Boer & Savage 1980, de Boer, Koornneef and Savage 1980, de Boer & Nash 1982, de Boer et al. 1985). The data will be analyzed together with IUE spectra to stars in this region of the LMC. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). No additional resources are needed to conduct the proposed project. All members of the team currently have unlimited access to DEC/VAX stations 3100, and higher. ------------------------------------------------------------------------------------ 11. Address Information Name: KLAAS S. DE BOER Category: PI Institution: Universitat Bonn Address: STERNWARTE BONN AUF DEM HUEGEL 71 City: 5300 BONN 1 State: Zip Code: Country: GERMANY Telephone: [49]-(228)733655 Telex (or e-mail): 8 86 440 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4359c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 SK-66118 B,113, PLATE-ID=06AF, 2000 1 V = 11.81 +/- 0.02 GSC8891.0337 H,515,517,917 RA = 05H 30M 51.95S +/- 2 TYPE = B2 I 2 0.3", 3 E(B-V) = 0.07 +/- 0.05 DEC = -66D 54' 08.6" +/- 4 B-V = -0.05 +/- 0.03 0.3" 5 U-B = -0.86 +/- 0.03 6 F(1300) = 2.4 +/- 0.2 E-12 7 F(1550) = 1.6 +/- 0.2 E-12 Comments: GSC LABEL 'MULTIPLE' IUE HIGH DIS. SPECTRUM ------------------------------------------------------------------------------------------------------------------------------------ 2 SK-67169 B,113, PLATE-ID=06AF, 2000 1 V = 12.18 +/- 0.02 GSC8891.0363 H,515,517,917 RA = 05H 31M 51.62S +/- 2 TYPE = B0 I 8 0.3", 3 E(B-V) = 0.07 +/- 0.05 DEC = -67D 02' 21.8" +/- 4 B-V = -0.12 +/- 0.03 0.3" 5 U-B = -0.90 +/- 0.03 6 F(1300) = 1.1 +/- 0.2 E-12 7 F(1550) = 6.1 +/- 0.2 E-13 Comments: GSC LABLE 'MULTIPLE IUE HIGH DISP SPECTRA ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4359c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1.01 SK-66118 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=5 1 5S 1 1 ONBOARD ACQ FOR BRIGHT=RETURN 2 1.02, 1.03 LOCATE=YES 3 CYCLE 3 4 Comments: ACQ FOR SK-66 118 CROWDED FIELD SHAPLEY CONSTELLATION III IN THE LMC BRIGHTEST STAR IN 10" REGION STEP-TIME = 0.2S ------------------------------------------------------------------------------------------------------------------------------------ 1.02 SK-66118 HRS ACCUM 2.0 G160M 1303 STEP-PATT=5 2 300S 34 6 1 CYCLE 3 FP-SPLIT=FOUR 590S COMB=FOUR DOPPLER=ON Comments: SPECTRA REGION OF SIII 1304 A NEUTRAL GAS AND COLD GAS OI, SIII, NIII, CII, CII*, CI VELOCITY STRUCTURE OF THE SHELL ------------------------------------------------------------------------------------------------------------------------------------ 1.03 SK-66118 HRS ACCUM 2.0 G160M 1550 STEP-PATT=5 4 632S 50 7 1 CYCLE 3 FP-SPLIT=FOUR 2481S COMB=FOUR DOPPLER=ON Comments: SPECTRAL REGION OF THE CIV DOUBLETT SEARCH FOR INTERSTELLAR CIV FROM THE HOT INTERIOR OF SUPERGIANT SHELL LMC4 WEAK LINES ------------------------------------------------------------------------------------------------------------------------------------ 2.01 SK-67169 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=5 1 5S 1 1 ONBOARD ACQ FOR BRIGHT=RETURN 2 2.02, 2.03 LOCATE=YES 3 CYCLE 3 4 Comments: ACQ FOR SK-67 169 CROWDED FIELD SHAPLEY CONSTELLATION III IN THE LMC BRIGHTEST STAR IN THE 10" REGION STEP-TIME = 0.2S ------------------------------------------------------------------------------------------------------------------------------------ 2.02 SK-67169 HRS ACCUM 2.0 G160M 1303 STEP-PATT=5 2 650S 34 6 1 CYCLE 3 FP-SPLIT=FOUR 1300S COMB=FOUR DOPPLER=ON Comments: SPECTRA REGION OF SIII 1304 A NEUTRAL GAS AND COLD GAS OI, SIII, NIII, CII, CII*, CI VELOCITY STRUCTURE OF THE SHELL ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4359c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 2.03 SK-67169 HRS ACCUM 2.0 G160M 1550 STEP-PATT=5 6 1150S 51 7 1 CYCLE 3 FP-SPLIT=FOUR 6800S COMB=FOUR DOPPLER=ON Comments: SPECTRAL REGION OF THE CIV DOUBLETT SEARCH FOR INTERSTELLAR CIV FROM THE HOT INTERIOR OF SUPERGIANT SHELL LMC4 WEAK LINES ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4359c [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE BRIGHT LOCATE STEP-PATT FP-SPLIT COMB DOPPLER ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 5.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ABSORPTION LINES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 1.02, 1.03; CYCLE 3 ONBOARD ACQ FOR 2.02, 2.03; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names SK-66118 GSC8891.03372 SK-67169 GSC8891.03638 ------------------------------------------------------------------------------------------------------------------------------------