! $Id: 5734,v 4.1 1994/11/14 21:23:20 pepsa Exp $ coverpage: title_1: PROBING THE IS GAS OF THE SUPERBUBBLE LMC2 sci_cat: INTERSTELLAR MEDIUM sci_subcat: ABSORPTION LINES proposal_for: GO/CAR cont_id: 3664 pi_fname: ADELINE pi_mi: M. pi_lname: CAULET pi_inst: SPACE TELESCOPE EUROPEAN COORDINATING FACILITY pi_country: GERMANY pi_phone: 49-89-32006-291 hours_pri: 13.23 num_pri: 7 hrs: Y off_fname: PIERO off_lname: BENVENUTI off_title: HEAD OF ST-ECF off_inst: SPACE TELESCOPE EUROPEAN COORDINATING FACILITY off_addr_1: EUROPEAN SOUTHERN OBSERVATORY off_addr_2: KARL SCHWARZSCHILD - STR. 2 off_addr_3: D-8046 off_city: GARCHING BEI MUNCHEN off_country: GERMANY off_phone: 49-89-32006-291 ! end of coverpage abstract: line_1: Supershells are gigantic bubbles of hot gas blown in galactic disks line_2: by stellar winds and supernovae. Providing an enormous energy line_3: input to the ISM, they have an important effect on local dynamics line_4: and on galactic halos. One of them, LMC2 in the Large Magellanic line_5: Cloud, has been well studied at radio, optical and X-ray wavelengths. line_6: We have shown its optical filaments to be expanding in LMC disk gas. line_7: Our recent ROSAT observations reveal that the diffuse X-ray emission line_8: covers a larger sky area than the optical filaments do. Did LMC2 line_9: burst open in the halo\?. What is the dynamics of the optically line_10: invisible IS gas layers within and around LMC2\?. To probe the IS line_11: gas of LMC2, we propose to obtain GHRS medium resolution UV spectra line_12: of 7 supergiant stars in the LMC2 field. The observational goal is line_13: to measure the velocities and strengths of UV IS absorption lines line_14: arising in the cold, warm and hot LMC2 gas. HST has the only line_15: existing UV spectrograph that can detect individual velocity line_16: components of IS hot gas (CIV and NV absorption) in connection with line_17: the X-ray diffuse emission seen towards the LMC supershells. line_18: The scientific goals are to find a satisfactory model of LMC2 that line_19: describes the physical characteristics of the superbubble and the line_20: effects of supershell expansion or break-out into the LMC halo. ! ! end of abstract general_form_proposers: lname: CAULET fname: ADELINE title: PI mi: M. inst: SPACE TELESCOPE EUROPEAN COORDINATING FACILITY country: FRANCE esa: Y ! lname: SMITH fname: ANDREW mi: M. inst: NASA GODDARD SPACE FLIGHT CENTER country: U.S.A. ! lname: PIETSCH fname: WOLFGANG mi: B. inst: MAX PLANCK INSTITUT FOR EXTRATERRESTRIAL PHYSICS country: GERMANY esa: Y ! lname: HASINGER fname: GUNTER inst: MAX PLANCK INSTITUT FOR EXTRATERRESTRIAL PHYSICS country: GERMANY esa: Y ! ! end of general_form_proposers block general_form_text: ! question: 3 section: 1 line_1: We propose to obtain GHRS medium resolution UV spectra of 7 LMC OB line_2: supergiants selected in various parts of the LMC2 field to probe line_3: thoroughly the IS gas throughout and around the superbubble cavity. line_4: For each star, 2 carousel settings of the G160M grating will center line_5: wavelengths 1249.36 and 1561.37 A on detector 2. For each line_6: carousel setting, a series of 5 minutes exposures will be made , line_7: the number of which depends on the target 's UV flux. Breaking the line_8: exposure into 5 minute intervals allows correction for image line_9: drift due to variations in the effect of the earth's magnetic field line_10: on the detector image stability. Step pattern 4 is chosen to yield line_11: 2 substeps and measurements of the background signal. Since line_12: target positions are accurately known, onboard acquisition line_13: will be employed. The small science aperture will be used. line_14: We are concerned with the IS spectra and particularly with line_15: absorption line velocities. Consequently, we plan to obtain Pt line_16: lamp wavelength calibrations for each carousel position. line_17: The carousel settings include IS lines in atoms and ions line_18: with ionization potentials ranging from 11eV (CI) to 97 eV (NV). line_19: CIV and NV absorption lines will sample gas in conduction fronts line_20: between hot gas and the superbubble or funnel walls, coronal gas, line_21: and gas in highly ionised regions formed by the UV radiation of line_22: hot OB stars. SiII and SII absorption lines will give line_23: information on the photoionised gas and clouds which have been ! question: 3 section: 2 line_1: compressed by shocks. The CI multiplets will line_2: sample the warm neutral gas and cold HI clouds trapped inside LMC2. ! question: 4 section: 1 line_1: HST has the only existing UV spectrograph (GHRS) that can detect the line_2: individual velocity components of IS hot gas (CIV and NV), in line_3: connection with the X-ray diffuse emission seen towards the line_4: superbubbles in the LMC. There is considerable information about line_5: the stars and the ISM in the direction of the LMC supershells. line_6: This includes detailed studies of the HI emission line gas line_7: (Rohlfs et al. 1984), our Fabry-Perot optical observations of the line_8: velocities of the LMC2 filaments (Caulet et al. 1982), and our line_9: extensive ROSAT survey data of soft X-ray emission arising in the line_10: LMC2 region (Hasinger and Pietsch 1991). Therefore, taking into line_11: account all this knowledge, the LMC is the best galaxy for line_12: supershell detailed studies. A complete study of superbubble line_13: dynamics requires the study of all IS superbubble gas phases. line_14: Our Fabry-Perot optical data on the visible LMC2 filaments line_15: revealed the expansion of the receding portion of LMC2, but could line_16: not trace most of the superbubble gas, which is optically line_17: invisible. According to the current superbubble models, many UV line_18: absorption lines are expected to arise in the expanding envelope, line_19: corresponding to the predicted temperature drop from 1.0xE6 K to line_20: 1000 K. The wavelengths of these lines lie below the atmospheric line_21: cut-off (3000 A), and cannot be observed using spectrographs line_22: on ground-based telescopes. Only HST has the sensitivity and line_23: resolving power to detect these absorption lines in the UV spectra ! question: 4 section: 2 line_1: of background LMC stars selected in the direction of LMC2. line_2: The spectrograph onboard IUE cannot do it. ! question: 5 section: 1 line_1: We have scheduled a wavelength calibration at each carousel setting. line_2: Since the study of the dynamics of the superbubble gas is a major line_3: objective of our proposal, we need velocity measurements at least line_4: as accurate as those obtained from the ground-based optical line_5: velocities. Accuracies of about +/- 3.5 km/s will be sufficient line_6: and should be obtainable with on-board Pt lamp calibrations line_7: performed at the same carousel settings at which the science data line_8: is recorded. ! question: 6 section: 1 line_1: OSF Line Number, Instrument, Mode , Special Calibration Requirement line_2: 1.0 , HRS , ACCUM, 1 WAVE CAL line_3: 2.0 , HRS , ACCUM, 1 WAVE CAL line_4: 3.0 , HRS , ACCUM, 1 WAVE CAL line_5: 4.0 , HRS , ACCUM, 1 WAVE CAL line_6: 5.0 , HRS , ACCUM, 1 WAVE CAL line_7: 6.0 , HRS , ACCUM, 1 WAVE CAL line_8: 7.0 , HRS , ACCUM, 1 WAVE CAL ! ! ! question: 8 section: 1 line_1: We have determined the coordinates of all targets (astrometry from line_2: the GASP plates from STScI). ! question: 9 section: 1 line_1: Andrew M. Smith has the following HST programs (as of August 1991): line_2: Program No. 1200 (GTO), "Search for Interstellar Molecules in the line_3: Spectra of Two B Stars", UNRELATED. line_4: Program No. 1201 (GTO), "Physical parameters in the Local line_5: Interstellar Medium", UNRELATED. line_6: Program No. 3024 (SAT), "Xi Per Interstellar Spectrum", UNRELATED. line_7: Observations were made by the GHRS of the cool, neutral gas in the line_8: line of sight to Xi Per. Heliocentric velocities and equivalent line_9: widths were measured for absorption lines of CI and SI. Synthetic line_10: spectra were computed and fitted to the observed CO 2-0 and 3-0 line_11: bands in the Fourth Positive System which were resolved by the line_12: GHRS into 3 and possibly 4 velocity components. Derived line_13: populations of the CI ground state fine structure levels and the line_14: CO ground state rotational levels were used to derive the line_15: densities of two of these velocity components. The component line_16: displaying the strongest C I absorption reveals extraordinarily line_17: high pressure (P/k > 4.3xE4 K/cm3). line_18: Along the same line of sight, the column densities were determined line_19: for neutral and singly ionized atoms using profile information in line_20: the form of velocity-dependent apparent column densities. line_21: Abundances determined from this analysis are very tightly line_22: constrained. GHRS ultraviolet absorption line measurements have line_23: become so accurate that the interpretations are now limited by the ! question: 9 section: 2 line_1: inaccuracies in atomic f-values and our knowledge of solar line_2: abundances. At velocities near 7.5 km/s ordinarily depleted line_3: elements are heavily depleted, but for velocities between 7.7 and line_4: 20 km/s the depletions decrease by a factor of 2 or more suggesting line_5: significant grain modification. At 25 km/s the abundances are nearly line_6: solar. line_7: "First Results from the GHRS: Interstellar C I, S I, and CO Toward line_8: Xi Persei and the Physical Conditions in Diffuse Clouds", Andrew M. line_9: Smith, Frederick C. Bruhweiler, David L. Lambert, Blair D. Savage, line_10: Jason A. Cardelli, Dennis C. Ebbets, Cheng-Hsuan Lyu, and Yaron line_11: Sheffer, Ap.J. Letters, 377, L61, 1991. line_12: "First Results from the Goddard High Resolution Spectrograph: line_13: Elemental Abundances in the Diffuse Clouds Toward Xi Per", Jason A. line_14: Cardelli, Blair D. Savage, Frederick C. Bruhweiler, Andrew M. line_15: Smith, Dennis C. Ebbets, Kenneth R. Sembach, and Ulysses J. Sofia, line_16: Ap.J. Letters, 377, L57, 1991. line_18: "First Results from the Goddard High Resolution Spectrograph: line_19: Elemental Abundances as a Function of Velocity in the Neutral Gas line_20: Toward Xi Persei", Jason A. Cardelli, Blair D. Savage, Frederick C. line_21: Bruhweiler, Andrew M. Smith, Dennis C. Ebbets, Kenneth R. Sembach, line_22: and Ulysses J. Sofia, Ap.J. Letters, 377, L53, 1991. ! question: 10 section: 1 line_1: Resources for data reduction and analysis are provided by the P.I. line_2: institution (ST-ECF) and by GSFC for A. Smith for the HST data, and line_3: by the Max-Planck Institute in Garching for the use of the ROSAT line_4: survey data (G. Hasinger and W. Pietsch). No funding is requested, line_5: since all resources necessary for this project exist already. ! !end of general form text general_form_address: lname: CAULET fname: ADELINE mi: M. category: PI inst: SPACE TELESCOPE EUROPEAN COORDINATING FACILITY addr_1: EUROPEAN SOUTHERN OBSERVATORY addr_2: KARL-SCHWARZSCHILD STR. 2 addr_3: D-8046 city: GARCHING BEI MUNCHEN country: GERMANY phone: 49-89-32006-291 ! ! end of general_form_address records fixed_targets: targnum: 3 name_1: SK-70111 name_2: GSC9167735 name_3: HD269993 descr_1: B, 113 pos_1: PLATE-ID=06B0, pos_2: RA = 05H 41M 36.93S +/- 0.5", pos_3: DEC = -70D 00' 52.38" +/- 0.5" equinox: 2000 fluxnum_1: 1 fluxval_1: V=11.8, TYPE=B1 IA fluxnum_2: 2 fluxval_2: F(1239)=5.7E-13 fluxnum_3: 3 fluxval_3: F(1549)=4.3E-13 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 7.000 targname: SK-70111 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 5.0S fluxnum_1: 1 priority: 1 param_1: BRIGHT=RETURN param_2: SEARCH-SIZE=5 req_1: ONBOARD ACQ FOR 7.1; req_2: CYCLE 4; comment_1: STEP-TIME = 0.2S ! linenum: 7.100 targname: SK-70111 config: HRS opmode: ACQ/PEAKUP aperture: 0.25 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 20.4S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 8.1-9.1; req_2: CYCLE 4; comment_1: STEP-TIME = 0.2S ! linenum: 8.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1249.36 num_exp: 1 time_per_exp: DEF priority: 1 param_1: STEP-PATT=4 req_1: CALIB FOR 8.1; req_2: CYCLE 4; req_3: SEQ 8.0-8.1 NO GAP; ! linenum: 8.100 targname: SK-70111 config: HRS opmode: ACCUM aperture: 0.25 sp_element: G160M wavelength: 1249.36 num_exp: 2 time_per_exp: 1968.0S s_to_n: 10 s_to_n_time: 2419.2S fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4 param_2: FP-SPLIT=STD req_1: CYCLE 4; ! linenum: 9.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1561.37 num_exp: 1 time_per_exp: DEF priority: 1 param_1: STEP-PATT=4 req_1: CALIB FOR 9.1; req_2: CYCLE 4; req_3: SEQ 9.0-9.1 NO GAP; ! linenum: 9.100 targname: SK-70111 config: HRS opmode: ACCUM aperture: 0.25 sp_element: G160M wavelength: 1561.37 num_exp: 2 time_per_exp: 1968.0S s_to_n: 10 s_to_n_time: 2419.2S fluxnum_1: 3 priority: 1 param_1: STEP-PATT=4 param_2: FP-SPLIT=STD req_1: CYCLE 4; ! ! end of exposure logsheet ! No scan data records found