6451( 5) - 08/15/96 17:17 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6451 Version: 5 Check-in Date: 15-Aug-1996 17:15:10 1.Proposal Title: HST and ORFEUS-II Observations of Highly Ionized Galactic Halo Gas Towards ESO 141- 55 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle INTERSTELLAR MEDIUM GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Blair Savage UNIVERSITY OF WISCONSIN-MADISON CoI: Kenneth Sembach Johns Hopkins University Y CoI: Mark Hurwitz University of California-Berkeley N ------------------------------------------------------------------------------------ 6. Abstract We propose to use 6 HST orbits to obtain GHRS 15 km/s resolution G160M integrations of interstellar absorption toward the bright Seyfert 1 galaxy ESO 141-55 in the highly ionized gas lines of N V, C IV, and Si IV. The HST measurements will be combined with observations of O VI absorption from the ORFEUS-II mission scheduled for November 1996. We will use the data to study the distribution and physical conditions in Galactic halo gas along the sight line to ESO 141-55 (l = 338.2 deg, b = -26.7 deg). We are particularly interested in checking the predictions of various theories for the origin of high temperature gas in the Galactic halo, including theories for the non-equilibrium cooling of hot gas in a Galactic fountain. Galactic rotation along the sight line should produce an extension of the high ionization lines to velocities as negative as -100 km/s. A study of the relative behavior of the absorption line profiles will provide information about the relative Galactic scale heights and distributions of the four high ions in the Galactic halo. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will use the LSA to obtain GHRS G160M integrations of the 1250, 1400, and 1550 A spectral region of ESO 141-55. The data will have a velocity resolution of 15-18 km/sec and S/N of 16-27. The high ion lines of C IV 1548, 1550, Si IV 1393, 1402, and N V 1238, 1242 will be observed, as will several low ionization lines (Si II 1260, 1526; Mg II 1239, 1240; S II 1250, 1253, 1259). Real Time Justification ----------------------- No special scheduling requirements are necessary. Calibration Justification ------------------------- No special calibration requirements are necessary beyond the wavecals indicated in the exposure logsheet lines below. Additional Comments ------------------- No additional comments at this time. ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Kenneth Sembach*The Johns Hopkins University*Department of Physics and Astronomy*Bloomberg Center*3400 N. Charles Street*Baltimore, MD 21218 Ship Via: UPS Email: sembach@profuse.pha.jhu.edu , ------------------------------------------------------------------------------------ 6451( 5) - 08/15/96 17:17 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 ESO141-55 Galaxy, Seyfert RA = 19H 16M 57.0S +/- 0.1S, DEC 1950.0 Z = V = 13.6 = -58D 45' 52" +/- 1.0", PLATE- 0.0368 F-CONT(1240)=1.4+/-0.7e-13 ID=03D3 F-CONT(1400)=1.1+/-0.5e-13 F-CONT(1550)=0.8+/-0.4e-13 Comments: Fluxes from low dispersion IUE data. Coordinates from SIMBAD catalogue. 6451( 5) - 08/15/96 17:17 - [ 2] Visit: 01 Visit Requirements: CVZ On Hold Comments: Additional Comments: Number exposures beginning with 1. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ESO141-55 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,SEARCH-SIZE=3 1 7.2 S ONBOARD ACQ FOR 2-8 Comments: STEP-TIME=0.8 seconds just to be safe. This should produce (within a factor of 10) about 10^4 cnt/s. No problem as long as BRIGHT=RETURN is used. ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G160M 1248 SPYBAL=YES 1 DEF SEQ 2-3 NON-INT Comments: Wavecal for exposure 3. Don't move carrousel between this exposure and the next. ------------------------------------------------------------------------------------------------------------------------------------ 3 ESO141-55 HRS ACCUM 2.0 G160M 1248 FP-SPLIT=FOUR,COMB=FOUR, 6 1632 S STEP-PATT=DEF,CENSOR=YES Comments: N V, Mg II, Si II, S II ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE HRS ACCUM SC2 G160M 1400 SPYBAL=YES 1 DEF SEQ 4-5 NON-INT Comments: Wavecal for exposure 5. Don't move carrousel between this exposure and the next. ------------------------------------------------------------------------------------------------------------------------------------ 5 ESO141-55 HRS ACCUM 2.0 G160M 1400 FP-SPLIT=FOUR,COMB=FOUR, 6 1632 S STEP-PATT=DEF,CENSOR=YES Comments: Si IV ------------------------------------------------------------------------------------------------------------------------------------ 6 WAVE HRS ACCUM SC2 G160M 1539 SPYBAL=YES 1 DEF SEQ 6-7 NON-INT Comments: Wavecal for exposure 7. Don't move carrousel between this exposure and the next. ------------------------------------------------------------------------------------------------------------------------------------ 7 ESO141-55 HRS ACCUM 2.0 G160M 1539 FP-SPLIT=FOUR,COMB=FOUR, 4 1632 S STEP-PATT=DEF,CENSOR=YES Comments: C IV, Si II ------------------------------------------------------------------------------------------------------------------------------------ 8 ESO141-55 HRS ACCUM 2.0 G160M 1539 FP-SPLIT=FOUR,COMB=FOUR, 3 1523.2 STEP-PATT=DEF,CENSOR=YES Comments: C IV, Si II ------------------------------------------------------------------------------------------------------------------------------------ 6451( 5) - 08/15/96 17:17 - [ 3] Summary Form for Proposal 6451 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 SPYBAL=YES CENSOR=YES STEP-PATT=DEF COMB=FOUR FP-SPLIT=FOUR ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ONBOARD ACQ FOR 2-8 SEQ 2-3 NON-INT SEQ 4-5 NON-INT SEQ 6-7 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names ESO141-55 WAVE ------------------------------------------------------------------------------------------------------------------------------------