! File: 4619C.PROP ! Database: PEPDB ! Date: 22-FEB-1994:20:01:21 coverpage: title_1: HIGHLY IONIZED HALO GAS AT LARGE GALACTOCENTRIC DISTANCES sci_cat: INTERSTELLAR MEDIUM sci_subcat: ABSORPTION LINES proposal_for: GO pi_fname: BLAIR pi_mi: D. pi_lname: SAVAGE pi_inst: UNIVERSITY OF WISCSONSIN-MADISON pi_country: USA hours_pri: 7.00 num_pri: 1 hrs: Y funds_length: 12 off_fname: ROBERT off_mi: W. off_lname: ERICKSON off_title: ADMINISTRATOR off_inst: UNIVERSITY OF WISCONSIN-MADISON off_addr_1: 750 UNIVERSITY AVENUE off_city: MADISON off_state: WI off_zip: 53706 off_country: USA off_phone: 608-262-3822 ! end of coverpage abstract: line_1: We propose to obtain GHRS G160M observations (FWHM=15 km/s) line_2: of the C IV 1548,1550 doublet and the N V 1238,1242 doublet line_3: absorption produced by the Milky Way disk and halo gas line_4: toward the bright quasar H1821+643. Existing GHRS line_5: observations of the N V doublet toward H1821+643 reveal line_6: the presence of a large amount of N V gas at large negative line_7: velocity (-140 km/s). This gas is probably associated with line_8: the outer warp of the Galaxy. The gas is estimated to have line_9: a Galactocentric distance of ~25 kpc, and to be ~11 kpc line_10: above the disk. The existence of a large amount of highly line_11: ionized gas in the outer halo of the Galaxy is difficult to line_12: understand. The proposed observations will allow us to line_13: supplement the existing N V data to accurately measure the line_14: N V column density, and to examine the detailed velocity line_15: structure. The N V absorption will be compared with the C IV line_16: absorption in order to understand the ionization mechanism line_17: of the outer halo gas. The comparison will also allow us line_18: to examine how the ionization level of the gas depends line_19: Galactocentric distance by using Galactic rotation as a tool line_20: to locate the gas. The study will be aided by low ion lines. ! ! end of abstract general_form_proposers: lname: SAVAGE fname: BLAIR title: PI mi: D. inst: UNIVERSITY OF WISCSONSIN-MADISON country: USA ! lname: SEMBACH fname: KENNETH mi: R. inst: MASSACHUSETTS INSTITUTE OF TECHNOLOGY country: USA esa: N ! lname: LU fname: LIMIN inst: UNIVERSITY OF WISCSONSIN-MADISON country: USA esa: N ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: The Science Justification section has been omitted. ! question: 3 section: 1 line_1: We will make GHRS observations of the quasar H 1821+643. line_2: The G160M grating and the Large Science Aperture will be line_3: used for two setups, one centered at 1540 angstroms, and line_4: the other centered at 1250 angstroms. The former will line_5: cover the C IV 1548, 1550 and Si II 1526 resonance lines, line_6: and the latter will cover the N V 1238, 1242, S II 1250, line_7: 1253, 1259, and Si II 1260 resonance lines. All measurements line_8: will be made with two samples per diode substepping, and line_9: with standard FP-SPLIT. All S/N and exposure time estimates line_10: are based on FOS spectrum of the target. ! question: 4 section: 1 line_1: The proposed study requires UV capabilities. The IUE is line_2: incapable of carrying out the proposed study because of line_3: its limited spectral resolution and S/N characteristics. line_4: The FOS observations (already exist) are of too low line_5: resolution for the proposed scientific analysis. The GHRS line_6: on board the HST is the only instrument that can achieve line_7: the required high resolution, high S/N observations. ! question: 5 section: 1 line_1: No request for special scheduling or real-time observations. ! question: 6 section: 1 line_1: We request a Pt lamp exposure be obtained immediately line_2: prior to each of the two science observations. This is line_3: necessary because the proposed scientific analysis line_4: requires comparison of absorption velocities between line_5: different ion species. Thus accurate wavelength calibration line_6: is crucial. ! question: 7 section: 1 line_1: Data reduction will be done using CALHRS developed by line_2: the GHRS science team. Two of the proposers are GHRS line_3: team members. ! question: 8 section: 1 line_1: The integrations requested have been slightly modified line_2: from those listed in the original proposal (ie, phase I). line_3: The C IV integration for NGC 3783 in the original proposal line_4: has been removed because the measurement was recently line_5: obtained by Dr. Steve Maran. The N V integration for line_6: H1821+643 was added in because the S/N in the existing line_7: data is inadequate. The total requested spacecraft time line_8: is within the allotment, and the science goals are nearly line_9: identical to those of the original proposal. ! question: 9 section: 1 line_1: The proposers are involved in the following HST programs: line_2: GTO1162-Interstellar Abundances Toward Extreme Depletion line_3: Sight Lines (Savage and Cardelli) line_4: GTO1165,3960,4094-Spectroscopy of Milky Way Halo Gas line_5: (Savage, Sembach, and Cardelli) line_6: GO2257-Physical Conditions in the Gaseous Galactic Halo line_7: (Savage, Sembach, and Cardelli) line_8: GO2424-Quasar Absorption Line Survey line_9: (Bahcall et al, including Savage) line_10: GO3463-Highly Ionized Nitrogen in the Galactic Halo line_11: (Savage, Sembach, and Lu) line_12: Most of the data have been received and analized. There line_13: have been 16 publications so far based on these data. ! question: 10 section: 1 line_1: The University of Wisconsin will provide data handling line_2: and analysis facilities available through the Midwest line_3: Astronomical Data Reduction and Analysis Facility. ! !end of general form text general_form_address: lname: SAVAGE fname: BLAIR mi: D. category: PI inst: UNIVERSITY OF WISCONSIN-MADISON addr_1: DEPARTMENT OF ASTRONOMY addr_2: 475 N. CHARTER STREET city: MADISON state: WI zip: 53706 country: USA phone: 608-262-2395 telex: 26542 UOFWISC MDS ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: H1821+643 descr_1: E,313,314 pos_1: RA=18H 21M 57.11S+/-.01S, pos_2: DEC=+64D 20' 36.7"+/-0.1" equinox: 2000 pm_or_par: NO rv_or_z: Z=0.297 fluxnum_1: 1 fluxval_1: V=14.1 fluxnum_2: 2 fluxval_2: F-CONT(1240)=3.5E-14 fluxnum_3: 3 fluxval_3: F-CONT(1550)=4.5E-14 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 100.000 targname: H1821+643 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 100S fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=5 param_2: BRIGHT=RETURN req_1: ONBOARD ACQ FOR 101; req_2: CYCLE 3 / 100-106; comment_1: STEP-TIME=4S ! linenum: 101.000 targname: H1821+643 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 204S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 102-106; comment_1: STEP-TIME=2S ! linenum: 102.000 targname: H1821+643 config: HRS opmode: IMAGE aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 5.12M fluxnum_1: 1 priority: 1 param_1: NX=16, param_2: NY=16, comment_1: TAKE MAP AFTER CENTERING comment_2: EXPECT 30 COUNTS AT PEAK comment_3: STEP-TIME=1.2S ! linenum: 103.000 targname: H1821+643 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1250 num_exp: 8 time_per_exp: 19.2M s_to_n: 10 s_to_n_time: 153.6M fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4 param_2: FP-SPLIT=STD ! linenum: 104.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1250 num_exp: 1 time_per_exp: 1M priority: 1 req_1: CALIB FOR 103 NO SLEW; req_2: GROUP 103-104 NO GAP ! linenum: 105.000 targname: H1821+643 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1540 num_exp: 14 time_per_exp: 19.2M s_to_n: 15 s_to_n_time: 268.8M fluxnum_1: 3 priority: 1 param_1: STEP-PATT=4 param_2: FP-SPLIT=STD ! linenum: 106.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1540 num_exp: 1 time_per_exp: 1M priority: 1 req_1: CALIB FOR 105 NO SLEW; req_2: GROUP 105-106 NO GAP ! ! end of exposure logsheet ! No scan data records found