! File: 4677C.PROP ! Database: PEPDB ! Date: 22-FEB-1994:22:07:43 coverpage: title_1: A SENSITIVE SEARCH FOR HIGH-VELOCITY GAS IN THE OUTER GALACTIC HALO title_2: -CYC3 sci_cat: INTERSTELLAR MEDIUM sci_subcat: ABSORPTION LINES proposal_for: GO pi_fname: DAVID pi_mi: M. pi_lname: MEYER pi_inst: NORTHWESTERN UNIVERSITY pi_country: USA hours_pri: 2.02 num_pri: 3 hrs: Y funds_length: 24 off_fname: WILLIAM off_mi: J. off_lname: GEALY off_title: DIRECTOR off_inst: 3020 off_addr_1: OFFICE OF RESEARCH AND SPONSORED PROGRAMS off_addr_2: NORTHWESTERN UNIVERSITY off_addr_3: 633 CLARK STREET off_city: EVANSTON off_state: IL off_zip: 60208 off_country: USA off_phone: 708-491-3003 ! end of coverpage abstract: line_1: We propose to obtain observations of the Mg II absorption toward a sample of line_2: eight bright Seyfert galaxies and BL Lac objects with the GHRS on HST in an line_3: effort to search for the metal-line counterparts of high-velocity H I clouds line_4: (HVCs) over pathlengths which cover the full extent of the Galactic halo. line_5: Based on a statistical extrapolation beyond the 10e18 cm-2 sensitivity of line_6: recent H I 21 cm emission surveys, Wakker (1991) has estimated that HVCs with line_7: N(H I)>2x10e17 cm-2 cover somewhere between 30% and 60% of the sky. Such a line_8: limiting column density of high-velocity gas would be detectable in Mg II line_9: absorption against bright extragalactic targets with GHRS provided that the gas line_10: is not too metal-poor (<0.1 solar). The lack of such high-velocity absorption line_11: toward Danly's (1989) IUE sample of bright halo stars has led Wakker to line_12: conclude that, in general, HVCs are located at large distances beyond the line_13: inner Galactic halo. With the exception of the Magellanic Cloud and 3C 273 line_14: sightlines, previous UV and optical absorption-line studies of halo gas toward line_15: extragalactic targets have not had the sensitivity to detect low N(H I) HVCs. line_16: Thus, the primary goal of our Mg II survey is to determine if such HVCs are a line_17: common constituent of the Galactic halo. Our results will also have an impact line_18: on the question of metallicity in HVCs. Furthermore, if we find ubiquitous line_19: high-velocity Mg II absorption, it would provide new support for the idea that line_20: at least some QSO absorbers are due to the halos of intervening galaxies. ! ! end of abstract general_form_proposers: lname: MEYER fname: DAVID title: PI mi: M. inst: NORTHWESTERN UNIVERSITY country: USA esa: N ! lname: SAVAGE fname: BLAIR mi: D. inst: UNIVERSITY OF WISCONSIN country: USA esa: N ! lname: LU fname: LIMIN inst: UNIVERSITY OF WISCONSIN country: USA esa: N ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: We propose to use the GHRS on HST to measure the veloctiy structure line_2: of the MG II absorptionline profiles through the Galactic halo line_3: toward the sample of Seyfert galaxies listed above. The primary line_4: selection criteria in choosing these extragalactic targets is their line_5: comparative UV brightness. They represent a reasonably well-distributed line_6: range of sightliness throught the halo with the H I 21 cm surveys line_7: indicating the presence of known high-velocity clouds (HVs) toward line_8: Fairall 9 and NGC 3783. At the LSA-degraded GHRS G270M resolution line_9: of R=10,000, we will be able to easily spearte any HVC (v>100 km/sec) line_10: MG II absorption from that of local disk gas. The enhanced throughput line_11: of the LSA and the optimal sensitivity of the GHRS near 2800 A will line_12: allow us to efficiently achieve 5 sigma detections of 100 mA MG II line_13: 2796 A features toward each of our targets. Assuming solar abundances, line_14: this threshold in MG II should enable us to detect NVCs in absorption line_15: at a level over an order of magnitude better than the H I 21 cm surveys. ! !end of general form text general_form_address: lname: Meyer fname: David mi: M. category: PI inst: Northwestern University addr_1: Department of Physics and Astronomy city: Evanston state: IL zip: 60208 country: USA phone: 708-491-4516 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: FAIRALL9 descr_1: E,312 pos_1: RA=1H23M45.7S+/-0.1S, pos_2: DEC=-58D48'22"+/-1" equinox: 2000 pm_or_par: NO rv_or_z: Z=0.045 fluxnum_1: 1 fluxval_1: V=13.2 fluxnum_2: 2 fluxval_2: F-CONT(2800)=2.5E-14 ! targnum: 2 name_1: AKN120 descr_1: E,312 pos_1: RA=5H16M11.4S+/-0.1S, pos_2: DEC=-0D8'59"+/-1" equinox: 2000 pm_or_par: NO rv_or_z: Z=0.033 fluxnum_1: 1 fluxval_1: V=13.9 fluxnum_2: 2 fluxval_2: F-CONT(2800)=3.5E-14 ! targnum: 3 name_1: NGC3783 descr_1: E,312 pos_1: RA=11H39M1.8S+/-0.1S, pos_2: DEC=-37D44'19"+/-1" equinox: 2000 pm_or_par: NO rv_or_z: Z=0.0096 fluxnum_1: 1 fluxval_1: V=13.4 fluxnum_2: 2 fluxval_2: F-CONT(2800)=3.0E-14 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: FAIRALL9 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 20.0S fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=5, param_2: BRIGHT=RETURN, req_1: CYCLE 3/1-3; req_2: ONBOARD ACQ FOR 2 comment_1: STEP-TIME=0.8S ! linenum: 2.000 targname: FAIRALL9 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 81.6S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 3 comment_1: STEP-TIME=0.8S ! linenum: 3.000 targname: FAIRALL9 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2808 num_exp: 3 time_per_exp: 15.6M s_to_n: 15 s_to_n_time: 46.8M fluxnum_1: 2 priority: 1 param_1: FP-SPLIT=STD param_2: STEP-PATT=4 ! linenum: 4.000 targname: AKN120 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 20.0S fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=5, param_2: BRIGHT=RETURN, req_1: CYCLE 3/4-6; req_2: ONBOARD ACQ FOR 5 comment_1: STEP-TIME=0.8S ! linenum: 5.000 targname: AKN120 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 81.6S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 6 comment_1: STEP-TIME=0.8S ! linenum: 6.000 targname: AKN120 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2808 num_exp: 2 time_per_exp: 18.0M s_to_n: 15 s_to_n_time: 36.0M fluxnum_1: 2 priority: 1 param_1: FP-SPLIT=STD param_2: STEP-PATT=4 ! linenum: 7.000 targname: NGC3783 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 20.0S fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=5, param_2: BRIGHT=RETURN, req_1: CYCLE 3/7-9; req_2: ONBOARD ACQ FOR 8 comment_1: STEP-TIME=0.8S ! linenum: 8.000 targname: NGC3783 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 81.6S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 9 comment_1: STEP-TIME=0.8S ! linenum: 9.000 targname: NGC3783 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2808 num_exp: 2 time_per_exp: 19.2M s_to_n: 15 s_to_n_time: 38.4M fluxnum_1: 2 priority: 1 param_1: FP-SPLIT=STD param_2: STEP-PATT=4 ! ! end of exposure logsheet ! No scan data records found