! File: 4433C.PROP ! Database: PEPDB ! Date: 22-FEB-1994:11:46:16 coverpage: title_1: AN INVESTIGATION OF STRONG, LOCAL LYMAN ALPHA CLOUDS sci_cat: QUASARS & AGN sci_subcat: QUASAR ABSORPTION proposal_for: GO pi_fname: CLAUDIA pi_mi: M pi_lname: URRY pi_inst: STSCI pi_country: USA hours_pri: 7.98 num_pri: 1 hrs: Y funds_length: 12 off_fname: HERVEY off_mi: S off_lname: STOCKMAN off_title: DEPUTY DIRECTOR off_inst: 3470 off_addr_1: 3700 SAN MARTIN DRIVE off_city: BALTIMORE off_state: MD off_zip: 21218 off_country: USA off_phone: 1-410-338-4730 ! end of coverpage abstract: line_1: Low-resolution GHRS spectra of the UV-bright BL Lac object PKS2155-304 line_2: (Bruhweiler et al. 1992) have revealed 5-6 new local Lyman-ALPHA line_3: systems, including a complex of 3 lines in the redshift range line_4: z=0.053-0.059. The central line at 1285 A is one of the strongest, line_5: lowest-redshift Lyman-ALPHA absorption lines known, but no associated line_6: CIV absorption line at the expected strength is seen. line_7: We propose to observe PKS2155-304 at higher resolution for the line_8: following reasons. First, we will see whether the lines separate line_9: cleanly into distinct clouds of smaller equivalent width and/or to line_10: measure their velocity structures. This will allow us to determine line_11: independently the HI column densitites and Doppler b parameters for line_12: each system, and possibly to say something about their kinematics line_13: and temperatures. Second, we will measure (or get limits on) the line_14: equivalent width of CIV associated with each system, as well as line_15: for the lower ionization MgII that might be more characteristic of line_16: the haloes of nearby galaxies. Third, the data will be used to line_17: find much weaker Lyman-ALPHA absorbing systems and to study the line_18: composition, ionization, and kinematics of the Galactic halo toward line_19: the South Galactic Pole. ! ! end of abstract general_form_proposers: lname: URRY fname: CLAUDIA title: PI mi: M inst: STSCI country: USA ! lname: BOWEN fname: DAVID inst: STSCI country: USA ! lname: MARASCHI fname: LAURA inst: UNIVERSITA DI MILANO country: ITALY esa: Y ! lname: DANLY fname: LAURA inst: STSCI country: USA ! lname: BRUHWEILER fname: FREDERICK mi: C inst: CATHOLIC UNIVERSITY country: USA ! lname: GRADY fname: CAROL mi: A inst: CATHOLIC UNIVERSITY country: USA ! lname: FALOMO fname: RENATO mi: E inst: UNIVERSITA DI PADOVA country: ITALY esa: Y ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: ! question: 3 section: 1 line_1: We propose obtaining GHRS moderate resolution spectra of PKS2155-304 using the line_2: G160M centered at 1285 \AA\ (the Ly$\alpha$ system), 1643 \AA\ (the line_3: corresponding CIV absorption), and using the G270M centered at 2960 \AA\ line_4: (MgII). Individual exposures are 5 minutes to reduce smearing of the line_5: spectral data due to geomagnetically induced image motion. FP-SPLITS of 4 line_6: and a default STEP-PATTERN of 1/4 substeps are used. ! question: 4 section: 1 line_1: The only way to measure local Ly$\alpha$ absorption is in the ultraviolet; line_2: indeed, this is the most sensitive probe of low column densities of gas. line_3: Only the IUE high-resolution spectrograph has resolution comparable to the line_4: GHRS G160M, and with a few exceptions extragalactic targets are too faint line_5: to observe with such a small telescope. Thus, our investigation line_6: is only possible with the HST. ! question: 4 section: 2 line_1: Our exposure time estimates for PKS 2155-304 are based on its low-state line_2: ultraviolet flux as derived from IUE low dispersion spectra line_3: [$F_\lambda$(1285 \AA)=$1.0 \times 10^{-13}$, $F_\lambda$(1638 \AA)=$8.0 line_4: \times 10^{-14}$, and $F_\lambda$(2960 \AA)=$4.4 \times 10^{-14}$ line_5: ergs/cm$^2$/s/\AA], and the sensitivity curves given in v3.0 of the GHRS line_6: Handbook. Exposures are through the LSA, and exposure times are designed to line_7: reach a S/N of 10 (per pixel) for each of the exposures. ! question: 5 section: 1 line_1: None ! question: 6 section: 1 line_1: None ! question: 7 section: 1 line_1: All the data should be reducible using standard IRAF and STSDAS reduction line_2: packages. For absorption lines in which we resolve components, we line_3: have profile fitting routines available for subjective fits to the data, plus line_4: automatic routines which produce a best fit based on minimizing chi-squared. ! question: 8 section: 1 line_1: ! question: 9 section: 1 line_1: ! question: 10 section: 1 line_1: ! !end of general form text general_form_address: lname: URRY fname: CLAUDIA mi: M category: PI inst: STScI addr_1: 3700 SAN MARTIN DRIVE city: BALTIMORE state: MD zip: 21218 country: USA phone: 1-410-338-4593 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: 2155-304 descr_1: E,316 pos_1: RA= 21H 58M 52.03S +/- 0.3", pos_2: DEC= -30D 13' 32.7" +/- 0.3", pos_3: PLATE-ID = 02J3 equinox: 2000 rv_or_z: Z=0.116 fluxnum_1: 1 fluxval_1: F-CONT(1285) = 1.0E-13 fluxnum_2: 2 fluxval_2: F-CONT(1638) = 8.0E-14 fluxnum_3: 3 fluxval_3: F-CONT(2960) = 4.4E-14 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: 2155-304 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 9S fluxnum_1: 2 priority: 1 param_1: SEARCH-SIZE=3 param_2: BRIGHT=RETURN req_1: CYCLE 3; req_2: ONBOARD ACQ FOR 2; ! linenum: 2.000 targname: 2155-304 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1285 num_exp: 8 time_per_exp: 21.76M s_to_n: 9 s_to_n_time: 174.08M fluxnum_1: 1 priority: 1 param_1: COMB=FOUR param_2: FP-SPLIT=FOUR param_3: STEP-PATT=DEF req_1: CYCLE 3 ! linenum: 3.000 targname: 2155-304 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1638 num_exp: 11 time_per_exp: 21.76M s_to_n: 10 s_to_n_time: 239.4M fluxnum_1: 2 priority: 1 param_1: COMB=FOUR param_2: FP-SPLIT=FOUR param_3: STEP-PATT=DEF req_1: CYCLE 3 ! linenum: 4.000 targname: 2155-304 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2960 num_exp: 3 time_per_exp: 21.76M s_to_n: 10 s_to_n_time: 65.3M fluxnum_1: 3 priority: 1 param_1: COMB=FOUR param_2: FP-SPLIT=FOUR param_3: STEP-PATT=DEF req_1: CYCLE 3 ! ! end of exposure logsheet ! No scan data records found