! File: 3051C.PROP ! Database: PEPDB ! Date: 18-FEB-1994:12:44:11 coverpage: title_1: HELIUM IN THE EARLY UNIVERSE sci_cat: QUASARS & AGN sci_subcat: QUASAR EMISSION proposal_for: SAT/FOS pi_fname: E. MARGARET pi_lname: BURBIDGE pi_inst: UC, SAN DIEGO pi_country: USA pi_phone: (619) 534-4477 keywords_1: UV SPECTROSCOPY, QUASAR, keywords_2: EMISSION LINE PROFILE, ABUNDANCE EVOLUTION, hours_pri: 1.71 num_pri: 1 fos: Y ! end of coverpage abstract: line_1: We will use the FOS to measure the strength of the He I line_2: lambda 584 line in the UV in a QSO which has a good probability line_3: of having light at that wavelength. We will test the ability line_4: of the FOS to detect weak emission lines against a line_5: background of weak absorption lines in a faint object with line_6: the degraded performance due to the slit losses, decreased line_7: resolution, possible increased scattered light and greater line_8: than expected particle-induced background. From this line line_9: we will determine the relative abundance of Helium in the line_10: early universe. ! ! end of abstract general_form_proposers: lname: BEAVER fname: EDWARD inst: UC, SAN DIEGO country: USA ! lname: BURBIDGE fname: E. MARGARET inst: UC, SAN DIEGO country: USA ! lname: MARGON fname: BRUCE inst: WASHINGTON, UNIVERSITY OF country: USA ! lname: ANGEL fname: J. ROGER mi: P. inst: ARIZONA, UNIVERSITY OF country: USA ! lname: BARTKO fname: FRANK inst: MARTIN MARIETTA CORPORATION country: USA ! lname: DAVIDSEN fname: ARTHUR mi: F. inst: JOHNS HOPKINS UNIVERSITY country: USA ! lname: HARMS fname: RICHARD mi: J. inst: APPLIED RESEARCH CORPORATION country: USA ! lname: BOHLIN fname: RALPH inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! lname: FORD fname: HOLLAND mi: C. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: Observations of 0150-202 will characterize the ability of the FOS to line_2: measure weak emission lines in faint objects as well as making a line_3: determination of the cosmic abundance of Helium at a look back time of more line_4: than 75% of the age of the universe. We will make this determination by line_5: comparing the strength of the He I lambda 584 recombination line with the line_6: strengths of other emission lines we will measure from the ground. This UV line_7: emission line has never been measured, and measurements of this line and He line_8: II lambda 304 are important HST goals. Additionally, we may be able to set line_9: constraints on the ionization level of the intergalactic medium of the line_10: early universe, a major indicator of the constituent parts of the early line_11: universe. Determining the initial cosmic Helium abundance can in principle line_12: refine our estimate of the baryon number of the universe. line_13: 0150 is the best object (see below) available to us within the line_14: proposed restrictions in right ascension which will enable us to perform line_15: this test. The FOS ability to measure emission lines differs from predicted line_16: in several ways. First, much less light gets through the aperture. Second, line_17: any (unresolved) absorption, although decreased in depth is broadened by a line_18: significant amount. Finally, all measurements of faint objects are line_19: increased in difficulty because the FOS background is approximately .01 line_20: c/s/d, considerably greater than predicted based on ground based line_21: calibrations. This is approximately 15% of the count rated expected for line_22: the object itself. The signal-to-noise per diode for a 6000s line_23: exposure will be approximately 20, assuming that the 1.0 arc sec diameter ! question: 2 section: 2 line_1: FOS aperture transmits 34.3% of the incident light. We have also included a line_2: short exposure with the 4.3 arc second aperture to obtain an accurate flux for line_3: the scientific analysis. This will also be useful for testing the line_4: predicted light loss through the 1.0 arc second aperture. line_5: Because of these problems, we do not feel that measurement of weak line_6: emission lines in a low-redshift, bright QSO is an adequate test of FOS line_7: performance for these difficult measurements. The bright objects are line_8: unaffected by background and will not have any absorption lines confusing line_9: the emission lines, whereas He I and He II will always occur in the Lyman line_10: alpha forest of absorption lines. Several brighter objects are available in line_11: our GTO program, but these are at 12 hours right ascension, and thus line_12: unavailable for the SAT program. Of those which are available, the line_13: combination of brightness, redshift (lower redshift objects will have much line_14: lower FOS efficiency at He I) and lack of obvious features indicating a line_15: cutoff in the UV spectrum caused by a lower redshift Lyman limit absorption line_16: make this the best candidate known to us for this test. This observation line_17: will also test the ability of the FOS to detect UV absorption in an object line_18: with relatively low signal-to-noise. line_19: With this test, we will first determine whether the FOS can detect a line_20: weak emission line, superposed on absorption lines, in the face of degraded line_21: spectral resolution, in an object, which, while brighter than many proposed line_22: targets, is still faint enough for a meaningful test. line_23: Second we can test deconvolution techniques for the emission ! question: 2 section: 3 line_1: and absorption on data of relatively low signal-to-noise. Third, we can line_2: split the observation into pieces to test the accuracy of the (highly line_3: orbital position dependant) particle induced background subtraction. It line_4: may also allow us to test for other effects, such as an increase in sky line_5: background near the limb of the earth. Because the particle induced line_6: background is significant for this object, this will be a critical test of line_7: the ability of the FOS to observe faint objects. ! question: 3 section: 1 line_1: This proposal contains 1 object which will be observed with line_2: G160L and the red detector of the FOS. S/N will be 20 per line_3: diode allowing us to detect a weak emission line. line_4: A very short exposure will be used to measure the absolute line_5: flux. All exposures are cycle 0. ! question: 4 section: 1 line_1: The main point of this program is to determine the effects of line_2: the actual HST and FOS performance on the abilities of the line_3: FOS to carry out some of its unique observations. ! question: 5 section: 1 line_1: The signal-to-noise calculation assumed transmission line_2: through the 1.0 arc second diameter of 34.3% and a total line_3: HST+FOS efficiency of 2.5% with G160L at 1838 Angstroms. line_4: The particle-induced background is assumed to be 0.01 c/s/d. ! question: 6 section: 1 line_1: The OV prerequisite programs for all observations are: line_2: Prop ID 2188, 2189, 1441, 1442, and 1443 line_3: The SV prerequisite program for all observations is: line_4: Prop ID 2195 ! question: 7 section: 1 line_1: To characterize the performance of the HST + FOS, we will line_2: measure the flux in a weak emission line, superposed on absorption, line_3: in the total observation as well as in shorter segments of line_4: the total integration. We will compare the flux levels in line_5: portions to check the particle-induced background subtraction. line_6: We will do spectral deconvolution to determine the effect line_7: of the decreased spectral resolution of the FOS on our line_8: observations. ! question: 8 section: 1 line_1: We will schedule ground-based observations at Lick Observatory line_2: as close to the HST observations in time as possible in order line_3: to check FOS fluxes and obtain other data for science analysis. ! !end of general form text general_form_address: lname: BURBIDGE fname: E. MARGARET category: PI inst: UC, SAN DIEGO ! lname: COHEN fname: ROSS mi: D. category: CON inst: UNIVERSITY OF CALIFORNIA, SAN DIEGO addr_1: CASS DEPT., C-011 city: LA JOLLA state: CA zip: 92093 country: USA phone: (619) 534-2664 telex: FAX: (619) 534-6316 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: UM675 name_2: 0150-202 descr_1: QUASAR pos_1: RA = 01H 52M 27.291S +/- 1.0", pos_2: DEC = -20D 01' 07.29" +/- 1.0", pos_3: PLATE-ID = 05XZ equinox: 2000 pm_or_par: NO rv_or_z: Z=2.15 fluxnum_1: 1 fluxval_1: V=17.1 +/- 0.5 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: UM675 config: FOS/RD opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 22S fluxnum_1: 1 priority: 1 param_1: BRIGHT = 700000 req_1: ONBOARD ACQ FOR 2-4; req_3: CYCLE 0 / 1-4 ! linenum: 2.000 targname: ^ config: ^ opmode: ACQ aperture: ^ sp_element: ^ num_exp: 1 time_per_exp: 22S fluxnum_1: 1 priority: ^ ! linenum: 3.000 targname: ^ config: ^ opmode: ACCUM aperture: 4.3 sp_element: G160L wavelength: 1600 num_exp: 1 time_per_exp: 100S s_to_n: 4 fluxnum_1: ^ priority: ^ param_1: STEP-PATT=SINGLE ! linenum: 4.000 targname: ^ config: ^ opmode: ACCUM aperture: 1.0 sp_element: G160L wavelength: 1600 num_exp: 1 time_per_exp: 6000S s_to_n: 20 fluxnum_1: ^ priority: ^ param_1: STEP-PATT=SINGLE ! ! end of exposure logsheet ! No scan data records found