! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6710,v 12.1 1996/08/28 21:39:47 pepsa Exp $ ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6710,v 12.1 1996/08/28 21:39:47 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Lubenow ! Phone: 410-338-4928 , E-mail: lubenow@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Name of Phase I Proposal: archive-0824.lequeux.prop ! Date generated: Fri Dec 22 16:20:25 EST 1995 ! Proposal_Information ! Section 4 Title: Abundances in the neutral medium of the blue compact galaxy IZw 18 Proposal_Category: GO Scientific_Category: GALAXIES & CLUSTERS Cycle: 6 Investigators PI_name: James Lequeux PI_Institution: Observatoire de Paris CoI_Name: David Bowen CoI_Institution: Royal Observatory, Edinburgh Contact: Y ! Y or N (designate at most one contact) CoI_Name: Daniel Kunth CoI_Institution: Institut d'Astrophysique Contact: ! Y or N (designate at most one contact) CoI_Name: Miguel Mas-Hesse CoI_Institution: Laboratorio de Astrofisica Espacial y Fisica Fundamental Contact: ! Y or N (designate at most one contact) CoI_Name: Max Pettini CoI_Institution: Royal Greenwich Observatory Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) In a previous observation with the GHRS we obtained a very low value (1/1000 of solar) of the abundance of oxygen in the neutral medium surrounding the ionH2 regions of the blue compact galaxy IZw 18. This low value has profound consequences on the evolution of blue compact galaxies, on the mixing processes in such objects, and on the possible existence of the Population III. Unfortunately, this abundance determination is of very low accuracy due to the saturation of the ionO1 line. We now propose using the GHRS with the G140M grating at full resolution to observe ionS2 absorption lines at 1251, 1254 and 1260 Angstrom\ arising from the gas in front of the ionizing stars of the ionH2 region. The relatively low column density of ionS2, the broad range of oscillator strengths in the three lines, and the good wavelength-resolving power of G140M, will allow us to obtain an accurate value of the column density of ionS2 and of the velocity dispersion. These measurements will enable us to directly test whether the metallicity of the absorbing gas is as low as previously deduced. The sightline toward IZw 18 also passes through a Milky Way High Velocity H I Cloud (HVC); the data we propose to obtain will enable us to determine a limit to the metallicity of the gas in this HVC, a measurement not yet made for any of these types of clouds. Questions ! Free format text (please update) Observing_Description: We propose to accumulate GHRS spectra obtained with the LSA and with G140M centered at 1250 Angstrom . Exposure times are estimated from the known UV flux, F_lambda(1250)\:~eq\:1.3*10^-14 ergs cm^-2 s^-1 Angstrom ^-1, which gives a count rate of 22 counts diode^-1 hr^-1. For half-stepped data, assuming a background count rate of 26 counts diode^-1 hr^-1, a S/N of 7.9 is reached in 15 hrs (18 orbits), which is necessary to differentiate between gas with metallicities of more or less than 1/400 Z_\odot. Simulated data with this S/N are presented in Fig. 1. A 2Sigma equivalent width limit of 16 mAngstrom\ is obtained. Not only will this limit enable us to detect low metallicty gas from IZw 18, but will all also provide extremely sensitive limits to absorption from the Milky Way HVC which the sightline intercepts. Real_Time_Justification: None None needed Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets Target_Number:1 Target_Name:IZw18 Alternate_Names: Description:Galaxy, Dwarf Compact Position:RA=09H 34M 2.03S +/- 0.005S, DEC=55D 14' 27.4" +/-0.05", Plate-Id=0009 Equinox:2000.0 RV_or_Z:v=740 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux:V=15.7, F-CONT(1250)=1.3e-14 Comments:RA & DEC are those given in Phase 2 of Cycle 2 observations Visits Visit_Number:1 Visit_Requirements: On_Hold_Comments: Visit_Comments: FIRST visit Exposure_Number:10 Target_Name:IZw18 Config:HRS Opmode:ACQ Aperture:2.0 Sp_Element:MIRROR-N2 Wavelength: Optional_Parameters:bright=return,search-size=3 Number_of_Iterations:1 Time_Per_Exposure:90s Special_Requirements:ONBOARD ACQ FOR 20-70 Comments:step-time=10s Exposure_Number:20 Target_Name:WAVE Config:HRS Opmode:ACCUM Aperture:SC2 Sp_Element:G160M Wavelength:1254 Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:def Special_Requirements: ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:Wave calib for 30 ! Wavelength set to 1254A in order to get a look at NV1242.8 from IZw18 and ! from the Galaxy. Worse case, Delta lambda = 26A, so lam_min=1241A, ! lam_max=1267A Exposure_Number:30 Target_Name:IZw18 Config:HRS Opmode:ACCUM Aperture:2.0 Sp_Element:G160M Wavelength:1254 Optional_Parameters:fp-split=no,step-patt=5,spybal=no Number_of_Iterations:15 Time_Per_Exposure:435.2s Special_Requirements: ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:FIRST set Exposure_Number:40 Target_Name:WAVE Config:HRS Opmode:ACCUM Aperture:SC2 Sp_Element:G160M Wavelength:1254 Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:def Special_Requirements: ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:Wave calib for 50; really to set SPYBAL again Exposure_Number:50 Target_Name:IZw18 Config:HRS Opmode:ACCUM Aperture:2.0 Sp_Element:G160M Wavelength:1254 Optional_Parameters:fp-split=no,step-patt=5,spybal=no Number_of_Iterations:15 Time_Per_Exposure:435.2s Special_Requirements: ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:SECOND set Exposure_Number:60 Target_Name:WAVE Config:HRS Opmode:ACCUM Aperture:SC2 Sp_Element:G160M Wavelength:1254 Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:def Special_Requirements: ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:Wave calib for 70 Exposure_Number:70 Target_Name:IZw18 Config:HRS Opmode:ACCUM Aperture:2.0 Sp_Element:G160M Wavelength:1254 Optional_Parameters:fp-split=no,step-patt=5,spybal=no Number_of_Iterations:19 Time_Per_Exposure:435.2s Special_Requirements: ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:THIRD set ! ***********************End of 1st visit********************************* ! ************************Begin 2nd visit******************************** Visits Visit_Number:2 Visit_Requirements: On_Hold_Comments: Visit_Comments: SECOND visit Exposure_Number:80 Target_Name:IZw18 Config:HRS Opmode:ACQ Aperture:2.0 Sp_Element:MIRROR-N2 Wavelength: Optional_Parameters:bright=return,search-size=3 Number_of_Iterations:1 Time_Per_Exposure:90s Special_Requirements:ONBOARD ACQ FOR 90-140 Comments:step-time=10s Exposure_Number:90 Target_Name:WAVE Config:HRS Opmode:ACCUM Aperture:SC2 Sp_Element:G160M Wavelength:1254 Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:def Special_Requirements: ! ONBOARD ACQuisition FOR NON-INTerruptible Comments:Wave calib for 100 Exposure_Number:100 Target_Name:IZw18 Config:HRS Opmode:ACCUM Aperture:2.0 Sp_Element:G160M Wavelength:1254 Optional_Parameters:fp-split=no,step-patt=5,spybal=no Number_of_Iterations:15 Time_Per_Exposure:435.2s ! Special_Requirements:USE OFFSET 888 ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:FIRST set Exposure_Number:110 Target_Name:WAVE Config:HRS Opmode:ACCUM Aperture:SC2 Sp_Element:G160M Wavelength:1254 Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:def ! Special_Requirements:USE OFFSET 888 ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:Wave calib for 120; really to set SPYBAL again Exposure_Number:120 Target_Name:IZw18 Config:HRS Opmode:ACCUM Aperture:2.0 Sp_Element:G160M Wavelength:1254 Optional_Parameters:fp-split=no,step-patt=5,spybal=no Number_of_Iterations:15 Time_Per_Exposure:435.2s ! Special_Requirements:USE OFFSET 888 ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:SECOND set Exposure_Number:130 Target_Name:WAVE Config:HRS Opmode:ACCUM Aperture:SC2 Sp_Element:G160M Wavelength:1254 Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:def ! Special_Requirements:USE OFFSET 888 ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:Wave calib for 140 Exposure_Number:140 Target_Name:IZw18 Config:HRS Opmode:ACCUM Aperture:2.0 Sp_Element:G160M Wavelength:1254 Optional_Parameters:fp-split=no,step-patt=5,spybal=no Number_of_Iterations:19 Time_Per_Exposure:435.2s ! Special_Requirements:USE OFFSET 888 ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:THIRD set ! ***************************End of 2nd visit*************************** ! ***************************Final visit****************************** Visits Visit_Number:3 Visit_Requirements: On_Hold_Comments: Visit_Comments: THIRD visit; would prefer this short visit to be combined with previous two if possible Exposure_Number:150 Target_Name:IZw18 Config:HRS Opmode:ACQ Aperture:2.0 Sp_Element:MIRROR-N2 Wavelength: Optional_Parameters:bright=return,search-size=3 Number_of_Iterations:1 Time_Per_Exposure:90s Special_Requirements:ONBOARD ACQ FOR 160-170 Comments:step-time=10s Exposure_Number:160 Target_Name:WAVE Config:HRS Opmode:ACCUM Aperture:SC2 Sp_Element:G160M Wavelength:1254 Optional_Parameters: Number_of_Iterations:1 Time_Per_Exposure:def ! Special_Requirements:USE OFFSET 888 ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:Wave calib for 170 Exposure_Number:170 Target_Name:IZw18 Config:HRS Opmode:ACCUM Aperture:2.0 Sp_Element:G160M Wavelength:1254 Optional_Parameters:fp-split=no,step-patt=5,spybal=no Number_of_Iterations:8 Time_Per_Exposure:435.2s ! Special_Requirements:USE OFFSET 888 ! ONBOARD ACQuisition FOR ! LOW-SKY ! NO SPLIT ! SEQuence NON-INTerruptible Comments:Last set Data_Distribution ! Defaults indicated; change if desired Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 ! Only astronomers with very old 9- ! track tape drives should consider ! a blocking factor of 1 Ship_To: Dr. David V. Bowen Royal Observatory, Edinburgh (R.O.E.) Blackford Hill Edinburgh EH9 3HJ United Kingdom ! ! Ship_Via: UPS ! UPS (2-day) or OVERNIGHT ! Overnight shipping done at PI expense Recipient_Email: dvb@roe.ac.uk