! Proposal 6412, submission 1 ! PI: Kenneth Sembach ! Received Wed Jan 31 13:54:25 EST 1996 ! From: sembach@sundoggie.mit.edu ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! ! 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: Alice Berman ! Phone: 410-338-4462 , E-mail: aberman@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Proposal_Information ! Section 4 Title: Ionization of C IV High Velocity Clouds in the Galactic Halo Proposal_Category: GO Scientific_Category: INTERSTELLAR MEDIUM Cycle: 6 Investigators PI_name: Kenneth Sembach PI_Institution: Johns Hopkins University CoI_Name: Blair Savage CoI_Institution: University of Wisconsin - Madison Contact: N ! Y or N (designate at most one contact) CoI_Name: Limin Lu CoI_Institution: California Institute of Technology Contact: N ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) Understanding the origin and properties of the high velocity cloud (HVC) system in the Milky Way has been a persistent problem for more than half a century. However, significant advances in studying HVCs have been made with the Hubble Space Telescope, and it is now possible to determine abundances and ionization properties of some HVCs through diagnostic line ratios at ultraviolet wavelengths. We recently discovered a pair of highly ionized HVCs in a Cycle 4 investigation of the C IV halo gas absorption toward the AGN Markarian 509. The HVCs are unique in their ionization properties for Galactic HVCs; they have been detected only in C IV and their general absorption properties more closely resemble those of the high ionization quasar metal line absorption systems than those for most interstellar clouds found in the Milky Way disk or halo. We request GHRS intermediate resolution observations of the strong resonance lines of C II and Si II-III-IV to study the ionization processes in the C IV HVCs toward Mrk 509. When combined with our existing C IV, N V, and Si II data, the proposed observations will allow us to distinguish between different ionization mechanisms believed to be operating in the Galactic halo. The results of this investigation have implications for the origin of the HVCs, the ionization of gas at large distances from the Galactic plane, and the relationship between Milky Way halo gas and gas in the halos of galaxies at high redshifts. Questions ! Free format text (please update) Observing_Description: We will obtain GHRS G160M observations of the interstellar lines in the 1200, 1330, and 1400 A spectral regions of Markarian 509. The large science aperture observations are designed to produce S/N = 10 per resolution element at a resolution (FWHM) of 16-18 km/sec. The strong spectral lines to be studied include C II 1334, Si II 1190, 1193, Si III 1206, and Si IV 1393, 1400. Strong lines of N I and S III will also be covered by the observations. Real_Time_Justification: No special scheduling requirements are necessary. Calibration_Justification: No special calibration requirements are necessary. Additional_Comments: No additional comments at this time. Fixed_Targets Target_Number: 1 Target_Name: MRK509 Alternate_Names: IRAS20414-1054 Description: Galaxy, Seyfert Position: RA = 20H 44M 9.75S +/- 0.1S, DEC = -10D 43' 24.53" +/- 1.0", PLATE-ID=00E1 Equinox: J2000 RV_or_Z: Z = 0.0355 RA_PM: Dec_PM: Epoch: Annual_Parallax: Flux: V = 13.0, F-CONT(1200) = 7.0 +/- 2.0 E-14, F-CONT(1330) = 6.0 +/- 2.0 E-14, F-CONT(1400) = 4.9 +/- 2.0 E-14 Comments: Fluxes from FOS G130H spectrum of Mrk 509 (1993). Visits Visit_Number: 1 Visit_Requirements: On_Hold_Comments: Visit_Comments: Number exposures beginning with 1. Exposure_Number: 1 Target_Name: MRK509 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Optional_Parameters: BRIGHT=RETURN,SEARCH-SIZE=3 Number_of_Iterations: 1 Time_Per_Exposure: 7.2S Special_Requirements: ONBOARD ACQ FOR 2-5 Comments: STEP-TIME=0.8 seconds. This worked fine before in GO program #3463. Exposure_Number: 2 Target_Name: MRK509 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1198.0 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=DEF, CENSOR=YES Number_of_Iterations: 2 Time_Per_Exposure: 1523.2S Comments: N I, Si II, Si III, S III Exposure_Number: 3 Target_Name: MRK509 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1198.0 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=DEF, CENSOR=YES Number_of_Iterations: 2 Time_Per_Exposure: 1523.2S Comments: N I, Si II, Si III, S III Exposure_Number: 4 Target_Name: MRK509 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1319.2 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=DEF, CENSOR=YES Number_of_Iterations: 3 Time_Per_Exposure: 1196.8S Comments: Si II, C II, C II* Exposure_Number: 5 Target_Name: MRK509 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1400.0 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=DEF, CENSOR=YES Number_of_Iterations: 4 Time_Per_Exposure: 1305.6S Comments: Si IV Data_Distribution Medium: 8MM Blocking_Factor: 10 Ship_To: PI_Address Ship_Via: UPS Recipient_Email: