8096( 3) - 03/07/00 15:54 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8096 Version: 3 Check-in Date: 08-Feb-1999 17:11:26 1.Proposal Title: The interstellar medium near to and beyond the Galactic Center ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Francis Keenan The Queen's University of Belfast CoI: Prof. Philip Dufton Queen's University of Belfast N CoI: Dr. Jonathan Smoker Queen's University of Belfast N CoI: Dr. Robert Ryans Queen's University of Belfast N CoI: Mr. Nicolas Lehner Queen's University of Belfast N CoI: Dr. Kenneth Sembach The Johns Hopkins University Y ------------------------------------------------------------------------------------ 5. Abstract We have recently identified a B-type supergiant, LS 4825, which lies on the far side of the Galaxy, at a Galactocentric distance of R_G = 12 kpc, and whose sightline passes within 1 kpc of the Galactic Center. Optical ionCa2 and ionNa1 interstellar observations of LS 4825 reveal a miriad of intermediate and high velocity clouds, several of which arise from gas near to and beyond the Galactic Center. We now propose to obtain medium resolution STIS spectra, primarily to observe the ultraviolet interstellar lines towards LS 4825. These data will allow us to determine the abundances of important elements such as Mg, Si, S, Cr, Mn, Fe, and Zn (and possibly C, N, and O) in interstellar gas as a function of Galactocentric distance, from the Solar position all the way in to the Galactic Center and beyond, which is vital for testing the competing models for the chemical evolution of our Galaxy. A secondary aim of the STIS observations will be to study the ultraviolet stellar absorption lines in LS 4825, which will provide reliable element abundances for this star, and hence the chemical composition of the interstellar medium at R_G = 12 kpc on the far side of the Galaxy. This will be compared with results at R_G = 12 kpc on the near side, to investigate the azimuthal dependence of the Galactic abundance gradient. ------------------------------------------------------------------------------------ 8096( 3) - 03/07/00 15:54 - [ 2] Observations Description ------------------------ We will use the STIS E140M and E230M gratings to R=30, 000 resolution spectra LS4825 at wavelengths between 1150 and 3100 We will use the 0.2x0.06 slits to preserve the full resolution offered by the echelle gratings. The setting with E140M will cover the 1150-1735A spectral region, and will yield information on the interstellar absorption of C I, C II, C IV, O I, N I, N V, Mg II, Al II, Si II, Si III, Si IV, S II, and S III. Two settings with E230M will cover the 1700 -3100A spectral region, and will yield information on the interstellar absorption of Mg I, Mg II, Si II, Al III, Cr II, Fe II, and Zn II. Real Time Justification ----------------------- None Calibration Justification ------------------------- None Additional Comments ------------------- None ------------------------------------------------------------------------------------ Data Distribution Paper Products: YES Media: 8MM Blocking Factor: 10 Ship To: Kenneth Sembach*Department of Physics & Astronomy*The Johns Hopkins University*3400 N. Charles Street*Baltimore, MD 21218 Ship Via: Email: sembach@pha.jhu.edu ------------------------------------------------------------------------------------ 8096( 3) - 03/07/00 15:54 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LS4825 STAR RA=18H 16M 00.46S +/- 0.02S, J2000 V=+9 V = 11.99 DEC=-30D 45' 23.1" +/-0.30" B-V = 0.05 F-CONT(1300)=5.2e-13 F-CONT(2600)=9.6e-14 Comments: Coords are from GSC. UV fluxes are estimated as described in Phase 1 proposal - comparison to stars of similar spectral type (B1 Ib) in IUE catalog. 8096( 3) - 03/07/00 15:54 - [ 4] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LS4825 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.0 S ONBOARD ACQ FOR 2 CD P Comments: Expect approx 20, 000 counts in 3x3 checkbox. Target acquisition ETC used with GAIN=4 e-/ADU, CR-SPLIT=1, 1x1 binning and B1V Kurucz model scaled to 1.0E-13 at 2600A. ------------------------------------------------------------------------------------------------------------------------------------ 2 LS4825 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.5 S ONBOARD ACQ FOR 3-4 CD K 6 Comments: Need about 5, 000 counts. Get about 17, 000 in 0.5 sec for clear aperture. Thus, assuming 50% slit throughput, we get about 8, 500. Use CCD with MIRROR and GAIN=4, CR-SPLIT=1, 1x1 binning, and B1V Kurucz model scaled to 1.0E-13 at 2600A. ------------------------------------------------------------------------------------------------------------------------------------ 3 LS4825 STIS/F ACCUM 0.2X0.0 E140M 1425 1 2070 S UV-MAM 6 A Comments: Far-UV MAMA exposure covers 1150-1700 A at ~10 km/s resolution. ------------------------------------------------------------------------------------------------------------------------------------ 4 LS4825 STIS/F ACCUM 0.2X0.0 E140M 1425 4 2950 S UV-MAM 6 A Comments: Far-UV MAMA exposure covers 1150-1700 A at ~10 km/s resolution. ------------------------------------------------------------------------------------------------------------------------------------ 8096( 3) - 03/07/00 15:54 - [ 5] Visit: 02 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LS4825 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 2.0 S ONBOARD ACQ FOR 2 CD P Comments: Same as Visit 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 LS4825 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.5 S ONBOARD ACQ FOR 3-5 CD K 6 Comments: Same as Visit 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 LS4825 STIS/N ACCUM 0.2X0.0 E230M 2707 1 2040 S UV-MAM 6 A Comments: Near-UV MAMA exposure covers 2303-3111 A at ~10 km/s resolution. ------------------------------------------------------------------------------------------------------------------------------------ 4 LS4825 STIS/N ACCUM 0.2X0.0 E230M 1978 1 2650 S UV-MAM 6 A Comments: Near-UV MAMA exposure covers 1574-2382 A at ~10 km/s resolution. ------------------------------------------------------------------------------------------------------------------------------------ 5 LS4825 STIS/N ACCUM 0.2X0.0 E230M 1978 1 2950 S UV-MAM 6 A Comments: Near-UV MAMA exposure covers 1574-2382 A at ~10 km/s resolution. ------------------------------------------------------------------------------------------------------------------------------------ 8096( 3) - 03/07/00 15:54 - [ 6] Summary Form for Proposal 8096 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 0.2X0.06 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3-4 ONBOARD ACQ FOR 3-5 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E140M E230M ------------------------------------------------------------------------------------------------------------------------------------ Target Names LS4825 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 2707 1978 ------------------------------------------------------------------------------------------------------------------------------------