5888( 9) - 11/22/95 09:00 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5888 Version: 9 Check-in Date: ********** 1.Proposal Title: Probing Tidal Debris in M 81 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Katherine Roth University of Hawaii, IfA CoI: David Bowen Space Telescope Science Institute N CoI: J. C. Blades Space Telescope Science Institute N ------------------------------------------------------------------------------------ 6. Abstract We propose GHRS G270M spectral observations of the bright nucleus of M 81 in order to probe the extent of the tidal debris giving rise to the complex Mg II absorption toward the bright supernova SN 1993J. We have found no evidence of this material in Na I spectra obtained toward M 81 with the KPNO coud'e feed earlier this year. Our Mg II observations will provide a more sensitive search for this gas and will sample material within which Na I cannot exist. In addition, these observations provide a rare opportunity to probe the entire extent of the Milky Way halo in two sightlines separated by only 2.6' on the sky. ------------------------------------------------------------------------------------ 5888( 9) - 11/22/95 09:00 - [ 2] Observations Description ------------------------ We are proposing GHRS G270M spectral observations of Mg II absorption toward the bright nucleus of NGC 3031 (M 81). We have retrieved the IUE spectrum from the on-line version of the Kinney et al.\ 1993 Atlas of Ultraviolet Spectra of Star -Forming Galaxies, from which we measure a flux at Lambda = 2800 of 1.0times10^-14 erg cm^-2 s^-1 AA^-1. The G270M grating has a sensitivity at this wavelength of S_lambda=46.73*10^11 counts s^-1 diode^-1 (erg cm^-2 s^-1 AA^ -1)^-1 (Table 8-2, GHRS Handbook 5.0). This gives us a predicted detection rate of 0.0467 counts s^-1 diode^-1. Assuming an average dark count in the D2 detector of 0.011 counts s^-1 diode^-1, we require ~ 3 hours of integration for a S/N ratio diode^-1 of 20. We have distributed this time into CVZ orbits assuming 96 minutes of visibility, a 12 minute guide star acquisition (with no subsequent reacquisitions necessary), an 11 minute large science aperture target acquisition, a 3 minute spybal, with the rest of the time devoted to 20 minute FPSPLITs with their associated 4 minute overheads. In three orbits we will actually have 3.7 hours of integration allowing us to achieve a signal-to- noise ratio of 22. Real Time Justification ----------------------- We are taking advantage of the high declination of our object to request observations in the continuous viewing zone. At this R.A. and Dec. (09 55.5, +69 04) there were 3 CVZ opportunities last year for a total of 110 hours. We are requesting only 3 orbits (4.8 hours) for this program, so we feel the extra efficiency afforded by the CVZ outweighs the slight scheduling risks associated with CVZ status. As described, we obtained high resolution Na I absorption data toward the nucleus of M 81 during 3 clear nights at the KPNO coud'e feed in early March of this year. We have no further plans for coordinated ground- based observations. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5888( 9) - 11/22/95 09:00 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3031-NUC EXT-MEDIUM, HI CLOUD, RA = 09H 55M 33.190S +/-0.001S, J2000 V = -34 V = 6.9 SURF(R) = 13.5 B-V = 1.0 E(B-V) HIGH VELOCITY CLOUD, DEC = +69D 03' 55.11" +/-0.01", = 0.04 F(2800) = 1.0 E-14 SIZE = 1.2 TIDAL TAIL, IGM; PLATE-ID=00M9 GALAXY, SPIRAL, Comments: 26.9' X 14.1' full size; Coordinates measured from 3/95 PC image 5888( 9) - 11/22/95 09:00 - [ 4] Visit: 01 Visit Requirements: CVZ 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 ------------------------------------------------------------------------------------------------------------------------------------ 101 NGC3031-NUC HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 18S ONBOARD ACQ FOR 102-103 Comments: STEP-TIME = 2S ------------------------------------------------------------------------------------------------------------------------------------ 102 WAVE HRS ACCUM SC2 G270M 2794.3 SPYBAL = YES 1 DEF - 2806.0 ------------------------------------------------------------------------------------------------------------------------------------ 103 NGC3031-NUC HRS ACCUM 2.0 G270M 2794.3 FP-SPLIT = TWO, 25 598.4S - STEP-PATT = 5, 2806.0 SPYBAL = NO Comments: Exposure time = 11x2(27.2)s ------------------------------------------------------------------------------------------------------------------------------------ 5888( 9) - 11/22/95 09:00 - [ 5] Summary Form for Proposal 5888 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SPYBAL = YES SPYBAL = NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ONBOARD ACQ FOR 102-103 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G270M ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3031-NUC WAVE ------------------------------------------------------------------------------------------------------------------------------------