Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 3210c Report Date: 09-May-96:18:11 Version: ********** Check-in Date: ********** 1.Proposal Title: R136 G160M CYCLE 2 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GTO/HRS 1188 Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. Dennis C. Ebbets BALL AEROSPACE SYSTEMS USA (303) 939-5964 PRIN MEM TECH STAFF ------------------------------------------------------------------------------------ 7. Abstract This is a new proposal submitted in March, 1992 to define GHRS medium resolution spectra (G160M) of R136 for the purpose of observing interstellar N V absrption lines in the LMC and the MW halo. It is based on exposure lines extracted from the previous cycle 2 proposal, modified now to account for the loss of all side 1 capabilities, and the denial of augmentation time. The observation contains an onboard acquisition, several image mode maps, a wavecal with SC2 and LSA spectra at a central wavelength of 1250. The orientation of the HST is specified to cause the brightest components to align with the long axis of the science diodes, minimizing the spatial smearing of the data. REVISION HISTORY: redlined for phase 2, 7/19/88, dce updated for cycle 1 phase 2 9/21/89 revised lines 1-7 for cycle zero 11/15/90 Revised for cycle 1 exposures February 09, 1991 Revised for cycles 2-5 May 22, 1991 Revised for cycle 2 only March 4, 1992 This proposal uses baseline GTO time only. ------------------------------------------------------------------------------------ 8. Scientific Key Words: ABSORPTION LINE SYSTEM, IGM ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 2.84 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 3210c PI: Dr. Dennis C. Ebbets Proposal Title: R136 G160M CYCLE 2 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Blair D. Savage WISCONSIN, UNIVERSITY OF USA Dennis C. Ebbets BALL AEROSPACE CORPORATION USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Cycle 2 baseline time: R136A LSA G160M 1250 S/N=45 step-patt=2 2 samples per diode width comb=four (def), fp-split=std (4) 12 subexposures, 5.33 minutes each should get 2000 cts/diode in each bin in continuum orient to align brightest components with diodes derive spatial distribution of stars from N2 images construct PSF from FOC image of single star deconvolve to enhance spectral resolution Onboard Acq should use standard search with faint limit Return to brightest point is not required. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. R136 is the brightest object in the LMC. The interstelar spectrum provides information about the entire line of sight, including our Milky Way galaxy and halo, the LMC halo and general interstellar environment, the 30 Doradus region, and the environment in the immediate vicinity of the R136 cluster. Nitrogen V is a good tracer of very hot gas, but its resonance lines are only accessible in the UV near 1240. These GHRS medium resolution spectra will be of higher spectral resolution and signal to noise ratio that was possible with IUE, or the existing ow resolution GHRS spectra obtained in cycle 0. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. Basic requirement was to get roughly 2000 cts/diode in each of two spectral bins. This S/N will show good detail in ISM absorption lines, and should allow at least some enhancement using deconvolution. The LSA is used because the count rate with the SSA would be too low to get decent S/N without a very long exposure. The flux at 1250 was derived from the cycle 0 G140L LSA exposure. The G160M sensitivity was derived from the inflight SV calibration. Sixty four minutes of total exposure time is required. This is broken into 5 minute sub- exposures to minimize magnetic and thermal drifts. The N2 maps are included to verify proper centering in the LSA, and allow construction of a line spread function by combining the observed spatial distribution and relative brightnesses of components of R136 with the FOC UV PSF of a single star. An onboard acq with a double locate is expected to be successful based on the observed initial pointing accuracy and N2 count rate from the cycle 0 observations. Page 3 ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. R136 is a tight cluster with nearly 60 stars visible in the LSA. The 6 brightest components contribute over 53% of the total light. They are arranged in such a way that 5 of them can be made to lie parallel to the long dimension of the science diodes with a judicious orientation of the aperture. I estimate that a line running 45 - 225 degrees measured north through east will give the best alignment. When this is added to the 45 degree GHRS orientation to U3, it gives the specified 90 degrees orientation requested. An orientation of 270 would be fine also. The tolerance +/- 10 degrees was calculated to place the most distant component R136A6 no more than 1/2 science diode width from the optimum alignment. This special orientation will minimize the broadening of the spectrum due to the spatial distribution of the stars, and provide the best possible spectral resolving power while still allowing use of the LSA, and its much more favorable count rate and exposure time. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The spectra will be calibrated and reduced using IDT facility at GSFC, University of Wisconsin and Ball Aerospace. An exact wavelength calibration will be derived from the SC2 wavecal. The 12 subexposures will be aligned and combined to minimize smearing from thermal or magnetic drifts. The spectra will be corrected for scattered light and rectified to a flat continuum. We will derive a line spread function for this observation, and attempt to enhance the resolution using block-iterative, Lucy and Jansson deconvolution algorithms. Features visible in the raw data, and for which the three techniques agree will be regarded as confident detections. All interstellar lines in the recorded region will be identified, analyzed for velocity components and structure, equivalent widths and profiles. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. This proposal reflects GHRS team Baseline GTO observing time for cycle 2 only. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Ebbets and Savage developed, executed and helped analyze virtually all of the GHRS proposals for the Science Verific- cation, Science Assessment and Early Release Observations. R136 was also observed in cycle 0 in proposal 1188. Early results were presented at the Atlanta AAS meeting, and in an upcoming Ap.J. Letter. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Computer facilities, research assistants, travel ------------------------------------------------------------------------------------ 11. Address Information Name: BLAIR D. SAVAGE Category: CON Institution: UNIVERSITY OF WISCONSIN Address: DEPARTMENT OF ASTRONOMY 475 N. CHARTER ST. City: MADISON State: WI Zip Code: 53706 Country: USA Telephone: (608) 262-4909 Telex (or e-mail): ------------------------------------------------------------------------------------ Page 4 Name: DENNIS C. EBBETS Category: PI Institution: BALL AEROSPACE SYSTEMS GROUP Address: GHRS PROJECT AR-1 P.O. BOX 1062 City: BOULDER State: CO Zip Code: 80306 Country: USA Telephone: (303) 939-5964 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 3210c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 R136A G,515,517,H,503,515,517 RA = 5H 38M 42.50S +/- 0.1S, 2000 COMP 1 V = 10.1 HD38268 DEC = -69D 06' 02.8" +/- 1" 2 F-CONT(1250) = 8.0 E-13 Comments: POSITION FROM PC IMAGE MEASURED BY ARCHIE BETWEEN A1 AND A2 UV CONTINUUM FLUXES ESTIMATED FROM G140L OBSERVATIONS IN CYCLE 0. GS PLATE ID = 06B0 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3210c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 R136A HRS ACQ 2.0 MIRROR-N2 FAINT=8000 1 5.0S 50 1 1 ONBOARD ACQ FOR 20 BRIGHT=65535 -80 SEARCH-SIZE=5 CYCLE 2 /10-80 SEQ 10-80 ORIENT 90D +/- 10D / 10-80 Comments: ORIENTATION OF 270 +/- 10D WOULD ALSO BE ACCEPTABLE STEP- TIME = 0.2 SECONDS ------------------------------------------------------------------------------------------------------------------------------------ 20 R136A HRS ACQ/ 2.0 MIRROR-N2 1 20.4S 50 1 1 PEAKUP Comments: STEP-TIME = .2 SECOND ------------------------------------------------------------------------------------------------------------------------------------ 30 R136A HRS IMAGE 2.0 MIRROR-N2 NX=22 1 96.8S 20 1 1 NY=22 ------------------------------------------------------------------------------------------------------------------------------------ 40 R136A HRS IMAGE 2.0 MIRROR-N2 NX=22 1 242S 30 1 1 NY=22 DELTA-X=2 DELTA-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 50 WAVE HRS ACCUM SC2 G160M 1250 STEP-PATT=2 1 64.0S 25 1 CALIB FOR 60 SEQ 50-70 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 60 R136A HRS ACCUM 2.0 G160M 1250 STEP-PATT=2 3 1280.0S 45 2 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 70 WAVE HRS ACCUM SC2 G160M 1250 STEP-PATT=2 1 64.0S 25 1 CALIB FOR 60 ------------------------------------------------------------------------------------------------------------------------------------ 80 R136A HRS IMAGE 2.0 MIRROR-N2 NX=22 1 96.8S 20 1 1 NY=22 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 3210c [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FAINT=8000 BRIGHT=65535 SEARCH-SIZE=5 NX=22 NY=22 DELTA-X=2 DELTA-Y=2 STEP-PATT=2 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/HRS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 2.84 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 20-80; CYCLE 2 /10-80; SEQ 10-80; ORIENT 90D +/- 10D / 10-80; CALIB FOR 60; SEQ 50-70 NO GAP; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names R136A HD38268 ------------------------------------------------------------------------------------------------------------------------------------