Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5459 Report Date: 18-Jul-95:17:26 Version: ********** Check-in Date: ********** 1.Proposal Title: ULTRAVIOLET INTERSTELLAR POLARIZATION CYCLE 4 HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GO 1 Long Term yrs Sub Category DUST ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone William Somerville 8090 UK 071-387-7050 X ------------------------------------------------------------------------------------ 7. Abstract Spectropolarimetric observations in the ultraviolet give unique information relevant to the size and shape distributions, the chemical composition and alignment properties of the interstellar dust grains, and the carrier of the strong absorption feature at 2175A. This work addresses four principal observational questions: does the empirical polarization curve (Serkowski's Law) extend into the UV\?; does the 2175A feature show polarization\?; does polarization reflect the strong rise in extinction found in the far-UV\?; are these results different in different directions, and if so how do they relate to other properties of the dust grains\? Targets are selected to have a variety of ultravolet extinction and optical polarization properties. We have observed three stars in Cycle 1, and have been awarded time in Cycle 3 to observe two more, through the full UV range. The recent WUPPE results show that UV polarization can depend on direction, so we propose to increase the number of sightlines studied. With the grating G270H, it will be possible to look for polarization in the profile of the 2175A feature, and departures from the Serkowski curve should also be clearly seen. The most important result from our HST work is that none of the three stars studied shows any trace of polarization associated with the 2175A feature, with very good-quality data. This casts doubt on the excess found by WUPPE in one star only, which it is essential to reobserve with HST and is included in the present target list. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 6.24 par: 0 10. Num targs pri: 6 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5459 PI: William Somerville Proposal Title: ULTRAVIOLET INTERSTELLAR POLARIZATION CYCLE 4 HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ William Somerville 8090 UK X Sir Robert Wilson 8090 UK X David Carnochan 8090 UK X Derek Mcnally 8090 UK X Kashi Nandy 8074 UK X David Morgan 8074 UK X Douglas Whittet 3220 USA Peter Martin 4664 CANADA Sang-Hee Kim 4664 CANADA Jeremy Walsh 5555 GERMANY X ------------------------------------------------------------------------------------ 3. Description of proposed observations. Each target requires observations with the Faint Object Spectrograph, using the Blue Digicon and Waveplate B with the grating G270H. This will cover the wavelength range 2222-3300\AA. The 1.0arcsec circular aperture will be used, and exposure times calculated to give the highest signal-to-noise that is consistent with the expected accuracy of calibration. All the targets are bright, isolated stars. The acquisition sequence will centre the target in the aperture to 0.2 arcsec, to give accurate polarimetry and spectral calibration. Eight position angles will be used, for accurate calibration of the linear polarization and to obtain at least an upper limit on the circular polarization. ------------------------------------------------------------------------------------ 11. Address Information Name: WILLIAM SOMERVILLE Category: PI Institution: 8090 Address: DEPARTMENT OF PHYSICS AND ASTRONOMY, UNIVERSITY COLLEGE LONDON, GOWER STREET, City: LONDON WC1E 6BT State: Zip Code: Country: UK Telephone: 071-387-7050 X 3477 Telex (or e-mail): 28722; SPAN: 19752::WBS ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5459 [ 3] ------------------------------------------------------------------------------------------------------------------------------------ 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 HD22253 A,113,G,508 RA= 3H 37M 44.12S +/- 0.5", 2000 1 V = 6.53 +/- 0.05, B-V = 0.34 +/- GSC5833- DEC = +56D 44' 21.8" +/- 2 0.05 00452 0.5", 3 TYPE=B0.5 III, E(B-V) = 0.61 +/- PLATE-ID=01W1 0.05 F-CONT (2500) = 9.92 +/- 0.67 E-12 Comments: GSC COORDINATES UV FLUXES FROM S2/68 ANOMALOUS UV EXTINCTION ------------------------------------------------------------------------------------------------------------------------------------ 2 HD36629 A,110,G,508 RA= 05H 32M 57.09S +/- 0.5", 2000 1 V = 7.65 +/- 0.05, B-V = 0.02 +/- GSC4774- DEC = -04D 33' 59.1" +/- 2 0.05 00924 0.5", 3 TYPE=B2 V, E(B-V) = 0.27 +/- 0.05 PLATE-ID=02NB F-CONT (2500) = 11.38 +/- 0.47 E- 12 Comments: GSC COORDINATES UV FLUXES FROM S2/68 ANOMALOUS UV EXTINCTION ------------------------------------------------------------------------------------------------------------------------------------ 3 HD38087 A,111,G,508 RA= 05H 43M 00.48S +/- 0.5", 2000 1 V = 8.30 +/- 0.05, B-V = 0.13 +/- GSC4771- DEC = -02D 18' 46.2" +/- 2 0.05 01146 0.5", 3 TYPE=B5 V, E(B-V) = 0.35 +/- 0.05 PLATE-ID=0084 F-CONT (2500) = 4.41 +/- 0.27 E-12 Comments: GSC COORDINATES UV FLUXES FROM S2/68 ANOMALOUS UV EXTINCTION ------------------------------------------------------------------------------------------------------------------------------------ 4 HD161961 A,113,G,508 RA= 17H 48M 36.84S +/- 0.5", 2000 1 V = 7.89 +/- 0.05, B-V = 0.23 +/- GSC5086- DEC = -02D 11' 45.9" +/- 2 0.05 00310 0.5", 3 TYPE=B0.5 III, E(B-V) = 0.51 +/- PLATE-ID=00JP 0.05 F-CONT (2500) = 5.79 +/- 0.34 E-12 Comments: GSC COORDINATES UV FLUXES FROM S2/68 ANOMALOUS UV EXTINCTION ------------------------------------------------------------------------------------------------------------------------------------ 5 HD197770 A,113,G,508 RA= 20H 43M 13.61S +/- 0.5", 2000 1 V = 6.32 +/- 0.05, B-V = 0.33 +/- GSC3959- DEC = +57D 06' 50.1" +/- 2 0.05 01686 0.5", 3 TYPE=B2 III, E(B-V) = 0.56 +/- PLATE-ID=003M 0.05 F-CONT (2500) = 9.91 +/- 0.45 E-12 Comments: GSC COORDINATES UV FLUXES FROM S2/68 ANOMALOUS UV EXTINCTION ------------------------------------------------------------------------------------------------------------------------------------ 6 HD207538 A,110,G,508 RA= 21H 47M 39.78S +/- 0.5", 2000 1 V = 7.29 +/- 0.05, B-V = 0.32 +/- GSC3980- DEC = +59D 42' 01.3" +/- 2 0.05 01047 0.5", 3 TYPE=B0 V, E(B-V) = 0.62 +/- 0.05 PLATE-ID=02X2 F-CONT (2500) = 5.81 +/- 0.39 E-12 Comments: GSC COORDINATES UV FLUXES FROM S2/68 ANOMALOUS UV EXTINCTION ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5459 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD22253 FOS/BL ACQ/ 4.3 G570H TYPE=UP 1 0.8S ONBOARD ACQ FOR 2 PEAK SEARCH-SIZE-X=1 CYCLE 4 / 1-24 SEARCH-SIZE-Y=3 COND IF FOS SCAN-STEP- POLARIMETRY Y=1.204 POSSIBLE WITH COSTAR / 1-24 Comments: COUNT RATE AT 4600 = 3200 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD22253 FOS/BL ACQ/ 1.0 G570H TYPE=UP 1 1.4S ONBOARD ACQ FOR 3 PEAK SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP- X=0.602 SCAN-STEP- Comments: COUNT RATE AT 4600 = 2050 Y=0.602 ------------------------------------------------------------------------------------------------------------------------------------ 3 HD22253 FOS/BL ACQ/ 0.3 G570H TYPE=UP 1 4.0S ONBOARD ACQ FOR 4 PEAK SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 SCAN-STEP- X=0.17 SCAN-STEP- Comments: COUNT RATE AT 4600 = 1300 Y=0.17 ------------------------------------------------------------------------------------------------------------------------------------ 4 HD22253 FOS/BL ACCUM 1.0 G270H POLSCAN=8B 1 44.0M 1440 3 1 Comments: POLARIZATION ERROR 0.1% IN 2 A AT 2500 A REQUIRES 127000 COUNTS IN 1 PIXEL RESULTING IN STATED S/N PER PIXEL IN SUM OF ALL 16 SPECTRA. ------------------------------------------------------------------------------------------------------------------------------------ 5 HD36629 FOS/BL ACQ/ 4.3 G570H TYPE=UP 1 1.6S ONBOARD ACQ FOR 6 PEAK SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP- Y=1.204 Comments: COUNT RATE AT 4600 = 1650 ------------------------------------------------------------------------------------------------------------------------------------ 6 HD36629 FOS/BL ACQ/ 1.0 G570H TYPE=UP 1 2.7S ONBOARD ACQ FOR 7 PEAK SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP- X=0.602 SCAN-STEP- Comments: COUNT RATE AT 4600 = 1060 Y=0.602 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5459 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 7 HD36629 FOS/BL ACQ/ 0.3 G570H TYPE=UP 1 8.0S ONBOARD ACQ FOR 8 PEAK SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 SCAN-STEP- X=0.17 SCAN-STEP- Comments: COUNT RATE AT 4600 = 680 Y=0.17 ------------------------------------------------------------------------------------------------------------------------------------ 8 HD36629 FOS/BL ACCUM 1.0 G270H POLSCAN=8B 1 36.0M 1440 3 1 Comments: POLARIZATION ERROR 0.1% IN 2 A AT 2500 A REQUIRES 127000 COUNTS IN 1 PIXEL RESULTING IN STATED S/N PER PIXEL IN SUM OF ALL 16 SPECTRA. ------------------------------------------------------------------------------------------------------------------------------------ 9 HD38087 FOS/BL ACQ/ 4.3 G570H TYPE=UP 1 2.1S ONBOARD ACQ FOR 10 PEAK SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP- Y=1.204 Comments: COUNT RATE AT 4600 = 1250 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD38087 FOS/BL ACQ/ 1.0 G570H TYPE=UP 1 3.6S ONBOARD ACQ FOR 11 PEAK SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP- X=0.602 SCAN-STEP- Comments: COUNT RATE AT 4600 = 800 Y=0.602 ------------------------------------------------------------------------------------------------------------------------------------ 11 HD38087 FOS/BL ACQ/ 0.3 G570H TYPE=UP 1 11.0S ONBOARD ACQ FOR 12 PEAK SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 SCAN-STEP- X=0.17 SCAN-STEP- Comments: COUNT RATE AT 4600 = 510 Y=0.17 ------------------------------------------------------------------------------------------------------------------------------------ 12 HD38087 FOS/BL ACCUM 1.0 G270H POLSCAN=8B 3 29.0M 1440 3 1 Comments: POLARIZATION ERROR 0.1% IN 2 A AT 2500 A REQUIRES 127000 COUNTS IN 1 PIXEL RESULTING IN STATED S/N PER PIXEL IN SUM OF ALL 16 SPECTRA. ------------------------------------------------------------------------------------------------------------------------------------ 13 HD161961 FOS/BL ACQ/ 4.3 G570H TYPE=UP 1 2.3S ONBOARD ACQ FOR 14 PEAK SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP- Y=1.204 Comments: COUNT RATE AT 4600 = 1150 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5459 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 14 HD161961 FOS/BL ACQ/ 1.0 G570H TYPE=UP 1 3.9S ONBOARD ACQ FOR 15 PEAK SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP- X=0.602 SCAN-STEP- Comments: COUNT RATE AT 4600 = 740 Y=0.602 ------------------------------------------------------------------------------------------------------------------------------------ 15 HD161961 FOS/BL ACQ/ 0.3 G570H TYPE=UP 1 12.0S ONBOARD ACQ FOR 16 PEAK SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 SCAN-STEP- X=0.17 SCAN-STEP- Comments: COUNT RATE AT 4600 = 470 Y=0.17 ------------------------------------------------------------------------------------------------------------------------------------ 16 HD161961 FOS/BL ACCUM 1.0 G270H POLSCAN=8B 3 31.5M 1440 3 1 Comments: POLARIZATION ERROR 0.1% IN 2 A AT 2500 A REQUIRES 127000 COUNTS IN 1 PIXEL RESULTING IN STATED S/N PER PIXEL IN SUM OF ALL 16 SPECTRA. ------------------------------------------------------------------------------------------------------------------------------------ 17 HD197770 FOS/BL ACQ/ 4.3 G570H TYPE=UP 1 0.8S ONBOARD ACQ FOR 18 PEAK SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP- Y=1.204 Comments: COUNT RATE AT 4600 = 3400 ------------------------------------------------------------------------------------------------------------------------------------ 18 HD197770 FOS/BL ACQ/ 1.0 G570H TYPE=UP 1 1.3S ONBOARD ACQ FOR 19 PEAK SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP- X=0.602 SCAN-STEP- Comments: COUNT RATE AT 4600 = 2180 Y=0.602 ------------------------------------------------------------------------------------------------------------------------------------ 19 HD197770 FOS/BL ACQ/ 0.3 G570H TYPE=UP 1 4.0S ONBOARD ACQ FOR 20 PEAK SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 SCAN-STEP- X=0.17 SCAN-STEP- Comments: COUNT RATE AT 4600 = 1390 Y=0.17 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD197770 FOS/BL ACCUM 1.0 G270H POLSCAN=8B 1 44.0M 1440 3 1 Comments: POLARIZATION ERROR 0.1% IN 2 A AT 2500 A REQUIRES 127000 COUNTS IN 1 PIXEL RESULTING IN STATED S/N PER PIXEL IN SUM OF ALL 16 SPECTRA. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5459 [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 21 HD207538 FOS/BL ACQ/ 4.3 G570H TYPE=UP 1 1.4S ONBOARD ACQ FOR 22 PEAK SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP- Y=1.204 Comments: COUNT RATE AT 4600 = 1900 ------------------------------------------------------------------------------------------------------------------------------------ 22 HD207538 FOS/BL ACQ/ 1.0 G570H TYPE=UP 1 2.4S ONBOARD ACQ FOR 23 PEAK SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP- X=0.602 SCAN-STEP- Comments: COUNT RATE AT 4600 = 1220 Y=0.602 ------------------------------------------------------------------------------------------------------------------------------------ 23 HD207538 FOS/BL ACQ/ 0.3 G570H TYPE=UP 1 7.0S ONBOARD ACQ FOR 24 PEAK SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 SCAN-STEP- X=0.17 SCAN-STEP- Comments: COUNT RATE AT 4600 = 780 Y=0.17 ------------------------------------------------------------------------------------------------------------------------------------ 24 HD207538 FOS/BL ACCUM 1.0 G270H POLSCAN=8B 1 74.5M 1440 3 1 Comments: POLARIZATION ERROR 0.1% IN 2 A AT 2500 A REQUIRES 127000 COUNTS IN 1 PIXEL RESULTING IN STATED S/N PER PIXEL IN SUM OF ALL 16 SPECTRA. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5459 [ 8] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters TYPE=UP SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP-Y=1.204 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP-X=0.602 SCAN-STEP-Y=0.602 SEARCH-SIZE-X=5 SEARCH-SIZE-Y=5 SCAN-STEP-X=0.17 SCAN-STEP-Y=0.17 POLSCAN=8B ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 6.24 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category DUST ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2; CYCLE 4 / 1-24; COND IF FOS POLARIMETRY POSSIBLE WITH COSTAR / 1-24 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4 ONBOARD ACQ FOR 6; ONBOARD ACQ FOR 7 ONBOARD ACQ FOR 8 ONBOARD ACQ FOR 10 ONBOARD ACQ FOR 11 ONBOARD ACQ FOR 12 ONBOARD ACQ FOR 14 ONBOARD ACQ FOR 15 ONBOARD ACQ FOR 16 ONBOARD ACQ FOR 18 ONBOARD ACQ FOR 19 ONBOARD ACQ FOR 20 ONBOARD ACQ FOR 22 ONBOARD ACQ FOR 23 ONBOARD ACQ FOR 24 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G570H G270H ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD22253 GSC5833-00452 HD36629 GSC4774-00924 HD38087 GSC4771-01146 HD161961 GSC5086-00310 HD197770 GSC3959-01686 HD207538 GSC3980-01047 ------------------------------------------------------------------------------------------------------------------------------------