Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5422 Report Date: 18-Jul-95:17:21 Version: ********** Check-in Date: ********** 1.Proposal Title: NEUTRAL GAS IN BLUE COMPACT GALAXIES: POPULATION III OR RECENT POLLUTION\? ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO Sub Category GAS & DUST ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Daniel R Kunth 5436 FRANCE 33-1-43201425 ------------------------------------------------------------------------------------ 7. Abstract Using GHRS we have recently obtained the striking evidence that the neutral HI gas in the very metal-poor dwarf galaxy IZw 18 contains oxygen but with very low abundance (roughly 10(-3) times the solar value). Moreover this result shows that the HI is more metal deficient than the nebular gas by a factor of a least 20. If this oxygen had been formed by past star formation episodes, only one of such bursts would be required to form all the metals which would have been subsequently dispersed in the HI gas. Alternatively there is the possibility that metals observed in the HI gas were produced in a pre-galactic era via a population III generation. We propose to test this idea by observing a set of 3 blue compact galaxies with different metallicities (obtained from the HII regions) using the GHRS and the LSA around the Lyman-ALPHA and the OI lambda 1302 regions. We wish to investigate whether the metallicity of the neutral gas is correlated with that of the HII regions, hence giving constraints on the star formation history in these galaxies. The absence of correlation would favor the population III hypothesis. We also expect to catch Galactic high velocity clouds along the line of sight of one of our targets and thus constrain their origin from the derivation of their metal abundances. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 14.93 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5422 PI: Daniel R Kunth Proposal Title: NEUTRAL GAS IN BLUE COMPACT GALAXIES: POPULATION III OR RECENT POLLUTION\? ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Daniel R Kunth 5436 FRANCE X James Lequeux 5468 FRANCE X Miguel Mas-Hesse LABORATORIO DE ASTROFISICA SPAIN X ESPACIAL Y FISICA FUNDAMENTAL Wallace L Sargent 1590 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We propose to observe 3 Blue Compact Galaxies using the following instrumental configuration: GHRS + LSA + G160M centered at 1215 and 1300 A. Under this configuration the GHRS provides ~0.28 A resolution (assuming binning over 4 diodes) in a wavelength range of 34 A. We plan to take two exposures per target with the grating centered at around 1215 A and 1300 A, respectively, dividing each one in sub-exposures around 5 minutes long. In this way we will be able to measure the Lyman-ALPHA (1216 A), OI (1302 A) and SiII (1304 A) lines. By fitting theoretical profiles to the Lyman-ALPHA absorption line it will be possible to derive the neutral hydrogen column density along the line of sight. As a by- product we will have the opportunity to analyze in detail if Lyman-ALPHA appears in emission in these galaxies. By measuring the equivalent widths of the OI and SiII absorption lines we will derive their column densities and hence their abundance relative to hydrogen. The redshifts of the selected galaxies are high enough to disentangle between Galactic and intrinsic absorption lines. All the objects have already been observed with IUE through the 10"x20" aperture in low resolution. They are compact (UV emission extended over around 5"x5") and peaked at the center. We plan to use the flux coming from the star-forming regions to probe the neutral gas in front of the galaxies. Therefore the exact pointing is not critical, and a tolerance of +/- 1" would be acceptable. The coordinates provided correspond to the brightest pixel measured on the digitized PSS scans with GASP. The intrinsic absorption is low, so that a good correlation between optical and UV flux is expected. We plan to acquire the targets by onboard acquisitions with the BRIGHT=RETURN option. We have selected a search size of 3 for the most compact objects, and 5 to avoid problems with UGC5720, which is a bit more extended. The corresponding STEP-TIMES have been estimated from the known optical-UV spectral energy distributions, temptatively scaled down to the LSA size. This observational strategy has been already used with success in IZw18. Page 3 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. All the targets have been observed with IUE at low resolution. The resolution is too poor to even disentangle the galactic from the redshifted lines.This discrimination may also be difficult with the FOS, hence our choice of the GHRS. Only a depression in the continum is noted with IUE around lambda 1300 but the overall signal to noise is too small. The analysis of the Lyman-ALPHA region with IUE is hampered by the geocoronal line. In most of the cases the GHRS instrumental profiles will be wider than the intrinsic absorption lines, so that the dispersion velocity of the gas can not be measured directly. Since most of the lines will be located on the saturated range of the curve of groth, knowledge of the dispersion velocity is needed to properly derive the corresponding column densities. To circumvent this difficulty we will use VLA observations of the targets or apply for VLA time in order to derive the velocity dispersion in the HI cloud: we have already used successfully this method for IZW 18.In the infrared K imaging and spectroscopy will be performed at the CFHT and La Palma in order to have an independant study of the past star-formation on these objects. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The proposed observations are neither real-time nor time critical and can be performed in any temporal order. The expected countrate during acquisition might be of the same order than the contribution due to geocoronal Lyman-ALPHA. Furthermore, strong geocoronal Lyman-ALPHA emission could hamper the detection of intrinsic Lyman-ALPHA emission, although this should appear 2-5 A redshifted. We have therefore requested DARK-TIME both for acquisition and for execution of the observations with the grid centered at 1215 A. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. the standard GHRS calibration would fulfill our requirements. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. The efficiency in using HST resources in the proposed way (78%) is very high, obtaining an important scientific return with low loss of spacecraft time. Page 4 ------------------------------------------------------------------------------------ 9. Description of previous HST work. GO Program: 2078 Title: A Search for Primordial Gas: is I Zw 18 a Young Galaxy? PI,Co-Is: J. Lequeux,D. Kunth, W. Sargent and F. Viallefond GO Program: 2424 Title: Quasar Absorption Line Survey PI,Co-Is: J. Bahcall, W. Sargent (plus some other investigators) GO Program: 3810 Title: The Stellar Population of Wolf-Rayet Galaxies PI,Co-Is: P. Conti, W. Sargent (plus some other investigators) GO Program: 3507 Title: Ultra-violet Spect. and High-Resolution Imaging of 4395 PI,Co-Is: A. Filippenko, W. Sargent GO Program: 3746 Title: The cooling of the local diffuse interstellar matter PI,Co-Is: C. Gry, J. Lequeux (plus some other investigators) GO Program: 3759 Title: Dust, molecular, atomic composition etc... PI,Co-Is: F. Boulanger, J. Lequeux (plus some other investigators) GO Program: 3589 Title: Parallel high-resolution imaging of diff. obj. in the MCs PI,Co-Is: J. Walsh, J. Lequeux (plus some other investigators) Related: id=2078. Completed. Paper submitted to A&A. HI gas in IZw 18 contains a very small, but not null, abundance of heavy elements and may be either primeval with enrichment by Population III or enriched by previous star formation. "HST Observations of NGC 4395, the Least Luminous Seyfert 1 Nucleus: Evidence Against the Starburst Hypothesis for Broad-Lined Active Galactic Nuclei." A. V. Filippenko, L. C. Ho, and W. L. W. Sargent; Astrophysical Journal (Letters), in press (June 20, 1993 issue). "The HST Quasar Absorption Line Key Project I. First Observational results, Including Lyman-ALPHA and Lyman Limit Systems." J. Bahcall and 11 other authors; Ap. J.; 000; 000,; 1993 (in press) "The HST Quasar Absorption Line Key Project II. Data Calibration and Absorption Line Selection."; D. Schneider and 11 other authors; Ap. J .; 000; 000,; 1993 (in press). "The HST Quasar Absorption Line Key Project III. First Observational Results on the Milky way Gas." B. Savage and 13 other authors; Ap. J.; 000; 000,; 1993 (in press). ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). All the participants have free access to the scientific infrastructure of their respective institutes, including data-analysis facilities already available, libraries, electronic networks and so on. They are also financially supported by the corresponding institutions and can dedicate all the time needed to the completion of this research programme. ------------------------------------------------------------------------------------ 11. Address Information Name: DANIEL R KUNTH Category: PI Institution: 5436 Address: 98BIS BOULEVARD ARAGO City: PARIS State: Zip Code: 75014 Country: FRANCE Telephone: 33-1-43201425 Telex (or e-mail): 205671 IAU F / KUNTH@IAP.FR ------------------------------------------------------------------------------------ Name: Category: CON Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5422 [ 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 UGC5720 E, 307 RA = 10H 32M 31.83S +/- J2000.0 V = EXT 1 V = 13.0 +/- 0.2 HARO2 0.02S, +1461 1 B-V = 0.36 +/- 0.4 GSC03816- DEC = +54D 24' 3.5" +/- 0.2" 2 E(B-V) = 0.20 +/- 0.05 00902 3 F-CONT(1300) = 60 +/- 6 E-15 4 F-CONT(1215) = 67 +/- 7 E-15 5 F-CONT(5500) = 34 +/- 4 E-16 Comments: CONTINUUM FLUXES THROUGH 2"X2" APERTURE ------------------------------------------------------------------------------------------------------------------------------------ 2 UGC9560 IIZW E, 307 RA = 14H 50M 56.50S +/- J2000.0 V = EXT 1 V = 14.6 +/- 0.1 70 GSC02561- 0.02S, +1218 1 B-V = 0.26 +/- 0.6 00455 DEC = +35D 34' 17.8" +/- 2 E(B-V) = 0.05 +/- 0.05 0.2" 3 F-CONT(1300) = 40 +/- 4 E-15 4 F-CONT(1215) = 36 +/- 4 E-15 5 F-CONT(5500) = 10 +/- 1 E-16 Comments: CONTINUUM FLUXES THROUGH 2"X2" APERTURE ------------------------------------------------------------------------------------------------------------------------------------ 3 MRK36 HARO4 E, 307 RA = 11H 4M 58.38S +/- J2000.0 V = +646 EXT 1 V = 15.4 +/- 0.2 0.05S, 1 B-V = 0.28 +/- 0.4 DEC = +29D 8' 15.2" +/- 0.5" 2 E(B-V) = 0.05 +/- 0.05 3 F-CONT(1300) = 20 +/- 3 E-15 4 F-CONT(1215) = 26 +/- 3 E-15 5 F-CONT(5500) = 3.0 +/- 0.3 E-16 Comments: CONTINUUM FLUXES THROUGH 2"X2" APERTURE ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5422 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 UGC5720 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 250S 30 1 3 CYCLE 4 SEARCH-SIZE=5 10S 2 ONBOARD ACQ FOR 2- LOCATE=YES 3 3 5 Comments: 10000 CTS EXPECTED IN STEP- TIME=10S. ------------------------------------------------------------------------------------------------------------------------------------ 2 UGC5720 HRS ACCUM 2.0 G160M 1210- STEP-PATT=DEF 6 20M 11 4 3 CYCLE 4 1240 FP-SPLIT=FOUR 120M DARK TIME DOPPLER=ON GROUP 2-3 NO GAP Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ 3 UGC5720 HRS ACCUM 2.0 G160M 1290- STEP-PATT=DEF 4 22M 13 3 3 CYCLE 4 1320 FP-SPLIT=FOUR 88M DOPPLER=ON Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ 4 UGC9560 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 500S 30 1 1 CYCLE 4 SEARCH-SIZE=5 20S 2 ONBOARD ACQ FOR 5- LOCATE=YES 3 6 5 Comments: 10000 CTS EXPECTED IN STEP- TIME=20S. ------------------------------------------------------------------------------------------------------------------------------------ 5 UGC9560 HRS ACCUM 2.0 G160M 1210- STEP-PATT=DEF 4 20M 8 4 1 CYCLE 4 1240 FP-SPLIT=DSFOUR 140M DARK TIME DOPPLER=ON GROUP 5-6 NO GAP Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ 5.1 UGC9560 HRS ACCUM 2.0 G160M 1210- STEP-PATT=DEF 3 20M 8 4 1 CYCLE 4 1240 FP-SPLIT=DSFOUR 140M DARK TIME DOPPLER=ON GROUP 5-6 NO GAP Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ 6 UGC9560 HRS ACCUM 2.0 G160M 1290- STEP-PATT=DEF 6 21M 12 3 1 CYCLE 4 1320 FP-SPLIT=FOUR 126M DOPPLER=ON Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ 7 MRK36 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 750S 30 1 2 CYCLE 4 SEARCH-SIZE=5 30S 2 ONBOARD ACQ FOR 8- LOCATE=YES 3 9.1 5 Comments: 10000 CTS EXPECTED IN STEP- TIME=30S. ------------------------------------------------------------------------------------------------------------------------------------ 8 MRK36 HRS ACCUM 2.0 G160M 1210- STEP-PATT=DEF 5 21M 8 4 2 CYCLE 4 1240 FP-SPLIT=FOUR 210M DARK TIME DOPPLER=ON GROUP 8-9.1 NO GAP Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5422 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 8.1 MRK36 HRS ACCUM 2.0 G160M 1210- STEP-PATT=DEF 5 21M 8 4 2 CYCLE 4 1240 FP-SPLIT=FOUR 210M DARK TIME DOPPLER=ON GROUP 8-9 NO GAP Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ 9 MRK36 HRS ACCUM 2.0 G160M 1285- STEP-PATT=DEF 5 20M 10 3 2 CYCLE 4 1315 FP-SPLIT=FOUR 200M DOPPLER=ON Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ 9.1 MRK36 HRS ACCUM 2.0 G160M 1285- STEP-PATT=DEF 5 20M 10 3 2 CYCLE 4 1315 FP-SPLIT=FOUR 200M DOPPLER=ON Comments: S/N FOR CONTINUUM PER DIODE. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5422 [ 8] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=5 LOCATE=YES STEP-PATT=DEF FP-SPLIT=FOUR DOPPLER=ON FP-SPLIT=DSFOUR FP-SPLIT= FOUR ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 14.93 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category GAS & DUST ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; ONBOARD ACQ FOR 2-3; DARK TIME; GROUP 2-3 NO GAP; ONBOARD ACQ FOR 5-6; GROUP 5-6 NO GAP; ONBOARD ACQ FOR 8-9.1; GROUP 8-9.1 NO GAP; GROUP 8-9 NO GAP; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names UGC5720 HARO2 GSC03816-00902 UGC9560 IIZW 70 GSC02561-00455 MRK36 HARO4 ------------------------------------------------------------------------------------------------------------------------------------