Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5408 Report Date: 18-Jul-95:17:19 Version: ********** Check-in Date: ********** 1.Proposal Title: STAR CLUSTERS AND CNO ABUNDANCES IN BLUE COMPACT GALAXIES WITH EXTREMELY LOW OXYGEN ABUNDANCE ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO Sub Category EVOLUTION/COSMOLOGY ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Trinh X Thuan UNIVERSITY OF VIRGINIA USA 804-924-7494 ------------------------------------------------------------------------------------ 7. Abstract WE PROPOSE TO OBTAIN HIGH-RESOLUTION IMAGING, UV AND OPTICAL SPECTROSCOPY OF THREE OF THE MOST METAL-DEFICIENT BLUE COMPACT GALAXIES (BCG) IN THE SECOND BYURAKAN OBJECTIVE PRISM SURVEY, SBS 0125-065 (Z=Z(ORION)/22), SBS 0335-052 (Z=Z(ORION)/30) AND SBS 1415+437 (Z=Z(ORION)/20). THE HIGH-RESOLUTION IMAGING WILL ALLOW TO DETERMINE THE SIZES (OR UPPER LIMITS), LUMINOSITIES AND COLORS OF THE IONIZING STAR CLUSTERS. DOES THE TREND TOWARDS MORE MASSIVE AND LARGER STAR CLUSTERS SEEN IN MODERATELY METAL- DEFICIENT IRREGULAR GALAXIES CONTINUE TOWARD EXTREMELY METAL- DEFICIENT BCGS? THESE OBSERVATIONS WILL PUT CONSTRAINTS ON THEORIES OF GAS COLLAPSE AND FRAGMENTATION IN LOW-METALLICITY ENVIRONMENTS. THEY WILL ALSO ALLOW US TO STUDY THE ENVIRONMENT OF THESE STAR CLUSTERS: IS THERE AN UNDERLYING OLD STELLAR POPULATION CO-EXISTENT WITH THE YOUNG STELLAR POPULATION? ARE THERE VISIBLE SIGNS OF A STELLAR WIND? THE UV AND OPTICAL SPECTROSCOPY WILL ALLOW TO DERIVE ACCURATE CNO ABUNDANCES. THESE MEASUREMENTS WILL CONSTRAIN POSSIBLE FORMATION AND CHEMICAL EVOLUTION SCENARIOS AND SHED LIGHT ON THE QUESTION OF WHETHER BCGS ARE YOUNG OR OLD GALAXIES. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 17.33 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS FOS WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5408 PI: Trinh X Thuan Proposal Title: STAR CLUSTERS AND CNO ABUNDANCES IN BLUE COMPACT GALAXIES WITH EXTREMELY LOW OXYGEN ABUNDANCE ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Trinh X Thuan USA Valentin A Lipovetsky RUSSIA Yuri I Izotov UKRAINE ------------------------------------------------------------------------------------ 3. Description of proposed observations. WE WISH TO USE THE FOS TO OBTAIN UV AND OPTICAL SPECTRA, THE WFPC2 TO OBTAIN V AND I PICTURES, AND THE GHRS TO OBTAIN HIGH-RESOLUTION UV SPECTRA OF 3 BLUE COMPACT GALAXIES (BCGs), TO RESPECTIVELY DERIVE THEIR CNO ABUNDANCES, STUDY THE PROPERTIES OF THEIR STAR CLUSTERS, AND DERIVE THE METAL CONTENT OF THEIR NEUTRAL HYDROGEN GAS ENVELOPE. THE 3 PROPOSED BCGS HAVE BEEN CHOOSEN OUT OF A COMPLETE SAMPLE OF 400 BCGS DISCOVERED IN THE SECOND BYURAKAN OBJECTIVE PRISM SURVEY BECAUSE THEY ARE THE BEST CANDIDATES FOR BEING PRIMEVAL GALAXIES: 1) THEY ARE AMONG THE MOST METAL-DEFICIENT BCGS IN THE SAMPLE: SBS 0125-065 HAS Z=Z(ORION)/22, SBS 0335-052 HAS Z=Z(ORION)/30 AND SBS 1415+437 HAS Z=Z(ORION)/20. FOR COMPARISON, IZW18 HAS Z= Z(ORION)/35. 2) THEY ARE VERY COMPACT AND HAVE A LARGE SURFACE BRIGHTNESS (19 B MAG/SQUARE ARCSEC). 3) THEY CONTAIN LARGE AMOUNT OF NEUTRAL HYDROGEN (> 1E9 SOLAR MASSES) AND A LARGE GAS MASS FRACTION (> 60 PERCENT). 4) THEY DO NOT SHOW AN UNDERLYING EXTENDED LOW-SURFACE-BRIGHTNESS COMPONENT ON DEEP CCD V PICTURES, INDICATIVE OF A LACK OF AN OLDER STELLAR POPULATION. The spectroscopy for each given target should be done as GROUP NO GAP as specified by the special requirements. The imaging ( which, by the way is independent of the spectroscopy, and is NOT intended as EARLY ACQ imaging for the spectroscopy ) for a given target should be done all at the SAME POS ( SAME POS = same position AND same orientation angle ). It is very important that the images of a given target be made at the same position and orient angle for facilitation of co-addition and cosmic-ray removal. The images should be made within a reasonably close time of each other, while the same ORIENT angle is still obtainable via off-nominal rolls of the HST for a given date. The GROUP WITHIN 7D special requirement is intended to help us avoid the situation of having to wait a year to get the same orientation for the second set of observations as the first. This period of time ( 7 days ) may be relaxed if necessary for scheduling as long as the requirements of same position and same orientation for all images of a given target are met. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. FOR THE SPECTROSCOPIC STUDIES, THE USE OF HST IS ESSENTIAL BECAUSE UV SPECTRA ARE NEEDED AND THE OBJECTS ARE FAINT ENOUGH THAT THE PROPOSED OBSERVATIONS CANNOT BE CARRIED OUT WITH IUE. TO DETECT THE CIII] 1909 LINE IN THE BCG IZW18, DUFOUR ET AL. (1988) NEEDED TO EXPOSE FOR 36 HOURS WITH IUE. FOR THE IMAGING STUDIES, THE HIGH RESOLUTION OF HST (FWHM=0.1AS) IS REQUIRED TO RESOLVE THE BCGS INTO STAR CLUSTERS. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. NONE ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. NONE Page 3 ------------------------------------------------------------------------------------ 8. Additional comments or special requests. NONE ------------------------------------------------------------------------------------ 9. Description of previous HST work. NONE ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). THE UNIVERSITY OF VIRGINIA IS EQUIPPED WITH IMAGE PROCESSING SYSTEMS INCLUDING WORKSTATIONS OF VARIOUS TYPES (SUN, VAX, ETC.). ------------------------------------------------------------------------------------ 11. Address Information Name: TRINH X THUAN Category: PI Institution: Address: UNIVERSITY OF VIRGINIA, CARRUTHERS HALL City: CHARLOTTESVILLE State: VA Zip Code: 22903 Country: USA Telephone: 804-924-7494 Telex (or e-mail): THUAN@VIRGINIA.EDU ------------------------------------------------------------------------------------ Name: Category: CON Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5408 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 2 SBS0125-065 E, RA = 01H 27M 35.47S +/- J2000.0 Z = EXT 1 V =15.03 +/- 0.05 MKN 996 307,922,928 0.07S, 0.0052 2 B-V = 0.44 +/- 0.05 DEC = -06D 19' 35.9" +/- 3 F(1900) = 50 +/- 20 E-16 1.0", 4 F(4500) = 10 +/- 3 E-16 PLATE-ID=04MW 5 F(6500) = 5 +/- 2 E-16 6 SURF(V) = 21.0 +/- 1.0 7 SURF(I) = 21.0 +/- 1.0 8 SIZE = 1.0 +/- 0.3 Comments: UNLIKE OTHER TARGETS IN THIS PROGRAM, THERE IS NO -OFFSET STAR USED HERE. ACQUIRE THE TARGET DIRECTLY ON THE BRIGHT NUCLEUS OF THE GALAXY. ------------------------------------------------------------------------------------------------------------------------------------ 3 SBS0335-052- J, RA = 03H 37M 45.74S +/- J2000.0 1 V = 13.3 +/- 0.3 OFFSET 707 0.07S, DEC = -05D 3' 31.20" +/- 1.0", PLATE-ID=044L Comments: OFFSET STAR FOR ACQUISITION ------------------------------------------------------------------------------------------------------------------------------------ 4 SBS0335-052 E, RA = 03H 37M 43.989S +/- J2000.0 Z = EXT 1 V = 16.24 +/- 0.05 307,922,928 0.07S, 0.0137 2 B-V = 0.32 +/- 0.05 DEC = -05D 2' 38.95" +/- 3 SURF(V) = 21.0 +/- 1.0 1.0", 4 SURF(I) = 21.0 +/- 1.0 PLATE-ID=044L 5 SIZE = 1.0 +/- 0.3 6 F(1232) = 100 +/- 30 E-14 7 F(1319) = 100 +/- 30 E-14 ------------------------------------------------------------------------------------------------------------------------------------ 5 SBS1415+437- J, RA = 14H 17M 00.26S +/- J2000.0 1 V = 14.1 +/- 0.4 OFFSET 707 0.07S, DEC = +43D 29' 42.4" +/- 1.0", PLATE-ID=00XZ Comments: OFFSET STAR FOR ACQUISITION ------------------------------------------------------------------------------------------------------------------------------------ 6 SBS1415+437 E, RA = 14H 17M 1.392S +/- J2000.0 Z = EXT 1 V = 16.0 +/- 0.5 CG 389 307,922,928 0.07S, 0.0021 2 B-V = 0.0 +/- 0.1 DEC = +43D 30' 4.94" +/- 3 F(1900) = 50 +/- 20 E-16 1.0", 4 F(4500) = 10 +/- 3 E-16 PLATE-ID=00XZ 5 F(6500) = 5 +/- 2 E-16 6 SURF(V) = 21.0 +/- 1.0 7 SURF(I) = 21.0 +/- 1.0 8 SIZE = 1.0 +/- 0.3 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5408 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 SBS0125-065 FOS/RD ACQ/ 4.3 MIRROR BRIGHT=33000.0 1 3S 1 2 ONBOARD ACQ FOR BINARY 2 2.0-4.0 GROUP 2.0-4.0 NO GAP CYCLE 4 Comments: BRIGHT NUCLEUS IS USED FOR ACQUISITION ------------------------------------------------------------------------------------------------------------------------------------ 2 SBS0125-065 FOS/RD ACCUM 1.0 G190H 1 31M 40 3 2 CYCLE 4 8 ------------------------------------------------------------------------------------------------------------------------------------ 3 SBS0125-065 FOS/RD ACCUM 1.0 G400H 1 16M 30 4 2 CYCLE 4 8 ------------------------------------------------------------------------------------------------------------------------------------ 4 SBS0125-065 FOS/RD ACCUM 1.0 G570H 1 22M 20 5 2 CYCLE 4 8 ------------------------------------------------------------------------------------------------------------------------------------ 5 SBS0125-065 WFPC2 IMAGE WF3 F569W 5623 CR-SPLIT=0.5 1 30M 30 6 2 CYCLE 4 CR- SAME POS FOR 6 AS TOLERANCE=0.0 5 GROUP 5-6 WITHIN 7D Comments: "GROUP 5-6 WITHIN" PERIOD MAY BE RELAXED SO LONG AS THE SAME POSITION AND ORIENT ANGLE ARE MAINTAINED AND THE DATA ARE TAKEN FAIRLY CLOSE TOGETHER IN TIME (E.G. NOT A YEAR APART). ------------------------------------------------------------------------------------------------------------------------------------ 6 SBS0125-065 WFPC2 IMAGE WF3 F791W 7829 CR-SPLIT=0.5 1 76M 30 7 2 CYCLE 4 CR- TOLERANCE=0.0 Comments: CR-SPLIT=0.5 & CR-TOLERANCE =0.0 TOGETHER YIELD 2 X 900S EXPOSURES IN F569W & 2 X 2200S EXPOSURES IN F791W. EACH SUBEXP IN F791W WILL BE ROUNDED DOWN BY 80S FOR A DECREASE OF 160S. ------------------------------------------------------------------------------------------------------------------------------------ 7 SBS0335-052 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 54S 1 1 ONBOARD ACQ FOR -OFFSET 8.0-9.0 CYCLE 4 Comments: STEP-TIME=6S ------------------------------------------------------------------------------------------------------------------------------------ 8 SBS0335-052 HRS ACCUM 2.0 G160M 1232 FP-SPLIT=DSFOUR 6 20M 7 6 1 CYCLE 4 5 ------------------------------------------------------------------------------------------------------------------------------------ 9 SBS0335-052 HRS ACCUM 2.0 G160M 1319 FP-SPLIT=DSFOUR 6 20M 7 7 1 CYCLE 4 5 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5408 [ 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 SBS0335-052 WFPC2 IMAGE WF3 F569W 5623 CR-SPLIT=0.5 1 30M 30 3 1 CYCLE 4 CR- SAME POS FOR 11 AS TOLERANCE=0.0 10 GROUP 10-11 WITHIN 7D Comments: "GROUP 10-11 WITHIN" PERIOD MAY BE RELAXED SO LONG AS THE SAME POSITION AND ORIENT ANGLE ARE MAINTAINED AND THE DATA ARE TAKEN FAIRLY CLOSE TOGETHER IN TIME (E.G. NOT A YEAR APART). ------------------------------------------------------------------------------------------------------------------------------------ 11 SBS0335-052 WFPC2 IMAGE WF3 F791W 7829 CR-SPLIT=0.5 1 76M 30 4 1 CYCLE 4 CR- TOLERANCE=0.0 Comments: CR-SPLIT=0.5 & CR-TOLERANCE =0.0 TOGETHER YIELD 2 X 900S EXPOSURES IN F569W & 2 X 2200S EXPOSURES IN F791W. EACH SUBEXP IN F791W WILL BE ROUNDED DOWN BY 80S FOR A DECREASE OF 160S. ------------------------------------------------------------------------------------------------------------------------------------ 12 SBS1415+437 FOS/RD ACQ/ 4.3 MIRROR BRIGHT=33000.0 1 1.6S 1 3 ONBOARD ACQ FOR -OFFSET BINARY 13.0-15.0 GROUP 13.0-15.0 NO GAP CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ 13 SBS1415+437 FOS/RD ACCUM 1.0 G190H 1 31M 40 3 3 CYCLE 4 8 ------------------------------------------------------------------------------------------------------------------------------------ 14 SBS1415+437 FOS/RD ACCUM 1.0 G400H 1 16M 30 4 3 CYCLE 4 8 ------------------------------------------------------------------------------------------------------------------------------------ 15 SBS1415+437 FOS/RD ACCUM 1.0 G570H 1 22M 20 5 3 CYCLE 4 8 ------------------------------------------------------------------------------------------------------------------------------------ 16 SBS1415+437 WFPC2 IMAGE WF3 F569W 5623 CR-SPLIT=0.5 1 30M 30 6 3 CYCLE 4 CR- SAME POS FOR 17 AS TOLERANCE=0.0 16 GROUP 16-17 WITHIN 7D Comments: "GROUP 16-17 WITHIN" PERIOD MAY BE RELAXED SO LONG AS THE SAME POSITION AND ORIENT ANGLE ARE MAINTAINED AND THE DATA ARE TAKEN FAIRLY CLOSE TOGETHER IN TIME (E.G. NOT A YEAR APART). ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5408 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 17 SBS1415+437 WFPC2 IMAGE WF3 F791W 7829 CR-SPLIT=0.5 1 76M 30 7 3 CYCLE 4 CR- TOLERANCE=0.0 Comments: CR-SPLIT=0.5 & CR-TOLERANCE =0.0 TOGETHER YIELD 2 X 900S EXPOSURES IN F569W & 2 X 2200S EXPOSURES IN F791W. EACH SUBEXP IN F791W WILL BE ROUNDED DOWN BY 80S FOR A DECREASE OF 160S. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5408 [ 8] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/RD WFPC2 HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACCUM IMAGE ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=33000.0 CR-SPLIT=0.5 CR-TOLERANCE=0.0 BRIGHT=RETURN FP-SPLIT=DSFOUR ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 17.33 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category EVOLUTION/COSMOLOGY ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2.0-4.0; GROUP 2.0-4.0 NO GAP; CYCLE 4; SAME POS FOR 6 AS 5; GROUP 5-6 WITHIN 7D; ONBOARD ACQ FOR 8.0-9.0; SAME POS FOR 11 AS 10; GROUP 10-11 WITHIN 7D; ONBOARD ACQ FOR 13.0-15.0; GROUP 13.0-15.0 NO GAP; SAME POS FOR 17 AS 16; GROUP 16-17 WITHIN 7D; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G190H G400H G570H F569W F791W MIRROR-N2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names SBS0125-065 MKN 996 SBS0335-052-OFFSET SBS0335-052 SBS1415+437-OFFSET SBS1415+437 CG 389 ------------------------------------------------------------------------------------------------------------------------------------