Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5342 Report Date: 18-Jul-95:17:12 Version: ********** Check-in Date: ********** 1.Proposal Title: UV Imaging of Intermediate-age Magellanic Cloud Clusters: Hot Stellar Populations in Composite Stellar Systems ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID Cool Stars GO 1 Long Term yrs Sub Category Old Clusters ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Wendy Freedman Observatories of the CIW USA 818 304-0204 ------------------------------------------------------------------------------------ 7. Abstract Hot stars were first recognized to be an important component of galactic spheroids with early vacuum ultraviolet observations of ellipticals and spiral bulges that were made with OAO. Now, 20 years later, we still do not have a full understanding of the VUV evolution of intermediate and old age stellar populations. Using the WFPC2, we therefore propose to undertake an ultraviolet survey of a sample of star clusters spanning a range in age in the Large Magellanic Cloud. The objective of this investigation is to determine the nature of the hot stellar components in rich, intermediate-to-old age LMC clusters. Ground-based optical/IR studies suggest the presence of short-lived hot horizontal branch and post-asymptotic giant branch stars in these clusters but detailed characterizations of the stars require the ultraviolet capability of HST. In this effort we will be aided by the absence of red leaks in the WFPC2 Woods filter and very high angular resolution of the HST. Although old star clusters in the Galaxy and M31 are, and will be, the subjects of intense investigation by HST, OUR SURVEY WILL BE THE FIRST OF ITS KIND FOR POPULATIONS OF INTERMEDIATE AGE. Such systems are critical for interpreting the spectra and colors of high redshift galaxies, and will provide important support to these studies. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.95 par: 0.00 10. Num targs pri: 6 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5342 PI: Wendy Freedman Proposal Title: UV Imaging of Intermediate-age Magellanic Cloud Clusters: Hot Stellar Populations in Composite Stellar Systems ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Wendy Freedman Observatories of the CIW USA John S Gallagher University of Wisconsin USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We propose to use the new WFPC2 with the Woods F160W VUV filter to obtain VUV and the F336W for NUV imaging of 6 rich LMC star clusters with ages of 0.1-10 Gyr. This filter pair provides a good UV color baseline. In an exposure of 1400 -1800s the Woods filter will reach m(1600)=20 with a SNR=30; so we have sufficient sensitivity to explore much of the LMC VUV luminosity function with an efficient series of exposures. ------------------------------------------------------------------------------------ 11. Address Information Name: Wendy Freedman Category: PI Institution: Observatories of the CIW Address: Carnegie Observatories 813 Santa Barbara St. City: Pasadena State: CA Zip Code: 91101 Country: USA Telephone: 818 304-0204 Telex (or e-mail): ------------------------------------------------------------------------------------ Name: John S Gallagher Category: Institution: University of Wisconsin Address: Department of Astronomy 475 North Charter St City: Madison State: WI Zip Code: 53706 Country: USA Telephone: 608 262-3071 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5342 [ 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 NGC1783 D,202 RA = 04h 59m 00s +/- 3", 1950 Dec = -66d 03' 30" +/- 3" ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1856 D,202 RA = 05h 09m 47s +/- 3", 1950 Dec = -69d 11' 18" +/- 3" ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1835 D,202 RA = 05h 05m 25s +/- 3", 1950 Dec = -69d 28' 12" +/- 3" ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC1978 D,202 RA = 06h 11m 47s +/- 3", 1950 Dec = -69d 07' 00" +/- 3", PLATE-ID = 06B0 Comments: THIS PLATE IS USED BY SPSS FOR GUIDE STAR ACQUISITION. ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC1866 D,202 RA = 05h 13m 29s +/- 3", 1950 Dec = -65d 31' 18" +/- 3" ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC2134 D,202 RA = 05h 28m 22s +/- 3", 1950 Dec = -66d 16' 00" +/- 3", PLATE-ID = 06B0 Comments: THIS PLATE IS USED BY SPSS FOR GUIDE STAR ACQUISITION. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5342 [ 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 DEFINE # WFPC2 IMAGE # F160BW CR-SPLIT=0.5 1 1400s 1 F160W ATD-GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 2 DEFINE # WFPC2 IMAGE # F160BW CR-SPLIT=0.5 2 1800s 1 F160WL ATD-GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 3 DEFINE # WFPC2 IMAGE # F336W CR-SPLIT=0.5 1 600s 1 F336WL ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 4 DEFINE # WFPC2 IMAGE # F336W CR-SPLIT=0.0 1 350s 1 F336W ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 5 USE NGC1783 WFALL- CYCLE 4 / 5-16 F160WL FIX PCS MODE F / 5-16 GROUP 5-6 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 6 USE NGC1783 WFALL- F336WL FIX ------------------------------------------------------------------------------------------------------------------------------------ 7 USE NGC1856 PC1-FIX GROUP 7-8 NO GAP F160W ------------------------------------------------------------------------------------------------------------------------------------ 8 USE NGC1856 PC1-FIX F336W ------------------------------------------------------------------------------------------------------------------------------------ 9 USE NGC1835 WFALL- GROUP 9-10 NO GAP F160WL FIX ------------------------------------------------------------------------------------------------------------------------------------ 10 USE NGC1835 WFALL- F336WL FIX ------------------------------------------------------------------------------------------------------------------------------------ 11 USE NGC1978 PC1-FIX GROUP 11-12 NO GAP F160W ------------------------------------------------------------------------------------------------------------------------------------ 12 USE NGC1978 PC1-FIX F336W ------------------------------------------------------------------------------------------------------------------------------------ 13 USE NGC1866 PC1-FIX x0.79 GROUP 13-14 NO GAP F160W ------------------------------------------------------------------------------------------------------------------------------------ 14 USE NGC1866 PC1-FIX x0.52 F336W ------------------------------------------------------------------------------------------------------------------------------------ 15 USE NGC2134 PC1-FIX x0.79 GROUP 15-16 NO GAP F160W ------------------------------------------------------------------------------------------------------------------------------------ 16 USE NGC2134 PC1-FIX x0.89 F336W ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5342 [ 5] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 ATD-GAIN=7 ATD-GAIN=15 CR-SPLIT=0.0 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.95 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category Old Clusters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4 / 5-16; PCS MODE F / 5-16; GROUP 5-6 NO GAP GROUP 7-8 NO GAP GROUP 9-10 NO GAP GROUP 11-12 NO GAP GROUP 13-14 NO GAP GROUP 15-16 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160BW F336W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1783 NGC1856 NGC1835 NGC1978 NGC1866 NGC2134 ------------------------------------------------------------------------------------------------------------------------------------