Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1019c Report Date: 09-May-96:16:02 Version: ********** Check-in Date: ********** 1.Proposal Title: THE STELLAR DENSITY DISTRIBUTIONS IN THE CENTERS OF GALACTIC GLOBULAR CLUSTERS ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR POPULATIONS GTO/OS Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. John N. Bahcall INSTITUTE FOR ADVANCED STUDY USA (609) 734-8054 DR. JOHN N. BAHCALL ------------------------------------------------------------------------------------ 7. Abstract Short exposures will be made of all galactic globular clusters with distance moduli less than 15.5 mag and galactic latitude above or below 15 degrees. A search will be made for cusps in the stellar density distributions and the colors will be measured for the brightest stars in the cores of the clusters. ST observations are required in order to reach the innermost regions of the clusters with sufficient resolution to separate individual stars. ------------------------------------------------------------------------------------ 8. Scientific Key Words: GLOBULAR CLUSTER, POPULATION II, BLACK HOLE ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 0.25 par: 0 10. Num targs pri: 20 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1019c PI: Dr. John N. Bahcall Proposal Title: THE STELLAR DENSITY DISTRIBUTIONS IN THE CENTERS OF GALACTIC GLOBULAR CLUSTERS ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ John N. Bahcall INSTITUTE FOR ADVANCED STUDY USA Neta A. Bahcall SPACE TELESCOPE SCIENCE USA INSTITUTE ------------------------------------------------------------------------------------ 3. Description of proposed observations. Two exposures will be taken for each object. They need not be consecutive, but the telescope roll angle should be the same for both exposures. This series of exposures will give both colors (V and I) and number densities for the brightest stars in the central regions of the globular clusters. Cycle 1 (SV: 1-6 months) plus Cycle 2 (7-18 months) = Exposures 1-40. The target position should be placed at the center of one CCD, immaterial which one. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. ST observations are required in order to resolve individual stars in the cores of the globular clusters in sufficient numbers to permit a determination of the stellar density law. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The telescope roll angle should be the same for both exposures on a given cluster, although the two exposures on a cluster need not be consecutive. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Data reduction and analysis will be performed at both the Institute for Advanced Study and at STScI. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. The target position should be placed at the center of one CCD, immaterial which one. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Computing support and research associates will be available at both IAS and STScI as required by the science. ------------------------------------------------------------------------------------ 13. Short exposures will be made of all galactic globular clusters with distance moduli less than 15.5 mag and galactic latitude above 15 degrees. A search will be made for cusps in the stellar density distributions and the colors will be measured for the brightest stars in the cores of the clusters. Short exposures will be made of all galactic globular clusters with distance moduli less than 15.5 mag, estimated core radii less than 1 arc minute, and galactic latitude above 15 degrees. We will search for a cusp in the stellar density distribution. ------------------------------------------------------------------------------------ 11. Address Information Page 3 Name: JOHN N. BAHCALL Category: PI Institution: INSTITUTE FOR ADVANCED STUDY Address: OLDEN LANE City: PRINCETON State: NJ Zip Code: 08540 Country: USA Telephone: (609) 734-8054 Telex (or e-mail): 837680 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 1019c [ 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| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1851 GALACTIC GLOBULAR RA = 05H 12M 28.15S +/- 1950 1 SURF(V) = 14.70 +/- 0.2 CLUSTER 0.1S, DEC = -40D 06' 05.4" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC7078 M15 GALACTIC GLOBULAR RA = 21H 27M 33.35S +/- 1950 1 SURF(V) = 15.09 +/- 0.2 CLUSTER 0.1S, DEC = +11D 56' 48.8" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1019c [ 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 NGC1851 PC IMAGE P6 F785LP PRE-FLASH=YES 1 160S 1 3 CYCLE 0 / 1-24 ------------------------------------------------------------------------------------------------------------------------------------ 11 NGC7078 PC IMAGE P6 F785LP PRE-FLASH=YES 1 160S 1 1 CYCLE 0 ------------------------------------------------------------------------------------------------------------------------------------ 15 NGC1851 PC IMAGE P6 F555W PRE-FLASH=YES 1 160S 1 3 CYCLE 0 SEQ 1,15 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 24 NGC7078 PC IMAGE P6 F555W PRE-FLASH=YES 1 160S 1 1 CYCLE 0 SEQ 11,24 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1019c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations PC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/OS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 0.25 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR POPULATIONS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 0 / 1-24 CYCLE 0 CYCLE 0; SEQ 1,15 NO GAP SEQ 11,24 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F785LP F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1851 NGC7078 M15 ------------------------------------------------------------------------------------------------------------------------------------