Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5324 Report Date: 18-Jul-95:17:09 Version: ********** Check-in Date: ********** 1.Proposal Title: GLOBULAR CLUSTER CORE IMAGING ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID COOL STARS GO Sub Category OLD CLUSTERS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Brian P Yanny INSTITUTE FOR ADVANCED STUDY USA 609-734-8082 ------------------------------------------------------------------------------------ 7. Abstract This proposal requests short WFPC2 exposures of the centers of M15 M30 and NGC6244 to test and extend conclusions that are based upon existing HST images of M15 taken with a spherically-aberrated PSF. These HST observations show (Yanny et al 1993) that M15 has either a power-law density cusp with slope consistent with a central black hole or an as-yet-unresolved core of radius less than 1.5 arcseconds. Corrected optics will allow the determination of the density profile to a radius of less than 0.3 arcsec (0.02 pc), well within the region (0.8 to 1.6 arcsec) in which binary heating and core oscillations are expected to produce a flattened core. Exposures in three bands (F569W, F439W and F336W) will permit the detection of more than 100 stars to B=22 mag in the innermost radial bins for M15 (a 7-fold improvement), with similar results expected for M30 and NGC6244. The multi-color observations permit determination of the relative fractions of blue straggler, horizontal branch and red giant branch stars in each of the clusters to levels of unprecedented accuracy, allowing one to put useful constraints on models of radial segregation. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 0.35 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5324 PI: Brian P Yanny Proposal Title: GLOBULAR CLUSTER CORE IMAGING ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Brian Yanny 2280 US Puragra Guhathakurta 3200 US Don Schneider 2280 US John Bahcall 2280 US ------------------------------------------------------------------------------------ 3. Description of proposed observations. Short (4 to 200 seconds) exposures in each of the F336W, F439W and F569W (U, B, and V) filters will be obtained with the PC camera for the centers of clusters M~15 (NGC~7078), M~30 (NGC~7099), and NGC~6624. A total of 18 exposures are requested. The center of the globular cluster should be centered on the PC1 Chip. The exposure times have been chosen to be as long as possible so that the brightest stars in the centers of the clusters do not badly saturate and streak. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The resolution of HST/WFPC2 at the 0.1 arcsec level is crucial to the success of this project. One needs to resolve at least 20 to 40 stars in the central $r=0\farcs 3$ to have sufficient number statistics to determine the radial profile of stars this far into the center. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Images of 19 clusters have been obtained. The processing software is complete. Two discovery papers have been published plus numerous conference proceedings. The main results are the discovery of the central concentration in blue stragglers in 47 Tuc and the apparent cusp in the stellar density distribution in M~15, as well as the publication of the most accurate existing stellar photometry in the cores of dense clusters. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Computer support will be provided by the Institute For Adv. ------------------------------------------------------------------------------------ 11. Address Information Name: BRIAN YANNY Category: PI Institution: 2280 Address: S OLDEN LANE City: PRINCETON State: NJ Zip Code: 08540 Country: US Telephone: 609-734-8082 Telex (or e-mail): yanny@guinness.ias.edu ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5324 [ 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 NGC6624 C,201 RA = 18H 23M 40.6S +/- 0.1S, 2000 1 V= 13.3 +/- 1.0 DEC = -30D 21' 41" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC7078 C,201 RA = 21H 29M 58.4S +/- 0.1S, 2000 1 V = 13.0 +/- 1.0 DEC = 12D 10' 0" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC7099 C,201 RA = 21H 40M 22.0S +/- 0.1S, 2000 1 V = 12.2 +/- 1.0 DEC = -23D 10' 45" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5324 [ 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 NGC6624 WFPC2 IMAGE PC1 F555W 4 10S 1 CYCLE 4 NON-INT / 1-9 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC6624 WFPC2 IMAGE PC1 F439W 2 50S 1 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC6624 WFPC2 IMAGE PC1 F336W 2 200S 1 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC7078 WFPC2 IMAGE PC1 F555W 4 8S 1 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC7078 WFPC2 IMAGE PC1 F439W 2 40S 1 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC7078 WFPC2 IMAGE PC1 F336W 2 200S 1 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC7099 WFPC2 IMAGE PC1 F555W 4 4S 1 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC7099 WFPC2 IMAGE PC1 F439W 2 40S 1 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ 9 NGC7099 WFPC2 IMAGE PC1 F336W 2 100S 1 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5324 [ 5] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 0.35 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COOL STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category OLD CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; NON-INT / 1-9 CYCLE 4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F439W F336W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC6624 NGC7078 NGC7099 ------------------------------------------------------------------------------------------------------------------------------------