! $Id: 5324,v 6.1 1994/07/27 16:36:09 pepsa Exp $ coverpage: title_1: GLOBULAR CLUSTER CORE IMAGING sci_cat: COOL STARS sci_subcat: OLD CLUSTERS proposal_for: GO pi_fname: BRIAN pi_mi: P pi_lname: YANNY pi_inst: INSTITUTE FOR ADVANCED STUDY pi_country: USA pi_phone: 609-734-8082 hours_pri: 0.35 num_pri: 3 wf_pc: Y off_fname: ALLAN off_lname: ROWE off_title: ASSOCIATE DIRECTOR off_inst: 2280 off_addr_1: S OLDEN LANE off_city: PRINCETON off_state: NJ off_zip: 08540 off_country: USA off_phone: 609-734-8205 ! end of coverpage abstract: line_1: This proposal requests short WFPC2 exposures of the centers of M15 M30 line_2: and NGC6244 to test and extend conclusions that are based upon line_3: existing HST images of M15 taken with a spherically-aberrated PSF. line_4: These HST observations show (Yanny et al 1993) that M15 has either a line_5: power-law density cusp with slope consistent with a central black hole line_6: or an as-yet-unresolved core of radius less than 1.5 arcseconds. line_7: Corrected optics will allow the determination of the density profile line_8: to a radius of less than 0.3 arcsec (0.02 pc), well within the region line_9: (0.8 to 1.6 arcsec) in which binary heating and core oscillations are line_10: expected to produce a flattened core. Exposures in three bands line_11: (F569W, F439W and F336W) will permit the detection of more than 100 line_12: stars to B=22 mag in the innermost radial bins for M15 (a 7-fold line_13: improvement), with similar results expected for M30 and NGC6244. The line_14: multi-color observations permit determination of the relative line_15: fractions of blue straggler, horizontal branch and red giant branch line_16: stars in each of the clusters to levels of unprecedented accuracy, line_17: allowing one to put useful constraints on models of radial line_18: segregation. ! ! end of abstract general_form_proposers: lname: YANNY fname: BRIAN inst: 2280 country: US ! lname: GUHATHAKURTA fname: PURAGRA inst: 3200 country: US ! lname: SCHNEIDER fname: DON inst: 2280 country: US ! lname: BAHCALL fname: JOHN inst: 2280 country: US ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Short (4 to 200 seconds) exposures in each of the F336W, F439W and line_2: F569W (U, B, and V) filters will be obtained with the PC camera for line_3: the centers of clusters M~15 (NGC~7078), M~30 (NGC~7099), and line_4: NGC~6624. A total of 18 exposures are requested. line_5: The center of the globular cluster should be centered on the PC1 line_6: Chip. The exposure times have been chosen to be as long as line_7: possible so that the brightest line_8: stars in the centers of the clusters do not badly saturate and line_9: streak. ! question: 4 section: 1 line_1: The resolution of HST/WFPC2 at the 0.1 arcsec level is crucial to the line_2: success of this project. One needs to resolve at least 20 to 40 stars line_3: in the central $r=0\farcs 3$ to have sufficient number statistics to line_4: determine the radial profile of stars this far into the center. ! ! question: 9 section: 1 line_1: Images of 19 clusters have been obtained. The processing software is line_2: complete. Two discovery papers have been published plus numerous line_3: conference proceedings. The main results are the discovery of the line_4: central concentration in blue stragglers in 47 Tuc and the apparent line_5: cusp in the stellar density distribution in M~15, as well as the line_6: publication of the most accurate existing stellar photometry in the line_7: cores of dense clusters. ! question: 10 section: 1 line_1: Computer support will be provided by the Institute For Adv. ! !end of general form text general_form_address: lname: YANNY fname: BRIAN category: PI inst: 2280 addr_1: S OLDEN LANE city: PRINCETON state: NJ zip: 08540 country: US phone: 609-734-8082 telex: yanny@guinness.ias.edu ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: NGC6624 descr_1: C,201 pos_1: RA = 18H 23M 40.6S +/- 0.1S, pos_2: DEC = -30D 21' 41" +/- 1" equinox: 2000 fluxnum_1: 1 fluxval_1: V= 13.3 +/- 1.0 ! targnum: 2 name_1: NGC7078 descr_1: C,201 pos_1: RA = 21H 29M 58.4S +/- 0.1S, pos_2: DEC = 12D 10' 0" +/- 1" equinox: 2000 fluxnum_1: 1 fluxval_1: V = 13.0 +/- 1.0 ! targnum: 3 name_1: NGC7099 descr_1: C,201 pos_1: RA = 21H 40M 22.0S +/- 0.1S, pos_2: DEC = -23D 10' 45" +/- 1" equinox: 2000 fluxnum_1: 1 fluxval_1: V = 12.2 +/- 1.0 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: NGC6624 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F555W num_exp: 4 time_per_exp: 10S priority: 1 req_1: CYCLE 4; req_2: NON-INT / 1-9 ! linenum: 2.000 targname: NGC6624 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F439W num_exp: 2 time_per_exp: 50S priority: 1 req_1: CYCLE 4 ! linenum: 3.000 targname: NGC6624 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F336W num_exp: 2 time_per_exp: 200S priority: 1 req_1: CYCLE 4 ! linenum: 4.000 targname: NGC7078 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F555W num_exp: 4 time_per_exp: 8S priority: 1 req_1: CYCLE 4 ! linenum: 5.000 targname: NGC7078 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F439W num_exp: 2 time_per_exp: 40S priority: 1 req_1: CYCLE 4 ! linenum: 6.000 targname: NGC7078 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F336W num_exp: 2 time_per_exp: 200S priority: 1 req_1: CYCLE 4 ! linenum: 7.000 targname: NGC7099 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F555W num_exp: 4 time_per_exp: 4S priority: 1 req_1: CYCLE 4 ! linenum: 8.000 targname: NGC7099 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F439W num_exp: 2 time_per_exp: 40S priority: 1 req_1: CYCLE 4 ! linenum: 9.000 targname: NGC7099 config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F336W num_exp: 2 time_per_exp: 100S priority: 1 req_1: CYCLE 4 ! ! end of exposure logsheet ! No scan data records found