8278( 3) - 02/17/99 11:38 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8278 Version: 3 Check-in Date: 17-Feb-1999 11:37:36 1.Proposal Title: High Precision Photometry of the Core of M13 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Charles Bailyn Yale University CoI: Dr. Eric Rubenstein Yale University N CoI: Prof. Pierre Demarque Yale University N CoI: Prof. Robert Zinn Yale University N CoI: Prof. Haldan Cohn Indiana University N CoI: Prof. Phyllis Lugger Indiana University N ------------------------------------------------------------------------------------ 5. Abstract We propose to obtain highly precise main sequence photometry in V and I in the core of the globular cluster M13. The data will be used to search for a binary sequence, and to obtain highly accurate main sequence ridge lines and a deep luminosity function in the core regions of the cluster. The dynamics and horizontal branch morphology of M13 are anomalous, and it seems likely than an understanding of the core binary population will be required to resolve the problems they raise. ------------------------------------------------------------------------------------ 8278( 3) - 02/17/99 11:38 - [ 2] Observations Description ------------------------ During each of the 5 orbits we will obtain 6 V (F555W) and 6 I (F814W) images. The images will be divided into 2 dither positions per orbit, for a total of 10 positions, offet from each other by 0.25''. RB97 have shown that analyzing a large number of dithered images individually and averaging the results greatly reduces the systematic errors and improves the precision of the photometry. The exposure times will be 80s in V and 120s in I. These exposure times should saturate ~ 1 magnitude brighter than the MS turnoff. We have estimated these exposure times based on the results of our recent WFPC2 photometry of M3, scaled for the distances and reddenings of the two clusters, and our desire for deeper data for this project. Preliminary results from the M3 project show a spread to the blue of the MS ridge line of ~ 0.04 magnitudes near the turnoff. Our study of NGC 6752 achieved ~ 0.01 magnitudes spread, and we easily resolved the binary sequence. Here we are requesting 1 .5 times more exposures, each of w hich is a magnitude deeper than the M3 study. We also are using 2 more dither positions. We therefore expect to achieve a precision of ~ 0.02 magnitudes for each star near the MS turnoff. We are confident that with photometric precision only a factor of 2 worse than our previous study of NGC 6752 we will clearly detect the binary sequence. Note for comparison that the spread on the main sequence of F97 is about 0.1 magnitude. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: YES Media: DAT Blocking Factor: 10 Ship To: Dept. of Astronomy, PO Box 280101, New Haven, CT 06520-8101 Ship Via: Email: bailyn@astro.yale.edu ------------------------------------------------------------------------------------ 8278( 3) - 02/17/99 11:38 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6205 STELLAR CLUSTER, RA=16H 41M 41.44S +/- 0.1S, 2000 V = 18.5 GLOBULAR CLUSTER DEC=36D 27' 36.9" +/- 0.5" Comments: The indicated flux value is for a single main-sequence turn-off star. 8278( 3) - 02/17/99 11:38 - [ 4] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 1 25 S ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 2 150 S ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 2 90 S ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 3 90 S POS TARG 0.500, 0.2500 ------------------------------------------------------------------------------------------------------------------------------------ 50 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 3 150 S ------------------------------------------------------------------------------------------------------------------------------------ 210 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 2 150 S POS TARG 0.75, 0.75 ------------------------------------------------------------------------------------------------------------------------------------ 215 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 1 15 S ------------------------------------------------------------------------------------------------------------------------------------ 220 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 2 90 S ------------------------------------------------------------------------------------------------------------------------------------ 230 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 3 90 S POS TARG 0.2500, 0.500 ------------------------------------------------------------------------------------------------------------------------------------ 235 NGC6205 WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7,CR-SPLIT=NO 1 25 S ------------------------------------------------------------------------------------------------------------------------------------ 240 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 3 150 S ------------------------------------------------------------------------------------------------------------------------------------ 310 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 2 150 S POS TARG -0.67, 0.67 ------------------------------------------------------------------------------------------------------------------------------------ 320 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 1 15 S ------------------------------------------------------------------------------------------------------------------------------------ 330 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 2 90 S ------------------------------------------------------------------------------------------------------------------------------------ 340 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 3 90 S POS TARG -0.500,-0.2500 ------------------------------------------------------------------------------------------------------------------------------------ 350 NGC6205 WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7,CR-SPLIT=NO 1 25 S ------------------------------------------------------------------------------------------------------------------------------------ 360 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 3 150 S ------------------------------------------------------------------------------------------------------------------------------------ 410 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 2 150 S POS TARG -0.75,-0.75 ------------------------------------------------------------------------------------------------------------------------------------ 420 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 1 15 S ------------------------------------------------------------------------------------------------------------------------------------ 430 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 2 90 S ------------------------------------------------------------------------------------------------------------------------------------ 440 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 3 90 S POS TARG -0.2500,-0.500 ------------------------------------------------------------------------------------------------------------------------------------ 450 NGC6205 WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7,CR-SPLIT=NO 1 25 S ------------------------------------------------------------------------------------------------------------------------------------ 460 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 3 150 S ------------------------------------------------------------------------------------------------------------------------------------ 8278( 3) - 02/17/99 11:38 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 510 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 2 150 S POS TARG 0.50,-0.50 ------------------------------------------------------------------------------------------------------------------------------------ 520 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 1 15 S ------------------------------------------------------------------------------------------------------------------------------------ 530 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 2 90 S ------------------------------------------------------------------------------------------------------------------------------------ 540 NGC6205 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO,ATD-GAIN=7 3 90 S POS TARG 0.7500, 0.000 ------------------------------------------------------------------------------------------------------------------------------------ 550 NGC6205 WFPC2 IMAGE PC1-FIX F814W ATD-GAIN=7,CR-SPLIT=NO 1 25 S ------------------------------------------------------------------------------------------------------------------------------------ 560 NGC6205 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=NO,ATD-GAIN=7 3 150 S ------------------------------------------------------------------------------------------------------------------------------------ 8278( 3) - 02/17/99 11:38 - [ 6] Summary Form for Proposal 8278 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ATD-GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG 0.500, 0.2500 POS TARG 0.75, 0.75 POS TARG 0.2500, 0.500 POS TARG -0.67, 0.67 POS TARG -0.500,-0.2500 POS TARG -0.75,-0.75 POS TARG -0.2500,-0.500 POS TARG 0.50,-0.50 POS TARG 0.7500, 0.000 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC6205 ------------------------------------------------------------------------------------------------------------------------------------