Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 2943c Report Date: 09-May-96:17:38 Version: ********** Check-in Date: ********** 1.Proposal Title: INTERNAL VELOCITY DISTRIBUTION IN GLOBULAR CLUSTERS PART ONE ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR POPULATIONS GTO/AST 5 Long Term yrs 1007 Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone William H. Jefferys TEXAS, UNIVERSITY OF USA 512-471-4461 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract The goal of this project is to study the internal velocity dispersion for six globular clusters with a range of characteristics. We expect to determine the virial mass for each cluster and a kinematic distance (statistical parallax) where radial velocity observations exist. The radial and azimuthal components of the velocity distribution will be analyzed to determine the degree of anisotropy in the velocities as a function of distance from the cluster center for three of the clusters. In addition, the degree to which equipartition of energy exists among the various mass groupings will be studied from the bright giants down to one-half solar mass in three of the clusters. The observations are designed to yield an accuracy of +/- 1 km/sec in the derived cluster velocity dispersion at each location in the cluster for the nearer clusters and +/- 2 km/sec for the more distant clusters. ------------------------------------------------------------------------------------ 8. Scientific Key Words: GLOBULAR CLUSTERS, PROPER MOTIONS, INTERNAL VELOCITIES ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 19.01 par: 0 10. Num targs pri: 22 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 2943c PI: William H. Jefferys Proposal Title: INTERNAL VELOCITY DISTRIBUTION IN GLOBULAR CLUSTERS PART ONE ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ William H. Jefferys TEXAS, UNIVERSITY OF USA George F. Benedict TEXAS, UNIVERSITY OF USA Raynor L. Duncombe TEXAS, UNIVERSITY OF USA Otto G. Franz LOWELL OBSERVATORY USA Laurence W. Fredrick VIRGINIA, UNIVERSITY OF USA Paul D. Hemenway TEXAS, UNIVERSITY OF USA Peter J. Shelus TEXAS, UNIVERSITY OF USA William F. Van Altena YALE UNIVERSITY USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. The observations for each cluster are divided into four separate regions with different exposure levels. Spatially, the regions selected are the central core, a region east of the center at 10 core radii, and two regions east and west of the center at 20 core radii. Observations at 10 and 20 core radii will be used to study the run of isotropy in the velocities. Due to the low density of stars far from the center, it is necessary to have two regions at 20 core radii. Each "exposure" consists of 5 separate exposures offset from each other by small amounts on the order of an arcsec. The purpose of these offsets is to average out the pixel to pixel variations in the CCD detectors. In addition, the first three of these exposures are taken with the V filter and the last two with the R filter. This group of exposures is defined by sequence PC5. Due to image crowding in the center, only a short 25 second exposure is taken, while at the other positions both a short 100 second and a long 1000 second exposure is taken. This range of exposures allows us to reach from the horizontal branch to the main sequence with a positional accuracy of 0.001 arcsec. These exposures will be repeated after five years to obtain the proper motions. The sequence PC10 is used to spatially calibrate the detector system both before and after the observations. The sequence consists of ten exposures randomly placed over the 32 x 32 subgrid of the CCD. It is hoped to use these observations to further increase the accuracy of the relative positions of the stars through a bootstrap calibration developed procedure suggested by Eichhorn. Due to time limitations, three of the clustes are to be observed only in their centers. The outer regions are included in the observing logsheets as priority 3 objects. The total observing time listed on the cover sheet assumes that priority 3 objects will not be observed and that filter changes can be made during the 60 second read out of the CCD. Cycle 1 18.22 hours Cycle 2 0.45 hours Cycle 3 0.00 hours Cycle 4 0.00 hours Cycle 5 0.00 hours ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Ground based observations of the proper motions are limited by the first epoch plates, which usually have a very bright limiting magnitude. In addition, the poor seeing makes it impossible to observe near the center of the cluster and limits the positional accuracy to a value some 15 times poorer than is possible with the PC. Since the difference in the positional accuracy translates directly into a difference in the epoch difference, we would have to wait at least 65 years for the second epoch on the ground. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The only special scheduling requirements are to maintain the same roll angle for all of the exposures in one sequence. This is necessary if we are to have the same stars on all exposures. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Sequence PC10 is used to obtain observations of the central region of NGC 6656 before and after the observations, which will hopefully be completed during the first year of operations. The ten offset exposures will be used to obtain a bootstrap calibration of the spatial characteristics of the PC, and to study the changes in the system over the observational period. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The data reduction will be done with the Astrometric Data Reduction Software developed by the Astrometry Team on computational facilities already available at the home institutions of the Team members. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Computational facilities and the ADRS software package. ------------------------------------------------------------------------------------ 13. Planetary Camera exposures will be taken of six of the globular clusters (NGC 104, NGC 1851, NGC 6205, NGC 6656, NGC 6752, NGC 7078, NGC 7099) to determine their internal motions from the horizontal branch to the main sequence. These motions will also be used to study the degree of relaxation and isotropy in stars of differing masses. In addition, exposures will be taken of Pal 1 to determine its membership and tangential velocity in the galactic frame of reference. ------------------------------------------------------------------------------------ 11. Address Information Name: WILLIAM H. JEFFERYS Category: PI Institution: UNIVERSITY OF TEXAS Address: ASTRONOMY DEPARTMENT City: AUSTIN State: TX Zip Code: 78712 Country: USA Telephone: (212) 471-4461 Telex (or e-mail): ------------------------------------------------------------------------------------ Name: WILLIAM F. VAN ALTENA Category: CON Institution: YALE UNIVERSITY Address: 260 WHITNEY AVENUE City: NEW HAVEN State: CT Zip Code: 06511 Country: USA Telephone: (203) 436-8318 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 2943c [ 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 NGC6752 C,201 RA= 19H 10M 52.47S +/- 2000 EXT 0.08S, DEC= -59D 59' 04.2" +/- 0.5" ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC6752-R1 ^ RA= 19H 11M 05.41S +/- ^ ^ 0.08S, DEC= -59D 56' 27.4" +/- 0.5" ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC6752-R2 ^ RA= 19H 10M 57.85S +/- ^ ^ 0.08S, DEC= -59D 53' 11.0" +/- 0.5" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2943c [ 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 DEFINE # PC IMAGE PCALL- F555W 5479 CR-SPLIT=NO 1 100S # POS TARG +10.00,- PC10 FIX PRE-FLASH=YES 10.00 / 1-10 CLOCKS=YES SEQ 1-10 NO GAP Comments: POS TARG OFFSETS ARE BASED ON CYCLE 2 COORD SYSTEM (I.E. PCALL-FIX TOGETHER WITH POS TARG +10.0,-10.0 EQUALS APEX) ------------------------------------------------------------------------------------------------------------------------------------ 2 ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ SAME ORIENT FOR 2- ^ 10 AS 1 SPATIAL SCAN ------------------------------------------------------------------------------------------------------------------------------------ 6 ^ ^ ^ ^ ^ F785LP 8958 ^ ^ ^ ^ SPATIAL SCAN ^ ------------------------------------------------------------------------------------------------------------------------------------ 10 ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ------------------------------------------------------------------------------------------------------------------------------------ 11 DEFINE # PC IMAGE PCALL- F555W 5479 CR-SPLIT=NO 1 100S # POS TARG +10.00,- PC5 FIX PRE-FLASH=YES 10.00 / 11-14 CLOCKS=YES SEQ 11-14 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 12 ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ SAME ORIENT FOR 12 ^ -14 AS 11 SPATIAL SCAN ------------------------------------------------------------------------------------------------------------------------------------ 14 ^ ^ ^ ^ ^ F785LP 8958 ^ ^ ^ ^ SPATIAL SCAN ^ ------------------------------------------------------------------------------------------------------------------------------------ 16 USE NGC6752 X1.0 1 CYCLE 1 / 16-19 PC10 Comments: ASTROMETRIC CALIBRATION OF PC + F555W AND F785LP ------------------------------------------------------------------------------------------------------------------------------------ 17 USE PC5 NGC6752 X0.26 1 ------------------------------------------------------------------------------------------------------------------------------------ 18 USE PC5 NGC6752-R1 X10 2 ------------------------------------------------------------------------------------------------------------------------------------ 19 USE PC5 NGC6752-R2 X10 2 ------------------------------------------------------------------------------------------------------------------------------------ Scan Paramters Form Proposal ID: 2943c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 1 Exposure Logsheet lines: 2.0 FGS Scan: DWELL Dwell Only: dwell points/line: 2 Seconds per dwell: 0.00 Scan width (arc-secs): 8.6000 Scan length (arc-secs): 8.6000 Angle between sides (degrees) 270.00 Number of lines: 2 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 90.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 4.3000 Width Offset (arc-sec): 4.3000 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 2 Exposure Logsheet lines: 6.0 FGS Scan: DWELL Dwell Only: dwell points/line: 2 Seconds per dwell: 0.00 Scan width (arc-secs): 4.3000 Scan length (arc-secs): 4.3000 Angle between sides (degrees) 270.00 Number of lines: 2 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 45.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 2.1500 Width Offset (arc-sec): 2.1500 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 3 Exposure Logsheet lines: 12.0 FGS Scan: DWELL Dwell Only: dwell points/line: 2 Seconds per dwell: 0.00 Scan width (arc-secs): 8.6000 Scan length (arc-secs): 8.6000 Angle between sides (degrees) 270.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 90.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 0.00 Width Offset (arc-sec): 4.3000 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 4 Exposure Logsheet lines: 14.0 FGS Scan: DWELL Dwell Only: dwell points/line: 2 Seconds per dwell: 0.00 Scan width (arc-secs): 8.6000 Scan length (arc-secs): 8.6000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 90.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 0.00 Width Offset (arc-sec): 4.3000 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 2943c [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations PC ^ ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ^ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO PRE-FLASH=YES CLOCKS=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/AST ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 19.01 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR POPULATIONS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG +10.00,-10.00 / 1-10; SEQ 1-10 NO GAP; SAME ORIENT FOR 2-10 AS 1; SPATIAL SCAN POS TARG +10.00,-10.00 / 11-14; SEQ 11-14 NO GAP; SAME ORIENT FOR 12-14 AS 11; CYCLE 1 / 16-19 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W ^ F785LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC6752 NGC6752-R1 NGC6752-R2 ------------------------------------------------------------------------------------------------------------------------------------