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    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID 5344
                                                       Report Date: 18-Jul-95:17:12
                                                       Version: **********
                                                       Check-in Date: **********

1.Proposal Title:
SEARCH FOR OPTICAL COUNTERPARTS OF GLOBULAR CLUSTER X-RAY SOURCES  CYCLE4MEDIUM
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2. Scientific Category   3. Proposal For  4. Proposal Type        5. Continuation ID
HOT STARS                   GO                                       <none>
Sub Category
X-RAY BINARIES
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6. Principal Investigator   Institution                    Country    Telephone
 Charles D Bailyn           YALE UNIVERSITY                USA        (203) 432 3022

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7. Abstract
Our previous HST WFPC imaging uncovered 3 promising candidate optical counterparts
for low luminosity X-ray sources in the nearby globular cluster NGC 6397.
Identification of these sources is essential to determine their nature, evolution,
and contribution to the dynamics of the clusters.  Here we propose to use WFPC2 to
search for counterparts to X-ray sources in two other clusters (NGC 6752 and M22 =
NGC 6656) in which high spatial resultion ROSAT imaging has been carried out.  Our
procedure is the same as previously: we will image the cluster cores in H-alpha, R
and B filters, and identify blue H-alpha bright objects.  Particular aims of this
study include identifying any differences in X-ray source populations which
correlate with the different dynamical states of the target clusters, and exploring
the possibility that some fo the sources may be quiescent neutron stars.
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9. Est obs time (hours) pri: 2.30     par: 0       10. Num targs pri: 2      par: 0
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11. Instruments requested:  WF/PC
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I. GENERAL FORM    Proposal 5344
PI:  Charles D Bailyn
Proposal Title:
SEARCH FOR OPTICAL COUNTERPARTS OF GLOBULAR CLUSTER X-RAY SOURCES  CYCLE4MEDIUM
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1. Proposers:
Proposers                        Institution                       Country       ESA
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  Bailyn
 Adrienne Cool                   CFA, 60 GARDEN ST. CAMBRIDGE, MA
                                 02138
 Josh Grindlay                   CFA, 60 GARDEN ST. CAMBRIDGE, MA
                                 02138
 Paul Callanan                   CFA, 60 GARDEN ST. CAMBRIDGE, MA
                                 02138
 Haldan Cohn                     INDIANA UNIV. SAWIN, WEST 319,
                                 BLOOMINGTON, IN 47405
 Phyllis Lugger                  INDIANA UNIV. SAWIN, WEST 319,
                                 BLOOMINGTON, IN 47405
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  3. Description of proposed observations.
  We adopt a plan for our observations which we used in our successful cycle 2
 program.  Each observation in each filter is divided into at least 2 long
 exposures (<=1200s), and a single exposure 10 times shorter than the individual
 long exposures.  This procedure allows us to control for cosmic rays and
 saturated stars.  The individual exposures for each traget are listed below:
 cluster       H-alpha (=F656N)       R (=F675W)       B (=F439W) NGC 6752      5
 x 1200s              2 x 180s         2 x 700s 1 x 120s               1 x 18s
 1 x 70s M22           3 x 1100s              2 x 100s         2 x 400s (=NGC
 6656)   1 x 120s               1 x 10s          1 x 40s
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  4. Justification of need for HST observations.
  The crowded conditions in the cluster center make faint objects impossible to
 observe from the ground, and indeed difficult to observe with HST prior to the
 refurbishment mission.
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  5. Description of special scheduling requirements.
  none
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  6. Description of special calibration exposures.
  none
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  8. Additional comments or special requests.
  For scheduling purposes it is worth noting that the coordinates of the NGC 6752
 observation are the same as one of the fields requested for WFPC2 observations in
 proposal Z379 "Search for Main Sequence Binaries in the Globular Cluster NGC
 6752" PI=Bailyn.
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  9. Description of previous HST work.
  Previous successful HST proposals include the following: GO-2555 "Cataclysmic
 Variables and Millisecond Pulsars in Globular Cluster Cusps", PI Grindlay; GO-
 2237 "HST Observations of the Eclipsing Millisecond Pulsar 1957+20", PI
 Bookbinder GO-3851 "Deep Search for CVs and Compact Binaries in the Collapsed
 Close Globular NGC 6397", PI Grindlay GO-4751 "Spectroscopic Identification of
 Candidate Optical Counterparts of X-ray Sources in the Nearby Collapsed Globular
 Cluster NGC 6397", PI Grindlay GO-4425 "Search for Optical Counterparts of X-ray
 Sources in Nearby Clusters", PI Bailyn AR-3793 "Comparison of HST Data on
 Globular Clusters with Other Data Sets", PI Bailyn AR/DD-4915 "Synergistic Ground
 and Space Based Observations of Globular Cluster Cores", PI Bailyn
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 10. Resources to be supplied by investigator's institution(s).
  The Yale, Indiana and CfA astronomy programs each support a network of
 scientific workstations which will be used to reduce the data. The PI and Co-I's
 time is paid for by their respective institutions and by other grant sources, and
 is therefore not charged to this grant.  The funding requested will support 1/2
 year of a graduate student at Yale, and 1 summer of a graduate student at
 Indiana.
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11. Address Information
Name:  Charles D Bailyn                                    Category: PI
Institution:
Address:  Dept. of Astronomy
          Yale University
          P.O. Box 6666
City: New Haven                                 State: CT
Zip Code: 06511                                 Country: USA
Telephone: (203) 432 3022
Telex (or e-mail): bailyn@binary.astro.yale.edu
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TARGET LIST    a) Fixed Targets                                                                    ID = 5344             [  4]
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 1 |     2      |           3           |              4             |  5     |   6    |  7  |              8
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Tar|   Target   |         Target        |            Target          |Coord   | Radial |Acqui|FLX|     Flux data
No |    Name    |       Description     |           Position         |Eqnx    |  Vel.  |Prblm|REF|
   |            |                       |                            |        |        |     |   |
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1   NGC6752      C, 201                  RA= 19H10M51.8S +/- 0.1S,    2000                    1   V=19.5
                                         DEC=-59D58'55" +/- 1"
     Comments: THIS TARGET HAS THE SAME COORDINATE AS
             THE FIRST TARGET IN THE PROPOSAL Z379,
             "SEARCH FOR MAIN SEQUENCE BINARIES...", PI
             BAILYN
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2   NGC6656 M22  C, 201                  RA= 18H36M24.2S +/- 0.1",    2000                    1   V=19.5
                                         DEC=-23D54'12" +/- 1"
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EXPOSURE LOGSHEET                                                                                  ID = 5344             [  5]
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 1      |   2   |      3    |  4   |   5   |   6   |    7   |   8   |       9       |10 |   11  |   12    |13 |14|        15
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  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
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1                NGC6752     WFPC2  IMAGE   PC1-FIX F439W            CR-SPLIT=NO     1   70S     5         1   1  CYCLE 4 / 1-16
     Comments: PLEASE IGNORE S/N REQUIREMENTS
               EXPOSURE TIMES ESTIMATED FROM
               PREVIOUS HST IMAGES.
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2.1              NGC6752     WFPC2  IMAGE   PC1-FIX F439W            CR-SPLIT=NO     1   700S    5         1   1  SAME POS FOR 2.1-
                                                                                                                  6.5 AS 1
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2.2              NGC6752     WFPC2  IMAGE   PC1-FIX F439W            CR-SPLIT=NO     1   700S    5         1   1
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3                NGC6752     WFPC2  IMAGE   PC1-FIX F675W            CR-SPLIT=NO     1   18S     5         1   1
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4                NGC6752     WFPC2  IMAGE   PC1-FIX F675W            CR-SPLIT=NO     2   180S    5         1   1
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5                NGC6752     WFPC2  IMAGE   PC1-FIX F656N            CR-SPLIT=NO     1   120S    5         1   1
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6.1              NGC6752     WFPC2  IMAGE   PC1-FIX F656N            CR-SPLIT=NO     1   1200S   5         1   1
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6.2              NGC6752     WFPC2  IMAGE   PC1-FIX F656N            CR-SPLIT=NO     1   1200S   5         1   1
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6.3              NGC6752     WFPC2  IMAGE   PC1-FIX F656N            CR-SPLIT=NO     1   1200S   5         1   1
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6.4              NGC6752     WFPC2  IMAGE   PC1-FIX F656N            CR-SPLIT=NO     1   1200S   5         1   1
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6.5              NGC6752     WFPC2  IMAGE   PC1-FIX F656N            CR-SPLIT=NO     1   1200S   5         1   1
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11               NGC6656     WFPC2  IMAGE   PC1-FIX F439W            CR-SPLIT=NO     1   40S     5         1   1
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12               NGC6656     WFPC2  IMAGE   PC1-FIX F439W            CR-SPLIT=NO     2   400S    5         1   1  SAME POS FOR 12-16
                                                                                                                  AS 11
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13               NGC6656     WFPC2  IMAGE   PC1-FIX F675W            CR-SPLIT=NO     1   10S     5         1   1
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14               NGC6656     WFPC2  IMAGE   PC1-FIX F675W            CR-SPLIT=NO     2   100S    5         1   1
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15               NGC6656     WFPC2  IMAGE   PC1-FIX F656N            CR-SPLIT=NO     1   120S    5         1   1
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16               NGC6656     WFPC2  IMAGE   PC1-FIX F656N            CR-SPLIT=NO     3   1100S   5         1   1
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            Summary Form for Proposal 5344                                                                               [  6]

  Item                          Used in this proposal
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  Configurations                WFPC2
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  Opmodes                       IMAGE
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  Optional Parameters           CR-SPLIT=NO
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  Proposal for                  GO
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  S/C Hours                     2.30
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  Scientific Category           HOT STARS
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  Scientific Sub-category       X-RAY BINARIES
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  Special Requirements          CYCLE 4 / 1-16 SAME POS FOR 2.1-6.5 AS 1 SAME POS FOR 12-16 AS 11
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  Spectral Elements             F439W F675W F656N
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  Target Names                  NGC6752 NGC6656 M22
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