Resubmission to change last exposure to F606W band. ----- Attempting Submission 1 (Fri Oct 23 19:24:25 GMT 2009) ----- Phase II Proposal 12012 (hst_n3201.apt) successfully submitted. ----- Attempting Submission 2 (Fri Oct 23 19:34:27 GMT 2009) ----- Bright X-ray sources in globular clusters, X-ray binaries, cataclysmic variables, active binaries, and millisecond pulsars, are all binary systems or thought to be the products of such systems. Studies of X-ray sources in GCs thus probe binary formation. Most past observations have concentrated on dense GCs; these systems show clear evidence for strong dynamical formation of binaries; however, sparse clusters seem to fall off this pattern. Potential explanantions include, among others, primordial binary formation and a misunderstanding of the dynamical state of some GCs. We propose an 85 ks ACIS-S observation of NGC~3201, the nearest sparse GC unobserved by Chandra to test these explanations. We request 1 orbit of HST to discriminate CVs from ABs, and 1 hour of GBT time to search for MSPs.

We request a single orbit of F435W (B) imaging with HST to provide B-V colors. We choose ACS for its high sensitivity. Thr orbit is packed with one short exposure to avoid saturation for giant stars below the red clump, four long exposures using a box dither designed to avoid saturation for stars below the main sequence turnover. We also add a second 405 F606W exposure (to double the existing data). We will reach approximately 8 magnitudes below the main sequence in B. This will match the depth in F606W for typical CV spectra (~A0), and would reach deep enough to identify the majority of CVs seen in 47 Tuc. Thus, these HST observations will significantly increase the utility of our proposed Chandra observations by allowing us to differentiate CVs from chromospherically active binaries. If possible, we request an orientation and position that matches close to Datasets J9L946010/J9L946020 to maximize coverage when making color magnitude diagrams. 12 false 0.0 0.0 false false false false false false SUPPORTED STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 00 00 0.0000 +00 00 0.00 J2000 POS-TARG DITHER 0.265 LINE 0.187 false false 69.05 4 20.67 ACS-WFC-DITHER-BOX 1 false The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. /tmp/OPVisit1917.xml 1256326424073 (Tic-Visit :proposal-id 12012 :visit-id "01" :proposal-version -1 :trans-version "20090702" :date "23-Oct-2009 15:33:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1705344 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12012 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12012 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2944 :al-overhead-at-end 0 :internal-dur-at-end 349 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3398 :pcs-gap 0 ) true 1 0