Scientific Category is a required field. Science Keywords is a required field. Science Keywords: Select from 3 to 5 items. 0 Assigned ID: 1156 ----- Attempting Submission 1 (Wed Sep 09 11:06:46 GMT 2015) ----- Joint Chandra/HST Proposal 0 ----- Attempting Submission 1 (Thu Sep 24 01:36:15 GMT 2015) ----- The Black Hole Population in Galactic Globular Clusters We are engaged in a systematic search for stellar-mass black holes (BHs) in Galactic globular clusters, using a combination of deep radio continuum data, high-resolution X-ray observations, and optical images. Here we request 128 ksec of Chandra/ACIS observations to image the seven GCs in our sample with no or minimal archival Chandra data, enabling differentiation between accreting BHs, neutron stars, cataclysmic variables, and background galaxies. We also request two orbits of HST imaging to detect the optical counterpart to a BH candidate in one of these clusters. These observations consistent of broadband imaging of the globular cluster NGC 6712 with WFC3 to characterize the counterpart to a candidate accreting stellar-mass black hole. In the first orbit we take one short exposure and then a 4-point dither in F275W. In the second orbit we observe with F606W and F814W, with most of the time going to an un-equal length 3-point dither in F606W and a 2-point line dither in F814W. This orbit is bracketed by short exposures in the two filters. 12 false false false false SUPPORTED STELLAR CLUSTER GLOBULAR CLUSTER J2000 J2000 WFC3/UVIS Imaging No No F275W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1 false /private/var/folders/8k/sxlgy5ts2xdbykzf_vw6jrfw0001c5/T/OPVisit2929118838598290157.xml The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14351 :visit-id "01" :proposal-version -1 :trans-version "20150609" :date "24-Sep-2015 11:08:36.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 3464992 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14351 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14351 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2880 :al-overhead-at-end 123 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3213 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14351 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2991 :al-overhead-at-end 125 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3213 :pcs-gap 0 ) true 2 0