We are continuing our study of the dynamical properties of globular clusters and we propose to obtain surface brightness profiles for high concentration clusters. Our results to date show that the distribution of central surface brightness slopes do not conform to standard models. This has important implications for how they form and evolve, and suggest the possible presence of central intermediate-mass black holes. From our previous archival proposals (AR-9542 and AR-10315), we find that many high concentration globular clusters do not have flat cores or steep central cusps, instead they show weak cusps. Numerical simulations suggest that clusters with weak cusps may harbor intermediate-mass black holes and we have one confirmation of this connection with omega Centauri. This cluster shows a shallow cusp in its surface brightness profile, while kinematical measurements suggest the presence of a black hole in its center. Our goal is to extend these studies to a sample containing 85% of the Galactic globular clusters with concentrations higher than 1.7 and look for objects departing from isothermal behavior. The ACS globular cluster survey (GO-10775) provides enough objects to have an excellent coverage of a wide range of galactic clusters, but it contains only a couple of the ones with high concentration. The proposed sample consists of clusters whose light profile can only be adequately measured from space-based imaging. This would take us close to completeness for the high concentration cases and therefore provide a more complete list of candidates for containing a central black hole. The dataset will also be combined with our existing kinematic measurements and enhanced with future kinematic studies to perform detailed dynamical modeling.

We plan to observe most objects in the F438W and F555W filters, but for the few cases with very faint horizontal branches, for which very long integrations are required in the B-band, we use F555W and F814W instead. The S/N needed to perform isophotal analysis that would detect flattening is higher that the one required for obtaining an accurate SB profile, so, for the clusters with the brightest horizontal branches, we increased the exposure times for the F555 filter making sure that the observation fits into a single orbit for each object. We will take multiple dither images in order to provide the best spatial resolution possible. All of the observations can be performed under one orbit per object. N/A N/A N/A RESOLVED STELLAR POPULATIONS 12 false 0.0 0.0 false false false false false SUPPORTED STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 15 35 28.6000 -50 39 35.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 16 27 40.4000 -38 50 56.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 16 59 32.7000 -37 07 17.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 17 17 59.3000 -23 45 58.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 17 21 10.1000 -19 35 15.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 17 23 58.6000 -26 21 12.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 17 34 28.4000 -39 04 11.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 17 50 51.7000 -34 36 0.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. J2000 18 01 50.4000 -08 57 34.00 J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the NED database. M75 J2000 20 06 4.8000 -21 55 20.00 J2000 WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F625W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F625W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F625W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F438W POS-TARG DITHER 0.145 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE 1 false The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "01" :proposal-version -1 :trans-version "20080807" :date "16-Sep-2008 06:31:34.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3091 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3453 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "02" :proposal-version -1 :trans-version "20080807" :date "16-Sep-2008 06:32:17.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2971 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3310 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "03" :proposal-version -1 :trans-version "20080807" :date "16-Sep-2008 06:31:51.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2725 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3310 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "04" :proposal-version -1 :trans-version "20080515" :date "30-Jun-2008 15:34:59.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2911 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3258 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "05" :proposal-version -1 :trans-version "20080515" :date "30-Jun-2008 15:35:01.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2851 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "06" :proposal-version -1 :trans-version "20080515" :date "30-Jun-2008 15:35:04.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2911 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3267 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "07" :proposal-version -1 :trans-version "20080515" :date "30-Jun-2008 15:35:06.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2905 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3310 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "08" :proposal-version -1 :trans-version "20080515" :date "30-Jun-2008 15:35:09.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "08" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2941 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3283 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "09" :proposal-version -1 :trans-version "20080515" :date "30-Jun-2008 15:35:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "09" :obset-id "09" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "09" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2905 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3242 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 11628 :visit-id "10" :proposal-version -1 :trans-version "20080515" :date "30-Jun-2008 15:35:14.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732480 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11628 :visit-id "10" :obset-id "10" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11628 :visit-id "10" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2911 :al-overhead-at-end 118 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3258 :pcs-gap 0 ) false 1 0