An important discriminator between different models for the dark matter (DM) in the universe (cold vs. warm) is the density profile slope near the center of DM halos. CDM predicts a steep cusp, whereas WDM predicts a homogeneous core. Interpretation of observational results from disk galaxy rotation curves has been ambiguous, due to the influence of the luminous baryons on the measured DM halo structure. To better address this so-called "core-cusp" problem it is important to focus on the most DM-dominated systems known: Milky Way dwarf spheroidal galaxies. While good line-of-sight (LOS) velocity datasets exist (some thousand stars per galaxy), interpretation is plagued by the well-known mass vs. velocity-anisotropy degeneracy of stellar dynamics. This can be resolved with stellar proper motion measurements, but none exist to date. Such measurements were anticipated to be a key program for the NASA/SIM mission, but this was canceled. Fortunately, time baselines are now long enough for HST to address this problem for the very first time. We will image previously imaged fields in Draco and Sculptor (five fields total) to measure the internal proper motion dynamics for hundreds of stars. This will yield the best determinations to date of the DM density slope in any galaxy, discriminating between a core or cusp at 3-sigma confidence. This will provide important new constraints on the nature of DM. To determine proper motions, we will reobserve five fields (three in the Draco dSph and two in the Sculptor dSph) with ACS/WFC and the same filter as used for the first epoch data. We will expose each Draco field for 3 orbits, and each Sculptor field for 4 orbits (i.e., 17 total orbits). We will use similar exposure times of about 400 sec as in the first epoch. We will use dither patterns pecifically tailored by CoI Jay Anderson for this program. These are specificied using POS TARGs on the individual exposures; no pre-specified patterns are used. We will also take one short additional exposure at the first dither position of each orbit in a second filter for each field, to construct V-I color-magnitude diagrams (CMDs). These will aid in the identification of member stars in each galaxy. We will also observe parallel fields with WFC3 in coordinated parallel mode. Whereas these parallel data will not yield PMs, they will allow construction of CMDs for analysis of the stellar populations of these galaxies. There will be only two WFC3 exposures per orbit (limited by the time needed to do buffer dumps). These will execute in a V and an I filter, respectively. To mitigate the impact of CTE in our science, we plan to use POST-FLASH on all of the ACS and WFC3 exposures. The ACS and WFC3 teams at STScI have committed to fully calibrate the POST-FLASH capabilities in time for Cycle 20, as communicated in a recent STScI white paper to the astronomical community. However, at this time, the POST-FLASH capabilities (and in particular the exposure times) have not been calibrated. Our exposure-level optional parameters on all exposures related to POST-FLASH are therefore only placeholders at this time. THEY WILL NEED TO BE EDITED AND REFINED BEFORE THE PROPOSAL CAN EXECUTE. For this reason, all visits are currently placed ON HOLD. ACS POST-FLASH optional parameters can only be entered at this time as an "available-but-unsupported" mode. We therefore marked the box for this on the Phase II cover page. RESOLVED STELLAR POPULATIONS 12 false false 0.0 0.0 false false false AVAILABLE GALAXY DWARF SPHEROIDAL This object was generated by the targetselector and retrieved from the NED database. J2000 J2000 GALAXY DWARF SPHEROIDAL This object was generated by the targetselector and retrieved from the NED database. J2000 J2000 GALAXY DWARF SPHEROIDAL This object was generated by the targetselector and retrieved from the NED database. J2000 J2000 GALAXY DWARF SPHEROIDAL J2000 J2000 GALAXY DWARF SPHEROIDAL J2000 J2000 ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F775W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F775W ACS/WFC Imaging No No F606W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W The scheduling data was generated by CASM 21.0. CASM was run in Phase II mode. This visit is for DRACO-F1. (Tic-Visit :proposal-id 12966 :visit-id "01" :proposal-version -1 :trans-version "20121031" :date "12-Mar-2013 13:01:35.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 5995824 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12966 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12966 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2979 :al-overhead-at-end 14 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3312 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3090 :al-overhead-at-end 14 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3312 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3090 :al-overhead-at-end 14 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3312 :pcs-gap 0 ) true 3 0 The scheduling data was generated by CASM 21.0. CASM was run in Phase II mode. This visit is for DRACO-F2. 1351104356000 48.0 (Tic-Visit :proposal-id 12966 :visit-id "02" :proposal-version -1 :trans-version "20121031" :date "12-Mar-2013 12:53:00.0" :trans-errors '(:WARNINGS 3 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 5995824 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12966 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12966 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3168 :al-overhead-at-end 113 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3491 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3279 :al-overhead-at-end 12 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3491 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "02" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3279 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3491 :pcs-gap 0 ) false 3 3 The scheduling data was generated by CASM 21.0. CASM was run in Phase II mode. This visit is for DRACO-F3. 1351281372000 44.17400000000001 (Tic-Visit :proposal-id 12966 :visit-id "03" :proposal-version -1 :trans-version "20121031" :date "12-Mar-2013 12:53:05.0" :trans-errors '(:WARNINGS 3 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 5995824 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12966 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12966 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3168 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3491 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3279 :al-overhead-at-end 12 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3491 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "03" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3279 :al-overhead-at-end 12 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3491 :pcs-gap 0 ) false 3 3 The scheduling data was generated by CASM 21.0. CASM was run in Phase II mode. This visit is for SCULPTOR-F1. (Tic-Visit :proposal-id 12966 :visit-id "04" :proposal-version -1 :trans-version "20121031" :date "12-Mar-2013 13:06:34.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 7994432 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12966 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12966 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2664 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2997 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "04" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2775 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2997 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "04" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2775 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2997 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "04" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2775 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2997 :pcs-gap 0 ) false 4 0 The scheduling data was generated by CASM 21.0. CASM was run in Phase II mode. This visit is for SCULPTOR-F2. (Tic-Visit :proposal-id 12966 :visit-id "05" :proposal-version -1 :trans-version "20121031" :date "12-Mar-2013 13:09:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 7994432 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12966 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12966 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2664 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2997 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "05" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2775 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2997 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "05" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2775 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2997 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12966 :visit-id "05" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2775 :al-overhead-at-end 13 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2997 :pcs-gap 0 ) false 4 0