0 Assigned ID: 685 ----- Attempting Submission 1 (Fri Apr 08 18:50:05 GMT 2016) ----- HST Phase I Proposal 685 (bh_prop.apt) successfully submitted. Receipt: # 685-1 ----- Attempting Submission 2 (Fri Apr 08 21:42:50 GMT 2016) ----- HST Phase I Proposal 685 (bh_prop.apt) successfully submitted. Receipt: # 685-2 ----- Attempting Submission 3 (Fri Apr 08 21:56:28 GMT 2016) ----- HST Phase I Proposal 685 (bh_prop.apt) successfully submitted. Receipt: # 685-3 ----- Attempting Submission 4 (Fri Apr 08 22:24:58 GMT 2016) ----- HST Phase I Proposal 685 (bh_prop.apt) successfully submitted. Receipt: # 685-4 ----- Attempting Submission 5 (Sat Apr 09 00:37:24 GMT 2016) ----- visit planner already run with no errors FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser BETWEEN added to visit 1. No other change. 42397616 ----- Attempting Submission 1 (Thu Jul 21 19:45:59 GMT 2016) ----- Your proposal could not be saved. Submission aborted. ----- Attempting Submission 2 (Wed Jan 25 16:45:43 GMT 2017) ----- BETWEEN added to visit 1. No other change. Detecting Isolated Black Holes through Astrometric Microlensing A significant fraction of the mass of an old stellar population should be in the form of non-luminous, isolated black holes (BHs). Yet there has never been an unambiguous detection of a solitary BH--not surprisingly, since they emit essentially no radiation. The only technique available to detect such isolated BHs is astrometric microlensing---the relativistic deflection of light from background stars. HST is the only instrument currently capable of detecting such tiny deflections. We have underway a multi-year program of HST high-precision astrometry of long-duration microlensing events in the Galactic bulge, using the WFC3 camera. Our aim is the first detection of stellar-mass black holes, by monitoring five optimally selected events. Our program has met with success, with clear detections of the deflections, indicative of non-luminous massive lenses in 3 cases. However, for these long-duration (T_E > 100 days) events, the deflection due to microlensing is present at all our observed epochs, which causes some degeneracy between the proper motion (PM) and the deflection, making the mass estimate uncertain. The deflection due to microlensing is now neglible, so observations at this stage can unambiguously determine the PM, and remove this degeneracy. For 2 of our targets, we need 2 observations spaced by about one year to unambiguously determine the PM. The other target is a high-amplification event for which the deflection at the peak was negligible, so only one more observation will provide an unambiguous measurement of the PM. We thus need 5 orbits, which will lead to a robust determination of the lens masses, thus completing the original objectives of the program. We will employ the same observational strategy we have followed earlier. Basically, we will image each field using WFC3, primarily with the F814W filter, but also with F606W. As before, we will employ a 6-point dithering pattern, where we will observe the target star and the reference stars at a variety of pixel phases, thereby allowing us to construct an exquisite model of the PSF, and also randomize any remaining (small) systematic errors related to pixelization. Our dithers will also involve offsets of 100 pixels, so that we will observe the target star at different places on the detector, so that any remaining distortion errors will average out. We expect such errors to be small (< 0.01 pixel), but randomizing them will be worthwhile. The procedure described here does not require the observations at different epochs to be taken in the same ORIENT, which makes the scheduling easier. 4 Stellar Populations Stellar Physics 6 false false false false false false SUPPORTED EXT-STAR A0-A3 III-I J2000 J2000 EXT-STAR A0-A3 III-I J2000 J2000 EXT-STAR A0-A3 III-I J2000 J2000 WFC3/UVIS Imaging No No F814W WFC3/UVIS 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 1502426613000 75.2274196710811 (Tic-Visit :proposal-id 14783 :visit-id "01" :proposal-version -1 :trans-version "20160601" :date "21-Jul-2016 15:38:07.0" :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 492704 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14783 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14783 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2889 :al-overhead-at-end 165 :internal-dur-at-end 575 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 1 0 1489522735000 270.37988578552967 (Tic-Visit :proposal-id 14783 :visit-id "02" :proposal-version -1 :trans-version "20160601" :date "21-Jul-2016 15:40:04.0" :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 492704 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14783 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14783 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2869 :al-overhead-at-end 165 :internal-dur-at-end 575 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) false 1 0 (Tic-Visit :proposal-id 14783 :visit-id "03" :proposal-version -1 :trans-version "20160601" :date "21-Jul-2016 15:41:35.0" :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 492704 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14783 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14783 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2869 :al-overhead-at-end 165 :internal-dur-at-end 575 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) true 1 0 53 1489387206000 270.0 (Tic-Visit :proposal-id 14783 :visit-id "04" :proposal-version -1 :trans-version "20160601" :date "25-Jan-2017 11:43:24.0" :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 633488 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14783 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14783 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2732 :al-overhead-at-end 173 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180.0 :pcs-gap 0 ) false 1 0 56 (Tic-Visit :proposal-id 14783 :visit-id "04" :proposal-version -1 :trans-version "20160601" :date "21-Jul-2016 15:43:09.0" :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 633488 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14783 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14783 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2732 :al-overhead-at-end 173 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) false 1 0 (Tic-Visit :proposal-id 14783 :visit-id "01" :proposal-version -1 :trans-version "20160601" :date "21-Jul-2016 15:38:07.0" :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 492704 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14783 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14783 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2889 :al-overhead-at-end 165 :internal-dur-at-end 575 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 0