0 Assigned ID: 1571 ----- Attempting Submission 1 (Sat Sep 30 22:13:55 GMT 2017) ----- HST Phase I Proposal 1571 (Planckarc_LyC.apt) successfully submitted. Receipt: # 1571-1 ----- Attempting Submission 2 (Sat Sep 30 23:47:23 GMT 2017) ----- 0 ----- Attempting Submission 1 (Tue Dec 12 22:20:45 GMT 2017) ----- Recent Magellan spectra of a strongly gravitationally lensed starburst galaxy at z=2.4 show clear evidence of direct escape of Lyman-alpha photons through a riddled neutral medium. The observed Lyman-alpha line profile has been theoretically predicted, but never unambiguously seen so far, and it is considered to be a smoking gun for the escape of Lyman-continuum photons from star-forming galaxies. The unique Lyman-alpha line profile, in addition to the unique brightness and apparent angular size of the strongly lensed galaxy, makes it an instantly compelling target for direct detection of LyC photons, utilizing the UV capabilities of HST while they are still available. We propose WFC3/UVIS F275W-band imaging to directly reveal the spatial distribution of the escape of ionizing photons. Coupled with scheduled Cycle 25 HST imaging and grism spectroscopy at longer wavelengths, this will reveal the physical conditions for Lyman continuum leakage, across ~4000 resolution elements at <100pc resolution. We have been allocated 3 orbits for WFC3/UVIS imaging in the F275W filter. We split the allocation into two visits, of two and one orbits, respectively, to improve schedulability. No a priori restriction is given on roll angle, but the roll angle should be the same for both visits. Two exposures are made during each orbit, with dither offsets to ensure that the gap between the chips in a given exposure is always covered by the five other exposures. Postflash of 8 electrons is applied to ensure a background level of 12 electrons to mitigate CTE losses. Galaxies and the IGM 3 false true false false false false SUPPORTED GALAXY GRAVITATIONAL LENS HIGH REDSHIFT GALAXY STARBURST J2000 J2000 R=17.82, z=17.38, J=16.75, Ks=15.43 (Vega) WFC3/UVIS Imaging No No F275W POS-TARG DITHER 2.5 LINE false false 4 46.84 WFC3-UVIS-DITHER-LINE 1 false POS-TARG DITHER 2.5 LINE false false 2 46.84 WFC3-UVIS-DITHER-LINE 2 false 1513116277076 /Users/hdahle/Documents/OP-cache/Cycle25_LyC_phaseII-v01.xml The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15418 :visit-id "01" :proposal-version -1 :trans-version "20171009" :date "12-Dec-2017 23:04:37.0" :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 1154976 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15418 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15418 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3246 :al-overhead-at-end 122 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3579 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15418 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3356 :al-overhead-at-end 122 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3579 :pcs-gap 0 ) true 2 0 1513116213000 /Users/hdahle/Documents/OP-cache/Cycle25_LyC_phaseII-v02.xml The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15418 :visit-id "02" :proposal-version -1 :trans-version "20171009" :date "12-Dec-2017 23:03:32.0" :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 577488 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15418 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15418 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3246 :al-overhead-at-end 122 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3579 :pcs-gap 0 ) true 1 0