Please let me know if you have any problems reading this proposal. Thanks very much. -637075016 Assigned ID: 931 ----- Attempting Submission 1 (Fri Apr 11 22:10:40 GMT 2014) ----- 0 ----- Attempting Submission 1 (Mon Jul 14 15:43:04 GMT 2014) ----- The Double Supernova in NGC 6984 In 2012 and 2013, two Type Ib/c supernovae -- SN2012im and SN2013ek -- were discovered at virtually the same location (< 0.4 arcsec) in NGC 6984 (D ~ 65 Mpc). A double supernova of this sort has never been observed before and it is possible that the two explosions are somehow physically linked. The uniqueness of the discovery prompted HST/WFC3 images of the region to be obtained in Cycle 21 via Director's Discretionary time led by our group. Those images revealed a weak source nearby to SN2013ek that could be late-time emission from SN2012im. We propose a program of four orbits of Cycle 22 time to complete our original mission of determining the nature of this rare supernova coupling. A return visit with HST will conclusively verify whether the secondary source is indeed SN2012im. If the secondary source fades then this would mean a curious case of two neighboring but unrelated supernovae occurring within a year of each other. Alternatively, if the secondary source does not fade, then it is likely that the two events SN2012im/2013ek are connected -- a discovery that will have important ramifications in areas of high-mass binary star evolution and explosion mechanisms of core-collapse supernovae. The proposed UV and optical observations will enable us to perform a detailed investigation of the explosion site and model properties of the parent star cluster and its immediate environment. These observations are designed to obtain a suite of optical and UV images of SN 2013ek and its host galaxy NGC 6984. The WFC3/UVIS will be used in a total of four orbits over two visits of Cycle 22 time. The filters F275W, F336W, F475W, F555W, F665N, and F814W will be used. The images will be dithered in a three-point sub-pixel pattern. The entire galaxy fits nicely on the UVIS2 chip. We have incorporated the use of post-flash to improve charge transfer efficiency. HOT STARS Default false true false false false SUPPORTED EXT-STAR SUPERNOVA J2000 J2000 WFC3/UVIS Imaging No No F336W WFC3/UVIS Imaging No No F438W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F275W WFC3/UVIS Imaging No No F665N POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false /Users/danmil/proposals/hst-cycle22-2014/OP-cache/hst-cycle22-2014-2013ek-phase2-v01.xml The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13782 :visit-id "01" :proposal-version -1 :trans-version "20140605" :date "14-Jul-2014 11:29:58.0" :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 6930032 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13782 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13782 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3055 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3409 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13782 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3166 :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 3409 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13782 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3173 :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 3409 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13782 :visit-id "01" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3173 :al-overhead-at-end 123 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3409 :pcs-gap 0 ) true 4 0