0 Assigned ID: 1231 ----- Attempting Submission 1 (Fri Dec 04 20:31:32 GMT 2015) ----- If the target coordinates are not known to 0.4" (or better), an ACQ/SEARCH should precede the ACQ/IMAGE. 0 ----- Attempting Submission 1 (Sat Dec 12 00:06:55 GMT 2015) ----- HST Phase II Proposal 14450 (HSTSLSNDDT2phaseII.apt) successfully submitted. Receipt: # 14450-1 ----- Attempting Submission 2 (Mon Dec 14 22:57:31 GMT 2015) ----- It warns about doing a courser acquisition with COS if the position is not known to better than 0.4", which is the accuracy of our position. If an additional acquisition is needed we can add it. ASASSN-15lh/SN2015L has been classified as a hydrogen-poor superluminous supernova (SLSN-I) which is more luminous than any supernova previously observed. It has already emitted more than 3 x 10^51 ergs of luminosity, most of which was emitted at UV wavelengths. After fading for two months it began rebrightening in the UV, a behavior never before seen. We propose to obtain HST/STIS UV spectroscopy in order to determine the nature of the UV emission (thermal or line emission) and the composition of the ejecta and intervening material. While this phase is not yet understood--and the motivation for this proposal--we do not expect it to last long. For this reason we request Director's Discretionary Time for a non-distruptive Target of Opportunity observation. We will use STIS/MAMA with G230L to obtain NUV spectroscopy of the SN covering the bulk of the flux seen with Swift/UVOT photometry. We will use STIS/CCD with G430L to obtain NUV/optical spectroscopy bridging the UV with optical. We will use COS/FUV with G140L to cover the spectral region around Lyman alpha. The target becomes unobservable from January 2-Feb 20, so we desire to observe the last week of December as the source may fade before it becomes observable again. HOT STARS 0 SUPPORTED EXT-STAR SUPERNOVA NO SN2015L J2000 J2000 uvm2=17 (vega) STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 1450133814465 /private/var/folders/sv/8hpycl2s5kj0mwz1_6q6c5340000gn/T/OPVisit2339423094436921062.xml The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14450 :visit-id "01" :proposal-version -1 :trans-version "20150609" :date "14-Dec-2015 16:56:53.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 264608 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14450 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 14450 :visit-id "01" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14450 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2838 :al-overhead-at-end 0 :internal-dur-at-end 375 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3172 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14450 :visit-id "01" :orbit-number 2 :pcs-time 333 :si-vis-utilization 2839 :al-overhead-at-end 0 :internal-dur-at-end 350 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3172 :pcs-gap 0 ) true 2 0