14450( 3) - 14-Dec-2015 23:03:07 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14450 Version: 3 Check-in Time: 14-Dec-2015 23:03:07 STScI Edit Number: 0 Title Ultraviolet Spectroscopy of the Unprecedented Rebrightening of the Most Luminous Supernova ------------------------------------------------------------------------------------ Type Cycle GO/DD 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Peter J. Brown Texas A & M University Y CoI: Dr. Jeff Cooke Swinburne University of Technology N CoI: Dr. Jeremy R. Mould Swinburne University of Technology N CoI: Dr. Lifan Wang Texas A & M University N CoI: Mr. Yi Yang Texas A & M University N ------------------------------------------------------------------------------------ Abstract 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. ------------------------------------------------------------------------------------ Observations Description ------------------------ 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. ------------------------------------------------------------------------------------ 14450( 3) - 14-Dec-2015 23:03:07 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 ASASSN-15LH EXT-STAR, SUPERNOVA RA=22H02M15.4200S +/- 0.3", J2000 V = 18 +/- 0.1 uvm2=17 (vega) DEC=-61D39'34.70" +/- 0.3" Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 14450( 3) - 14-Dec-2015 23:03:07 - [ 3] Visit: 01 Visit Requirements: SCHED 80%; BETWEEN 20-DEC-2015:00:00:00 AND 02-JAN-2016:00:00:00 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ASASSN-15LH STIS/CCD ACQ F28X50LP MIRROR 1 7 S (7 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ASASSN-15LH STIS/CCD ACQ/PEA 52X0.1 MIRROR 1 10 S (10 K S) ------------------------------------------------------------------------------------------------------------------------------------ 3 ASASSN-15LH STIS/CCD ACCUM 52X0.1 G430L 4300 1 400 S see below (434 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ASASSN-15LH STIS/NUV ACCUM 52X0.1 G230L 2376 1 800 S -MAMA see below (1217 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 ASASSN-15LH COS/NUV ACQ/IMA PSA MIRRORA 1 10 S (10 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 6 ASASSN-15LH COS/FUV TIME-TA PSA G140L 1105 FP-POS=ALL, FLASH=YES, 1 2200 S G BUFFER-TIME=1800 see below (2121 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ASASSN-15LH 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A ASASSN-15LH 2 STIS/CCD ACQ/PEA 52X0.1 MIRROR none none none none 1 N/A K ASASSN-15LH 3 STIS/CCD ACCUM 52X0.1 G430L 4300 none none none 1 1 217.0 S ASASSN-15LH 3 STIS/CCD ACCUM 52X0.1 G430L 4300 none none none 2 1 217.0 S ASASSN-15LH 4 STIS/NUV ACCUM 52X0.1 G230L 2376 none none none none 1 1217.0 S -MAMA ASASSN-15LH 5 COS/NUV ACQ/IMA PSA MIRRORA none none none none 2 N/A GE ASASSN-15LH 6 COS/FUV TIME-TA PSA G140L 1105 none none none 1 2 523.0 S G ASASSN-15LH 6 COS/FUV TIME-TA PSA G140L 1105 none none none 2 2 523.0 S G ASASSN-15LH 6 COS/FUV TIME-TA PSA G140L 1105 none none none 3 2 523.0 S G 14450( 3) - 14-Dec-2015 23:03:07 - [ 4] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ASASSN-15LH 6 COS/FUV TIME-TA PSA G140L 1105 none none none 4 2 552.0 S G 14450( 3) - 14-Dec-2015 23:03:07 - [ 5] Summary Form for Proposal 14450 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.1, F28X50LP, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV, STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/IMAGE, ACQ/PEAK, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1800, FLASH=YES, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 20-DEC-2015:00:00:00 AND 02-JAN-2016:00:00:00, SCHED 80% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G230L, G430L, MIRROR, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names ASASSN-15LH ------------------------------------------------------------------------------------------------------------------------------------