13479( 2) - 26-Jun-2013 19:46:51 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13479 Version: 2 Check-in Time: 26-Jun-2013 19:46:51 STScI Edit Number: 0 Title The host and location of the candidate relativistic tidal disruption event Swift 2058+0516 ------------------------------------------------------------------------------------ Type Cycle GO 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Andrew J. Levan The University of Warwick Y CoI: Dr. Stephen Bradley Cenko University of California - Berkeley N CoI: Prof. Nial R. Tanvir University of Leicester N CoI: Prof. Joshua S. Bloom University of California - Berkeley N CoI: Dr. Andrew S. Fruchter Space Telescope Science Institute N CoI: Dr. Klaas Wiersema University of Leicester N CoI: Dr. Nathaniel Butler University of California - Berkeley N CoI: Ms. Rachel Tunnicliffe The University of Warwick N CoI: Mr. Gregory Brown The University of Warwick N ------------------------------------------------------------------------------------ Abstract Recent panchromatic observations have revealed a new class of high energy transient. These systems persist as bright gamma-ray sources for days, with luminosities in excess of the Eddington limit for a 10^10 solar mass black hole. They are accompanied by bright, long-lived (months to years) X-ray emission, and rather fainter, but still clearly detectable optical and IR counterparts. They are suggested to arise from the tidal disruption of stars in the nuclei of their host galaxies, which create a powerful relativistic outflow. In the first case (Swift J1644+57) astrometry ties the transient to nucleus of its host galaxy, lending support to this picture. However, other models have been postulated, such as the collapse of a giant star, where the outer envelope forms a disc that powers the observed transients, akin to a scaled-up gamma-ray burst. A key distinguishing feature between the two progenitors is their expected locations. Tidal disruptions must be uniquely nuclear, while GRB-like events are consistent with the nuclei of their hosts only 1/6 of the time. Here we propose to obtain deep observations of the second of these events -- Swift J2058+0516. These deep observations will detect and resolve its host galaxy, providing (via our earlier DDT observations) a precise location on the host. An IR visit will also provide a color for the host, and an estimate of its stellar and (through the bulge mass -- black hole mass relation) black hole mass. These data will provide the key astrometric and photometric evidence to disentagle competing models for these events, and will greatly aid the development of a definitive understanding of this new class of transient. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose deep observations of the location of the candidate tidal disruption event Swift J2058+0516. We will conduct two orbits of observations with ACS/WFC in F606W. These observations will utilize a 4-point dither, with indivdual ~1200s exposures. As we are interested in a compact point source we will place the source at the WFC1-CTE aperture. 13479( 2) - 26-Jun-2013 19:46:51 - [ 2] We will also obtain a single orbit of F160W observations with WFC3/IR channel. The source will be placed at the default aim point with a 4-point dither. In case there is any ongoing transient emission we ask for the observations to be placed relatively close to one another in time ~+/- 2 weeks. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 13479( 2) - 26-Jun-2013 19:46:51 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SWIFT2058+05 GALAXY, HIGH REDSHIFT RA=20H58M19.8500S +/- 0.1", J2000 V = 25 +/- 1 16 GALAXY DEC=+05D13'33.00" +/- 0.1" Reference Frame: Other: Chandra ------------------------------------------------------------------------------------------------------------------------------------ 13479( 2) - 26-Jun-2013 19:46:51 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.265 Line_Spacing 0.187 Coordinate_Frame POS-TARG Pattern_Orient 20.67 Angle_Between_Sides 69.05 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 13479( 2) - 26-Jun-2013 19:46:51 - [ 5] Visit: 01 Visit Requirements: 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 SWIFT2058+0 ACS/WFC ACCUM WFC1-CTE F606W 1 900 S PATTERN 1 1 516 see below (5236 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 | ------------------------------------------------------------------------------------------------------------------------------------ SWIFT2058+0516 1 ACS/WFC ACCUM WFC1-CTE F606W 1 none none none 1 1261.0 S SWIFT2058+0516 1 ACS/WFC ACCUM WFC1-CTE F606W 2 none none none 1 1261.0 S SWIFT2058+0516 1 ACS/WFC ACCUM WFC1-CTE F606W 3 none none none 2 1357.0 S SWIFT2058+0516 1 ACS/WFC ACCUM WFC1-CTE F606W 4 none none none 2 1357.0 S 13479( 2) - 26-Jun-2013 19:46:51 - [ 6] Visit: 02 Visit Requirements: 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 SWIFT2058+0 WFC3/IR MULTIAC IR F160W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF PATTERN 2 1 516 CUM (2611.753 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 | ------------------------------------------------------------------------------------------------------------------------------------ SWIFT2058+0516 1 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM SWIFT2058+0516 1 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM SWIFT2058+0516 1 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM SWIFT2058+0516 1 WFC3/IR MULTIAC IR F160W 4 none none none 1 N/A CUM 13479( 2) - 26-Jun-2013 19:46:51 - [ 7] Summary Form for Proposal 13479 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, WFC1-CTE ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=14, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, PATTERN 2 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W, F606W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SWIFT2058+0516 ------------------------------------------------------------------------------------------------------------------------------------