14255( 3) - 06-May-2016 14:12:01 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14255 Version: 3 Check-in Time: 06-May-2016 14:12:01 STScI Edit Number: 0 Title A First Look at the Late Stages of Accretion in Tidal Disruption Flares ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Sjoert van Velzen The Johns Hopkins University Y CoI: Dr. Nicholas Stone Columbia University in the City of New N York CoI: Dr. Andrew S. Fruchter Space Telescope Science Institute N CoI: Dr. Thomas M. Brown Space Telescope Science Institute N CoI: Prof. Suvi Gezari University of Maryland N CoI: Prof. Brian Metzger Columbia University in the City of New N York CoI: Prof. Glennys Farrar New York University N ------------------------------------------------------------------------------------ Abstract A star that passes too close to a supermassive black hole will be disrupted by the black hole's tidal gravity. The result is an electromagnetic flare that can outshine the optical luminosity of the host galaxy for a few months. The return rate of stellar debris decreases from highly super-Eddington to sub-Eddington in a few years, making stellar tidal disruptions flares (TDFs) a unique laboratory to study accretion physics. Synoptic surveys have so far yielded about 10 strong TDF candidates, and many more (10-100 per month) can be discovered by ongoing and near-future surveys. So far we have only observed the optical/UV emission in the first ~100 days after the discovered event. The luminosity of this emission is too large to be produced in a compact accretion disk, and instead likely originates from ~100s-1000s of gravitational radii from the black hole. After a few years, however, these outer regions will cool significantly, allowing us to directly observe the inner disk with short wavelength observations. Even in the most pessimistic scenario, the flux is readily detected at FUV wavelengths in ~1 HST orbit. Here we propose HST ACS/SBC observations to measure the luminosity and temperature of newly formed accretion disks in a carefully selected sample of 8 known TDFs. These would be the first observations of late-time disk emission from tidal flares, greatly increasing our currently limited understanding of TDF emission mechanisms. In a broader sense, these observations might prove essential to fully realize the potential of TDFs as general tools in the era of time-domain astronomy. ------------------------------------------------------------------------------------ Observations Description ------------------------ ACS SBC observations of eight targets. One orbit per source. Our targets are faint point sources (FUV>20) at the center of resolved galaxies. For the first 3 targets we plan both imaging in two filters (F125LP and F150LP) and slitless spectroscopic observations with PR130L. For these three targets, the spectroscopic observations should be about 25% of the full time for science observations of the orbit. For targets 4 to 8 we request only imaging (again, 14255( 3) - 06-May-2016 14:12:01 - [ 2] in F125LP and F150LP). We have decided to use 1x2 (LINE) dithering for the imaging observations and for the PR130L observations. Analysis using BOT revealed no bright targets that yielded warning flags. All our targets are covered by GALEX imaging, no FUV-bright stars are in the field of view. ------------------------------------------------------------------------------------ 14255( 3) - 06-May-2016 14:12:01 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PTF-09GE GALAXY, ACCRETION DISK RA=14H57M3.1800S +/- 0.5", J2000 V = 17.5 +/- 0.1 DEC=+49D36'40.97" +/- 0.5" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 D23H-1 GALAXY, ACCRETION DISK RA=23H31M59.5344S, J2000 V = 19.6 +/- 0.1 DEC=+00D17'14.57" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 TDE1 GALAXY, ACCRETION DISK RA=23H42M1.4064S, J2000 V = 19.7 +/- 0.1 DEC=+01D06'29.27" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 PTF-09DJL GALAXY, ACCRETION DISK RA=16H33M55.9728S, J2000 V = 20.1 +/- 0.1 DEC=+30D14'16.66" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 5 PS1-10JH GALAXY, ACCRETION DISK RA=16H09M28.2761S, J2000 V = 21.4 +/- 0.1 DEC=+53D40'23.99" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 6 D3-13 GALAXY, ACCRETION DISK RA=14H19M29.8086S, J2000 V = 21.1 +/- 0.1 DEC=+52D52'6.36" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 7 D1-9 GALAXY, ACCRETION DISK RA=02H25M16.9699S, J2000 V = 21.4 +/- 0.1 DEC=-04D32'59.13" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 8 TDE2 GALAXY, ACCRETION DISK RA=23H23M48.6144S, J2000 V = 20.1 +/- 0.1 DEC=-01D08'10.25" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 14255( 3) - 06-May-2016 14:12:01 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-SBC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.472 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 44.4 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 14255( 3) - 06-May-2016 14:12:01 - [ 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 PTF-09GE ACS/SBC ACCUM SBC F125LP 1 480 S (960 PATTERN 2 1-2 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PTF-09GE ACS/SBC ACCUM SBC F150LP 1 480 S (960 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PTF-09GE ACS/SBC ACCUM SBC PR130L 1 280 S (560 PATTERN 2 3 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 | ------------------------------------------------------------------------------------------------------------------------------------ PTF-09GE 1 ACS/SBC ACCUM SBC F125LP 1 none none none 1 N/A PTF-09GE 1 ACS/SBC ACCUM SBC F125LP 2 none none none 1 N/A PTF-09GE 2 ACS/SBC ACCUM SBC F150LP 1 none none none 1 N/A PTF-09GE 2 ACS/SBC ACCUM SBC F150LP 2 none none none 1 N/A PTF-09GE 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 N/A PTF-09GE 3 ACS/SBC ACCUM SBC PR130L 2 none none none 1 N/A 14255( 3) - 06-May-2016 14:12:01 - [ 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 D23H-1 ACS/SBC ACCUM SBC F125LP 1 455 S (910 PATTERN 2 1-2 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D23H-1 ACS/SBC ACCUM SBC F150LP 1 455 S (910 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 D23H-1 ACS/SBC ACCUM SBC PR130L 1 260 S (520 PATTERN 2 3 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 | ------------------------------------------------------------------------------------------------------------------------------------ D23H-1 1 ACS/SBC ACCUM SBC F125LP 1 none none none 1 N/A D23H-1 1 ACS/SBC ACCUM SBC F125LP 2 none none none 1 N/A D23H-1 2 ACS/SBC ACCUM SBC F150LP 1 none none none 1 N/A D23H-1 2 ACS/SBC ACCUM SBC F150LP 2 none none none 1 N/A D23H-1 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 N/A D23H-1 3 ACS/SBC ACCUM SBC PR130L 2 none none none 1 N/A 14255( 3) - 06-May-2016 14:12:01 - [ 7] Visit: 03 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 TDE1 ACS/SBC ACCUM SBC F125LP 1 455 S (910 PATTERN 2 1-2 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 TDE1 ACS/SBC ACCUM SBC F150LP 1 455 S (910 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 TDE1 ACS/SBC ACCUM SBC PR130L 1 260 S (520 PATTERN 2 3 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 | ------------------------------------------------------------------------------------------------------------------------------------ TDE1 1 ACS/SBC ACCUM SBC F125LP 1 none none none 1 N/A TDE1 1 ACS/SBC ACCUM SBC F125LP 2 none none none 1 N/A TDE1 2 ACS/SBC ACCUM SBC F150LP 1 none none none 1 N/A TDE1 2 ACS/SBC ACCUM SBC F150LP 2 none none none 1 N/A TDE1 3 ACS/SBC ACCUM SBC PR130L 1 none none none 1 N/A TDE1 3 ACS/SBC ACCUM SBC PR130L 2 none none none 1 N/A 14255( 3) - 06-May-2016 14:12:01 - [ 8] Visit: 04 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 PTF-09DJL ACS/SBC ACCUM SBC F125LP 1 635 S PATTERN 2 1-2 (1270 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PTF-09DJL ACS/SBC ACCUM SBC F150LP 1 635 S (1270 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 | ------------------------------------------------------------------------------------------------------------------------------------ PTF-09DJL 1 ACS/SBC ACCUM SBC F125LP 1 none none none 1 N/A PTF-09DJL 1 ACS/SBC ACCUM SBC F125LP 2 none none none 1 N/A PTF-09DJL 2 ACS/SBC ACCUM SBC F150LP 1 none none none 1 N/A PTF-09DJL 2 ACS/SBC ACCUM SBC F150LP 2 none none none 1 N/A 14255( 3) - 06-May-2016 14:12:01 - [ 9] Visit: 05 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 PS1-10JH ACS/SBC ACCUM SBC F125LP 1 670 S PATTERN 2 1-2 (1340 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PS1-10JH ACS/SBC ACCUM SBC F150LP 1 670 S (1340 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 | ------------------------------------------------------------------------------------------------------------------------------------ PS1-10JH 1 ACS/SBC ACCUM SBC F125LP 1 none none none 1 N/A PS1-10JH 1 ACS/SBC ACCUM SBC F125LP 2 none none none 1 N/A PS1-10JH 2 ACS/SBC ACCUM SBC F150LP 1 none none none 1 N/A PS1-10JH 2 ACS/SBC ACCUM SBC F150LP 2 none none none 1 N/A 14255( 3) - 06-May-2016 14:12:01 - [ 10] Visit: 06 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 D3-13 ACS/SBC ACCUM SBC F125LP 1 670 S PATTERN 2 1-2 (1340 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D3-13 ACS/SBC ACCUM SBC F150LP 1 670 S (1340 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 | ------------------------------------------------------------------------------------------------------------------------------------ D3-13 1 ACS/SBC ACCUM SBC F125LP 1 none none none 1 N/A D3-13 1 ACS/SBC ACCUM SBC F125LP 2 none none none 1 N/A D3-13 2 ACS/SBC ACCUM SBC F150LP 1 none none none 1 N/A D3-13 2 ACS/SBC ACCUM SBC F150LP 2 none none none 1 N/A 14255( 3) - 06-May-2016 14:12:01 - [ 11] Visit: 07 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 D1-9 ACS/SBC ACCUM SBC F125LP 1 625 S PATTERN 2 1-2 (1250 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D1-9 ACS/SBC ACCUM SBC F150LP 1 625 S (1250 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 | ------------------------------------------------------------------------------------------------------------------------------------ D1-9 1 ACS/SBC ACCUM SBC F125LP 1 none none none 1 N/A D1-9 1 ACS/SBC ACCUM SBC F125LP 2 none none none 1 N/A D1-9 2 ACS/SBC ACCUM SBC F150LP 1 none none none 1 N/A D1-9 2 ACS/SBC ACCUM SBC F150LP 2 none none none 1 N/A 14255( 3) - 06-May-2016 14:12:01 - [ 12] Visit: 08 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 TDE2 ACS/SBC ACCUM SBC F125LP 1 625 S PATTERN 2 1-2 (1250 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 TDE2 ACS/SBC ACCUM SBC F150LP 1 625 S (1250 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 | ------------------------------------------------------------------------------------------------------------------------------------ TDE2 1 ACS/SBC ACCUM SBC F125LP 1 none none none 1 N/A TDE2 1 ACS/SBC ACCUM SBC F125LP 2 none none none 1 N/A TDE2 2 ACS/SBC ACCUM SBC F150LP 1 none none none 1 N/A TDE2 2 ACS/SBC ACCUM SBC F150LP 2 none none none 1 N/A 14255( 3) - 06-May-2016 14:12:01 - [ 13] Summary Form for Proposal 14255 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures SBC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/SBC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 2 1-2, PATTERN 2 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F125LP, F150LP, PR130L ------------------------------------------------------------------------------------------------------------------------------------ Target Names D1-9, D23H-1, D3-13, PS1-10JH, PTF-09DJL, PTF-09GE, TDE1, TDE2 ------------------------------------------------------------------------------------------------------------------------------------