12015( 4) - 16-Sep-2010 14:06:16 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12015 Version: 4 Check-in Time: 16-Sep-2010 14:06:16 STScI Edit Number: 0 Title Rapid Follow-Up Observations of Tidal Disruption Events Discovered by Pan-STARRS1 ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Suvi Gezari The Johns Hopkins University CoI: Dr. Martin Elvis Smithsonian Institution Astrophysical N Observatory CoI: Dr. Timothy M. Heckman The Johns Hopkins University N CoI: Dr. Andy Lawrence University of Edinburgh, Institute for N Astronomy ------------------------------------------------------------------------------------ Abstract We propose for rapid follow-up Chandra TOO ACIS-S observations and HST/COS NUV imaging and FUV low-resolution spectroscopy of 5 flares from the tidal disruption of stars by supermassive black holes discovered in the Pan-STARRS1 Medium Deep Survey. With TOO observations obtained within a month of the peak of the flare, and 5 months later, we aim to 1) constrain the flare's broadband SED and bolometric luminosity, 2) follow the decay of the flare and look for spectral evolution, and 3) place strong limits on the presence of a persistent AGN nucleus. Tidal disruption events provide a cosmic laboratory to study the physics of accretion onto black holes, and are a unique probe of the mass of black holes in the nuclei of distant galaxies. ------------------------------------------------------------------------------------ Observations Description ------------------------ We request 3 orbits with COS for NUV imaging and FUV low-resolution spectroscopy triggered at the same time as the initial \textsl{Chandra} TOO observation for each target, for a total of 15 orbits. Sensitive COS NUV imaging ($\lambda_{eff}=2032$ \AA) in the ACQ/IMAGE mode will measure the $NUV-g$ color of the flare, and confirm the spatial coincidence of the flare with the nucleus of the galaxy. COS low-resolution spectroscopy with the wide spectral range of the G140L grating ($1230 - 2050$\AA) will allow us to directly measure the nature of the flare UV continuum that we have previously inferred from \textsl{GALEX} broadband photometry, and look for the contribution of Ly$\alpha~\lambda$1216, C IV $\lambda$1550, and CIII] $\lambda$1909 emission lines that may result from the reprocessing of the photoionizing continuum. A TDE with $g < 22$ and $kT_{bb}>0.01$ keV, and a Galactic extinction of $E(B-V)=0.02$ with $z<0.2$ will require an NUV ACQ/IMAGE with $t_{exp}=120$ sec for a S/N $> 40$ (the S/N requirement for an acquisition image). A FUV G140L spectrum with a S/N $> 10$ per resolution element will require $t_{exp}=7600$ sec (Calculated using the COS ETC). Each target should be observed by COS with a response time of $21-30$ days, i.e. just above the rapid TOO activation limit for \textsl{HST}. The orbits should be structured as follows. Orbit 1: HST initial guide star, NUV ACQ/IMAGE with $t_{exp}=120$ sec and FUV G140L spectrum (TIME-TAG mode) with $t_{exp}=2000$ sec. Orbits 2 \& 3: HST reaquisition, FUV G140L spectrum (TIME-TAG mode) with $t_{exp}=2800$ sec. 12015( 4) - 16-Sep-2010 14:06:16 - [ 2] Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 12015( 4) - 16-Sep-2010 14:06:16 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 TDE-PS1-1 GALAXY, NUCLEUS RA=16H01M16.0510S +/- 0.1", J2000 Z = V = 21.5 +/- 0.2 DEC=+55D28'38.12" +/- 0.1" 0.181 Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 12015( 4) - 16-Sep-2010 14:06:16 - [ 4] TARGET LIST Generic Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Selection Criteria | Flux data No | Name | Description | | ------------------------------------------------------------------------------------------------------------------------------------ 2 TDE-PS1-2 GALAXY, NUCLEUS HOST GALAXY HAS NO EVIDENCE OF AN V = 21.0 +/- 1.0 AGN, HAS A REDSHIFT < 0.2, AND THE FLARE HAS G < 22. ------------------------------------------------------------------------------------------------------------------------------------ 3 TDE-PS1-3 HOST GALAXY HAS NO EVIDENCE OF AN V = 21.0 +/- 1.0 AGN, HAS A REDSHIFT < 0.2, AND THE FLARE HAS G < 22. ------------------------------------------------------------------------------------------------------------------------------------ 12015( 4) - 16-Sep-2010 14:06:16 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 12015( 4) - 16-Sep-2010 14:06:16 - [ 6] Visit: 01 Visit Requirements: BEFORE 15-OCT-2010:00:00:00 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TDE-PS1-1 WFC3/UVI ACCUM UVIS1 F225W CR-SPLIT=NO 1 600 S PATTERN 1 1-2 S ------------------------------------------------------------------------------------------------------------------------------------ 2 TDE-PS1-1 WFC3/UVI ACCUM UVIS1 F275W CR-SPLIT=NO 1 600 S 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 | ------------------------------------------------------------------------------------------------------------------------------------ TDE-PS1-1 1 WFC3/UVI ACCUM UVIS1 F225W 1 none none none 1 N/A S TDE-PS1-1 1 WFC3/UVI ACCUM UVIS1 F225W 2 none none none 1 N/A S TDE-PS1-1 2 WFC3/UVI ACCUM UVIS1 F275W 1 none none none 1 N/A S TDE-PS1-1 2 WFC3/UVI ACCUM UVIS1 F275W 2 none none none 1 N/A S 12015( 4) - 16-Sep-2010 14:06:16 - [ 7] Visit: 02 Visit Requirements: AFTER 01 BY 17 D TO 21 D 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TDE-PS1-1 COS/NUV ACQ/IMA PSA MIRRORA 1 120 S GE ------------------------------------------------------------------------------------------------------------------------------------ 2 TDE-PS1-1 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=2000 1 2000 S G ------------------------------------------------------------------------------------------------------------------------------------ 3 TDE-PS1-1 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=2800 1 2800 S G ------------------------------------------------------------------------------------------------------------------------------------ 4 TDE-PS1-1 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=2800 1 2800 S G ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ TDE-PS1-1 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE TDE-PS1-1 2 COS/FUV TIME-TA PSA G140L 1105 none none none none 1 N/A G TDE-PS1-1 3 COS/FUV TIME-TA PSA G140L 1105 none none none none 2 N/A G TDE-PS1-1 4 COS/FUV TIME-TA PSA G140L 1105 none none none none 3 N/A G 12015( 4) - 16-Sep-2010 14:06:16 - [ 8] Visit: 03 Visit Requirements: ON HOLD On Hold Comments: Target of Opportunity Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TDE-PS1-2 WFC3/UVI ACCUM UVIS1 F225W CR-SPLIT=NO 1 600 S PATTERN 1 1-2 S ------------------------------------------------------------------------------------------------------------------------------------ 2 TDE-PS1-2 WFC3/UVI ACCUM UVIS1 F275W CR-SPLIT=NO 1 500 S 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 | ------------------------------------------------------------------------------------------------------------------------------------ TDE-PS1-2 1 WFC3/UVI ACCUM UVIS1 F225W 1 none none none 1 N/A S TDE-PS1-2 1 WFC3/UVI ACCUM UVIS1 F225W 2 none none none 1 N/A S TDE-PS1-2 2 WFC3/UVI ACCUM UVIS1 F275W 1 none none none 1 N/A S TDE-PS1-2 2 WFC3/UVI ACCUM UVIS1 F275W 2 none none none 1 N/A S 12015( 4) - 16-Sep-2010 14:06:16 - [ 9] Visit: 04 Visit Requirements: ON HOLD On Hold Comments: Target of Opportunity Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TDE-PS1-2 COS/NUV ACQ/IMA PSA MIRRORA 1 120 S GE ------------------------------------------------------------------------------------------------------------------------------------ 2 TDE-PS1-2 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=2000 1 2000 S G ------------------------------------------------------------------------------------------------------------------------------------ 3 TDE-PS1-2 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=2800 1 2800 S G ------------------------------------------------------------------------------------------------------------------------------------ 4 TDE-PS1-2 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=2800 1 2800 S G ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ TDE-PS1-2 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE TDE-PS1-2 2 COS/FUV TIME-TA PSA G140L 1105 none none none none 1 N/A G TDE-PS1-2 3 COS/FUV TIME-TA PSA G140L 1105 none none none none 2 N/A G TDE-PS1-2 4 COS/FUV TIME-TA PSA G140L 1105 none none none none 3 N/A G 12015( 4) - 16-Sep-2010 14:06:16 - [ 10] Visit: 05 Visit Requirements: ON HOLD On Hold Comments: Target of Opportunity Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TDE-PS1-3 WFC3/UVI ACCUM UVIS1 F225W CR-SPLIT=NO 1 600 S PATTERN 1 1-2 S ------------------------------------------------------------------------------------------------------------------------------------ 2 TDE-PS1-3 WFC3/UVI ACCUM UVIS1 F275W CR-SPLIT=NO 1 600 S 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 | ------------------------------------------------------------------------------------------------------------------------------------ TDE-PS1-3 1 WFC3/UVI ACCUM UVIS1 F225W 1 none none none 1 N/A S TDE-PS1-3 1 WFC3/UVI ACCUM UVIS1 F225W 2 none none none 1 N/A S TDE-PS1-3 2 WFC3/UVI ACCUM UVIS1 F275W 1 none none none 1 N/A S TDE-PS1-3 2 WFC3/UVI ACCUM UVIS1 F275W 2 none none none 1 N/A S 12015( 4) - 16-Sep-2010 14:06:16 - [ 11] Summary Form for Proposal 12015 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA, UVIS1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=2000, BUFFER-TIME=2800, CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 17 D TO 21 D, BEFORE 15-OCT-2010:00:00:00, ON HOLD , PATTERN 1 1-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F225W, F275W, G140L, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names TDE-PS1-1, TDE-PS1-2, TDE-PS1-3 ------------------------------------------------------------------------------------------------------------------------------------