18081( 2) - 11-Aug-2025 22:39:27 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18081 Version: 2 Check-in Time: 11-Aug-2025 22:39:27 STScI Edit Number: 0 Title Using 35 year old tidal disruption events to test the fundamentals of accretion disk theory ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Andy Mummery Institute For Advanced Study Y CoI: Muryel Guolo The Johns Hopkins University Y CoI: Dr. Suvi Gezari Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract Tidal Disruption Events (TDEs) occur when stars pass too close to supermassive black holes and are torn apart by tidal forces and subsequently accreted. The oldest known TDE candidates are six sources discovered by the ROSAT X-ray satellite in the 1990's, which showed soft X-ray flares which decayed to unobservable X-ray flux levels over $\sim 5-10$ years. In the following 20 years our theoretical and observational understanding of TDEs has strengthened, and a substantial breakthrough has occurred: while significant uncertainties remain in the origin of the UV/optical light emitted during the initial flare, late-time optical/UV emission is known to originate from accretion disks in these events, and to last for at least $\gtrsim 2000$ days. This means, despite their X-ray emission having faded decades ago, all six ROSAT TDEs should be bright and detectable in the UV today, over 30 years after disruption. The detection with HST of bright UV emission from these six events would allow six black hole mass measurements to be performed, but the detection or non-detection of each of these systems will teach the disk theory community a great deal about black hole accretion disk stability at low luminosities, something which is observationally inaccessible to any other known massive black hole disk systems. ------------------------------------------------------------------------------------ Observations Description ------------------------ The proposal aims to observe decade-old (1990s) tidal disruption events (TDEs) using multi-band UV/optical imaging. We will observe each of the 6 TDEs in 3 filters for 2 orbits each. The first orbit will be in F225W, and the second orbit will be split between F438W and F625W. ------------------------------------------------------------------------------------ 18081( 2) - 11-Aug-2025 22:39:27 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-5905 GALAXY, ACCRETION DISK RA=15H15M23.3281S, J2000 V = 12 DEC=+55D31'1.93" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 1.2505325989676283E-4 0.001188 0.0014305000000000001 ------------------------------------------------------------------------------------------------------------------------------------ 2 RXJ1242-11 GALAXY, ACCRETION DISK RA=12H42M36.9000S, J2000 V = 14 DEC=-11D19'35.00" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 RXJ1624+75 GALAXY, ACCRETION DISK RA=16H24M56.5000S, J2000 V = 15 DEC=+75D54'55.80" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 RXJ1420+53 GALAXY, ACCRETION DISK RA=22H17M57.1000S, J2000 V = 15 DEC=-59D41'34.00" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 5 TDXFJ1347-32 GALAXY, ACCRETION DISK RA=13H47M30.3300S, J2000 V = 15 DEC=-32D54'50.60" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 6 RBS1032 GALAXY, ACCRETION DISK RA=11H47M26.7300S, J2000 V = 15 DEC=+49D42'57.30" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 18081( 2) - 11-Aug-2025 22:39:27 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.173 Line_Spacing 0.112 Coordinate_Frame POS-TARG Pattern_Orient 23.884 Angle_Between_Sides 81.785 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 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 ------------------------------------------------------------------------------------------------------------------------------------ 18081( 2) - 11-Aug-2025 22:39:27 - [ 4] Visit: 01 (NGC-5905) 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 NGC-5905 WFC3/UVI ACCUM UVIS2 F225W FLASH=15 1 555 S PATTERN 1 1 S see below (2245 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC-5905 WFC3/UVI ACCUM UVIS2 F438W FLASH=15 1 555 S PATTERN 2 2 S see below (1102 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC-5905 WFC3/UVI ACCUM UVIS2 F625W FLASH=5 1 555 S PATTERN 2 3 S see below (1102 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-5905 1 WFC3/UVI ACCUM UVIS2 F225W 1 none none none 1 580.0 S S NGC-5905 1 WFC3/UVI ACCUM UVIS2 F225W 2 none none none 1 N/A S NGC-5905 1 WFC3/UVI ACCUM UVIS2 F225W 3 none none none 1 N/A S NGC-5905 1 WFC3/UVI ACCUM UVIS2 F225W 4 none none none 1 N/A S NGC-5905 2 WFC3/UVI ACCUM UVIS2 F438W 1 none none none 2 551.0 S S NGC-5905 2 WFC3/UVI ACCUM UVIS2 F438W 2 none none none 2 551.0 S S NGC-5905 3 WFC3/UVI ACCUM UVIS2 F625W 1 none none none 2 551.0 S S NGC-5905 3 WFC3/UVI ACCUM UVIS2 F625W 2 none none none 2 551.0 S S 18081( 2) - 11-Aug-2025 22:39:27 - [ 5] Visit: 02 (RXJ1241-11) 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 RXJ1242-11 WFC3/UVI ACCUM UVIS2 F225W FLASH=15 1 555 S PATTERN 1 1 S see below (2173 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RXJ1242-11 WFC3/UVI ACCUM UVIS2 F438W FLASH=15 1 555 S PATTERN 2 2 S see below (1068 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 RXJ1242-11 WFC3/UVI ACCUM UVIS2 F625W FLASH=5 1 555 S PATTERN 2 3 S see below (1068 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 | ------------------------------------------------------------------------------------------------------------------------------------ RXJ1242-11 1 WFC3/UVI ACCUM UVIS2 F225W 1 none none none 1 562.0 S S RXJ1242-11 1 WFC3/UVI ACCUM UVIS2 F225W 2 none none none 1 537.0 S S RXJ1242-11 1 WFC3/UVI ACCUM UVIS2 F225W 3 none none none 1 537.0 S S RXJ1242-11 1 WFC3/UVI ACCUM UVIS2 F225W 4 none none none 1 537.0 S S RXJ1242-11 2 WFC3/UVI ACCUM UVIS2 F438W 1 none none none 2 534.0 S S RXJ1242-11 2 WFC3/UVI ACCUM UVIS2 F438W 2 none none none 2 534.0 S S RXJ1242-11 3 WFC3/UVI ACCUM UVIS2 F625W 1 none none none 2 534.0 S S RXJ1242-11 3 WFC3/UVI ACCUM UVIS2 F625W 2 none none none 2 534.0 S S 18081( 2) - 11-Aug-2025 22:39:27 - [ 6] Visit: 03 (RXJ1624+75) 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 RXJ1624+75 WFC3/UVI ACCUM UVIS2 F225W FLASH=15 1 555 S PATTERN 1 1 S see below (2353 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RXJ1624+75 WFC3/UVI ACCUM UVIS2 F438W FLASH=15 1 555 S PATTERN 2 2 S see below (1156 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 RXJ1624+75 WFC3/UVI ACCUM UVIS2 F625W FLASH=5 1 555 S PATTERN 2 3 S see below (1156 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 | ------------------------------------------------------------------------------------------------------------------------------------ RXJ1624+75 1 WFC3/UVI ACCUM UVIS2 F225W 1 none none none 1 607.0 S S RXJ1624+75 1 WFC3/UVI ACCUM UVIS2 F225W 2 none none none 1 582.0 S S RXJ1624+75 1 WFC3/UVI ACCUM UVIS2 F225W 3 none none none 1 582.0 S S RXJ1624+75 1 WFC3/UVI ACCUM UVIS2 F225W 4 none none none 1 582.0 S S RXJ1624+75 2 WFC3/UVI ACCUM UVIS2 F438W 1 none none none 2 578.0 S S RXJ1624+75 2 WFC3/UVI ACCUM UVIS2 F438W 2 none none none 2 578.0 S S RXJ1624+75 3 WFC3/UVI ACCUM UVIS2 F625W 1 none none none 2 578.0 S S RXJ1624+75 3 WFC3/UVI ACCUM UVIS2 F625W 2 none none none 2 578.0 S S 18081( 2) - 11-Aug-2025 22:39:27 - [ 7] Visit: 04 (RXJ1420+53) 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 RXJ1420+53 WFC3/UVI ACCUM UVIS2 F225W FLASH=15 1 555 S PATTERN 1 1 S see below (2245 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RXJ1420+53 WFC3/UVI ACCUM UVIS2 F438W FLASH=15 1 555 S PATTERN 2 2 S see below (1102 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 RXJ1420+53 WFC3/UVI ACCUM UVIS2 F625W FLASH=5 1 555 S PATTERN 2 3 S see below (1102 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 | ------------------------------------------------------------------------------------------------------------------------------------ RXJ1420+53 1 WFC3/UVI ACCUM UVIS2 F225W 1 none none none 1 580.0 S S RXJ1420+53 1 WFC3/UVI ACCUM UVIS2 F225W 2 none none none 1 555.0 S S RXJ1420+53 1 WFC3/UVI ACCUM UVIS2 F225W 3 none none none 1 555.0 S S RXJ1420+53 1 WFC3/UVI ACCUM UVIS2 F225W 4 none none none 1 555.0 S S RXJ1420+53 2 WFC3/UVI ACCUM UVIS2 F438W 1 none none none 2 551.0 S S RXJ1420+53 2 WFC3/UVI ACCUM UVIS2 F438W 2 none none none 2 551.0 S S RXJ1420+53 3 WFC3/UVI ACCUM UVIS2 F625W 1 none none none 2 551.0 S S RXJ1420+53 3 WFC3/UVI ACCUM UVIS2 F625W 2 none none none 2 551.0 S S 18081( 2) - 11-Aug-2025 22:39:27 - [ 8] Visit: 05 (TDXFJ1347-32) 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 TDXFJ1347-3 WFC3/UVI ACCUM UVIS2 F225W FLASH=15 1 555 S PATTERN 1 1 2 S see below (2185 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 TDXFJ1347-3 WFC3/UVI ACCUM UVIS2 F438W FLASH=15 1 555 S PATTERN 2 2 2 S see below (1074 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 TDXFJ1347-3 WFC3/UVI ACCUM UVIS2 F625W FLASH=5 1 555 S PATTERN 2 3 2 S see below (1074 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 | ------------------------------------------------------------------------------------------------------------------------------------ TDXFJ1347-32 1 WFC3/UVI ACCUM UVIS2 F225W 1 none none none 1 565.0 S S TDXFJ1347-32 1 WFC3/UVI ACCUM UVIS2 F225W 2 none none none 1 540.0 S S TDXFJ1347-32 1 WFC3/UVI ACCUM UVIS2 F225W 3 none none none 1 540.0 S S TDXFJ1347-32 1 WFC3/UVI ACCUM UVIS2 F225W 4 none none none 1 540.0 S S TDXFJ1347-32 2 WFC3/UVI ACCUM UVIS2 F438W 1 none none none 2 537.0 S S TDXFJ1347-32 2 WFC3/UVI ACCUM UVIS2 F438W 2 none none none 2 537.0 S S TDXFJ1347-32 3 WFC3/UVI ACCUM UVIS2 F625W 1 none none none 2 537.0 S S TDXFJ1347-32 3 WFC3/UVI ACCUM UVIS2 F625W 2 none none none 2 537.0 S S 18081( 2) - 11-Aug-2025 22:39:27 - [ 9] Visit: 06 (RBS1032) 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 RBS1032 WFC3/UVI ACCUM UVIS2 F225W FLASH=15 1 555 S PATTERN 1 1 S see below (2209 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 RBS1032 WFC3/UVI ACCUM UVIS2 F438W FLASH=15 1 555 S PATTERN 2 2 S see below (1086 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 RBS1032 WFC3/UVI ACCUM UVIS2 F625W FLASH=5 1 555 S PATTERN 2 3 S see below (1086 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 | ------------------------------------------------------------------------------------------------------------------------------------ RBS1032 1 WFC3/UVI ACCUM UVIS2 F225W 1 none none none 1 571.0 S S RBS1032 1 WFC3/UVI ACCUM UVIS2 F225W 2 none none none 1 546.0 S S RBS1032 1 WFC3/UVI ACCUM UVIS2 F225W 3 none none none 1 546.0 S S RBS1032 1 WFC3/UVI ACCUM UVIS2 F225W 4 none none none 1 546.0 S S RBS1032 2 WFC3/UVI ACCUM UVIS2 F438W 1 none none none 2 543.0 S S RBS1032 2 WFC3/UVI ACCUM UVIS2 F438W 2 none none none 2 543.0 S S RBS1032 3 WFC3/UVI ACCUM UVIS2 F625W 1 none none none 2 543.0 S S RBS1032 3 WFC3/UVI ACCUM UVIS2 F625W 2 none none none 2 543.0 S S 18081( 2) - 11-Aug-2025 22:39:27 - [ 10] Summary Form for Proposal 18081 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=15, FLASH=5 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, PATTERN 2 2, PATTERN 2 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F225W, F438W, F625W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC-5905, RBS1032, RXJ1242-11, RXJ1420+53, RXJ1624+75, TDXFJ1347-32 ------------------------------------------------------------------------------------------------------------------------------------