18084( 4) - 01-May-2026 21:50:16 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18084 Version: 4 Check-in Time: 01-May-2026 21:50:16 STScI Edit Number: 1 Title Searching for the Survivor: Deep HST Imaging of the Explosion Site of SN2022jli ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Jianing Su University of Toronto Y CoI: Dr. Ori Dosovitz Fox Space Telescope Science Institute N CoI: Maria Drout University of Toronto Y CoI: Dr. Jennifer Andrews NOIRLab - Gemini North (HI) N CoI: Dr. Kyra Azalee Bostroem University of Arizona N CoI: Prof. Alex V. Filippenko University of California - Berkeley N CoI: Dr. Patrick Kelly University of Minnesota - Twin Cities N CoI: Dr. Dan Milisavljevic Purdue University N CoI: Prof. Selma E. de Mink Max Planck Institute for Astrophysics N CoI: Dr. Stuart Ryder Macquarie University N CoI: Dr. Nathan Smith University of Arizona N CoI: Dr. Niharika Sravan Drexel University N CoI: Dr. Schuyler D. Van Dyk California Institute of Technology N CoI: Dr. Benjamin F. Williams University of Washington N CoI: Dr. Emmanouil Zapartas FORTH - Institute of Astrophysics N CoI: Dr. WeiKang Zheng University of California - Berkeley N CoI: Dr. Sebastian Gomez University of Texas at Austin N CoI: Dr. Justin Pierel Space Telescope Science Institute N CoI: Dr. Melissa Shahbandeh Space Telescope Science Institute N CoI: Dr. Armin Rest Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract Binary physics is important as >60% massive stars form in some kind of interacting binary system. The identification of progenitor systems of stripped-envelope supernovae (SESNe) offers one means to directly constrain binary evolution pathways, with implications ranging from the evolution of massive stars to the integrated stellar light from distant galaxies. Although the method by which SESN progenitors lose their envelopes remains uncertain, growing evidence have been shifting the paradigm from single star models to binary models. In recent years, five direct detections of surviving companions to SESN have been detected. However, the sample size is still too small to be statistically meaningful. Since suitable candidates for this type of search are rare, each additional new data point carries significant statistical weight. Here, we propose deep WFC3/UVIS optical and UV imaging of the only suitable SESNe target for a deep companions search in Cycle 33: SN 2022jli, which already has strong evidence of having a surviving companion. As with other companion searches, we plan to detect or place meaningful limits on any surviving companion. We also propose one orbit each to obtain F555W astrometry on the recent SN2024abfo and SN2024iss for potential future follow-up companion searches. This study will utilize HST's unique UV capabilities and build a statistically significant sample that will advance our current understanding of binary evolution. Given the rarity of relevant events and the limited HST lifetime, acquiring these observations is critical. 18084( 4) - 01-May-2026 21:50:16 - [ 2] ------------------------------------------------------------------------------------ Observations Description ------------------------ In this proposal, we will obtain deep WFC3/UVIS optical and UV imaging of the explosion site of SN 2022jli in order to either detect or place meaningful limits on any surviving companion to the supernova progenitor. Specifically, we will observe in the F336W, F438W, and F555W filters with total exposures time of 12880, 8295 and 3807 seconds, respectively. The source is expected to be faint, so we have placed it at the UVIS2-512C-CTE aperture. However, we read out the entire array to increase the number of stars that can be used for image alignment. The impacts of a reduced gyro operations on this program are primarily reduced schedualability due to the smaller field of regard. To help mitigate, we have split the 10 orbits allocated to observations of SN2022jli into four visits with 2 or 3 orbits each. However, as the target is expected to be variabily on the timescale of ~year, and we wish to use the observations in three filters to place constraints on the SED of the surviving companion, we require that all orbits are obtained within ~1 month (30 days) of each other. We have implemented manual dithering via the POS TARG values for the observations in different filters that will be split between different visits. Finally, we also obtain one orbit of imaging each for the fields of SN2024abfo and SN2024iss. Our goal is image the supernova themselves to obtain precise astrometry for the explosions. ------------------------------------------------------------------------------------ 18084( 4) - 01-May-2026 21:50:16 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN-2022JLI EXT-STAR, SUPERNOVA RA=00H34M45.6900S +/- 0.5", J2000 V = 28 DEC=-08D23'12.16" +/- 0.5" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2024ABFO EXT-STAR, SUPERNOVA RA=03H57M25.6220S +/- 0.5", J2000 V = 25 DEC=-46D11'7.67" +/- 0.5" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 SN-2024ISS EXT-STAR, SUPERNOVA RA=12H59M6.1300S +/- 0.5", J2000 V = 25 DEC=+28D48'42.62" +/- 0.5" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 18084( 4) - 01-May-2026 21:50:16 - [ 4] 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 ------------------------------------------------------------------------------------------------------------------------------------ 18084( 4) - 01-May-2026 21:50:16 - [ 5] Visit: 01 (SN2024ABFO Astrometry) 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 SN-2024ABFO WFC3/UVI ACCUM UVIS2 F555W FLASH=3 1 556 S PATTERN 1 1 S (2224 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2024ABFO 1 WFC3/UVI ACCUM UVIS2 F555W 1 none none none 1 N/A S SN-2024ABFO 1 WFC3/UVI ACCUM UVIS2 F555W 2 none none none 1 N/A S SN-2024ABFO 1 WFC3/UVI ACCUM UVIS2 F555W 3 none none none 1 N/A S SN-2024ABFO 1 WFC3/UVI ACCUM UVIS2 F555W 4 none none none 1 N/A S 18084( 4) - 01-May-2026 21:50:16 - [ 6] Visit: 02 (SN2024ISS Astrometry) 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 SN-2024ISS WFC3/UVI ACCUM UVIS2 F555W FLASH=3 1 549 S PATTERN 1 1 S (2196 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2024ISS 1 WFC3/UVI ACCUM UVIS2 F555W 1 none none none 1 N/A S SN-2024ISS 1 WFC3/UVI ACCUM UVIS2 F555W 2 none none none 1 N/A S SN-2024ISS 1 WFC3/UVI ACCUM UVIS2 F555W 3 none none none 1 N/A S SN-2024ISS 1 WFC3/UVI ACCUM UVIS2 F555W 4 none none none 1 N/A S 18084( 4) - 01-May-2026 21:50:16 - [ 7] Visit: 03 (SN2022JLI-UV1) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F336W FLASH=9 1 2588 S POS TARG 0, 0 S 2C-CTE (2588 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F336W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 8] Visit: 04 (SN2022JLI-UV2) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F336W FLASH=9 1 2588 S POS TARG 0.3437, 0.3674 S 2C-CTE (2588 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F336W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 9] Visit: 05 (SN2022jli-VIS1) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F438W FLASH=3 1 1665 S POS TARG 0, 0 S 2C-CTE (1665 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F555W 1 765 S (765 SAME POS AS 1 S 2C-CTE 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F438W none none none none 1 N/A S 12C-CTE SN-2022JLI 2 WFC3/UVI ACCUM UVIS2-C5 F555W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 10] Visit: 06 (SN2022jli-VIS2) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F438W FLASH=3 1 1665 S POS TARG 0.3437, 0.3674 S 2C-CTE (1665 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F555W 1 765 S (765 SAME POS AS 1 S 2C-CTE 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F438W none none none none 1 N/A S 12C-CTE SN-2022JLI 2 WFC3/UVI ACCUM UVIS2-C5 F555W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 11] Visit: 07 (SN2022JLI-UV1) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F336W FLASH=9 1 2568 S POS TARG 0.1719, 0.1837 S 2C-CTE (2568 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F336W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 12] Visit: 08 (SN2022JLI-UV2) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F336W FLASH=9 1 2568 S POS TARG 0.4760, 0.5286 S 2C-CTE (2568 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F336W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 13] Visit: 09 (SN2022JLI-UV2) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F336W FLASH=9 1 2568 S POS TARG 0.6544, 0.6796 S 2C-CTE (2568 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F336W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 14] Visit: 10 (SN2022jli-VIS1) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F438W FLASH=3 1 1655 S POS TARG 0.1719, 0.1837 S 2C-CTE (1655 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F555W 1 759 S (759 SAME POS AS 1 S 2C-CTE 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F438W none none none none 1 N/A S 12C-CTE SN-2022JLI 2 WFC3/UVI ACCUM UVIS2-C5 F555W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 15] Visit: 11 (SN2022jli-VIS2) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F438W FLASH=3 1 1655 S POS TARG 0.4760, 0.5286 S 2C-CTE (1655 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F555W 1 759 S (759 SAME POS AS 1 S 2C-CTE 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F438W none none none none 1 N/A S 12C-CTE SN-2022JLI 2 WFC3/UVI ACCUM UVIS2-C5 F555W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 16] Visit: 12 (SN2022jli-VIS2) 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 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F438W FLASH=3 1 1655 S POS TARG 0.6544, 0.6796 S 2C-CTE (1655 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2022JLI WFC3/UVI ACCUM UVIS2-C51 F555W 1 759 S (759 SAME POS AS 1 S 2C-CTE 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2022JLI 1 WFC3/UVI ACCUM UVIS2-C5 F438W none none none none 1 N/A S 12C-CTE SN-2022JLI 2 WFC3/UVI ACCUM UVIS2-C5 F555W none none none none 1 N/A S 12C-CTE 18084( 4) - 01-May-2026 21:50:16 - [ 17] Summary Form for Proposal 18084 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2, UVIS2-C512C-CTE ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=3, FLASH=9 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, POS TARG 0, 0, POS TARG 0.1719, 0.1837, POS TARG 0.3437, 0.3674, POS TARG 0.4760, 0.5286, POS TARG 0.6544, 0.6796, SAME POS AS 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F336W, F438W, F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN-2022JLI, SN-2024ABFO, SN-2024ISS ------------------------------------------------------------------------------------------------------------------------------------