18046( 3) - 08-Sep-2025 15:18:44 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18046 Version: 3 Check-in Time: 08-Sep-2025 15:18:44 STScI Edit Number: 0 Title Testing the Mass Threshold of Reionization-Quenching with Isolated Dwarf Galaxy Hedgehog ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Mr. Jiaxuan Li Princeton University Y CoI: Prof. Jenny Emma Greene Princeton University N CoI: Dr. Shany Danieli Tel Aviv University - Wise Observatory N CoI: Dr. Grace Telford University of Utah N CoI: Scott Carlsten Princeton University N CoI: Dr. Alessandro Savino University of California - Berkeley N CoI: Ms. Xiaojing Lin Tsinghua University N ------------------------------------------------------------------------------------ Abstract Cosmic reionization has long been thought to quench star formation in low-mass dwarf galaxies. However, no direct observational evidence exists beyond satellites of the Local Group. The mass range where reionization quenching is dominant remains elusive. We request HST WFC3/UVIS imaging in F606W+F814W for Hedgehog, a newly discovered isolated quiescent dwarf galaxy at 2.4 Mpc. Having no neighbors within 1 Mpc, Hedgehog's evolution was very likely unaffected by environmental effects, making it preserve the cleanest possible signature of reionization quenching. Compared with other ultra-faint dwarfs, Hedgehog's relatively high stellar mass (6x10^5 Msun) makes it particularly valuable for understanding the mass threshold of reionization quenching. A deep color-magnitude diagram analysis will reveal its ancient star formation history by resolving the horizontal branch, a key feature of the oldest, most metal-poor stellar populations. Our observations will provide a decisive test of reionization's impact on galaxy evolution at the critical mass threshold (M* ~ 10^5-10^6 Msun). Alternatively, if Hedgehog is a backsplash satellite from the Centaurus~A group, it would be the most distant backsplash galaxy ever confirmed, revealing the dynamical history of the nearby Centaurus A group and offering tests for backsplash models. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this proposal is to measure the star formation history (SFH) of a newly discovered dwarf galaxy named "Hedgehog" from a deep color-magnitude diagram (CMD) of stars within it. With the total allocated 30 orbits, we will definitively distinguish the two quenching mechanisms -- reionization quenching and backsplash quenching -- for this isolated quiescent dwarf galaxy. We request HST WFC3/UVIS imaging in F606W and F814W using the UVIS2 aperture. Each visit has two orbits, and each orbit is split between F606W and F814W exposures (with no CR-splits). Small dithers are performed between orbits using POS-TARG following a 4-point DITHER-BOX pattern. 18046( 3) - 08-Sep-2025 15:18:44 - [ 2] We do not add any constraints on the orientation. The bright star near the target will be saturated, but the diffraction spikes will have a length of ~10 arcsec, shorter than the angular size of the target galaxy (30 arcsec) and thus would not significantly affect the analysis. ------------------------------------------------------------------------------------ 18046( 3) - 08-Sep-2025 15:18:44 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HEDGEHOG GALAXY, DWARF RA=13H22M47.0857S, J2000 V = 280 V = 17.06 +/- 0.06 ELLIPTICAL, LSB DEC=-20D53'53.72" Reference Frame: ICRS Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ 18046( 3) - 08-Sep-2025 15:18:44 - [ 4] 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0, 0 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG 0.158, 0.070 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 5] 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0.099, 0.165 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG -0.060, 0.095 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 6] 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0, 0 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG 0.158, 0.070 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 7] 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0.099, 0.165 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG -0.060, 0.095 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 8] 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0, 0 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG 0.158, 0.070 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 9] 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0.099, 0.165 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG -0.060, 0.095 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 10] 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0, 0 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG 0.158, 0.070 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 11] 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0.099, 0.165 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG -0.060, 0.095 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 12] Visit: 09 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0, 0 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG 0.158, 0.070 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 13] Visit: 10 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0.099, 0.165 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG -0.060, 0.095 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 14] Visit: 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0, 0 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG 0.158, 0.070 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 15] Visit: 12 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0.099, 0.165 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG -0.060, 0.095 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 16] Visit: 13 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0, 0 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG 0.158, 0.070 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 17] Visit: 14 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0.099, 0.165 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG -0.060, 0.095 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 18] Visit: 15 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 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S POS TARG 0, 0 S (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S SAME POS AS 1 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HEDGEHOG WFC3/UVI ACCUM UVIS2 F606W CR-SPLIT=NO 1 1070 S POS TARG 0.158, 0.070 S (1070 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HEDGEHOG WFC3/UVI ACCUM UVIS2 F814W CR-SPLIT=NO 1 1300 S SAME POS AS 3 S (1300 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 | ------------------------------------------------------------------------------------------------------------------------------------ HEDGEHOG 1 WFC3/UVI ACCUM UVIS2 F814W none none none none 1 N/A S HEDGEHOG 2 WFC3/UVI ACCUM UVIS2 F606W none none none none 1 N/A S HEDGEHOG 3 WFC3/UVI ACCUM UVIS2 F606W none none none none 2 N/A S HEDGEHOG 4 WFC3/UVI ACCUM UVIS2 F814W none none none none 2 N/A S 18046( 3) - 08-Sep-2025 15:18:44 - [ 19] Summary Form for Proposal 18046 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG -0.060, 0.095, POS TARG 0, 0, POS TARG 0.099, 0.165, POS TARG 0.158, 0.070, SAME POS AS 1, SAME POS AS 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names HEDGEHOG ------------------------------------------------------------------------------------------------------------------------------------