17761( 3) - 11-Feb-2026 16:45:34 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17761 Version: 3 Check-in Time: 11-Feb-2026 16:45:34 STScI Edit Number: 1 Title Mg II maps to reveal how ionizing photons escape local LyC emitting galaxies ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Floriane Leclercq Centre de Recherche Astrophysique de Lyon Y CoI: Dr. Alberto Saldana-Lopez Stockholm University N CoI: Prof. Daniel Schaerer University of Geneva, Department of N Astronomy CoI: Prof. Anne Jaskot Williams College N CoI: Dr. Bingjie Wang Princeton University N CoI: Dr. Alaina L. Henry Space Telescope Science Institute N CoI: Dr. Zhiyuan Ji University of Arizona N CoI: Dr. Swara Ravindranath Catholic University of America N CoI: Dr. Maxime Trebitsch Observatoire de Paris N CoI: Dr. Xinfeng Xu Northwestern University N CoI: Prof. Trinh Xuan Thuan The University of Virginia N CoI: Dr. Hakim Atek CNRS, Institut d'Astrophysique de Paris N CoI: Dr. Sanchayeeta Borthakur Arizona State University N CoI: Timothy M. Heckman The Johns Hopkins University N CoI: Prof. John Chisholm University of Texas at Austin N CoI: Prof. Steven L. Finkelstein University of Texas at Austin N CoI: Prof. Matthew James Hayes Stockholm University N CoI: Dr. Michael James Rutkowski Minnesota State University, Mankato N CoI: Dr. Cody Andrew Carr Zhejiang University (ZJU) N CoI: Prof. Claudia Scarlata University of Minnesota - Twin Cities N CoI: Prof. Stephan Robert McCandliss The Johns Hopkins University N CoI: Dr. Yuri I. Izotov National Academy of Sciences of Ukraine, N BITP CoI: Dr. Laura Pentericci INAF - Osservatorio Astronomico di Roma N CoI: Dr. Ricardo Amorin Instituto de Astrofisica de Andalucia N (IAA) CoI: Dr. Omkar Bait University of Geneva, Department of N Astronomy CoI: Prof. Mauro Giavalisco University of Massachusetts - Amherst N CoI: Dr. Eros Vanzella INAF - Osservatorio di Astrofisica e N Scienza dello Spazio CoI: Dr. Natalia G. Guseva National Academy of Sciences of Ukraine, N BITP CoI: Dr. Simon Gazagnes University of Texas at Austin N CoI: Prof. Anne Verhamme University of Geneva, Department of N Astronomy CoI: Rui Marques-Chaves University of Geneva, Department of N Astronomy CoI: Prof. Goeran Oestlin Stockholm University N CoI: Dr. Lena Komarova Universidad de Valencia, Observatorio N Astronomico CoI: Dr. Brian Fleming University of Colorado at Boulder N 17761( 3) - 11-Feb-2026 16:45:34 - [ 2] ------------------------------------------------------------------------------------ Abstract Upcoming observations aim to constrain the soures of cosmic reionization, but the high-redshift intergalactic medium precludes direct observations of ionizing photons (or LyC photons). Alternative methods must indirectly estimate the escape of ionizing photons from high redshift galaxies. The extragalactic community has invested vast resources to amass a collective sample of 90 nearby galaxies with ionizing continuum observations. However, these reveal an unsettling fact: while the observed LyC escape fraction correlates with indirect indicators, there is substantial scatter. Indicators cannot infer the escape fraction of individual galaxies. Here, we propose 31 orbits of HST/ACS ramp-filter imaging to determine if geometry drives this scatter. We will map the Mg II, [O II], and [O III] at <250 pc resolution in 5 galaxies with LyC observations and pre-existing seeing-limited ground based IFU. Our targets show compact/unresolved configurations of both neutral and ionized gas, span similar ranges in [OIII]/[OII] line flux ratio and Lyman alpha peak separation, but have a factor of 30 difference in the observed LyC escape fractions (fesc(LyC)~3-90%). The spatial resolution of the IFU data does not probe the location where the LyC is detected and therefore cannot explain such a high factor difference. Higher resolution HST observations must reveal the impact of the HI geometry on LyC leakage. These maps will (1) stringently explore the role of geometry in the escape of LyC, (2) uncover the origin of the scatter in indirect LyC indicators, and (3) guide how JWST can use indirect tracers to infer the LyC escape fraction at high redshift. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose 31 orbits of HST ACS/WFC imaging with the ramp filters. Our science goals are to spatially map the highly ionized gas (using the [O III] 5007 A emission line), the ionized gas (using the [O II] 3727 A emission line), and the low column density neutral gas (using the Mg II 2800 A resonant emission line) on the r<1" spatial scales. While ground-based observations have provided clues to the geometry of LyC escape, they also demonstrate that much of the important astrophysics happens on spatial scales that are not resolvable from the ground. The exquisite 0.05" (250 pc at the redshift of our sources) resolution of the HST/ACS imaging are crucial to resolving the geometry of LyC escape. To isolate emission and continuum regions, we will use the tunable narrow and medium ACS ramp filters. These filters are ideal for this science because they isolate narrow wavelength bands (between 70-100 A for the narrow-band filters) with only the desired emission lines. We aim to observe Mg II, [O III] 5007 A, and [O II] 3727 A plus a continuum filter for each line. We will tune the filter to the emission line wavelength and tune the continuum filters to more than 150 A (twice the filter width) from the nebular emission lines and ensure that there are no other strong nebular emission lines within the bandpass. Our three strong leakers already have observations of [O III] 5007, and [O II] 3727 A plus their continuum from the PID 16245 HST program, so only Mg II observations are requested from these sources to probe their small-scales H I neutral gas distributions. We wish to compare the small-scale gaseous geometry of compact galaxies with 17761( 3) - 11-Feb-2026 16:45:34 - [ 3] different fesc . We selected confirmed LyC leakers from the LzLCS (Flury et al. 2022) and Izotov et al. (2022) observed with the ground-based IFU Keck/KCWI instrument, whose spatial analysis is presented in Leclercq et al. (2024). Our targets are chosen to be compact in Mg II and [O II] (i.e., unresolved, or close to be unresolved in KCWI data), and to have a 30 factor difference in fesc(LyC). We aim at understanding if and how unresolved differences can explain such different escape fractions. Our 5 selected targets are at z > 0.34 and therefore their Mg II is observable with the bluest ACS ramp filter (FR388N). Note that we excluded one target with compact Mg II (r < 1 kpc) because the exposure time requested to map Mg II was too high (>20 orbits). Our ground-based IFU observations of Mg II and [O II] have seeing of ~1" and cannot inform on the spatial distribution of the gas that allows ionizing photons to escape the galaxy, but they can inform on the estimated flux levels of the two emission lines. We used the available SDSS spectra to determine the [O III] flux levels. Our targets are pure Mg II emitters with total Mg II fluxes ranging from 1.1 to 3.5x10^{-16} erg/s/cm^2. Using the ACS ramp filter ETC, the FR388N filter tuned to a center wavelength of the Mg II line center, and assuming that the total Mg II emission is uniformly distributed over the NUV size, it takes between 2, 121 and 20, 159 s to reach a signal-to-noise of 10 in the default extraction region of a 5x5 box. We will use Voronoi tessellation to reach lower surface brightnesses. This setup will test the gaseous geometry on sizes relevant to impact the observed LyC escape fractions. We take a similar procedure to determine the [O III] and [O II] emission. Our three strong leakers already have [O III] and [O II] and their continuum observations from the program PID 16245. We find that the required total exposure times for the two weaker leakers are less than 100 s for the incredibly bright [O III] emission using the FR656N filter for J1137 and the FR716N filter for J0141. The exposures for the [O II] emission line using the FR505N filter are between 200-300 s. We estimate continuum fluxes using the SDSS magnitudes in the g-band. To increase the speeds of the continuum detections, we use the medium band tunable filters with bandpasses 9% of the central wavelength. We will use F647M centered at lbda_c=7100 A to obtain [O III] continuum and two different tunings of the F459M filter to obtain Mg II (lbda_c=4200A) and [O II] (lbda_c=4800A) continuum. We aim to detect the continuum at a signal-to-noise ratio of 100 in the continuum to accurately subtract the continuum from the emission lines. These SNR can be obtained in between 800-5000 s, depending on the galaxy and the filters chosen. To properly sample the PSF we will dither between the observations using the line 2-point dither pattern (ACS-WFC-DITHER-LINE with parameters recommended in the section 7.2 of the ACS handbook allowing simultaneous elimination of hot pixels and cosmic ray hits in post-observation processing), breaking the total exposure times into at least two observations. We assume that each orbit has 2, 400 s of usable time. This means that the [O II], [O III], and continuum observations can be obtained in 2 to 3 orbits depending on the objects. Meanwhile, the Mg II observations require between 1-8 orbits per galaxy. In total, we will require 31 orbits to obtain the total integration. We choose to use the WFC1-MRAMP aperture. We will use the three different stellar continuum observations to model the stellar plus nebular continuum shape to properly account for the underlying continua. We will then study the spatial distribution of the Mg II and compare it to the [O II] and [O III] emission. By testing the physical picture of LyC 17761( 3) - 11-Feb-2026 16:45:34 - [ 4] escape, we will reveal whether the gas morphologies of LyC emitting galaxies are different than non-LyC emitting galaxies and see if geometry contributes to the scatter observed in the indirect indicator plots. ------------------------------------------------------------------------------------ 17761( 3) - 11-Feb-2026 16:45:34 - [ 5] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J1256 GALAXY, DWARF COMPACT, RA=12H56M44.1500S, J2000 Z = V = 22.01 +/- 0.05 FUV=21.66, NUV=21.85 STARBURST DEC=+45D09'17.01" 0.353 Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 J1243 GALAXY, DWARF COMPACT, RA=12H43M0.6300S, J2000 Z = V = 21.48 +/- 0.05 FUV=21.31, NUV=21.61 STARBURST DEC=+46D46'50.40" 0.432 Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 J1154 GALAXY, DWARF COMPACT, RA=11H54M48.8500S, J2000 Z = V = 21.77 +/- 0.05 FUV=22.10, NUV=21.57 STARBURST DEC=+24D43'33.03" 0.369 Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 J1137 GALAXY, DWARF COMPACT, RA=11H37M47.7700S, J2000 Z = V = 21.79 +/- 0.05 NUV=22.46 STARBURST DEC=+36D05'4.62" 0.3439 Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 5 J0141 GALAXY, DWARF COMPACT, RA=01H41M42.8500S, J2000 Z = V = 21.25 +/- 0.05 FUV=21.35, NUV=22.04 STARBURST DEC=-03D04'51.12" 0.3816 Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 17761( 3) - 11-Feb-2026 16:45:34 - [ 6] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.146 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 47.17 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 17761( 3) - 11-Feb-2026 16:45:34 - [ 7] Visit: 01 (J1256) 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 J1256 ACS/WFC ACCUM WFC1-MRAM FR388N 3788 1 1000 S PATTERN 1 1 P see below (2284 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1256 ACS/WFC ACCUM WFC1-MRAM FR388N 3788 1 1000 S PATTERN 1 2 P see below (2386 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1256 ACS/WFC ACCUM WFC1-MRAM FR388N 3788 1 1000 S PATTERN 1 3 P see below (2366 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1256 1 ACS/WFC ACCUM WFC1-MRA FR388N 3788 1 none none none 1 1142.0 S MP J1256 1 ACS/WFC ACCUM WFC1-MRA FR388N 3788 2 none none none 1 1142.0 S MP J1256 2 ACS/WFC ACCUM WFC1-MRA FR388N 3788 1 none none none 2 1193.0 S MP J1256 2 ACS/WFC ACCUM WFC1-MRA FR388N 3788 2 none none none 2 1193.0 S MP J1256 3 ACS/WFC ACCUM WFC1-MRA FR388N 3788 1 none none none 3 1183.0 S MP J1256 3 ACS/WFC ACCUM WFC1-MRA FR388N 3788 2 none none none 3 1183.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 8] Visit: 02 (J1256) 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 J1256 ACS/WFC ACCUM WFC1-MRAM FR388N 3788 1 1000 S PATTERN 1 1 P see below (2284 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1256 ACS/WFC ACCUM WFC1-MRAM FR388N 3788 1 1000 S PATTERN 1 2 P see below (2386 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1256 ACS/WFC ACCUM WFC1-MRAM FR388N 3788 1 1000 S PATTERN 1 3 P see below (2366 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1256 1 ACS/WFC ACCUM WFC1-MRA FR388N 3788 1 none none none 1 1142.0 S MP J1256 1 ACS/WFC ACCUM WFC1-MRA FR388N 3788 2 none none none 1 1142.0 S MP J1256 2 ACS/WFC ACCUM WFC1-MRA FR388N 3788 1 none none none 2 1193.0 S MP J1256 2 ACS/WFC ACCUM WFC1-MRA FR388N 3788 2 none none none 2 1193.0 S MP J1256 3 ACS/WFC ACCUM WFC1-MRA FR388N 3788 1 none none none 3 1183.0 S MP J1256 3 ACS/WFC ACCUM WFC1-MRA FR388N 3788 2 none none none 3 1183.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 9] Visit: 03 (J1256) 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 J1256 ACS/WFC ACCUM WFC1-MRAM FR459M 4200 2 1000 S PATTERN 1 1 P see below (2028 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1256 1 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none 1 none 1 500 S MP J1256 1 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none 2 none 1 528.0 S MP J1256 1 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none 1 none 1 500 S MP J1256 1 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none 2 none 1 500 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 10] Visit: 04 (J1243) 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 J1243 ACS/WFC ACCUM WFC1-MRAM FR388N 4009 2 1000 S PATTERN 1 1 P see below (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1243 ACS/WFC ACCUM WFC1-MRAM FR459M 4200 2 1000 S PATTERN 1 2 P see below (2076 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1243 1 ACS/WFC ACCUM WFC1-MRA FR388N 4009 1 none 1 none 1 500.0 S MP J1243 1 ACS/WFC ACCUM WFC1-MRA FR388N 4009 1 none 2 none 1 500 S MP J1243 1 ACS/WFC ACCUM WFC1-MRA FR388N 4009 2 none 1 none 1 500.0 S MP J1243 1 ACS/WFC ACCUM WFC1-MRA FR388N 4009 2 none 2 none 1 500 S MP J1243 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none 1 none 2 500.0 S MP J1243 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none 2 none 2 576.0 S MP J1243 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none 1 none 2 500.0 S MP J1243 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none 2 none 2 500 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 11] Visit: 05 (J1154) 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 J1154 ACS/WFC ACCUM WFC1-MRAM FR388N 3833 1 1000 S PATTERN 1 1 P see below (2270 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1154 ACS/WFC ACCUM WFC1-MRAM FR388N 3833 1 1000 S PATTERN 1 2 P see below (2332 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1154 ACS/WFC ACCUM WFC1-MRAM FR388N 3833 1 1000 S PATTERN 1 3 P see below (2332 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1154 1 ACS/WFC ACCUM WFC1-MRA FR388N 3833 1 none none none 1 1135.0 S MP J1154 1 ACS/WFC ACCUM WFC1-MRA FR388N 3833 2 none none none 1 1135.0 S MP J1154 2 ACS/WFC ACCUM WFC1-MRA FR388N 3833 1 none none none 2 1166.0 S MP J1154 2 ACS/WFC ACCUM WFC1-MRA FR388N 3833 2 none none none 2 1166.0 S MP J1154 3 ACS/WFC ACCUM WFC1-MRA FR388N 3833 1 none none none 3 1166.0 S MP J1154 3 ACS/WFC ACCUM WFC1-MRA FR388N 3833 2 none none none 3 1166.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 12] Visit: 06 (J1154) 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 J1154 ACS/WFC ACCUM WFC1-MRAM FR388N 3833 1 1000 S PATTERN 1 1 P see below (2270 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1154 ACS/WFC ACCUM WFC1-MRAM FR388N 3833 1 1000 S PATTERN 1 2 P see below (2332 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1154 ACS/WFC ACCUM WFC1-MRAM FR388N 3833 1 1000 S PATTERN 1 3 P see below (2332 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1154 1 ACS/WFC ACCUM WFC1-MRA FR388N 3833 1 none none none 1 1135.0 S MP J1154 1 ACS/WFC ACCUM WFC1-MRA FR388N 3833 2 none none none 1 1135.0 S MP J1154 2 ACS/WFC ACCUM WFC1-MRA FR388N 3833 1 none none none 2 1166.0 S MP J1154 2 ACS/WFC ACCUM WFC1-MRA FR388N 3833 2 none none none 2 1166.0 S MP J1154 3 ACS/WFC ACCUM WFC1-MRA FR388N 3833 1 none none none 3 1166.0 S MP J1154 3 ACS/WFC ACCUM WFC1-MRA FR388N 3833 2 none none none 3 1166.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 13] Visit: 07 (J1154) 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 J1154 ACS/WFC ACCUM WFC1-MRAM FR388N 3833 1 1000 S PATTERN 1 1 P see below (2270 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1154 ACS/WFC ACCUM WFC1-MRAM FR459M 4200 2 1000 S PATTERN 1 2 P see below (2022 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1154 1 ACS/WFC ACCUM WFC1-MRA FR388N 3833 1 none none none 1 1135.0 S MP J1154 1 ACS/WFC ACCUM WFC1-MRA FR388N 3833 2 none none none 1 1135.0 S MP J1154 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none 1 none 2 500 S MP J1154 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none 2 none 2 522.0 S MP J1154 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none 1 none 2 500 S MP J1154 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none 2 none 2 500 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 14] Visit: 08 (J1137) 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 J1137 ACS/WFC ACCUM WFC1-MRAM FR388N 3763 1 1000 S PATTERN 1 1 P see below (2280 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1137 ACS/WFC ACCUM WFC1-MRAM FR388N 3763 1 1000 S PATTERN 1 2 P see below (2342 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1137 ACS/WFC ACCUM WFC1-MRAM FR388N 3763 1 1000 S PATTERN 1 3 P see below (2342 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1137 1 ACS/WFC ACCUM WFC1-MRA FR388N 3763 1 none none none 1 1140.0 S MP J1137 1 ACS/WFC ACCUM WFC1-MRA FR388N 3763 2 none none none 1 1140.0 S MP J1137 2 ACS/WFC ACCUM WFC1-MRA FR388N 3763 1 none none none 2 1171.0 S MP J1137 2 ACS/WFC ACCUM WFC1-MRA FR388N 3763 2 none none none 2 1171.0 S MP J1137 3 ACS/WFC ACCUM WFC1-MRA FR388N 3763 1 none none none 3 1171.0 S MP J1137 3 ACS/WFC ACCUM WFC1-MRA FR388N 3763 2 none none none 3 1171.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 15] Visit: 09 (J1137) 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 J1137 ACS/WFC ACCUM WFC1-MRAM FR388N 3763 1 1000 S PATTERN 1 1 P see below (2280 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1137 ACS/WFC ACCUM WFC1-MRAM FR388N 3763 1 1000 S PATTERN 1 2 P see below (2342 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1137 ACS/WFC ACCUM WFC1-MRAM FR388N 3763 1 1000 S PATTERN 1 3 P see below (2342 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1137 1 ACS/WFC ACCUM WFC1-MRA FR388N 3763 1 none none none 1 1140.0 S MP J1137 1 ACS/WFC ACCUM WFC1-MRA FR388N 3763 2 none none none 1 1140.0 S MP J1137 2 ACS/WFC ACCUM WFC1-MRA FR388N 3763 1 none none none 2 1171.0 S MP J1137 2 ACS/WFC ACCUM WFC1-MRA FR388N 3763 2 none none none 2 1171.0 S MP J1137 3 ACS/WFC ACCUM WFC1-MRA FR388N 3763 1 none none none 3 1171.0 S MP J1137 3 ACS/WFC ACCUM WFC1-MRA FR388N 3763 2 none none none 3 1171.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 16] Visit: 10 (J1137) 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 J1137 ACS/WFC ACCUM WFC1-MRAM FR388N 3763 1 1000 S PATTERN 1 1 P see below (2280 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1137 ACS/WFC ACCUM WFC1-MRAM FR388N 3763 1 1000 S PATTERN 1 2 P see below (2342 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1137 1 ACS/WFC ACCUM WFC1-MRA FR388N 3763 1 none none none 1 1140.0 S MP J1137 1 ACS/WFC ACCUM WFC1-MRA FR388N 3763 2 none none none 1 1140.0 S MP J1137 2 ACS/WFC ACCUM WFC1-MRA FR388N 3763 1 none none none 2 1171.0 S MP J1137 2 ACS/WFC ACCUM WFC1-MRA FR388N 3763 2 none none none 2 1171.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 17] Visit: 11 (J1137) 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 J1137 ACS/WFC ACCUM WFC1-MRAM FR459M 4200 2 1000 S PATTERN 1 1 P see below (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1137 ACS/WFC ACCUM WFC1-MRAM FR656N 6731 1 340 S (680 PATTERN 1 2 P S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1137 ACS/WFC ACCUM WFC1-MRAM FR459M 4850 1 600 S PATTERN 1 3 P (1200 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J1137 ACS/WFC ACCUM WFC1-IRAM FR647M 7130 1 600 S PATTERN 1 4 P see below (1246 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 J1137 ACS/WFC ACCUM WFC1-MRAM FR505N 5009 1 340 S PATTERN 1 5 P see below (726 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1137 1 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none 1 none 1 500.0 S MP J1137 1 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none 2 none 1 500.0 S MP J1137 1 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none 1 none 1 500.0 S MP J1137 1 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none 2 none 1 500.0 S MP J1137 2 ACS/WFC ACCUM WFC1-MRA FR656N 6731 1 none none none 2 N/A MP J1137 2 ACS/WFC ACCUM WFC1-MRA FR656N 6731 2 none none none 2 N/A MP J1137 3 ACS/WFC ACCUM WFC1-MRA FR459M 4850 1 none none none 2 N/A MP J1137 3 ACS/WFC ACCUM WFC1-MRA FR459M 4850 2 none none none 2 N/A MP J1137 4 ACS/WFC ACCUM WFC1-IRA FR647M 7130 1 none none none 3 623.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 18] 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1137 4 ACS/WFC ACCUM WFC1-IRA FR647M 7130 2 none none none 3 623.0 S MP J1137 5 ACS/WFC ACCUM WFC1-MRA FR505N 5009 1 none none none 3 363.0 S MP J1137 5 ACS/WFC ACCUM WFC1-MRA FR505N 5009 2 none none none 3 363.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 19] Visit: 12 (J0141) 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 J0141 ACS/WFC ACCUM WFC1-MRAM FR388N 3870 2 1000 S PATTERN 1 1 P see below (1968 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0141 ACS/WFC ACCUM WFC1-MRAM FR459M 4200 1 1000 S PATTERN 1 2 P see below (1194 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0141 ACS/WFC ACCUM WFC1-IRAM FR716N 6921 1 340 S (680 PATTERN 1 3 P S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J0141 ACS/WFC ACCUM WFC1-IRAM FR647M 7330 1 500 S PATTERN 1 4 P see below (944 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 J0141 ACS/WFC ACCUM WFC1-MRAM FR505N 5150 1 500 S PATTERN 1 5 P see below (944 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0141 1 ACS/WFC ACCUM WFC1-MRA FR388N 3870 1 none 1 none 1 492.0 S MP J0141 1 ACS/WFC ACCUM WFC1-MRA FR388N 3870 1 none 2 none 1 492.0 S MP J0141 1 ACS/WFC ACCUM WFC1-MRA FR388N 3870 2 none 1 none 1 492.0 S MP J0141 1 ACS/WFC ACCUM WFC1-MRA FR388N 3870 2 none 2 none 1 492.0 S MP J0141 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 1 none none none 2 580.0 S MP J0141 2 ACS/WFC ACCUM WFC1-MRA FR459M 4200 2 none none none 2 614.0 S MP J0141 3 ACS/WFC ACCUM WFC1-IRA FR716N 6921 1 none none none 2 N/A MP J0141 3 ACS/WFC ACCUM WFC1-IRA FR716N 6921 2 none none none 2 N/A MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 20] 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0141 4 ACS/WFC ACCUM WFC1-IRA FR647M 7330 1 none none none 3 472.0 S MP J0141 4 ACS/WFC ACCUM WFC1-IRA FR647M 7330 2 none none none 3 472.0 S MP J0141 5 ACS/WFC ACCUM WFC1-MRA FR505N 5150 1 none none none 3 472.0 S MP J0141 5 ACS/WFC ACCUM WFC1-MRA FR505N 5150 2 none none none 3 472.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 21] Visit: 13 (J0141) 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 J0141 ACS/WFC ACCUM WFC1-MRAM FR505N 5150 1 500 S PATTERN 1 1 P see below (944 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0141 1 ACS/WFC ACCUM WFC1-MRA FR505N 5150 1 none none none 1 472.0 S MP J0141 1 ACS/WFC ACCUM WFC1-MRA FR505N 5150 2 none none none 1 472.0 S MP 17761( 3) - 11-Feb-2026 16:45:34 - [ 22] Summary Form for Proposal 17761 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1-IRAMP, WFC1-MRAMP ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, PATTERN 1 2, PATTERN 1 3, PATTERN 1 4, PATTERN 1 5 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements FR388N, FR459M, FR505N, FR647M, FR656N, FR716N ------------------------------------------------------------------------------------------------------------------------------------ Target Names J0141, J1137, J1154, J1243, J1256 ------------------------------------------------------------------------------------------------------------------------------------