17430( 14) - 24-Mar-2026 20:30:28 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17430 Version: 14 Check-in Time: 24-Mar-2026 20:30:28 STScI Edit Number: 7 Title Pulling Back the Curtain Veiling Extreme UV Galaxies: Revealing the Mysterious Sources of He II Emission ------------------------------------------------------------------------------------ Type Cycle GO 31 ------------------------------------------------------------------------------------ Investigators Contact? PI: Kaelee S Parker University of Texas at Austin Y CoI: Dr. Danielle Berg University of Texas at Austin N CoI: Prof. John Chisholm University of Texas at Austin N CoI: Dra. Karla Ziboney Arellano University of Edinburgh, Institute for N Cordova Astronomy CoI: Ilyse Yayoi Clark University of California - San Diego N CoI: Prof. Matthew James Hayes Stockholm University N CoI: Prof. Dawn K. Erb University of Wisconsin - Milwaukee N CoI: Dr. Bethan Lesley James Space Telescope Science Institute - ESA - N JWST CoI: Dr. Matilde Mingozzi Space Telescope Science Institute - ESA - N JWST CoI: Dr. Peter Senchyna Carnegie Institution of Washington N CoI: Prof. Daniel P. Stark University of California - Berkeley N CoI: Dr. Nika Jurlin University of Texas at Austin N CoI: Dr. Kate Rubin San Diego State University N CoI: Dr. Karin Marie Sandstrom University of California - San Diego N CoI: Alexander Menchaca University of Texas at Austin N ------------------------------------------------------------------------------------ Abstract Our first deep observations of high redshift galaxies revealed exceptionally strong high-ionization nebular emission lines. Characterizing and describing the detailed observations of the earliest galaxies with JWST and future extremely large telescopes will hinge on our understanding of these lines. However, current stellar population synthesis models catastrophically fail to reproduce the observed strengths of these extreme emission lines, often invoking theories of rare phenomena to understand this emission. Fortunately, progress is possible: high-spatial-resolution maps of very-high-ionization emission can help constrain the options for these potentially exotic sources. Here, we propose 25 orbits of high-spatial-resolution HST imaging to map the spatial morphology of HeII 4686 emission in five nearby low-metallicity, highly-ionized galaxies selected for their strong HeII emission. We will compare the spatial distribution of HeII emission with maps of the stellar population and the nebular gas traced by the Balmer lines, [OII], and [OIII], in order to distinguish between photoionization from massive and metal-poor stars, X-ray binaries, shocks, Wolf Rayet stars, and AGN. The compact nature for many of these sources requires a high spatial resolution (< 50 pc) that is only possible with HST. These observations will provide the necessary constraints to create the next generation of ionizing radiation models in highly-ionized galaxies, like those common during the Epoch of Reionization. ------------------------------------------------------------------------------------ Observations Description 17430( 14) - 24-Mar-2026 20:30:28 - [ 2] ------------------------ We propose high-resolution HST WFC3/UVIS and ACS/WFC imaging of five nearby extreme emission-line galaxies, so as to strongly constrain the source(s) of their extreme and, currently, unexplained He II 4686 emission. These observations will also allow us to relate the production of this excess emission to the stars and gas in these extreme galaxies and provide insights on the intense radiation observed from similar galaxies at high-z. -------------------------------------------- Targets: 1. J0944-0038 (z = 0.005) 2. J1016+3754 (z = 0.004) 3. J1044+0353 (z = 0.013) 4. J1418+2102 (z = 0.009) 5. J1545+0858 (z = 0.038) -------------------------------------------- Features of interest: - He II: For Targets 1, 2, and 4, He II can be mapped with the ACS/WFC FR462N ramp filter. To remove the stellar continuum and Ar IV contamination from our He II observations, we plan for a series of three observations with this filter, using slightly different central wavelengths chosen to observe: 1) He II 4686A + Ar IV 4711, 4740AA + stellar continuum 2) Ar IV 4711, 4740AA + stellar continuum 3) only the stellar continuum Target 3 already has archival He II observations. Target 5 uses the WFC3/UVIS F487N filter to map He II (with ArIV and continuum), while the ACS/WFC FR505N and FR462N ramp filters are used to observe ArIV (with continuum) and the continuum near He II, respectively. - Nebular emission: H-alpha 6563A, H-beta 4861A, [O II] 3726, 9A, and [O III] 4959, 5008A. Trace low and high ionization zones (HII regions). Balmer decrement can distinguish variations in dust attenuation. For Targets 1 and 2, these correspond to the WFC3/UVIS filters F665N, F487N, F373N, and F502N, respectively. For Target 3, H-beta with FQ492N, [O II] will be observed with FQ378N, and [O III] with F502N. There is archival H-alpha data for Target 3. Target 4 has archival data for H-alpha, H-beta, [O II], and [O III]. Target 5 needs ACS/WFC ramp filters: FR505N to map H-beta and [O III], FR656N to map H-alpha, and FR388N to map [O II]. - Continuum: We will observe the stellar continuum near multiple regions of interest. Targets 1, 2, 3, and 5, involve observations of the stellar continuum using WFC3/UVIS F275W (traces the young stellar population) and F336W (near O II). Targets 1, 2, and 5, also use the WFC3/UVIS filter F645N for the continuum near H-alpha. -------------------------------------------- Visits: 17430( 14) - 24-Mar-2026 20:30:28 - [ 3] 1. J0944: 1 visit with 4 total orbits -- orbit 1-2: seven WFC3/UVIS filters (F275W, F336W, F373N, F487N, F502N, F645N, F665N) and the UVIS2-2K2C-SUB aperture. These observations will use a 2-point dither pattern (WFC3-UVIS-DITHER-LINE), where each of the filters is used for one exposure in each orbit. -- orbit 3-4: a ACS/WFC filter (FR462N), set to three different central wavelengths: 4750A (He II + Ar IV + continuum), 4780A (Ar IV + continuum), and 4580A (continuum). WFC2-ORAMP aperture. This combination of observations will allow us to produce maps of the He II emission, without contamination from Ar IV and the stellar continuum. These observations will use a 2-point dither pattern (ACS-WFC-DITHER-LINE), where each of the filters is used for one exposure in each orbit. 2. J1016: 1 visit with 5 total orbits -- orbit 1-3: same seven WFC3/UVIS filters as used for Target 1 and the UVIS2-2K2C-SUB aperture. Unike Target 1, these observations will use a 3-point dither pattern (WFC3-UVIS-DITHER-LINE-3PT), where each of the filters is used for one exposure per orbit. -- orbit 4-5: ACS/WFC FR462N set to three different central wavelengths: 4740A (He II + Ar IV + continuum), 4765A (Ar IV + continuum), and 4580A (continuum). WFC2-ORAMP aperture. These observations will use a 2-point dither pattern (ACS-WFC-DITHER-LINE), where each of the filters is used for one exposure in each orbit. 3. J1044: 1 visit with 5 total orbits -- orbit 1: one WFC3/UVIS filter (FQ378N) and UVIS-QUAD aperture. 3-point dither with WFC3-UVIS-DITHER-LINE-3PT. -- orbit 2-5: three WFC3/UVIS filters (F502N, F275W, F336W) and UVIS2 aperture. 4-point dither with WFC3-UVIS-DITHER-BOX. 4. J1418: 1 visit with 4 total orbits -- ACS/WFC FR462N set to three different central wavelengths: 4760A (He II + Ar IV + continuum), 4790A (Ar IV + continuum), and 4600A (continuum). WFC2-ORAMP aperture. 4-point dither with ACS-WFC-DITHER-BOX, with an exposure from each filter in all four orbits. 5. J1545: 1 visit with 7 total orbits -- orbit 1-2: four WFC3/UVIS filters (F275W, F336W, F487N, F645N) + UVIS2 aperture. 2-point dither pattern WFC3-UVIS-DITHER-LINE, with an exposure from each filter in both orbits. -- orbit 3-4: two ACS/WFC filters (2xFR505N, FR656N) + WFC2-MRAMP aperture. 2-point dither pattern (ACS-WFC-DITHER-LINE) with an exposure from each of the 3 filters in each orbit (FR505N set at 5030A, FR505N at 5180A, and FR656N at 6800A). -- orbit 5-6: two ACS/WFC filters (FR388N, FR505N) + WFC2-MRAMP aperture. 2-point dither pattern (ACS-WFC-DITHER-LINE) with an exposure from each of the 2 filters in each orbit (FR388N set at 3870A and FR505N set at 4940A). -- orbit 7: one ACS/WFC filter (FR462N) + WFC2-ORAMP aperture. 2-point dither pattern (ACS-WFC-DITHER-LINE) with FR462N set to 4750 A, to observe the continuum near He II 4686. -------------------------------------------- 17430( 14) - 24-Mar-2026 20:30:28 - [ 4] Additional notes: To limit spatial variations of central wavelengths with the ramp filter, the dithers for observations with these filters have intentionally small, sub-pixel step sizes. The number of post-flash electrons to add to the ACS ramp and UVIS imaging is calculated filter-by-filter using the imaging ETCs. ------------------------------------------------------------------------------------ 17430( 14) - 24-Mar-2026 20:30:28 - [ 5] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J0944-0038 GALAXY, STAR FORMING RA=09H44M1.8720S, J2000 V = 15.69 REGION DEC=-00D38'32.17" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 2 J1016+3754 GALAXY, STAR FORMING RA=10H16M24.4800S, J2000 V = 16.06 REGION DEC=+37D54'46.08" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 J1044+0353 GALAXY, STAR FORMING RA=10H44M57.7900S, J2000 V = 17.86 REGION DEC=+03D53'13.10" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 J1418+2102 GALAXY, STAR FORMING RA=14H18M51.1190S, J2000 V = 17.74 REGION DEC=+21D02'39.84" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 5 J1545+0858 GALAXY, STAR FORMING RA=15H45M43.4400S, J2000 V = 17.78 REGION DEC=+08D58'1.34" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 17430( 14) - 24-Mar-2026 20:30:28 - [ 6] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.135 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 4 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 ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 5 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 ------------------------------------------------------------------------------------------------------------------------------------ 17430( 14) - 24-Mar-2026 20:30:28 - [ 7] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 6 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.171 Line_Spacing 0.171 Coordinate_Frame POS-TARG Pattern_Orient 30.16 Angle_Between_Sides 145.82 Center_Pattern NO Pattern_Comments: compact version of ACS-WFC-Dither-Box, in order to minimize spatial variations on ramp filter central wavelengths ------------------------------------------------------------------------------------------------------------------------------------ 17430( 14) - 24-Mar-2026 20:30:28 - [ 8] Visit: 01 (J0944 (WFC3)) Visit Requirements: On Hold Comments: Additional Comments: 2 orbits: WFC3/UVIS 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 J0944-0038 WFC3/UVI ACCUM UVIS2-2K2 F275W FLASH=20 1 70 S PATTERN 3 1-7 S C-SUB see below (243 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0944-0038 WFC3/UVI ACCUM UVIS2-2K2 F336W FLASH=20 1 40 S S C-SUB see below (183 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0944-0038 WFC3/UVI ACCUM UVIS2-2K2 F645N FLASH=20 1 170 S S C-SUB see below (443 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J0944-0038 WFC3/UVI ACCUM UVIS2-2K2 F665N FLASH=20 1 105 S S C-SUB see below (313 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 J0944-0038 WFC3/UVI ACCUM UVIS2-2K2 F373N FLASH=20 1 390 S S C-SUB see below (883 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 J0944-0038 WFC3/UVI ACCUM UVIS2-2K2 F487N FLASH=20 1 215 S S C-SUB see below (533 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 J0944-0038 WFC3/UVI ACCUM UVIS2-2K2 F502N FLASH=20 1 115 S S C-SUB see below (333 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0944-0038 1 WFC3/UVI ACCUM UVIS2-2K F275W 1 none none none 1 122.0 S S 2C-SUB J0944-0038 1 WFC3/UVI ACCUM UVIS2-2K F275W 2 none none none 2 121.0 S S 2C-SUB J0944-0038 2 WFC3/UVI ACCUM UVIS2-2K F336W 1 none none none 1 92.0 S S 2C-SUB J0944-0038 2 WFC3/UVI ACCUM UVIS2-2K F336W 2 none none none 2 91.0 S S 2C-SUB 17430( 14) - 24-Mar-2026 20:30:28 - [ 9] 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0944-0038 3 WFC3/UVI ACCUM UVIS2-2K F645N 1 none none none 1 222.0 S S 2C-SUB J0944-0038 3 WFC3/UVI ACCUM UVIS2-2K F645N 2 none none none 2 221.0 S S 2C-SUB J0944-0038 4 WFC3/UVI ACCUM UVIS2-2K F665N 1 none none none 1 157.0 S S 2C-SUB J0944-0038 4 WFC3/UVI ACCUM UVIS2-2K F665N 2 none none none 2 156.0 S S 2C-SUB J0944-0038 5 WFC3/UVI ACCUM UVIS2-2K F373N 1 none none none 1 442.0 S S 2C-SUB J0944-0038 5 WFC3/UVI ACCUM UVIS2-2K F373N 2 none none none 2 441.0 S S 2C-SUB J0944-0038 6 WFC3/UVI ACCUM UVIS2-2K F487N 1 none none none 1 267.0 S S 2C-SUB J0944-0038 6 WFC3/UVI ACCUM UVIS2-2K F487N 2 none none none 2 266.0 S S 2C-SUB J0944-0038 7 WFC3/UVI ACCUM UVIS2-2K F502N 1 none none none 1 167.0 S S 2C-SUB J0944-0038 7 WFC3/UVI ACCUM UVIS2-2K F502N 2 none none none 2 166.0 S S 2C-SUB 17430( 14) - 24-Mar-2026 20:30:28 - [ 10] Visit: 02 (J0944 (ACS)) Visit Requirements: On Hold Comments: Additional Comments: 2 orbits: ACS/WFC 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 J0944-0038 ACS/WFC ACCUM WFC2-ORAM FR462N 4750 FLASH=20 1 1000 S PATTERN 4 1-3 P see below (2165 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0944-0038 ACS/WFC ACCUM WFC2-ORAM FR462N 4580 FLASH=20 1 500 S P see below (1165 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0944-0038 ACS/WFC ACCUM WFC2-ORAM FR462N 4780 FLASH=20 1 500 S P see below (1165 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0944-0038 1 ACS/WFC ACCUM WFC2-ORA FR462N 4750 1 none none none 1 1072.0 S MP J0944-0038 1 ACS/WFC ACCUM WFC2-ORA FR462N 4750 2 none none none 2 1093.0 S MP J0944-0038 2 ACS/WFC ACCUM WFC2-ORA FR462N 4580 1 none none none 1 572.0 S MP J0944-0038 2 ACS/WFC ACCUM WFC2-ORA FR462N 4580 2 none none none 2 593.0 S MP J0944-0038 3 ACS/WFC ACCUM WFC2-ORA FR462N 4780 1 none none none 1 572.0 S MP J0944-0038 3 ACS/WFC ACCUM WFC2-ORA FR462N 4780 2 none none none 2 593.0 S MP 17430( 14) - 24-Mar-2026 20:30:28 - [ 11] Visit: 03 (J1016 (WFC3)) Visit Requirements: On Hold Comments: Additional Comments: 3 orbits: WFC3/UVIS 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 J1016+3754 WFC3/UVI ACCUM UVIS2-2K2 F665N FLASH=20 1 120 S PATTERN 2 1-7 S C-SUB see below (472 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1016+3754 WFC3/UVI ACCUM UVIS2-2K2 F336W FLASH=20 1 40 S S C-SUB see below (232 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1016+3754 WFC3/UVI ACCUM UVIS2-2K2 F275W FLASH=20 1 75 S S C-SUB see below (337 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J1016+3754 WFC3/UVI ACCUM UVIS2-2K2 F502N FLASH=20 1 140 S S C-SUB see below (532 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 J1016+3754 WFC3/UVI ACCUM UVIS2-2K2 F373N FLASH=20 1 430 S S C-SUB see below (1402 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 J1016+3754 WFC3/UVI ACCUM UVIS2-2K2 F487N FLASH=20 1 240 S S C-SUB see below (832 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 J1016+3754 WFC3/UVI ACCUM UVIS2-2K2 F645N FLASH=20 1 195 S S C-SUB see below (697 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1016+3754 1 WFC3/UVI ACCUM UVIS2-2K F665N 1 none none none 1 158.0 S S 2C-SUB J1016+3754 1 WFC3/UVI ACCUM UVIS2-2K F665N 2 none none none 2 157.0 S S 2C-SUB J1016+3754 1 WFC3/UVI ACCUM UVIS2-2K F665N 3 none none none 3 157.0 S S 2C-SUB J1016+3754 2 WFC3/UVI ACCUM UVIS2-2K F336W 1 none none none 1 78.0 S S 2C-SUB 17430( 14) - 24-Mar-2026 20:30:28 - [ 12] 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1016+3754 2 WFC3/UVI ACCUM UVIS2-2K F336W 2 none none none 2 77.0 S S 2C-SUB J1016+3754 2 WFC3/UVI ACCUM UVIS2-2K F336W 3 none none none 3 77.0 S S 2C-SUB J1016+3754 3 WFC3/UVI ACCUM UVIS2-2K F275W 1 none none none 1 113.0 S S 2C-SUB J1016+3754 3 WFC3/UVI ACCUM UVIS2-2K F275W 2 none none none 2 112.0 S S 2C-SUB J1016+3754 3 WFC3/UVI ACCUM UVIS2-2K F275W 3 none none none 3 112.0 S S 2C-SUB J1016+3754 4 WFC3/UVI ACCUM UVIS2-2K F502N 1 none none none 1 178.0 S S 2C-SUB J1016+3754 4 WFC3/UVI ACCUM UVIS2-2K F502N 2 none none none 2 177.0 S S 2C-SUB J1016+3754 4 WFC3/UVI ACCUM UVIS2-2K F502N 3 none none none 3 177.0 S S 2C-SUB J1016+3754 5 WFC3/UVI ACCUM UVIS2-2K F373N 1 none none none 1 468.0 S S 2C-SUB J1016+3754 5 WFC3/UVI ACCUM UVIS2-2K F373N 2 none none none 2 467.0 S S 2C-SUB J1016+3754 5 WFC3/UVI ACCUM UVIS2-2K F373N 3 none none none 3 467.0 S S 2C-SUB J1016+3754 6 WFC3/UVI ACCUM UVIS2-2K F487N 1 none none none 1 278.0 S S 2C-SUB J1016+3754 6 WFC3/UVI ACCUM UVIS2-2K F487N 2 none none none 2 277.0 S S 2C-SUB J1016+3754 6 WFC3/UVI ACCUM UVIS2-2K F487N 3 none none none 3 277.0 S S 2C-SUB J1016+3754 7 WFC3/UVI ACCUM UVIS2-2K F645N 1 none none none 1 233.0 S S 2C-SUB J1016+3754 7 WFC3/UVI ACCUM UVIS2-2K F645N 2 none none none 2 232.0 S S 2C-SUB J1016+3754 7 WFC3/UVI ACCUM UVIS2-2K F645N 3 none none none 3 232.0 S S 2C-SUB 17430( 14) - 24-Mar-2026 20:30:28 - [ 13] Visit: 04 (J1016 (ACS)) Visit Requirements: On Hold Comments: Additional Comments: 2 orbits: ACS/WFC 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 J1016+3754 ACS/WFC ACCUM WFC2-ORAM FR462N 4580 FLASH=20 1 500 S PATTERN 4 1-3 P see below (1127 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1016+3754 ACS/WFC ACCUM WFC2-ORAM FR462N 4765 FLASH=20 1 500 S P see below (1127 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1016+3754 ACS/WFC ACCUM WFC2-ORAM FR462N 4740 FLASH=20 1 1100 S P see below (2327 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1016+3754 1 ACS/WFC ACCUM WFC2-ORA FR462N 4580 1 none none none 1 553.0 S MP J1016+3754 1 ACS/WFC ACCUM WFC2-ORA FR462N 4580 2 none none none 2 574.0 S MP J1016+3754 2 ACS/WFC ACCUM WFC2-ORA FR462N 4765 1 none none none 1 553.0 S MP J1016+3754 2 ACS/WFC ACCUM WFC2-ORA FR462N 4765 2 none none none 2 574.0 S MP J1016+3754 3 ACS/WFC ACCUM WFC2-ORA FR462N 4740 1 none none none 1 1153.0 S MP J1016+3754 3 ACS/WFC ACCUM WFC2-ORA FR462N 4740 2 none none none 2 1174.0 S MP 17430( 14) - 24-Mar-2026 20:30:28 - [ 14] Visit: 05 (J1044 (WFC3)) Visit Requirements: On Hold Comments: Additional Comments: 1 orbit - WFC3/UVIS 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 J1044+0353 WFC3/UVI ACCUM UVIS-QUAD FQ378N FLASH=20 1 650 S PATTERN 2 1 S see below (2337 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1044+0353 1 WFC3/UVI ACCUM UVIS-QUA FQ378N 1 none none none 1 779.0 S S D J1044+0353 1 WFC3/UVI ACCUM UVIS-QUA FQ378N 2 none none none 1 779.0 S S D J1044+0353 1 WFC3/UVI ACCUM UVIS-QUA FQ378N 3 none none none 1 779.0 S S D 17430( 14) - 24-Mar-2026 20:30:28 - [ 15] Visit: 06 (J1418 (ACS)) Visit Requirements: On Hold Comments: Additional Comments: 4 orbits - ACS/WFC 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 J1418+2102 ACS/WFC ACCUM WFC2-ORAM FR462N 4600 FLASH=20 1 400 S PATTERN 6 1-3 P see below (1444 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1418+2102 ACS/WFC ACCUM WFC2-ORAM FR462N 4790 FLASH=20 1 400 S P see below (1444 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1418+2102 ACS/WFC ACCUM WFC2-ORAM FR462N 4760 FLASH=20 1 1000 S P see below (5699 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1418+2102 1 ACS/WFC ACCUM WFC2-ORA FR462N 4600 1 none none none 1 364.0 S MP J1418+2102 1 ACS/WFC ACCUM WFC2-ORA FR462N 4600 2 none none none 2 360.0 S MP J1418+2102 1 ACS/WFC ACCUM WFC2-ORA FR462N 4600 3 none none none 3 360.0 S MP J1418+2102 1 ACS/WFC ACCUM WFC2-ORA FR462N 4600 4 none none none 4 360.0 S MP J1418+2102 2 ACS/WFC ACCUM WFC2-ORA FR462N 4790 1 none none none 1 364.0 S MP J1418+2102 2 ACS/WFC ACCUM WFC2-ORA FR462N 4790 2 none none none 2 360.0 S MP J1418+2102 2 ACS/WFC ACCUM WFC2-ORA FR462N 4790 3 none none none 3 360.0 S MP J1418+2102 2 ACS/WFC ACCUM WFC2-ORA FR462N 4790 4 none none none 4 360.0 S MP J1418+2102 3 ACS/WFC ACCUM WFC2-ORA FR462N 4760 1 none none none 1 1382.0 S MP J1418+2102 3 ACS/WFC ACCUM WFC2-ORA FR462N 4760 2 none none none 2 1439.0 S MP J1418+2102 3 ACS/WFC ACCUM WFC2-ORA FR462N 4760 3 none none none 3 1439.0 S MP J1418+2102 3 ACS/WFC ACCUM WFC2-ORA FR462N 4760 4 none none none 4 1439.0 S MP 17430( 14) - 24-Mar-2026 20:30:28 - [ 16] Visit: 07 (J1545 (WFC3)) Visit Requirements: On Hold Comments: Additional Comments: 2 orbits - WFC3/UVIS 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 J1545+0858 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 400 S PATTERN 3 1-4 S see below (867 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1545+0858 WFC3/UVI ACCUM UVIS2 F645N FLASH=20 1 600 S S see below (1267 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1545+0858 WFC3/UVI ACCUM UVIS2 F487N FLASH=20 1 700 S S see below (1467 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J1545+0858 WFC3/UVI ACCUM UVIS2 F336W FLASH=20 1 290 S S see below (647 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1545+0858 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 436.0 S S J1545+0858 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 2 431.0 S S J1545+0858 2 WFC3/UVI ACCUM UVIS2 F645N 1 none none none 1 636.0 S S J1545+0858 2 WFC3/UVI ACCUM UVIS2 F645N 2 none none none 2 631.0 S S J1545+0858 3 WFC3/UVI ACCUM UVIS2 F487N 1 none none none 1 736.0 S S J1545+0858 3 WFC3/UVI ACCUM UVIS2 F487N 2 none none none 2 731.0 S S J1545+0858 4 WFC3/UVI ACCUM UVIS2 F336W 1 none none none 1 326.0 S S J1545+0858 4 WFC3/UVI ACCUM UVIS2 F336W 2 none none none 2 321.0 S S 17430( 14) - 24-Mar-2026 20:30:28 - [ 17] Visit: 08 (J1545 (ACS)) Visit Requirements: On Hold Comments: Additional Comments: 2 orbits - ACS/WFC 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 J1545+0858 ACS/WFC ACCUM WFC2-MRAM FR505N 5030 FLASH=20 1 650 S PATTERN 4 1-3 P see below (1386 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1545+0858 ACS/WFC ACCUM WFC2-MRAM FR505N 5180 FLASH=20 1 650 S P see below (1386 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1545+0858 ACS/WFC ACCUM WFC2-MRAM FR656N 6800 FLASH=20 1 650 S P see below (1386 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1545+0858 1 ACS/WFC ACCUM WFC2-MRA FR505N 5030 1 none none none 1 689.0 S MP J1545+0858 1 ACS/WFC ACCUM WFC2-MRA FR505N 5030 2 none none none 2 697.0 S MP J1545+0858 2 ACS/WFC ACCUM WFC2-MRA FR505N 5180 1 none none none 1 689.0 S MP J1545+0858 2 ACS/WFC ACCUM WFC2-MRA FR505N 5180 2 none none none 2 697.0 S MP J1545+0858 3 ACS/WFC ACCUM WFC2-MRA FR656N 6800 1 none none none 1 689.0 S MP J1545+0858 3 ACS/WFC ACCUM WFC2-MRA FR656N 6800 2 none none none 2 697.0 S MP 17430( 14) - 24-Mar-2026 20:30:28 - [ 18] Visit: 20 (J0944 (ACS)) Visit Requirements: On Hold Comments: Additional Comments: 1 orbit: ACS/WFC HOPR 93005 repeat of visit 2. 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 J0944-0038 ACS/WFC ACCUM WFC2-ORAM FR462N 4750 FLASH=20 1 1000 S P see below (1005 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0944-0038 ACS/WFC ACCUM WFC2-ORAM FR462N 4580 FLASH=20 1 500 S P see below (505 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0944-0038 ACS/WFC ACCUM WFC2-ORAM FR462N 4780 FLASH=20 1 500 S P see below (577 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0944-0038 1 ACS/WFC ACCUM WFC2-ORA FR462N 4750 none none none none 1 1005.0 S MP J0944-0038 2 ACS/WFC ACCUM WFC2-ORA FR462N 4580 none none none none 1 505.0 S MP J0944-0038 3 ACS/WFC ACCUM WFC2-ORA FR462N 4780 none none none none 1 577.0 S MP 17430( 14) - 24-Mar-2026 20:30:28 - [ 19] Visit: 21 (J1044 (WFC3 - continued)) Visit Requirements: On Hold Comments: Additional Comments: 4 orbits 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 J1044+0353 WFC3/UVI ACCUM UVIS2 F502N FLASH=20 1 750 S PATTERN 5 1-3 S see below (3099 S) Comments: only OIII 4959 (no OIII 5008) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1044+0353 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 700 S S see below (2899 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1044+0353 WFC3/UVI ACCUM UVIS2 F336W FLASH=20 1 750 S S see below (3099 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1044+0353 1 WFC3/UVI ACCUM UVIS2 F502N 1 none none none 1 780.0 S S J1044+0353 1 WFC3/UVI ACCUM UVIS2 F502N 2 none none none 2 773.0 S S J1044+0353 1 WFC3/UVI ACCUM UVIS2 F502N 3 none none none 3 773.0 S S J1044+0353 1 WFC3/UVI ACCUM UVIS2 F502N 4 none none none 4 773.0 S S J1044+0353 2 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 730.0 S S J1044+0353 2 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 2 723.0 S S J1044+0353 2 WFC3/UVI ACCUM UVIS2 F275W 3 none none none 3 723.0 S S J1044+0353 2 WFC3/UVI ACCUM UVIS2 F275W 4 none none none 4 723.0 S S J1044+0353 3 WFC3/UVI ACCUM UVIS2 F336W 1 none none none 1 780.0 S S J1044+0353 3 WFC3/UVI ACCUM UVIS2 F336W 2 none none none 2 773.0 S S J1044+0353 3 WFC3/UVI ACCUM UVIS2 F336W 3 none none none 3 773.0 S S 17430( 14) - 24-Mar-2026 20:30:28 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1044+0353 3 WFC3/UVI ACCUM UVIS2 F336W 4 none none none 4 773.0 S S 17430( 14) - 24-Mar-2026 20:30:28 - [ 21] Visit: 22 (J1545 (ACS - continued)) Visit Requirements: On Hold Comments: Additional Comments: 3 visits 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 J1545+0858 ACS/WFC ACCUM WFC2-MRAM FR388N 3870 FLASH=20 1 1100 S PATTERN 4 1-2 P (2209 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1545+0858 ACS/WFC ACCUM WFC2-MRAM FR505N 4940 FLASH=20 1 1100 S P (2209 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1545+0858 ACS/WFC ACCUM WFC2-ORAM FR462N 4750 FLASH=20 1 1100 S PATTERN 4 3 P see below (2292 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1545+0858 1 ACS/WFC ACCUM WFC2-MRA FR388N 3870 1 none none none 1 N/A MP J1545+0858 1 ACS/WFC ACCUM WFC2-MRA FR388N 3870 2 none none none 2 1109.0 S MP J1545+0858 2 ACS/WFC ACCUM WFC2-MRA FR505N 4940 1 none none none 1 N/A MP J1545+0858 2 ACS/WFC ACCUM WFC2-MRA FR505N 4940 2 none none none 2 1109.0 S MP J1545+0858 3 ACS/WFC ACCUM WFC2-ORA FR462N 4750 1 none none none 3 1146.0 S MP J1545+0858 3 ACS/WFC ACCUM WFC2-ORA FR462N 4750 2 none none none 3 1146.0 S MP 17430( 14) - 24-Mar-2026 20:30:28 - [ 22] Summary Form for Proposal 17430 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS-QUAD, UVIS2, UVIS2-2K2C-SUB, WFC2-MRAMP, WFC2-ORAMP ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=20 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 2 1, PATTERN 2 1-7, PATTERN 3 1-4, PATTERN 3 1-7, PATTERN 4 1-2, PATTERN 4 1-3, PATTERN 4 3, PATTERN 5 1-3, PATTERN 6 1-3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F275W, F336W, F373N, F487N, F502N, F645N, F665N, FQ378N, FR388N, FR462N, FR505N, FR656N ------------------------------------------------------------------------------------------------------------------------------------ Target Names J0944-0038, J1016+3754, J1044+0353, J1418+2102, J1545+0858 ------------------------------------------------------------------------------------------------------------------------------------