18435( 2) - 19-Aug-2026 14:43:52 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18435 Version: 2 Check-in Time: 19-Aug-2026 14:43:52 STScI Edit Number: 0 Title Lyman Continuum and Lyman Alpha escape in the high-ionization conditions observed in the Epoch of Reionization ------------------------------------------------------------------------------------ Type Cycle GO 34 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. John Chisholm University of Texas at Austin Y CoI: Dr. Yuri I. Izotov National Academy of Sciences of Ukraine, Y BITP CoI: Dr. Natalia G. Guseva National Academy of Sciences of Ukraine, N BITP CoI: Prof. Daniel Schaerer University of Geneva, Department of N Astronomy CoI: Dr. Gabor Worseck Unaffiliated N CoI: Dr. Sophia R Flury University of Edinburgh, Institute for N Astronomy CoI: Dr. Floriane Leclercq Centre de Recherche Astrophysique de Lyon N CoI: Dr. Vasily Kokorev University of Texas at Austin N CoI: Dr. Alberto Saldana-Lopez Stockholm University N CoI: Ms. Maya Helene Debski University of Texas at Austin N CoI: Michelle Jecmen University of Texas at Austin N ------------------------------------------------------------------------------------ Abstract JWST has revealed the properties of the galaxies that likely reionized the universe: compact star-forming galaxies that are highly ionized and very efficient producers of ionizing photons. These observed conditions push the limit of low-redshift observations and the current generation of stellar models. Theory suggests that these extreme coniditions may be due to very bursty star formation histories, accreting black holes, exotic stellar population, top-heavy initial mass function, extremely dense conditions, gas that is undergoing catastrophic cooling, or have a highly clumpy gaseous distribution. Low-redshift observations of galaxies with similar ionization conditions are extremely rare, such that only three galaxies with similar ionization properties have LyC observations with HST. Here, we propose 55 orbits of HST/COS G140L+G160M observations to probe the LyC and Ly-alpha properties of the 11 most extremely ionized and efficient producers of ionizing photons in the SDSS at z~0.3. These observations will 1) test the astrophysics of LyC escape in highly ionized nebular conditions to infer whether indirect LyC indicators can be used for the highly ionized conditions of the epoch of reionization, 2) discern whether highly ionized conditions enable Ly-alpha photons to efficiently escape, and 3) reveal whether the nebular continuum dominates the light of highly ionized high-redshift galaxies. These observations will fortify HST's legacy of LyC observations by revealing the astrophysics of extremely rare local conditions that have been commonly found during the epoch of reionization, and cement the methods to reveal the sources of cosmic reionization. ------------------------------------------------------------------------------------ Observations Description ------------------------ 18435( 2) - 19-Aug-2026 14:43:52 - [ 2] Each target will first be acquired with ACQ/IMAGE using MIRRORA. The acquisition ETC calculations use the observed GALEX NUV magnitudes, with SED-based estimates when required. Exposure times are chosen to obtain S/N (>20) in a (9x9) pixel box. The maximum ACQ/IMAGE time per exposure is 700 s for any target. All galaxies are assumed to have radii (<0.2''), ensuring that essentially all of the UV emission falls within the COS aperture. We will use two COS/FUV spectroscopic configurations: 1) G140L/800 to measure the Lyman continuum. The observations use COS/FUV, G140L, CENWAVE=800, TIME-TAG, SEGMENT=A, with All FP-POS positions. The LyC is observed near 912(1+z), corresponding to observed wavelengths of approximately (1185-1310) for the sample. The ETC calculations are designed to detect an escaping LyC continuum corresponding to (f_{\rm esc}=5%) at (>3\sigma) significance after binning by 400 pixels. Following Izotov et al. 2018, the intrinsic LyC flux density is estimated from the extinction-corrected SDSS H-alpha flux using the (I_H-alpha)/I(912))-EW relation, and the ETC normalization is reduced by a factor of 20 to represent (fesc=5%). The resulting expected LyC flux densities are approximately 1.3x10^-18-2.0x10^-17 erg s-1 cm-2 A^-1 across the sample. In addition to the LyC measurement, G140L/800 provides broad FUV spectral coverage extending to approximately rest-frame 1500 for the lower-redshift targets, allowing independent measurements of the UV continuum. 2) G160M to resolve the Ly-alpha line profile. The observations use COS/FUV, G160M, TIME-TAG, with target-specific central wavelengths of 1533, 1577, 1589, or 1623 selected according to redshift so that Ly-alpha falls securely in the center of the detector and away from the detector gap. The Ly-alpha line is observed at (1215.67(1+z)), corresponding to approximately 1581-1744 for the sample. For the ETC calculations, the continuum is normalized using the GALEX NUV photometry, supplemented by the SED-based estimates where appropriate, and extrapolated to rest-frame 1216 assuming (f_\lambda \propto \lambda^{-2}). The resulting continuum flux densities near Ly-alpha span approximately (3.9\times10^-17-5.5x10^-16 erg s^-1 cm^-2 A^{-1}. Exposure times are chosen to obtain S/N (>3) in the continuum near Ly-alpha after binning by 100 pixels. The Ly-alpha emission itself is expected to be substantially brighter than the continuum, and the G160M resolution of <50 km/ resolves the blue and red Ly-alpha peaks and measure their velocity structure. Each target requires approximately 0.5 orbit for target acquisition, 1.5 orbits for the G160M spectrum, and 3 orbits for the G140L spectrum, for a total of 5 orbits per target and 55 orbits for the full sample. ------------------------------------------------------------------------------------ 18435( 2) - 19-Aug-2026 14:43:52 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J0125+0834 GALAXY, EMISSION LINE RA=01H25M30.7100S +/- 0.1", J2000 Z = V = 20.22 +/- 0.02 FUV=21.57+/-0.39, NEBULA, STARBURST DEC=+08D34'2.04" +/- 0.1" 0.3393 NUV=20.78+/-0.21 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1629) = 2e-16 F(912 *(1+z) = 1221) = 1.33e-17 ------------------------------------------------------------------------------------------------------------------------------------ 2 J0135+2206 GALAXY, EMISSION LINE RA=01H35M40.1600S +/- 0.1", J2000 Z = V = 22.01 +/- 0.18 NUV=20.84+/-0.40 NEBULA, STARBURST DEC=+22D06'6.97" +/- 0.1" 0.3004 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1581) = 2e-16 F(912*(1+z) = 1186.0) = 5e-18 ------------------------------------------------------------------------------------------------------------------------------------ 3 J0142+0641 GALAXY, EMISSION LINE RA=01H42M19.1300S +/- 0.1", J2000 Z = V = 21.5 +/- 0.07 NUV=22.50+/-0.64 NEBULA, STARBURST DEC=+06D41'30.87" +/- 0.1" 0.3836 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1682.5) = 3.85e-17 F(912*(1+z) = 1261.8) = 1.3e-18 ------------------------------------------------------------------------------------------------------------------------------------ 4 J0149+2935 GALAXY, EMISSION LINE RA=01H49M14.4500S +/- 0.1", J2000 Z = V = 22.09 +/- 0.05 NUV=22.46+/-0.64 NEBULA, STARBURST DEC=+29D35'48.54" +/- 0.1" 0.3103 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1593.3) = 4.45e-17 F(912*(1+z) = 1195.0) = 1.03e-17 ------------------------------------------------------------------------------------------------------------------------------------ 5 J0741+1739 GALAXY, EMISSION LINE RA=07H41M37.9400S +/- 0.1", J2000 Z = V = 21.05 +/- 0.03 FUV=20.97+/-0.19, NEBULA, STARBURST DEC=+17D39'50.59" +/- 0.1" 0.3405 NUV=21.37+/-0.23 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1630.0) = 1.16e-16 F(912*(1+z) = 1222.5) = 3.33e-18 ------------------------------------------------------------------------------------------------------------------------------------ 6 J0933+3413 GALAXY, EMISSION LINE RA=09H33M22.5100S +/- 0.1", J2000 Z = V = 22.12 +/- 0.08 NUV=22.29+/-0.51 NEBULA, STARBURST DEC=+34D13'35.03" +/- 0.1" 0.3574 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1650.6) = 4.85e-17 F(912*(1+z) = 1237.9) = 7.52e-18 ------------------------------------------------------------------------------------------------------------------------------------ 7 J1055+4758 GALAXY, EMISSION LINE RA=10H56M42.4200S +/- 0.1", J2000 Z = V = 21.45 +/- 0.04 FUV=21.74+/-0.54, NEBULA, STARBURST DEC=+47D58'50.81" +/- 0.1" 0.4347 NUV=21.35+/-0.33 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1744) = 1.03e-16 F(912*(1+z) = 1308) = 3.02e-18 ------------------------------------------------------------------------------------------------------------------------------------ 8 J1155+5922 GALAXY, EMISSION LINE RA=11H55M23.8200S +/- 0.1", J2000 Z = V = 22.02 +/- 0.05 FUV=22.38+/-0.56, NEBULA, STARBURST DEC=+59D22'3.95" +/- 0.1" 0.3589 NUV=21.60+/-0.13 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1652) = 9.13e-17 F(912*(1+z) = 1239.3) = 1.89e-17 ------------------------------------------------------------------------------------------------------------------------------------ 18435( 2) - 19-Aug-2026 14:43:52 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 9 J1330+5213 GALAXY, EMISSION LINE RA=13H30M47.0800S +/- 0.1", J2000 Z = V = 21.28 +/- 0.04 NUV = 19.70 +/- 0.1, NEBULA, STARBURST DEC=+52D13'58.53" +/- 0.1" 0.3316 FUV = 21.00+/- 0.29 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1619) = 5.47e-16 F(912*(1+z) = 1214) = 1.97e-17 ------------------------------------------------------------------------------------------------------------------------------------ 10 J1431+3825 GALAXY, EMISSION LINE RA=14H31M7.1000S +/- 0.1", J2000 Z = V = 22.22 +/- 0.10 NUV = 22.10 NEBULA, STARBURST DEC=+38D25'33.95" +/- 0.1" 0.3289 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1616) = 6.03e-17 F(912*(1+z) = 1212) = 6.62e-18 ------------------------------------------------------------------------------------------------------------------------------------ 11 J1458+3637 GALAXY, EMISSION LINE RA=14H58M6.5200S +/- 0.1", J2000 Z = V = 22.31 +/- 0.10 FUV=22.1+/--0.29, NEBULA, STARBURST DEC=+36D37'30.23" +/- 0.1" 0.3587 NUV=22.05+/-0.25 Reference Frame: ICRS Extended: NO Comments: F(1216*(1+z) = 1615) = 6.04e-17 F(912*(1+z) = 1239) = 4.16e-18 ------------------------------------------------------------------------------------------------------------------------------------ 18435( 2) - 19-Aug-2026 14:43:52 - [ 5] Visit: 01 (J0125) 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 J0125+0834 COS/NUV ACQ/IMA PSA MIRRORA 1 477 S (477 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0125+0834 COS/FUV TIME-TA PSA G140L 800 BUFFER-TIME=12015, FP-POS=ALL, 1 1200 S G LIFETIME-POS=LP11, SEGMENT=A see below (6231 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0125+0834 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=17013, FP-POS=ALL, 1 1200 S G LIFETIME-POS=LP10, see below SEGMENT=BOTH (4850 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0125+0834 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J0125+0834 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 1294.0 S G J0125+0834 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1214.0 S G J0125+0834 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1214.0 S G J0125+0834 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2509.0 S G J0125+0834 3 COS/FUV TIME-TA PSA G160M 1533 none none none 1 4 1211.0 S G J0125+0834 3 COS/FUV TIME-TA PSA G160M 1533 none none none 2 4 1211.0 S G J0125+0834 3 COS/FUV TIME-TA PSA G160M 1533 none none none 3 5 1214.0 S G J0125+0834 3 COS/FUV TIME-TA PSA G160M 1533 none none none 4 5 1214.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 6] Visit: 02 (J0135) 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 J0135+2206 COS/NUV ACQ/IMA PSA MIRRORA 1 507 S (507 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0135+2206 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=12030 see below (6177 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0135+2206 COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4608 S) BUFFER-TIME=17013 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0135+2206 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J0135+2206 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 1236.0 S G J0135+2206 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1215.0 S G J0135+2206 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1215.0 S G J0135+2206 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2511.0 S G J0135+2206 3 COS/FUV TIME-TA PSA G160M 1533 none none none 1 4 1103.0 S G J0135+2206 3 COS/FUV TIME-TA PSA G160M 1533 none none none 2 4 1201.0 S G J0135+2206 3 COS/FUV TIME-TA PSA G160M 1533 none none none 3 5 1151.0 S G J0135+2206 3 COS/FUV TIME-TA PSA G160M 1533 none none none 4 5 1153.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 7] Visit: 03 (J0142) 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 J0142+0641 COS/NUV ACQ/IMA PSA MIRRORA 1 700 S (700 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0142+0641 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=12037 see below (5809 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0142+0641 COS/FUV TIME-TA PSA G160M 1589 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4580 S) BUFFER-TIME=17694 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0142+0641 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J0142+0641 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 848.0 S G J0142+0641 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1214.0 S G J0142+0641 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1214.0 S G J0142+0641 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2533.0 S G J0142+0641 3 COS/FUV TIME-TA PSA G160M 1589 none none none 1 4 1091.0 S G J0142+0641 3 COS/FUV TIME-TA PSA G160M 1589 none none none 2 4 1187.0 S G J0142+0641 3 COS/FUV TIME-TA PSA G160M 1589 none none none 3 5 1151.0 S G J0142+0641 3 COS/FUV TIME-TA PSA G160M 1589 none none none 4 5 1151.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 8] Visit: 04 (J0149) 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 J0149+2935 COS/NUV ACQ/IMA PSA MIRRORA 1 700 S (700 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0149+2935 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=12020 see below (5827 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0149+2935 COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4592 S) BUFFER-TIME=17456 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0149+2935 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J0149+2935 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 854.0 S G J0149+2935 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1214.0 S G J0149+2935 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1220.0 S G J0149+2935 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2539.0 S G J0149+2935 3 COS/FUV TIME-TA PSA G160M 1533 none none none 1 4 1091.0 S G J0149+2935 3 COS/FUV TIME-TA PSA G160M 1533 none none none 2 4 1193.0 S G J0149+2935 3 COS/FUV TIME-TA PSA G160M 1533 none none none 3 5 1151.0 S G J0149+2935 3 COS/FUV TIME-TA PSA G160M 1533 none none none 4 5 1157.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 9] Visit: 05 (J0741) 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 J0741+1739 COS/NUV ACQ/IMA PSA MIRRORA 1 700 S (700 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0741+1739 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=12033 see below (5806 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0741+1739 COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4578 S) BUFFER-TIME=17250 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0741+1739 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J0741+1739 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 847.0 S G J0741+1739 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1213.0 S G J0741+1739 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1214.0 S G J0741+1739 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2532.0 S G J0741+1739 3 COS/FUV TIME-TA PSA G160M 1533 none none none 1 4 1091.0 S G J0741+1739 3 COS/FUV TIME-TA PSA G160M 1533 none none none 2 4 1186.0 S G J0741+1739 3 COS/FUV TIME-TA PSA G160M 1533 none none none 3 5 1150.0 S G J0741+1739 3 COS/FUV TIME-TA PSA G160M 1533 none none none 4 5 1151.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 10] Visit: 06 (J0933) 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 J0933+3413 COS/NUV ACQ/IMA PSA MIRRORA 1 700 S (700 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0933+3413 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=12026 see below (5839 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0933+3413 COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4600 S) BUFFER-TIME=17666 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0933+3413 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J0933+3413 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 858.0 S G J0933+3413 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1214.0 S G J0933+3413 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1224.0 S G J0933+3413 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2543.0 S G J0933+3413 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 4 1096.0 S G J0933+3413 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 4 1192.0 S G J0933+3413 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 5 1151.0 S G J0933+3413 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 5 1161.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 11] Visit: 07 (J1056) 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 J1055+4758 COS/NUV ACQ/IMA PSA MIRRORA 1 700 S (700 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1055+4758 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1200 S G SEGMENT=A, BUFFER-TIME=12034 see below (5887 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1055+4758 COS/FUV TIME-TA PSA G160M 1623 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4672 S) BUFFER-TIME=17585 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1055+4758 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J1055+4758 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 882.0 S G J1055+4758 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 2567.0 S G J1055+4758 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 3 1219.0 S G J1055+4758 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 1219.0 S G J1055+4758 3 COS/FUV TIME-TA PSA G160M 1623 none none none 1 4 1168.0 S G J1055+4758 3 COS/FUV TIME-TA PSA G160M 1623 none none none 2 4 1168.0 S G J1055+4758 3 COS/FUV TIME-TA PSA G160M 1623 none none none 3 5 1168.0 S G J1055+4758 3 COS/FUV TIME-TA PSA G160M 1623 none none none 4 5 1168.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 12] Visit: 08 (J1155) 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 J1155+5922 COS/NUV ACQ/IMA PSA MIRRORA 1 700 S (700 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1155+5922 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=12005 see below (5986 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1155+5922 COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4738 S) BUFFER-TIME=17560 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1155+5922 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J1155+5922 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 915.0 S G J1155+5922 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1247.0 S G J1155+5922 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1248.0 S G J1155+5922 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2576.0 S G J1155+5922 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 4 1137.0 S G J1155+5922 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 4 1232.0 S G J1155+5922 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 5 1184.0 S G J1155+5922 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 5 1185.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 13] Visit: 09 (J1330) 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 J1330+5213 COS/NUV ACQ/IMA PSA MIRRORA 1 165 S (165 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1330+5213 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=11121 see below (7026 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1330+5213 COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4678 S) BUFFER-TIME=16513 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1330+5213 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J1330+5213 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 1967.0 S G J1330+5213 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1234.0 S G J1330+5213 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1243.0 S G J1330+5213 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2582.0 S G J1330+5213 3 COS/FUV TIME-TA PSA G160M 1533 none none none 1 4 1116.0 S G J1330+5213 3 COS/FUV TIME-TA PSA G160M 1533 none none none 2 4 1211.0 S G J1330+5213 3 COS/FUV TIME-TA PSA G160M 1533 none none none 3 5 1175.0 S G J1330+5213 3 COS/FUV TIME-TA PSA G160M 1533 none none none 4 5 1176.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 14] Visit: 10 (J1431) 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 J1431+3825 COS/NUV ACQ/IMA PSA MIRRORA 1 700 S (700 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1431+3825 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=12027 see below (5854 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1431+3825 COS/FUV TIME-TA PSA G160M 1533 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4610 S) BUFFER-TIME=17410 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1431+3825 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J1431+3825 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 863.0 S G J1431+3825 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1221.0 S G J1431+3825 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1222.0 S G J1431+3825 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2548.0 S G J1431+3825 3 COS/FUV TIME-TA PSA G160M 1533 none none none 1 4 1099.0 S G J1431+3825 3 COS/FUV TIME-TA PSA G160M 1533 none none none 2 4 1194.0 S G J1431+3825 3 COS/FUV TIME-TA PSA G160M 1533 none none none 3 5 1158.0 S G J1431+3825 3 COS/FUV TIME-TA PSA G160M 1533 none none none 4 5 1159.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 15] Visit: 11 (J1458) 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 J1458+3637 COS/NUV ACQ/IMA PSA MIRRORA 1 700 S (700 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1458+3637 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, LIFETIME-POS=LP11, 1 1500 S G SEGMENT=A, BUFFER-TIME=12032 see below (5830 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1458+3637 COS/FUV TIME-TA PSA G160M 1577 FP-POS=ALL, FLASH=NO, 1 1200 S G SEGMENT=BOTH, see below LIFETIME-POS=LP10, (4634 S) BUFFER-TIME=17661 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1458+3637 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE J1458+3637 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 863.0 S G J1458+3637 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 2 1221.0 S G J1458+3637 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1222.0 S G J1458+3637 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 3 2524.0 S G J1458+3637 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 4 1158.0 S G J1458+3637 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 4 1159.0 S G J1458+3637 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 5 1158.0 S G J1458+3637 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 5 1159.0 S G 18435( 2) - 19-Aug-2026 14:43:52 - [ 16] Summary Form for Proposal 18435 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=11121, BUFFER-TIME=12005, BUFFER-TIME=12015, BUFFER-TIME=12020, BUFFER-TIME=12026, BUFFER-TIME=12027, BUFFER-TIME=12030, BUFFER-TIME=12032, BUFFER-TIME=12033, BUFFER-TIME=12034, BUFFER-TIME=12037, BUFFER-TIME=16513, BUFFER-TIME=17013, BUFFER-TIME=17250, BUFFER-TIME=17410, BUFFER-TIME=17456, BUFFER-TIME=17560, BUFFER-TIME=17585, BUFFER-TIME=17661, BUFFER-TIME=17666, BUFFER-TIME=17694, FLASH=NO, FP-POS=ALL, LIFETIME-POS=LP10, LIFETIME-POS=LP11, SEGMENT=A, SEGMENT=BOTH ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G160M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names J0125+0834, J0135+2206, J0142+0641, J0149+2935, J0741+1739, J0933+3413, J1055+4758, J1155+5922, J1330+5213, J1431+3825, J1458+3637 ------------------------------------------------------------------------------------------------------------------------------------