18117( 4) - 09-Oct-2025 17:23:58 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18117 Version: 4 Check-in Time: 09-Oct-2025 17:23:58 STScI Edit Number: 0 Title Probing the Source of Extreme Nitrogen Enrichment in MRK 203 ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Christy A. Tremonti University of Wisconsin - Madison Y CoI: Dr. Ralf Kotulla University of Wisconsin - Madison N CoI: Mr. Adam Linus Schaefer University of Wisconsin - Madison N CoI: Owen s Matthews Acuna University of Wisconsin - Madison N CoI: Dr. Marsha Wolf University of Wisconsin - Madison N ------------------------------------------------------------------------------------ Abstract One of the most startling discoveries made by JWST is a population of UV-bright z > 6 galaxies that are metal-poor and extremely nitrogen-rich with N/O ratios 15 times higher than expected for their metallicity. While this unusual enrichment pattern appears to be a rare phenomenon at high-z, it is notable that the C/N/O abundance patterns match those of second generation stars in globular clusters, suggesting that this may be a common, albeit short-lived, phase associated with the formation of massive star clusters in dense environments. Only 1 local analog of the N-rich high-z galaxies is known, suggesting that the conditions that give rise to these abundance patterns are extremely rare in the local universe. Here we propose to study a second galaxy, MRK 203, which has a high density central region with an N/O ratio 5 times the solar value (comparable to the high-z galaxies) and a normal N/O ratio outside the nucleus. The galaxy has much higher metallicity and lower ionization than the N-rich high-z galaxies, but it enables us to probe the phenomenon of N-enrichment over a much wider range of galactic conditions. We propose U, B, I-band WFC3 imaging to characterize galactic conditions giving rise to the N-rich nuclear cluster(s) and H-alpha narrow band imaging to provide key constraints on the photoionization rate. We additionally propose COS FUV spectroscopy of the nuclear regions of MRK 203 to precisely constrain the cluster age and determine if the N-enrichment is due to rapid cooling of stellar wind ejecta from Wolf-Rayet stars or very massive stars (M > 150 M_sun). ------------------------------------------------------------------------------------ Observations Description ------------------------ We seek to obain WFC3 imaging and COS FUV spectroscopy of Mrk 203, a nearby (D~100 Mpc) interacting sprial galaxy. The chief goal is to understand the stellar populations of the bright nuclear star cluster(s) to determine the cause of the unusual N/O ratio in the nucleus. WFC3 imaging: Our goal is to measure the stellar masses and approximate stellar ages of the massive star clusters in Mrk 203's nuclear region using 3 broadbands and H-alpha narrow-band photometry. We also wish to measure the ionizing photon output of the clusters via their H-alpha luminosities. At the galaxy's 18117( 4) - 09-Oct-2025 17:23:58 - [ 2] distance, we do not expect to resolve the sizes of the star clusters, but we will determine whether there is a single dominant central star cluster or a complex of smaller clusters. We will image the galaxy in 4 filters (F336W, F438W, F814W, F673N). Exposures are spread over 3 orbits which make up 2 Visits. Because we seek to use the F336W image as pre-imaging to define precise coordinates for COS, we have created a 1-oribt visit containing the F336W and F438W exposures to improve scheduling. The other filters make up a 2-obit Visit. We have left a minute of unscheduled time in each orbit to improve scheduling. We use the "UVIS2-FIX" position to place the galaxy's nucleus near the center of chip 2. While this is less optimal for CTE, it will enable the galaxy's merging companion to be included on the chips with only mild roll angle restrictions that would limit visibility. Using the "Roll Ranges Report" we find that the galaxy is only schedulable at ORIENTS = 200 - 335 when there are no restrictions. We restrict the ORIENT to 205-270, 300-335 to keep the companion galaxy out of the chip gap. Because of the short exposures in each filter, we have elected to use a two-point dither pattern which will cover the chip gap (WFC3-UVIS-GAP-LINE). We tried to create 3 exposures for all filters, but ran into problems with exposures being shorter than the 350 sec buffer dump. Some filters are split into 2 sub-exposures and some into 3 so we have added a third point to the default WFC3-UVIS-GAP-LINE pattern for the filters with 3 dithers. We have adjusted the flash to reach the recommended minimum of 20 e- in each sub-exposure using the WFC3 ETC. Given that our target is at the center of a fairly extended bright galaxy, we are not as concerned about CTE issues; therefore we did not add extra FLASH to account for spatial variations. COS spectroscopy: Our goal is to obtain a UV spectrum of the of the most massive nuclear star cluster to look for spectral signatures of Very Massive Stars (M > 150 M_sun). Acquisition: We request that our COS Visits take place at least 30 days after our WFC3 imaging (we have submitted a TTRB request). The nuclear region of the galaxy is not well resolved in available ground based imaging and therefore we wish to use our F336W images to update the coordinates of our COS visits to focus on the brightest cluster. Because COS peak-up may not work in the crowded center of the galaxy, we have opted to target a nearby bright star for acquisition and then do an offset to Mrk 203. The star is g=16 and NUV=20.89 mag and is 105 arcseconds away. Using the ETC and the GALEX NUV mag, we estimate that we can achieve S/N = 20 in 10 seconds. We opt for a 30 second ACQ/IMAGE exposure to be on the safe side, yielding S/N=34. After the first acquisition and move to MRK 203, we take a 60 second NUV IMAGE to confirm the target centering and provide additional NUV photometry for our SED fitting. We have assumed that the 3"-diameter nuclear region has a flux of 18.5 mag AB in the GALEX FUV filter. Assuming 1/3 of that flux is in the central star cluster gives m=19.7 mag. For a NUV image the ETC reaches S/N = 20 18117( 4) - 09-Oct-2025 17:23:58 - [ 3] in 17.5 seconds. We adopt an exposure time of 60 seconds (COS.ta.2027085) in case the central star cluster is fainter. We will use the G140L grating centered at 1105 to obtain R~3000 spectra from 1120- 2000 A. This will enable us to measure several key diagnostics of massive stars: NV 1240, Si IV 1440, C IV 1550, He II 1640. Following standard recommendations to reduce fixed pattern noise, we chose FP-POS=ALL. We have used the magnitude estimated for the 3" diameter nuclear region (m_FUV = 18.5) to estimate our Buffer time of 7580 seconds. We assume a point source for our calculations, but recognize that some of the flux may be more diffusely distributed. A total exposure time of 16, 320 seconds meets our requirement of S/N=15 per resolution element at 1550 A. (ETC =COS.sp.2027092). We require 8 orbits for our COS exposures which we split into 3 Visits for ease of scheduling. ------------------------------------------------------------------------------------ 18117( 4) - 09-Oct-2025 17:23:58 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 MRK203 GALAXY, SPIRAL, RA=12H18M12.8632S +/- 0.01", J2000 Z = V = 13.85 +/- 0.01 M_FUV = 16.75 STARBURST DEC=+44D10'23.68" +/- 0.01" 0.0245 Reference Frame: ICRS Extended: YES Comments: The galaxy is fairly nearby (D~111 Mpc) spiral galaxy with a diameter of about 30". Our coordinates are from GAIA. For our WFC3 imaging, coordinate uncertainties are not a concern. We will be targeting the bright nuclear star cluster for our COS observations. We will update the coordiates of our COS pointings based on our WFC3 imaging. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2016 0.0 0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 MRK203-OFFSE STAR, G V-IV RA=12H18M3.3482S +/- 0.01", J2000 V = 16.02 +/- 0.5 SDSS u=17.35, g=16.0, T-STAR DEC=+44D10'51.13" +/- 0.01" GALEX NUV = 20.89 Reference Frame: ICRS Extended: NO Comments: Star to be used for COS Offset targeting Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2016 -0.0019649628068002085 -0.014381999999999999 0.6930 ------------------------------------------------------------------------------------------------------------------------------------ 18117( 4) - 09-Oct-2025 17:23:58 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 5 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-GAP-LINE Pattern_Purpose MOSAIC Number_Of_Points 3 Point_Spacing 2.414 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 85.759 Angle_Between_Sides Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 6 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-GAP-LINE Pattern_Purpose MOSAIC Number_Of_Points 2 Point_Spacing 2.414 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 85.759 Angle_Between_Sides Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ 18117( 4) - 09-Oct-2025 17:23:58 - [ 6] Visit: 01 (WFC3 - Visit 1) 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 MRK203 WFC3/UVI ACCUM UVIS2-FIX F336W FLASH=18 1 465 S (930 PATTERN 6 1 S S) ------------------------------------------------------------------------------------------------------------------------------------ 2 MRK203 WFC3/UVI ACCUM UVIS2-FIX F438W FLASH=16 1 350 S PATTERN 5 2 S (1050 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 | ------------------------------------------------------------------------------------------------------------------------------------ MRK203 1 WFC3/UVI ACCUM UVIS2-FI F336W 1 none none none 1 N/A S X MRK203 1 WFC3/UVI ACCUM UVIS2-FI F336W 2 none none none 1 N/A S X MRK203 2 WFC3/UVI ACCUM UVIS2-FI F438W 1 none none none 1 N/A S X MRK203 2 WFC3/UVI ACCUM UVIS2-FI F438W 2 none none none 1 N/A S X MRK203 2 WFC3/UVI ACCUM UVIS2-FI F438W 3 none none none 1 N/A S X 18117( 4) - 09-Oct-2025 17:23:58 - [ 7] Visit: 02 (WFC3 - Visit 2) 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 MRK203 WFC3/UVI ACCUM UVIS2-FIX F814W FLASH=9 1 350 S PATTERN 5 1 S (1050 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 MRK203 WFC3/UVI ACCUM UVIS2-FIX F673N FLASH=17 1 470 S (940 PATTERN 6 2 S S) ------------------------------------------------------------------------------------------------------------------------------------ 3 MRK203 WFC3/UVI ACCUM UVIS2-FIX F673N FLASH=16 1 759 S PATTERN 5 3 S (2277 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 | ------------------------------------------------------------------------------------------------------------------------------------ MRK203 1 WFC3/UVI ACCUM UVIS2-FI F814W 1 none none none 1 N/A S X MRK203 1 WFC3/UVI ACCUM UVIS2-FI F814W 2 none none none 1 N/A S X MRK203 1 WFC3/UVI ACCUM UVIS2-FI F814W 3 none none none 1 N/A S X MRK203 2 WFC3/UVI ACCUM UVIS2-FI F673N 1 none none none 1 N/A S X MRK203 2 WFC3/UVI ACCUM UVIS2-FI F673N 2 none none none 1 N/A S X MRK203 3 WFC3/UVI ACCUM UVIS2-FI F673N 1 none none none 2 N/A S X MRK203 3 WFC3/UVI ACCUM UVIS2-FI F673N 2 none none none 2 N/A S X MRK203 3 WFC3/UVI ACCUM UVIS2-FI F673N 3 none none none 2 N/A S X 18117( 4) - 09-Oct-2025 17:23:58 - [ 8] Visit: 03 (COS - Visit 3) Visit Requirements: AFTER 01 BY 30.0 D TO 365.0 D; ON HOLD FOR 01 On Hold Comments: We require the WFC3 imaging in Visit 1 to happen first in order to center the COS aperture on our target. The target is the brightest UV cluster in a crowded region at the center of the galaxy. We will use our WFC3 F336W imaging to select the cluster for COS spectroscopy and update the target coordinates. 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 MRK203-OFFS COS/NUV ACQ/IMA PSA MIRRORA 1 30 S (30 ET-STAR GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 MRK203 COS/NUV ACCUM PSA MIRRORA 1 60 S (60 S) Comments: Image to help us understand which clusters in the crowded nuclear region are observed in the COS aperture. We have assumed that the 3"-diameter nuclear region has a flux of 18.5 mag AB in the GALEX FUV filter. Assuming 1/3 of that flux is in the central star cluster gives m=19.7 mag. For a NUV image the ETC reaches S/N = 20 in 17.5 seconds. We adopt an exposure time of 60 seconds. ------------------------------------------------------------------------------------------------------------------------------------ 3 MRK203 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=7580, FP-POS=ALL 1 425 S G (1700 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 MRK203 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=7580, FP-POS=ALL 1 545 S G (2180 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 MRK203 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=7580, FP-POS=ALL 1 545 S G (2180 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 | ------------------------------------------------------------------------------------------------------------------------------------ MRK203-OFFSET-STAR 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE MRK203 2 COS/NUV ACCUM PSA MIRRORA none none none none 1 N/A MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 1 1 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 2 1 N/A G 18117( 4) - 09-Oct-2025 17:23:58 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 3 1 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 4 1 N/A G MRK203 4 COS/FUV TIME-TA PSA G140L 1105 none none none 1 2 N/A G MRK203 4 COS/FUV TIME-TA PSA G140L 1105 none none none 2 2 N/A G MRK203 4 COS/FUV TIME-TA PSA G140L 1105 none none none 3 2 N/A G MRK203 4 COS/FUV TIME-TA PSA G140L 1105 none none none 4 2 N/A G MRK203 5 COS/FUV TIME-TA PSA G140L 1105 none none none 1 3 N/A G MRK203 5 COS/FUV TIME-TA PSA G140L 1105 none none none 2 3 N/A G MRK203 5 COS/FUV TIME-TA PSA G140L 1105 none none none 3 3 N/A G MRK203 5 COS/FUV TIME-TA PSA G140L 1105 none none none 4 3 N/A G 18117( 4) - 09-Oct-2025 17:23:58 - [ 10] Visit: 04 (COS - Visit 4) Visit Requirements: AFTER 01 BY 30.0 D TO 365.0 D; ON HOLD FOR 01 On Hold Comments: We require the WFC3 imaging in Visit 1 to happen first in order to center the COS aperture on our target. The target is the brightest UV cluster in a crowded region at the center of the galaxy. We will use our WFC3 F336W imaging to select the cluster for COS spectroscopy and update the target coordinates. 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 MRK203-OFFS COS/NUV ACQ/IMA PSA MIRRORA 1 30 S (30 ET-STAR GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 MRK203 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=7580, FP-POS=ALL 1 465 S G (1860 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 MRK203 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=7580, FP-POS=ALL 1 545 S G (2180 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 MRK203 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=7580, FP-POS=ALL 1 545 S G (2180 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 | ------------------------------------------------------------------------------------------------------------------------------------ MRK203-OFFSET-STAR 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE MRK203 2 COS/FUV TIME-TA PSA G140L 1105 none none none 1 1 N/A G MRK203 2 COS/FUV TIME-TA PSA G140L 1105 none none none 2 1 N/A G MRK203 2 COS/FUV TIME-TA PSA G140L 1105 none none none 3 1 N/A G MRK203 2 COS/FUV TIME-TA PSA G140L 1105 none none none 4 1 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 1 2 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 2 2 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 3 2 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 4 2 N/A G MRK203 4 COS/FUV TIME-TA PSA G140L 1105 none none none 1 3 N/A G 18117( 4) - 09-Oct-2025 17:23:58 - [ 11] 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 | ------------------------------------------------------------------------------------------------------------------------------------ MRK203 4 COS/FUV TIME-TA PSA G140L 1105 none none none 2 3 N/A G MRK203 4 COS/FUV TIME-TA PSA G140L 1105 none none none 3 3 N/A G MRK203 4 COS/FUV TIME-TA PSA G140L 1105 none none none 4 3 N/A G 18117( 4) - 09-Oct-2025 17:23:58 - [ 12] Visit: 05 (COS - Visit 5) Visit Requirements: AFTER 01 BY 30 D TO 365 D; ON HOLD FOR 01 On Hold Comments: We require the WFC3 imaging in Visit 1 to happen first in order to center the COS aperture on our target. The target is the brightest UV cluster in a crowded region at the center of the galaxy. We will use our WFC3 F336W imaging to select the cluster for COS spectroscopy and update the target coordinates. 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 MRK203-OFFS COS/NUV ACQ/IMA PSA MIRRORA 1 30 S (30 ET-STAR GE S) Comments: We will use the coordintates from our WFC3 F336W image to update the COS pointing coordinates to center on the brightest nuclear star cluster. ------------------------------------------------------------------------------------------------------------------------------------ 2 MRK203 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=7580, FP-POS=ALL 1 465 S G (1860 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 MRK203 COS/FUV TIME-TA PSA G140L 1105 BUFFER-TIME=7580, FP-POS=ALL 1 545 S G (2180 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 | ------------------------------------------------------------------------------------------------------------------------------------ MRK203-OFFSET-STAR 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE MRK203 2 COS/FUV TIME-TA PSA G140L 1105 none none none 1 1 N/A G MRK203 2 COS/FUV TIME-TA PSA G140L 1105 none none none 2 1 N/A G MRK203 2 COS/FUV TIME-TA PSA G140L 1105 none none none 3 1 N/A G MRK203 2 COS/FUV TIME-TA PSA G140L 1105 none none none 4 1 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 1 2 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 2 2 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 3 2 N/A G MRK203 3 COS/FUV TIME-TA PSA G140L 1105 none none none 4 2 N/A G 18117( 4) - 09-Oct-2025 17:23:58 - [ 13] Summary Form for Proposal 18117 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA, UVIS2-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=7580, FLASH=16, FLASH=17, FLASH=18, FLASH=9, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 30 D TO 365 D, AFTER 01 BY 30.0 D TO 365.0 D, ON HOLD FOR 01, PATTERN 5 1, PATTERN 5 2, PATTERN 5 3, PATTERN 6 1, PATTERN 6 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F336W, F438W, F673N, F814W, G140L, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names MRK203, MRK203-OFFSET-STAR ------------------------------------------------------------------------------------------------------------------------------------