17597( 10) - 13-Jan-2025 20:35:46 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17597 Version: 10 Check-in Time: 13-Jan-2025 20:35:46 STScI Edit Number: 4 Title Probing the galactic origin of ultra-compact dwarf galaxies ------------------------------------------------------------------------------------ Type Cycle GO 31 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Eric W. Peng NOIRLab - (AZ) Y CoI: Dr. Matthew Taylor University of Calgary N ------------------------------------------------------------------------------------ Abstract Ultra-compact dwarfs (UCDs) are among the densest stellar systems in the Universe. Their resemblance to nuclear star clusters (NSCs) suggests that they may be the remnants of tidally-stripped dwarfs, but they could also be massive globular clusters. In many cases, it is difficult to determine which is the correct origin scenario. From a new sample of over 600 UCDs and 735 dE, Ns in the nearby Virgo cluster, ~100 objects have been identified that are potentially "caught in the act" of transformation: UCDs with a faint stellar envelope (eUCDs) and dE, Ns with a prominent NSC. Over half of the brightest UCDs have been found to display faint stellar envelopes (eUCDs), but most of the ones with no detectable enevlope also have no HST observations, pointing to a clear observational bias. We aim to remedy this by observing 9 bright Virgo cluster UCDs with WFC3/UVIS to constrain the size of the central star cluster and reveal any existing stellar envelope, and determine the true "galactic" fraction of bright UCDs. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our program is to image 9 bright Virgo cluster ultra-compact dwarf galaxies with WFC3/UVIS/F475W, one orbit for each object, with a corresponding ACS/WFC imaging of nearby fields. ------------------------------------------------------------------------------------ 17597( 10) - 13-Jan-2025 20:35:46 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGVS-UCD171 GALAXY, DWARF COMPACT RA=12H24M43.8525S, J2000 g'=19.10 DEC=+05D37'46.67" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 NGVS-UCD352 GALAXY, DWARF COMPACT RA=12H30M6.0593S, J2000 g'=19.40 DEC=+12D39'53.97" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 NGVS-UCD412 GALAXY, DWARF COMPACT RA=12H30M47.3972S, J2000 g'=19.39 DEC=+12D33'1.70" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 NGVS-UCD471 GALAXY, DWARF COMPACT RA=12H31M31.7034S, J2000 g'=19.42 DEC=+12D41'30.35" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 5 NGVS-UCD502 GALAXY, DWARF COMPACT RA=12H32M13.6570S, J2000 g'=19.46 DEC=+14D24'13.65" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 6 NGVS-UCD560 GALAXY, DWARF COMPACT RA=12H34M13.3807S, J2000 g'=19.21 DEC=+07D41'7.04" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 7 NGVS-UCD588 GALAXY, DWARF COMPACT RA=12H35M30.3049S, J2000 g'=19.13 DEC=+12D38'24.31" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 8 NGVS-UCD650 GALAXY, DWARF COMPACT RA=12H38M20.5825S, J2000 g'=19.40 DEC=+12D50'33.98" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 9 NGVS-UCD781 GALAXY, DWARF COMPACT RA=12H45M24.0223S, J2000 g'=19.34 DEC=+11D05'35.16" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 17597( 10) - 13-Jan-2025 20:35:46 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 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 ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 17597( 10) - 13-Jan-2025 20:35:46 - [ 4] Visit: 01 (UCD171 - 4 exp - FF) Visit Requirements: On Hold Comments: Additional Comments: ORIENT limits are to avoid a bright (g=12.49) star from landing on the UVIS2 detector or being in the zone where it could cause Dragon's Breath. The best solution is to place this star on the UVIS1 detector. The ORIENT restrictions still enable a wide range of schedulability in April-July 2024. This object is the brightest in the sample, and would potentially be saturated in a 3-exposure visit. Therefore, this visit has 4 exposures, although they are of unequal lengths. The flash level is determined from the ETC, which seems to assume a higher zodiacal light background than the APT does. The post-flash is actually only needed for the first and last UVIS sub-exposures, although I don't seem to be able to set it for individual sub-exposures. In order to mitigate the effects of CTE for the faint stellar envelopes in these shorter exposures, the target was placed using the UVIS2-C1K1C-CTE aperture, but then was offset to allow for a greater range of ORIENT, opening up windows for observation in mid-2024. 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 NGVS-UCD171 WFC3/UVI ACCUM UVIS2-C1K F475W FLASH=6 1 340 S POS TARG S 1C-CTE see below 15.719630523771807, (2126 S) 15.68758367354229; PATTERN 1 1-2; PAR 2 WITH 1 Comments: Necessary flash is estimated from ETC using zodiacal light model for this sky position on 1 May 2024, with an extra 20% to account for the positioning of the target at the UVIS2-C1K1C-CTE aperture. The ETC Run # above is for the shortest exposure (410 sec). ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 300 S see below (1898 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD171 1 WFC3/UVI ACCUM UVIS2-C1 F475W 1 none none none 1 320.0 S S K1C-CTE NGVS-UCD171 1 WFC3/UVI ACCUM UVIS2-C1 F475W 2 none none none 1 698.0 S S K1C-CTE 17597( 10) - 13-Jan-2025 20:35:46 - [ 5] 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD171 1 WFC3/UVI ACCUM UVIS2-C1 F475W 3 none none none 1 698.0 S S K1C-CTE NGVS-UCD171 1 WFC3/UVI ACCUM UVIS2-C1 F475W 4 none none none 1 410.0 S S K1C-CTE ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 240.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 660.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 660.0 S ANY 2 ACS/WFC ACCUM WFC F475W 4 none none none 1 338.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 6] Visit: 02 (UCD352) 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 NGVS-UCD352 WFC3/UVI ACCUM UVIS2 F475W 1 817 S PATTERN 2 1-2; PAR 2 S see below WITH 1 (2325 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 730 S see below (2028 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD352 1 WFC3/UVI ACCUM UVIS2 F475W 1 none none none 1 775.0 S S NGVS-UCD352 1 WFC3/UVI ACCUM UVIS2 F475W 2 none none none 1 775.0 S S NGVS-UCD352 1 WFC3/UVI ACCUM UVIS2 F475W 3 none none none 1 775.0 S S ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 685.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 705.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 638.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 7] Visit: 03 (UCD412) 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 NGVS-UCD412 WFC3/UVI ACCUM UVIS2 F475W 1 817 S PATTERN 2 1-2; PAR 2 S see below WITH 1 (2355 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 730 S see below (2057 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD412 1 WFC3/UVI ACCUM UVIS2 F475W 1 none none none 1 785.0 S S NGVS-UCD412 1 WFC3/UVI ACCUM UVIS2 F475W 2 none none none 1 785.0 S S NGVS-UCD412 1 WFC3/UVI ACCUM UVIS2 F475W 3 none none none 1 785.0 S S ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 698.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 698.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 661.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 8] Visit: 04 (UCD471) 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 NGVS-UCD471 WFC3/UVI ACCUM UVIS2 F475W 1 817 S PATTERN 2 1-2; PAR 2 S see below WITH 1 (2325 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 730 S see below (2023 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD471 1 WFC3/UVI ACCUM UVIS2 F475W 1 none none none 1 775.0 S S NGVS-UCD471 1 WFC3/UVI ACCUM UVIS2 F475W 2 none none none 1 775.0 S S NGVS-UCD471 1 WFC3/UVI ACCUM UVIS2 F475W 3 none none none 1 775.0 S S ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 680.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 705.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 638.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 9] Visit: 05 (UCD502) 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 NGVS-UCD502 WFC3/UVI ACCUM UVIS2 F475W 1 817 S PATTERN 2 1-2; PAR 2 S see below WITH 1 (2325 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 730 S see below (2028 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD502 1 WFC3/UVI ACCUM UVIS2 F475W 1 none none none 1 775.0 S S NGVS-UCD502 1 WFC3/UVI ACCUM UVIS2 F475W 2 none none none 1 775.0 S S NGVS-UCD502 1 WFC3/UVI ACCUM UVIS2 F475W 3 none none none 1 775.0 S S ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 685.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 705.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 638.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 10] Visit: 06 (UCD560 - 4 exp - FF) Visit Requirements: ORIENT 210D TO 185 D On Hold Comments: Additional Comments: ORIENT limits are to avoid one bright star landing on the ACS/WFC detector. This object is the third brightest in the sample, and would potentially be saturated in a 3-exposure visit. Therefore, this visit has 4 exposures, although they are of unequal lengths. The flash level is determined from the ETC, which seems to assume a higher zodiacal light background than the APT does. The post-flash is actually only needed for the first and last UVIS sub-exposures, although I don't seem to be able to set it for individual sub-exposures. In order to mitigate the effects of CTE for the faint stellar envelopes in these shorter exposures, the target is placed using the UVIS2-C1K1C-CTE aperture. 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 NGVS-UCD560 WFC3/UVI ACCUM UVIS2-C1K F475W FLASH=7 1 410 S PATTERN 1 1-2; PAR 2 S 1C-CTE see below WITH 1 (2126 S) Comments: Necessary flash is estimated from ETC using zodiacal light model for this sky position on 1 May 2024. ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 300 S see below (1898 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD560 1 WFC3/UVI ACCUM UVIS2-C1 F475W 1 none none none 1 320.0 S S K1C-CTE NGVS-UCD560 1 WFC3/UVI ACCUM UVIS2-C1 F475W 2 none none none 1 698.0 S S K1C-CTE NGVS-UCD560 1 WFC3/UVI ACCUM UVIS2-C1 F475W 3 none none none 1 698.0 S S K1C-CTE NGVS-UCD560 1 WFC3/UVI ACCUM UVIS2-C1 F475W 4 none none none 1 410.0 S S K1C-CTE ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 240.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 660.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 660.0 S ANY 2 ACS/WFC ACCUM WFC F475W 4 none none none 1 338.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 11] Visit: 07 (UCD588 - 4 exp - FF) Visit Requirements: ORIENT 234D TO 195 D On Hold Comments: Additional Comments: ORIENT limits are to avoid one bright star landing on the ACS/WFC detector. This object is the second brightest in the sample, and would potentially be saturated in a 3-exposure visit. Therefore, this visit has 4 exposures, although they are of unequal lengths. The flash level is determined from the ETC, which seems to assume a higher zodiacal light background than the APT does. The post-flash is actually only needed for the first and last UVIS sub-exposures, although I don't seem to be able to set it for individual sub-exposures. In order to mitigate the effects of CTE for the faint stellar envelopes in these shorter exposures, the target is placed using the UVIS2-C1K1C-CTE aperture. 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 NGVS-UCD588 WFC3/UVI ACCUM UVIS2-C1K F475W FLASH=8 1 340 S PATTERN 1 1-2; PAR 2 S 1C-CTE see below WITH 1 (2126 S) Comments: Necessary flash is estimated from ETC using zodiacal light model for this sky position on 1 May 2024. ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 300 S see below (1898 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD588 1 WFC3/UVI ACCUM UVIS2-C1 F475W 1 none none none 1 320.0 S S K1C-CTE NGVS-UCD588 1 WFC3/UVI ACCUM UVIS2-C1 F475W 2 none none none 1 698.0 S S K1C-CTE NGVS-UCD588 1 WFC3/UVI ACCUM UVIS2-C1 F475W 3 none none none 1 698.0 S S K1C-CTE NGVS-UCD588 1 WFC3/UVI ACCUM UVIS2-C1 F475W 4 none none none 1 410.0 S S K1C-CTE ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 240.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 660.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 660.0 S ANY 2 ACS/WFC ACCUM WFC F475W 4 none none none 1 338.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 12] Visit: 08 (UCD650) Visit Requirements: ORIENT 238D TO 195 D On Hold Comments: Additional Comments: ORIENT constraints are to avoid two brights stars in the ACS/WFC field of view. 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 NGVS-UCD650 WFC3/UVI ACCUM UVIS2 F475W 1 817 S PATTERN 2 1-2; PAR 2 S see below WITH 1 (2325 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 730 S see below (2028 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD650 1 WFC3/UVI ACCUM UVIS2 F475W 1 none none none 1 775.0 S S NGVS-UCD650 1 WFC3/UVI ACCUM UVIS2 F475W 2 none none none 1 775.0 S S NGVS-UCD650 1 WFC3/UVI ACCUM UVIS2 F475W 3 none none none 1 775.0 S S ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 685.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 705.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 638.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 13] Visit: 09 (UCD781) Visit Requirements: On Hold Comments: Additional Comments: ORIENT constraints are to avoid two brights stars in the ACS/WFC field of view. 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 NGVS-UCD781 WFC3/UVI ACCUM UVIS2 F475W 1 817 S PATTERN 2 1-2; PAR 2 S see below WITH 1 (2265 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 730 S see below (1965 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD781 1 WFC3/UVI ACCUM UVIS2 F475W 1 none none none 1 755.0 S S NGVS-UCD781 1 WFC3/UVI ACCUM UVIS2 F475W 2 none none none 1 755.0 S S NGVS-UCD781 1 WFC3/UVI ACCUM UVIS2 F475W 3 none none none 1 755.0 S S ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 675.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 695.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 595.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 14] Visit: 51 (UCD171 - 4 exp - FF) Visit Requirements: On Hold Comments: Additional Comments: ORIENT limits are to avoid a bright (g=12.49) star from landing on the UVIS2 detector or being in the zone where it could cause Dragon's Breath. The best solution is to place this star on the UVIS1 detector. The ORIENT restrictions still enable a wide range of schedulability in April-July 2024. This object is the brightest in the sample, and would potentially be saturated in a 3-exposure visit. Therefore, this visit has 4 exposures, although they are of unequal lengths. The flash level is determined from the ETC, which seems to assume a higher zodiacal light background than the APT does. The post-flash is actually only needed for the first and last UVIS sub-exposures, although I don't seem to be able to set it for individual sub-exposures. In order to mitigate the effects of CTE for the faint stellar envelopes in these shorter exposures, the target was placed using the UVIS2-C1K1C-CTE aperture, but then was offset to allow for a greater range of ORIENT, opening up windows for observation in mid-2024. 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 NGVS-UCD171 WFC3/UVI ACCUM UVIS2-C1K F475W FLASH=6 1 340 S POS TARG S 1C-CTE see below 15.719630523771807, (2126 S) 15.68758367354229; PATTERN 1 1-2; PAR 2 WITH 1 Comments: Necessary flash is estimated from ETC using zodiacal light model for this sky position on 1 May 2024, with an extra 20% to account for the positioning of the target at the UVIS2-C1K1C-CTE aperture. The ETC Run # above is for the shortest exposure (410 sec). ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 300 S see below (1898 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD171 1 WFC3/UVI ACCUM UVIS2-C1 F475W 1 none none none 1 320.0 S S K1C-CTE NGVS-UCD171 1 WFC3/UVI ACCUM UVIS2-C1 F475W 2 none none none 1 698.0 S S K1C-CTE 17597( 10) - 13-Jan-2025 20:35:46 - [ 15] 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD171 1 WFC3/UVI ACCUM UVIS2-C1 F475W 3 none none none 1 698.0 S S K1C-CTE NGVS-UCD171 1 WFC3/UVI ACCUM UVIS2-C1 F475W 4 none none none 1 410.0 S S K1C-CTE ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 240.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 660.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 660.0 S ANY 2 ACS/WFC ACCUM WFC F475W 4 none none none 1 338.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 16] Visit: 58 (UCD650) Visit Requirements: ORIENT 238D TO 195 D On Hold Comments: Additional Comments: ORIENT constraints are to avoid two brights stars in the ACS/WFC field of view. 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 NGVS-UCD650 WFC3/UVI ACCUM UVIS2 F475W 1 817 S PATTERN 2 1-2; PAR 2 S see below WITH 1 (2325 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F475W 1 730 S see below (2028 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGVS-UCD650 1 WFC3/UVI ACCUM UVIS2 F475W 1 none none none 1 775.0 S S NGVS-UCD650 1 WFC3/UVI ACCUM UVIS2 F475W 2 none none none 1 775.0 S S NGVS-UCD650 1 WFC3/UVI ACCUM UVIS2 F475W 3 none none none 1 775.0 S S ANY 2 ACS/WFC ACCUM WFC F475W 1 none none none 1 685.0 S ANY 2 ACS/WFC ACCUM WFC F475W 2 none none none 1 705.0 S ANY 2 ACS/WFC ACCUM WFC F475W 3 none none none 1 638.0 S 17597( 10) - 13-Jan-2025 20:35:46 - [ 17] Summary Form for Proposal 17597 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2, UVIS2-C1K1C-CTE, WFC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=6, FLASH=7, FLASH=8 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 210D TO 185 D, ORIENT 234D TO 195 D, ORIENT 238D TO 195 D, PAR 2 WITH 1, PATTERN 1 1-2, PATTERN 2 1-2, POS TARG 15.719630523771807, 15.68758367354229 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ANY, NGVS-UCD171, NGVS-UCD352, NGVS-UCD412, NGVS-UCD471, NGVS-UCD502, NGVS-UCD560, NGVS-UCD588, NGVS-UCD650, NGVS-UCD781 ------------------------------------------------------------------------------------------------------------------------------------