16890( 2) - 07-Dec-2021 14:11:41 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16890 Version: 2 Check-in Time: 07-Dec-2021 14:11:41 STScI Edit Number: 0 Title Ultra-Diffuse Galaxy Formation in Groups -- Tidal or Born That Way? ------------------------------------------------------------------------------------ Type Cycle GO 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. David J. Sand University of Arizona Y CoI: Dr. Michael Gordon Jones University of Arizona N CoI: Dr. Kristine Spekkens Royal Military College of Canada N CoI: Ananthan Karunakaran Queen's University N CoI: Dr. Burcin Mutlu-Pakdil University of Chicago N CoI: Paul Bennet Space Telescope Science Institute N CoI: Dr. Denija Crnojevic University of Tampa N ------------------------------------------------------------------------------------ Abstract We request D-configuration HI observations as well as HST data to image three ultra-diffuse galaxies (UDGs) which are in a group environment and plausibly influenced by tidal forces. These dwarfs provide evidence that UDGs can form through interactions, although it is not clear whether they are normal dwarf galaxies that have been `puffed up' during an interaction or if they are tidal dwarf galaxies, the dark matter-free stellar aggregations that can result from gas-rich major galaxy encounters. Alternatively, these galaxies may have formed as UDGs through some other mechanism, and are now associated with a larger galaxy halo. The deep VLA observations are essential for pinpointing HI emission associated with each dwarf and any tidal material. The HST observations will allow for a detailed morphological analysis of each interacting dwarf and will measure their globular cluster content -- a powerful discriminant between formation scenarios. Our team has recently demonstrated the use of combined VLA HI and HST observations in two UDGs, showing that they likely formed via tidal heating of normal dwarf galaxies. This proposal will more than double the sample of objects studied in this way, with a focus on systems that show some evidence for recent star formation. ------------------------------------------------------------------------------------ Observations Description ------------------------ The observations are going to be performed with the ACS/WFC (primary) and WFC3/UVIS (parallel). We request imaging in F555W and F814W filters for both instruments in order to both measure the detailed morphology of each ultra-diffuse dwarf and their globular cluster (GC) content. The parallel WFC3 pointings will allows us to observe a field region next to our ultra-diffuse galaxy targets and will be invaluable to characterize the 'background' of points sources with consistent magnitudes and colors as the GCs we wish to identify. We require one orbit per filter, so two orbits for each of our three dwarf targets (six orbits total). Each visit will be two orbits. For two targets (KDG013 and KUG203Dw1), we use a standard four-point dither box for each orbit, with sub-pixel dithers in order to get closer to the native resolution of ACS. 16890( 2) - 07-Dec-2021 14:11:41 - [ 2] The dwarf target will be placed on the WFC1 aperture, as they both fit easily on a single chip. The third target is larger, and so we place it at the WFC aperture, and employ a 3-point dither pattern to cover the ACS chip gap with cosmic ray rejection. No ORIENTS for any of our targets are necessary. This program is relatively resilient to two-gyro mode as we have no ORIENT constraints and could switch to single orbit visits if necessary. Nor does this program have time constraints (other than the baseline excitement of the science!). We can also achieve our science goals with a longer acquisition time, if necessary. Note that this dataset was requested through the joint NRAO program. We will also be acquiring VLA HI observations of the three ultradiffuse galaxy targets in this proposal to get a more complete picture and narrow down the formation scenarios of these remarkable galaxies. We do not require concurrent VLA and HST imaging. ------------------------------------------------------------------------------------ 16890( 2) - 07-Dec-2021 14:11:41 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 KUG203-DW1 GALAXY, DWARF RA=02H05M47.0000S, J2000 V = 20.0 SPHEROIDAL DEC=-09D50'31.00" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 UGC9050-DW1 GALAXY, DWARF RA=14H09M13.0000S, J2000 V = 20.0 SPHEROIDAL DEC=+51D13'28.00" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 KDG013 GALAXY, DWARF RA=02H08M33.0000S, J2000 V = 20.0 SPHEROIDAL DEC=-07D50'59.00" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 16890( 2) - 07-Dec-2021 14:11:41 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.262 Line_Spacing 0.192 Coordinate_Frame POS-TARG Pattern_Orient 18.39 Angle_Between_Sides 68.14 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 3.034 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 85.29 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16890( 2) - 07-Dec-2021 14:11:41 - [ 5] Visit: 01 (KUG203Dw1) 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 KUG203-DW1 ACS/WFC ACCUM WFC1 F555W 1 600 S PATTERN 1 1-2; PAR 2 see below WITH 1 (2046 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFC3/UVI ACCUM UVIS1 F555W FLASH=4.0 1 355 S S see below (2275 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 KUG203-DW1 ACS/WFC ACCUM WFC1 F814W 1 600 S PATTERN 1 3-4; PAR 4 see below WITH 3 (2098 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/UVI ACCUM UVIS1 F814W FLASH=8.0 1 369 S S see below (2245 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 | ------------------------------------------------------------------------------------------------------------------------------------ KUG203-DW1 1 ACS/WFC ACCUM WFC1 F555W 1 none none none 1 340.0 S KUG203-DW1 1 ACS/WFC ACCUM WFC1 F555W 2 none none none 1 680.0 S KUG203-DW1 1 ACS/WFC ACCUM WFC1 F555W 3 none none none 1 680.0 S KUG203-DW1 1 ACS/WFC ACCUM WFC1 F555W 4 none none none 1 346.0 S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 1 none none none 1 420.0 S S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 2 none none none 1 715.0 S S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 3 none none none 1 715.0 S S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 4 none none none 1 425.0 S S KUG203-DW1 3 ACS/WFC ACCUM WFC1 F814W 1 none none none 2 375.0 S KUG203-DW1 3 ACS/WFC ACCUM WFC1 F814W 2 none none none 2 677.0 S KUG203-DW1 3 ACS/WFC ACCUM WFC1 F814W 3 none none none 2 676.0 S KUG203-DW1 3 ACS/WFC ACCUM WFC1 F814W 4 none none none 2 370.0 S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 1 none none none 2 420.0 S S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 2 none none none 2 703.0 S S 16890( 2) - 07-Dec-2021 14:11:41 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ ANY 4 WFC3/UVI ACCUM UVIS1 F814W 3 none none none 2 702.0 S S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 4 none none none 2 420.0 S S 16890( 2) - 07-Dec-2021 14:11:41 - [ 7] Visit: 02 (KDG013) 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 KDG013 ACS/WFC ACCUM WFC1 F555W 1 600 S PATTERN 1 1-2; PAR 2 see below WITH 1 (2046 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFC3/UVI ACCUM UVIS1 F555W FLASH=4.0 1 355 S S see below (2275 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 KDG013 ACS/WFC ACCUM WFC1 F814W 1 600 S PATTERN 1 3-4; PAR 4 see below WITH 3 (2089 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/UVI ACCUM UVIS1 F814W FLASH=8.0 1 369 S S see below (2245 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 | ------------------------------------------------------------------------------------------------------------------------------------ KDG013 1 ACS/WFC ACCUM WFC1 F555W 1 none none none 1 340.0 S KDG013 1 ACS/WFC ACCUM WFC1 F555W 2 none none none 1 680.0 S KDG013 1 ACS/WFC ACCUM WFC1 F555W 3 none none none 1 680.0 S KDG013 1 ACS/WFC ACCUM WFC1 F555W 4 none none none 1 346.0 S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 1 none none none 1 420.0 S S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 2 none none none 1 715.0 S S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 3 none none none 1 715.0 S S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 4 none none none 1 425.0 S S KDG013 3 ACS/WFC ACCUM WFC1 F814W 1 none none none 2 365.0 S KDG013 3 ACS/WFC ACCUM WFC1 F814W 2 none none none 2 677.0 S KDG013 3 ACS/WFC ACCUM WFC1 F814W 3 none none none 2 676.0 S KDG013 3 ACS/WFC ACCUM WFC1 F814W 4 none none none 2 371.0 S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 1 none none none 2 420.0 S S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 2 none none none 2 703.0 S S 16890( 2) - 07-Dec-2021 14:11:41 - [ 8] 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 | ------------------------------------------------------------------------------------------------------------------------------------ ANY 4 WFC3/UVI ACCUM UVIS1 F814W 3 none none none 2 702.0 S S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 4 none none none 2 420.0 S S 16890( 2) - 07-Dec-2021 14:11:41 - [ 9] Visit: 03 (UGC9050Dw1) 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 UGC9050-DW1 ACS/WFC ACCUM WFC F555W 1 802 S PATTERN 2 1-2; PAR 2 (2406 S) WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY WFC3/UVI ACCUM UVIS1 F555W FLASH=1.0 1 750 S S see below (2474 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 UGC9050-DW1 ACS/WFC ACCUM WFC F814W 1 800 S PATTERN 2 3-4; PAR 4 see below WITH 3 (2439 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY WFC3/UVI ACCUM UVIS1 F814W FLASH=1.0 1 750 S S see below (2473 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 | ------------------------------------------------------------------------------------------------------------------------------------ UGC9050-DW1 1 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A UGC9050-DW1 1 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A UGC9050-DW1 1 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A ANY 2 WFC3/UVI ACCUM UVIS1 F555W 1 none none none 1 858.0 S S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 2 none none none 1 808.0 S S ANY 2 WFC3/UVI ACCUM UVIS1 F555W 3 none none none 1 808.0 S S UGC9050-DW1 3 ACS/WFC ACCUM WFC F814W 1 none none none 2 813.0 S UGC9050-DW1 3 ACS/WFC ACCUM WFC F814W 2 none none none 2 813.0 S UGC9050-DW1 3 ACS/WFC ACCUM WFC F814W 3 none none none 2 813.0 S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 1 none none none 2 839.0 S S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 2 none none none 2 817.0 S S ANY 4 WFC3/UVI ACCUM UVIS1 F814W 3 none none none 2 817.0 S S 16890( 2) - 07-Dec-2021 14:11:41 - [ 10] Summary Form for Proposal 16890 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS1, WFC, WFC1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=1.0, FLASH=4.0, FLASH=8.0 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PAR 2 WITH 1, PAR 4 WITH 3, PATTERN 1 1-2, PATTERN 1 3-4, PATTERN 2 1-2, PATTERN 2 3-4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ANY, KDG013, KUG203-DW1, UGC9050-DW1 ------------------------------------------------------------------------------------------------------------------------------------