Science Keywords: Select from 2 to 5 items. Science Keywords is a required field. You have requested parallel orbits in your observations, but you have not requested any parallel orbits in any cycle. 0 Assigned ID: 2636 ----- Attempting Submission 1 (Thu Nov 11 15:07:55 GMT 2021) ----- Joint NRAO/HST FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser I have written a note to Patricia Boyle about slight issues with the phase II. I do not think they are a big deal. -833345118 ----- Attempting Submission 1 (Mon Dec 06 17:10:07 GMT 2021) ----- I have written to Patricia Boyle about these warnings. Not clear how to resolve them. Ultra-Diffuse Galaxy Formation in Groups -- Tidal or Born That Way? 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. 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. 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. n/a Galaxies 6 false false false false false false false false SUPPORTED GALAXY DWARF SPHEROIDAL J2000 J2000 GALAXY DWARF SPHEROIDAL J2000 J2000 GALAXY DWARF SPHEROIDAL J2000 J2000 ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F814W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F814W ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F814W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F814W ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F814W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F814W POS-TARG DITHER 0.262 LINE 0.192 false false 68.14 4 18.39 ACS-WFC-DITHER-BOX 1 false POS-TARG DITHER 3.034 LINE false false 3 85.29 ACS-WFC-DITHER-LINE 2 false The scheduling data was generated by CASM 29.2. 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CASM was run in Phase II mode. /private/var/folders/lk/kgyb23rx78z9r8t653drxmfw0000gn/T/OPVisit8460419959196558597.xml (Tic-Visit :proposal-id 16890 :visit-id "02" :proposal-version -1 :trans-version "20210514" :date "06-Dec-2021 10:06:13.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 4583776 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16890 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16890 :visit-id "02" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2762 :al-overhead-at-end 73 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16890 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2753 :al-overhead-at-end 45 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /private/var/folders/lk/kgyb23rx78z9r8t653drxmfw0000gn/T/OPVisit15446004141416737413.xml (Tic-Visit :proposal-id 16890 :visit-id "03" :proposal-version -1 :trans-version "20210514" :date "06-Dec-2021 09:31:08.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 3437840 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16890 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16890 :visit-id "03" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2950 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16890 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2940 :al-overhead-at-end 0 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) true 2 0