0 Assigned ID: 2666 ----- Attempting Submission 1 (Sun Jan 30 02:53:25 GMT 2022) ----- HST Phase I Proposal 2666 successfully submitted. Receipt: # 2666-1 ----- Attempting Submission 2 (Tue Feb 01 00:40:17 GMT 2022) ----- FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser I think this is in pretty good shape, but I may have missed something of course! One open question is whether the FLASH for UVIS can be adjusted for each subexposure. It's not a big deal but if that's possible then that would be a small improvement. -2030567450 ----- Attempting Submission 1 (Fri Mar 25 01:48:54 GMT 2022) ----- The FLASH is a bit too low for the short subexposure and a bit too high for the long subexposure. A trail of dark matter-free galaxies in the NGC1052 group The ultra diffuse galaxies DF2 and DF4 in the NGC1052 group share several unusual properties: they both have large sizes, rich populations of overluminous and large globular clusters, and very low velocity dispersions indiciating little or no dark matter. Recently it was found that DF2 and DF4 are very far apart along the line-of-sight, have a high relative velocity, and are part of a linear structure of 8-12 large, unusual galaxies in the group. It has been proposed that DF2, DF4, and the other galaxies along the trail originated in the aftermath of a "bullet dwarf'' event, a high speed collision between two galaxies ~9 Gyr ago that separated gas from dark matter. Four of the galaxies in the trail have been imaged previously with ACS. Here we propose to image the other 8 galaxies in the trail. The immediate goals are to measure the globular cluster populations, morphologies, colors, and surface brightness fluctuation distances of all the galaxies in this remarkable linear structure. These observations are critical for preparing follow-up spectroscopic and ultra deep HST imaging observations, and lay the foundation for a constraint on the self-interaction cross section of dark matter on kpc scales. The goal is to observe 7 of the 8 galaxies for 2 orbits (1 F606W, 1 F814W) and 1 galaxy for 1 orbit (0.5 F606W, 0.5 F814W). Exposures: --------- For the 7 galaxies each visit is 2 orbits. Within each orbit, 4 primary ACS exposures and 4 parallel UVIS exposures are obtained. It was difficult to fit these within 1 orbit; the model was an example visit on the STScI pages. The buffer dumps require a structure of the form short-long-long-short for the 4 exposures. The dither pattern does 2 exposures with a small offset, then the third with a big offset over the chip gap, and a fourth again with a small offset. For the galaxy with 1 orbit (LEDA4014647) only 2 exposures are obtained in each filter, and a different dither pattern is used that only has the chip gap jump. Location / apertures: ----------------- The galaxies are observed in the lower half of chip 1. As they are 10''-20'' in size the WFC position is too close to the chip gap, but if WFC1 were used then the galaxies would not be centered and we could miss associated globular clusters. We therefore use WFC but with a +20'' offset in Y (by having a Special Requirement). Flash: ----- Flash is used for all UVIS F814W exposures and for the UVIS F606W exposures in the 1-orbit visit. FLASH=8 e is a compromise, as it is slightly too low for the short subexposures (see Exposures above) and slightly too high for the long subexposures. If it is possible to adjust the FLASH for each subexposure then that would be better. The team has extensive experience with HST observations of this kind and are experts on the science. They discovered the remarkable properties of DF2 and DF4, and the trail of galaxies that is the subject of this proposal. The observations are very similar to the ones obtained in the Cohen et al. (2018) study; Pieter van Dokkum was the PI of that program and was the advisor of Yotam Cohen. Specifically, van Dokkum is an expert on ACS data and the science described here; Keim is an expert on measuring surface brightness profiles and structural parameters; Shen has led the most recent globular cluster analysis of the galaxies and measured the 2.1 Mpc distance difference between DF2 and DF4; Danieli has led several of the key DF2/DF4 studies over the past four years; Romanowsky is an expert on globular clusters and faint galaxies; Trujillo-Gomez has developed models for globular cluster formation in dwarf galaxies; Dutta Chowdhury has developed a dynamical model for DF2 and is currently modeling the bullet dwarf event; Abraham knows all there is to know about imaging observations and galaxy evolution; Conroy is an expert in stellar populations and surface brightness fluctuation techniques; Kruijssen is a galaxy and cluster formation expert; and Nagai is an expert on the hydrodynamics of the bullet interaction. All tools and expertise are in hand for a rapid processing of the data and publication of the results. Galaxies 3 false false false false false true false SUPPORTED GALAXY DWARF SPHEROIDAL YES J2000 J2000 GALAXY DWARF SPHEROIDAL YES J2000 J2000 GALAXY DWARF SPHEROIDAL YES J2000 J2000 GALAXY DWARF SPHEROIDAL YES J2000 J2000 GALAXY DWARF SPHEROIDAL YES J2000 J2000 GALAXY DWARF SPHEROIDAL YES J2000 J2000 GALAXY DWARF SPHEROIDAL YES J2000 J2000 GALAXY DWARF SPHEROIDAL YES J2000 J2000 ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W ACS/WFC Imaging No No F814W ACS/WFC Imaging No No F606W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W POS-TARG DITHER DITHER 2 3.034 Large dither over gap and then small dither to reject hot pixels and cosmic rays This is for the 2 orbit ones LINE false false 0.145 2 85.29 POS-TARG ACS-WFC-DITHER-LINE 47.23 1 true POS-TARG DITHER 3.034 Large dither over gap and then small dither to reject hot pixels and cosmic rays This is for the 2 orbit ones LINE false false 2 85.29 ACS-WFC-DITHER-LINE 2 false The scheduling data was generated by CASM 30.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16912 :visit-id "08" :proposal-version -1 :trans-version "20211222" :date "24-Mar-2022 21:45:18.0" :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 16912 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16912 :visit-id "08" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2762 :al-overhead-at-end 70 :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 16912 :visit-id "08" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2749 :al-overhead-at-end 76 :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 30.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16912 :visit-id "07" :proposal-version -1 :trans-version "20211222" :date "24-Mar-2022 21:47:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16912 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16912 :visit-id "07" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2762 :al-overhead-at-end 46 :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 1 0 The scheduling data was generated by CASM 30.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16912 :visit-id "01" :proposal-version -1 :trans-version "20211222" :date "24-Mar-2022 21:45:20.0" :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 16912 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16912 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2762 :al-overhead-at-end 70 :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 16912 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2749 :al-overhead-at-end 76 :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 30.1. CASM was run in Phase II mode. 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CASM was run in Phase II mode. (Tic-Visit :proposal-id 16912 :visit-id "03" :proposal-version -1 :trans-version "20211222" :date "24-Mar-2022 21:45:22.0" :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 16912 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16912 :visit-id "03" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2762 :al-overhead-at-end 70 :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 16912 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2749 :al-overhead-at-end 76 :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 30.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16912 :visit-id "04" :proposal-version -1 :trans-version "20211222" :date "24-Mar-2022 21:45:23.0" :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 16912 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16912 :visit-id "04" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2762 :al-overhead-at-end 70 :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 16912 :visit-id "04" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2749 :al-overhead-at-end 76 :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 30.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16912 :visit-id "05" :proposal-version -1 :trans-version "20211222" :date "24-Mar-2022 21:45:25.0" :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 16912 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16912 :visit-id "05" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2762 :al-overhead-at-end 70 :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 16912 :visit-id "05" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2749 :al-overhead-at-end 76 :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 30.1. 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