Imaging of three Ultra Diffuse Galaxies with measured stellar kinematics

0 Assigned ID: 56 ----- Attempting Submission 1 (Fri Apr 01 20:37:26 GMT 2016) ----- HST Phase I Proposal 56 (apt_phase1.apt) successfully submitted. Receipt: # 56-1 ----- Attempting Submission 2 (Fri Apr 08 21:18:20 GMT 2016) ----- First submission. I think everything is OK but please check! 541558568 ----- Attempting Submission 1 (Thu Jul 07 21:36:02 GMT 2016) ----- Imaging of three Ultra Diffuse Galaxies with measured stellar kinematics In 2015 we discovered a new population of galaxies. Initially found in the Coma cluster, "Ultra Diffuse Galaxies", or UDGs, have the sizes of Milky Way-like galaxies but the luminosities of dwarf galaxies. We recently succeeded in measuring the absorption line kinematics of three Coma UDGs, using 20 hr integrations with DEIMOS on the Keck telescope. Surprisingly, the velocity dispersions of the galaxies span a large range, from ~20 km/s to ~80 km/s. The most straightforward interpretation is that UDGs span a very large range in dynamical mass, with the most massive UDGs having halos masses similar to that of the Milky Way. Here we propose to test this using deep HST imaging of the three UDGs with velocity dispersion measurements. The primary aim is to count their globular clusters: if the interpretation of the dispersions is correct, the galaxy with sigma=80 km/s should have ~10x more globular clusters than the galaxies with sigma=20-30 km/s. Secondary goals include an analysis of the central regions of the UDGs; a search for star forming regions; a measurement of the radial variation in ellipticity and position angle; and a search for faint satellites around them. With primary ACS/WFC and parallel WFC3/UVIS observations we can image all three UDGs with dynamical measurements, as well as a fourth spectroscopically confirmed Coma UDG, in two pointings. The observations are split into 4 visits. Each visit consists of two orbits. Each orbit consists of 4 dithered exposures with ACS/WFC and WFC3/UVIS: visit 1: target DFX1+DFX2, 1 orbit F814W and 1 orbit F606W visit 2: target DFX1+DFX2, 2 orbits F606W visit 3: target DF42+DF44, 1 orbit F814W and 1 orbit F606W visit 4: target DF42+DF44, 2 orbits F606W A standard small box dither pattern is used. There is no need to dither over the ACS chip gap. The ORIENT constraints are necessary as two targets are observed simultaneously with ACS and WFC3. The ORIENT ranges are the maximum allowed with both objects having proper coverage within the WFC and UVIS chips. The visibility is limited to a few weeks around the end of April 2017; unfortunately this is the maximum visibility that is possible for this program (given the necessary ORIENT constraints). Galaxies 12 false false false false false false SUPPORTED GALAXY UNDESIGNATED J2000 J2000 GALAXY UNDESIGNATED J2000 J2000 ACS/WFC Imaging No No F814W WFC3/UVIS Imaging No No F814W ACS/WFC Imaging No No F814W WFC3/UVIS Imaging No No F814W ACS/WFC Imaging No No F606W WFC3/UVIS Imaging No No F606W ACS/WFC Imaging No No F606W WFC3/UVIS Imaging No No F606W POS-TARG DITHER 0.262 LINE 0.192 false false 68.14 4 18.39 ACS-WFC-DITHER-BOX 1

false

1467925668950 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14643 :visit-id "01" :proposal-version -1 :trans-version "20160601" :date "07-Jul-2016 17:07:48.0" :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 14643 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14643 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :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 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14643 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 35 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 2 0 1467927340570 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14643 :visit-id "02" :proposal-version -1 :trans-version "20160601" :date "07-Jul-2016 17:35:40.0" :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 14643 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14643 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :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 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14643 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2998 :al-overhead-at-end 28 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 2 0 1467927342211 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14643 :visit-id "03" :proposal-version -1 :trans-version "20160601" :date "07-Jul-2016 17:35:41.0" :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 14643 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14643 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :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 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14643 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 35 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 2 0 1467926429584 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14643 :visit-id "04" :proposal-version -1 :trans-version "20160601" :date "07-Jul-2016 17:20:29.0" :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 14643 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14643 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :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 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14643 :visit-id "04" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2998 :al-overhead-at-end 28 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 2 0