0 Assigned ID: 3158 ----- Attempting Submission 1 (Fri Mar 25 08:12:03 GMT 2022) ----- HST Phase I Proposal 3158 successfully submitted. Receipt: # 3158-1 ----- Attempting Submission 2 (Fri Mar 25 17:22:27 GMT 2022) ----- HST Phase I Proposal 3158 successfully submitted. Receipt: # 3158-2 ----- Attempting Submission 3 (Fri Mar 25 18:28:53 GMT 2022) ----- This pattern is not used in this proposal. This pattern is not used in this proposal. This pattern is not used in this proposal. Added POS TARG offset to prevent dragon's breath, given current scheduling window of March 2023. Also fine-tuned target coordinates. 448421444 ----- Attempting Submission 1 (Wed Jul 13 19:17:30 GMT 2022) ----- HST Phase II Proposal 17149 successfully submitted. Receipt: # 17149-1 ----- Attempting Submission 2 (Thu Jul 14 23:24:10 GMT 2022) ----- HST Phase II Proposal 17149 successfully submitted. Receipt: # 17149-2 ----- Attempting Submission 3 (Thu Jul 14 23:33:18 GMT 2022) ----- HST Phase II Proposal 17149 successfully submitted. Receipt: # 17149-3 ----- Attempting Submission 4 (Fri Jul 15 20:36:16 GMT 2022) ----- ----- Attempting Submission 5 (Tue Oct 11 20:02:34 GMT 2022) ----- Simple warnings about patterns not being used. We propose to characterize the star cluster population of the Fornax cluster low-surface brightness dwarf galaxy FCC 224. Current data suggest that the clusters are over-luminous relative to a standard globular cluster luminosity function (GCLF) -- missing the bulk of the expected clusters at faint magnitudes. This top-heavy LF has been seen previously in two old, dark matter free galaxies, NGC 1052-DF2 and -DF4, and is understood to be closely connected to the formation of these galaxies without dark matter. FCC 224 may therefore be only the third known example of this puzzling class of galaxies, and the first in a different environment from the NGC 1052 group. We will test definitively the resemblance of this galaxy's cluster population to those of DF2/DF4, where the clusters also have unusually large sizes and are further accompanied by a smaller population of "normal" clusters with a GCLF peak at the standard luminosity. Confirming these peculiarities in FCC 224 would complement deeper spectroscopic follow-up to test for the presence of dark matter, would potentially pave the way for using GCLF photometry to efficiently identify more dark-matter-free galaxy candidates, and would provide additional leverage on understanding star cluster formation in general. This program studies the low-surface-brightness dwarf galaxy FCC 224 in the Fornax cluster with two-band imaging (WFC3UVIS F475X, F814W). The primary goals relate to its system of star clusters: their luminosities, colors, sizes, and radial density profile. The diffuse starlight will also be studied (density profile, color, surface brightness flucutations as a distance metric). The goal of the star cluster photometry is S/N ~ 20 for magnitude and size measurements down to F475X ~ 26.5 and F814W ~ 25.2 (corresponding to ~1.5 mags fainter than the standard GCLF peak). For the brightest clusters (F555W ~ 22.5-24), an additional goal is to be able to measure a color spread at the ~0.01 mag level, requiring S/N ~ 100 or better, with well-controlled flat-fielding. Exposures in each field consist of one orbit per filter, using a four-point dither pattern with unrestricted orient ranges. The galaxy is placed on the UVIS1 chip with POS TARG offsets to prevent Dragon's Breath from stars close to the FOV, given an anticipated March 2023 observing window. A change in the observing window may require a different offset. The offset into the A quadrant also minimizes potential problems from droplets, although these are not expected to impact differential photometry. FLASH is included to allow for low sky backgrounds in the ~600 sec exposures. The team is experienced with planning and analyzing similar HST observations of globular cluster systems and SBF measurements of other galaxies (programs 14643,14644, 14846, 15235, 16284, etc.). The team also have ongoing access to integral-field spectrographs (Keck/KCWI and VLT/MUSE) for complementary obsrvations of this target. Galaxies 6 false false false false false false false SUPPORTED GALAXY DWARF ELLIPTICAL DWARF SPHEROIDAL Object coordinates from Legacy g-band imaging. J2000 J2000 star cluster magnitudes F555W ~ 22 - 27 WFC3/UVIS Imaging No No F475X WFC3/UVIS Imaging No No F814W POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1 false POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 2 false POS-TARG DITHER DITHER 2 2.4 WFC3-UVIS-MOS-DITH-LINE false true 0.119 2 85.754 POS-TARG WFC3-UVIS-MOS-DITH-LINE 33.606 3 true POS-TARG DITHER DITHER 2 2.4 Center Pattern turned off to allow POS ARG offset in Exposure specifications. WFC3-UVIS-MOS-DITH-LINE false false 0.119 2 85.754 POS-TARG WFC3-UVIS-MOS-DITH-LINE 33.606 4 true 1665508403305 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. /Users/romanow/Dropbox/work/active/FCC224-HST/OP-cache/FCC224-PhaseII_v2-v01.xml (Tic-Visit :proposal-id 17149 :visit-id "01" :proposal-version -1 :trans-version "20220630" :date "11-Oct-2022 10:13:12.0" :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 2310000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17149 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17149 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2795 :al-overhead-at-end 121 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17149 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2785 :al-overhead-at-end 123 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) true 2 0