0 Assigned ID: 393 ----- Attempting Submission 1 (Fri Apr 05 10:44:01 GMT 2019) ----- HST Phase I Proposal 393 (midcycle.apt.2019_01_31_11_52.aptbackup) successfully submitted. Receipt: # 393-1 ----- Attempting Submission 2 (Fri Apr 05 19:24:32 GMT 2019) ----- There is 169 seconds of unused time per orbit. I tried various combinations of Nsamp and samp-seq, however this was the most efficient in terms of S/N and integration time. -69302719 ----- Attempting Submission 1 (Mon Jul 22 10:26:24 GMT 2019) ----- The study of the most luminous star-forming galaxies at z > 7 has the potential to reveal key properties of reionization, as these sources likely occupy highly ionised regions within a predominantly neutral Universe. The number of bright sources however remains uncertain, due primarily to their rarity over the small area deep surveys typically used to detect them. We have expanded the search for bright z ~ 9 Lyman-break galaxies using the full 2 deg2 of deep ground-based optical/NIR photometry in the COSMOS and UDS fields, resulting in the selection of two extremely luminous galaxy candidates with best-fitting photometric redshifts at z ~ 9 and mAB < 24.5. Despite being the most robust z > 8 objects in our full SED fitting analysis, unfortunately current and future ground-based Y-band data in these two fields is insufficient to exclude the possibility that these objects are galactic brown dwarf interlopers. Due to the atmospheric transmission, the ground-based Y-bands peak too far to the blue, meaning the sharp expected Lyman-break cannot be confirmed. With a single orbit of HST/WFC3 imaging in the F105W (wide YJ) band it is possible to determine the high-redshift nature of these sources, as this filter efficiently targets below the expected Lyman-break where interloper objects will be detected. If confirmed, the existence of these ultra-luminous galaxies provides a clear challenge to current simulations. Furthermore, these galaxies will provide a unique insight into the EoR due to their accessibility for follow-up both with JWST and ALMA, where HST/WFC3 F105W data is essential for FIR line measurements that require precise photometric redshifts. The 2 objects we will imaging with HST/WFC3 are widely separated, hence we require 2 separate pointings. Each object is imaged for one orbit and in a single visit. The F105W filter is used with a simple 4 point dither pattern to enable improved PSF reconstruction, splitting each orbit into four separate exposures of ~ 600s each. We use the SPARS50 sampling rate with NSAMP = 14 to ensure a high number of non-destructive reads for cosmic ray rejection. Impact of reduced-gyro operations: In the event of reduced gyro mode (RGM) on these observations, the UDS -603 target would be out of the field of regard (reference slide 5 of J. Mackenty's slides, 6/6/16). For target UVISTA-1307 however we envision little impact of RGM on obtaining the proposed data. As we are only interested in the photometry of this source, the orientation of the observations is not set. Furthermore, the increased aquision time of approx. 120 seconds would not affect our integration time, as we currently have 169 seconds "free" in the orbit plan for this object (filling the orbit with more shorter integrations to reduce this did not increase the exposure time, or SN, hence this spare time). We have no coordinated observations, and only one visit of one orbit is required. The team are experts in the selection and study of high-redshift galaxies and have extensive experience in the reduction and analysis of data from WFC3/IR (both imaging and grism spectroscopy) the instrument used in the proposed observations. Dr R. Bowler and Dr D. McLeod have expertise in the reduction and analysis of WFC3 imaging data from leading a Cycle 22 program (GO 13793; PI: Bowler) and from analysing archival WFC3 data. These data have led to several publications (Bowler et al. 2017, 2018, McLeod et al. 2015, 2016). Prof. R. McLure, Prof. J. Dunlop and RB are co-Is of the Cycle 19 ultra-deep WFC3/IR UDF12 imaging program (GO 12498, PI: Ellis) and the CANDELS Treasury Program (12060, 12061, 12062, PI: S. Faber, H. Ferguson). We have considerable experience in using these datasets for the selection and study of high-redshift galaxies (e.g. McLure et al. 2010, 2011, 2013, Dunlop et al. 2013). The team has over 40 publications in the last decade directly using HST/WFC3 data. The most relevant first author publications are referenced here. Bowler, R., et al. 2017, MNRAS, 466, 3612 Bowler, R. et al. 2018, MNRAS, 481, 1631 McLeod, D. et al. 2015, MNRAS, 450, 3032 McLeod, D. et al. 2016, MNRAS, 459, 3812 Dunlop, J. et al., 2013, MNRAS, 432, 3520 McLure, R. et al. 2010, MNRAS, 403, 960 McLure, R. et al., 2011, MNRAS, 418, 2074 McLure, R. et al. 2013, MNRAS, 432, 2696 McLure, R. et al. 2018, MNRAS, 479, 25 Cosmology Galaxies and the IGM 6 false false false false false false false SUPPORTED GALAXY HIGH REDSHIFT GALAXY J2000 J2000 Total H-band magnitude of 24.4 GALAXY HIGH REDSHIFT GALAXY J2000 J2000 Total H-band magnitude of 24.8 WFC3/IR Imaging No No F105W WFC3/IR Imaging No No F105W POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 1 false 1563789272972 /Users/rebeccaabowler/Dropbox/proposals/HSTCycle27/OP-cache/PhaseII-v01.xml The scheduling data was generated by CASM 27.2. CASM was run in Phase II mode. 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