0 Assigned ID: 91 ----- Attempting Submission 1 (Tue Apr 02 17:19:25 GMT 2019) ----- As suggested, I swapped the order of the F160W and F105W observations to place the F105 exposures near the middle of the orbit and minimize airglow. 1628949843 ----- Attempting Submission 1 (Wed Jul 10 16:44:02 GMT 2019) ----- HST Phase II Proposal 15950 (HST15950.apt) successfully submitted. Receipt: # 15950-1 ----- Attempting Submission 2 (Wed Jul 10 16:50:24 GMT 2019) ----- ----- Attempting Submission 3 (Thu Aug 29 20:18:24 GMT 2019) ----- We request a single orbit of WFC3 imaging to discern whether the recently discovered quasar 2MASS J13260399+7023462 (z=2.88) is one of the most ultraluminous quasars in the Universe, or is instead a strongly-lensed system that is unresolved in ground-based and Gaia imaging. If the quasar remains unresolved at HST/WFC3 resolution, this will exclude lensing for plausible foreground lens masses. If it is resolved, then these observations will enable us to model the lens system and constrain the magnification. This quasar is physically interesting in either scenario -- for probing the bright tail of the QSO luminosity function if unlensed, or else for enabling future lensing-based programs, such as probing the foreground IGM on small scales. Given the brightness of this quasar, the primary concern is not attaining sufficient SNR, but rather avoiding saturation of the detector. We also desire multi-band photometry to enable clean separation of the QSO and the foreground lens (if there is one), and sufficient depth in the reddest band to detect a foreground lens down to 0.1 L*. We first select the F475W filter (which includes Ly-alpha for this source) and the F160W filter to the broadest possible wavelength coverage. In setting the exposure times, we thus have two criteria. First, we require that individual exposures will not be saturated even if the source is unlensed. This requirement limits us to exposure times shorter than 1 min for the WFC/UVIS F475W filter and <20 s for the WFC3/IR F160W filter. Because of the short exposures, we opt for us of a 512 x 512 sub-array with WFC3/UVIS to increase the efficiency of the program. For F475W, we are using the WFC3-UVIS-LINE-3PT dither pattern with 2x45s exposures at each dither position. This yields a total exposure time of 270s, which provides very high SNR for the QSO but reaches only ~L* for a lens at z = 1 with a passively evolving stellar population. Because of the short exposures and corresponding low background (estimated at 1e'/pixel) we have included FLASH=11 in the options to reach a 12e'/pixel background and mitigate CTE. **Note that we intentionally did not use AUTO-ADJUST in the orbit planning, as this extends the F475W exposures to 55s, which is uncomfortably close to the saturation limit. For the F160W we are using a 4 point dither patter in combination with the SAMP-SEQ=STEP100 and NSAMP=8, for a total exposure time of 796s. The purpose of the F160W imaging is two-fold: (1) to help deblend the QSO and foreground lens, and (2) to identify any galaxy overdensity in the field that may be associated with a protocluster at the redshift of the quasar. The quasar will be saturated beyond NSAMP=4, so the total usable time for the QSO will be 44s (which is sufficient). The total 796s will enable us to reach to <0.1 L* for a z=1 lens at SNR>10. The above imaging, including the associated overheads, fits well within a single orbit. With the remaining fraction of an orbit we therefore add one additional filter, F105W. This remaining time is sufficient for a 1197s F105W observation to match the F160W imaging in reaching < 0.1 L* for a z = 1 lens at SNR= 10. This filter gives additional leverage in deblending a foreground lens, and also for identifying any galaxy overdensity in the field that may be associated with a proto-cluster at the redshift of the quasar. As with F160W we use a 4 point dither pattern with SAMP-SEQ=STEP100, but in this instance set NSAMP=9. Reduced-gryo operations should have no impact on this program. This proposers are the team who discovered this source and are undertaking the WISE+Gaia bright QSO survey described in the text. Graduate student Sarik Jeram is the first author of the discovery paper for this object, and is conducting the broader survey effort under the supervision of Steve Eikenberry and Anthony Gonzalez. Both Eikenberry and Gonzalez have been PI for previous HST programs. Gonzalez in particular has extensive experience with both HST in general and the WFC3 camera in particular. He has been an investigator on 33 previous HST programs, and PI on 7. This work has included processing WFC3/IR and WFC3/UVIS imaging for complex analyses including weak lensing by a high-redshift galaxy cluster and intracluster light at intermediate redshift. The proposed observations are quite straightforward in contrast. For this program, Jeram will lead the data processing and analysis, supervised by Eikenberry and Gonzalez. Massive Black Holes And Their Host Galaxies 6 false false false false false false false SUPPORTED GALAXY QSO J2000 J2000 WFC3/UVIS Imaging No No F475W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F105W POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 2 false /private/var/folders/1r/vk7w6wpd7bdcd1wm0l89r9_00000gn/T/OPVisit2573817871072929442.xml 1567109702765 The scheduling data was generated by CASM 27.2. CASM was run in Phase II mode. 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