The final submit, with more typos and grammar errors corrected. -1773166863 Assigned ID: 1214 ----- Attempting Submission 1 (Wed Sep 30 00:30:47 GMT 2020) ----- HST Phase I Proposal 1214 successfully submitted. Receipt: # 1214-1 ----- Attempting Submission 2 (Wed Sep 30 00:37:39 GMT 2020) ----- HST Phase I Proposal 1214 successfully submitted. Receipt: # 1214-2 ----- Attempting Submission 3 (Wed Sep 30 07:17:56 GMT 2020) ----- HST Phase I Proposal 1214 successfully submitted. Receipt: # 1214-3 ----- Attempting Submission 4 (Wed Sep 30 21:00:32 GMT 2020) ----- 0 ----- Attempting Submission 1 (Fri Nov 27 19:57:27 GMT 2020) ----- Although a high fraction of quasars is predicted to be gravitationally lensed at high redshift, only one z>5 lensed quasar has been discovered to date (J0439+1634 at z=6.5). Recently we identified a promising candidate of a lensed quasar at z=5.07, J0025-0145, which would be the second lensed quasar at z>5 if confirmed. A number of observational evidences strongly suggest J0025-0145 being lensed, including (1) the existence of a foreground lens galaxy, (2) the ground-based image is extended and is well-fitted by a lensing model, and (3) the SMBH mass implies an exceptionally high super-Eddington accretion ratio, which can be explained by lensing magnification. The characteristics of J0025-0145 strongly resemble those of J0439+1634. Our model suggests that J0025-0145 is a compact lens (image separation ~0.1") with large magnification (~80). HST is needed to confirm the lensing scenario. Because of its high magnification, J0025-0145 will provide the first chance to study the host galaxy of a faint quasar at z>5 with high S/N and high spatial resolution, and to probe the SMBH/galaxy co-evolution in a low mass system at high-redshift in great details. We propose ACS/WFC imaging of J0025-0145. We will use F435W to capture the lens galaxy, and use F606W to measure the lensed quasar images. The proposed observation will be the definitive test of the lensing hypothesis, and will provide an accurate lensing model which will enable follow-up studies, especially high S/N JWST and ALMA observations. The proposed observation will be a crucial step towards building a sample of high-redshift lensed quasars, which is essential to a comprehensive view of high-redshift SMBH population. This program will perform high-resolution ACS/WFC imaging of a gravitationally lensed quasar candidate at z=5.07. We will take the images with two filters: F435W which captures the deflector galaxy, and F606W which captures the lensed quasar images. The program has been awarded for two orbits and we will finish the observation with one visit. The first orbit will obtain four F606W images, and the second orbit will obtain four F435W images. We will do dithering to improve the image sampling. Minghao Yue works on surveys and follow-up observations of high-redshift lensed quasars, and has extensive experiences in HST data analysis, especially for ACS and WFC3. Prof. Xiaohui Fan is an expert of high-redshift quasar survey, SMBH physics and reionization, and is experienced in HST data analysis. Dr. Jinyi Yang is an expert of high-redshift quasar survey, SMBH physics and reionization, and is experienced in HST data analysis. Dr. Feige Wang is an expert of high-redshift quasar survey, SMBH physics and reionization, and is experienced in HST data analysis. Mr. Haowen Zhang is experienced in the modeling of SMBH-host galaxy co-evolution. Supermassive Black Holes and Active Galaxies 3 false false false false false false false SUPPORTED GALAXY QSO QUASAR NO Coordinates and magnitudes from SDSS J2000 J2000 SDSS g=22.82, SDSS r=19.57 ACS/WFC Imaging No No F435W ACS/WFC 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 1606506512008 /private/var/folders/f9/qm61tlbj79l88v644x05s9z00000gn/T/OPVisit4570957636638846277.xml The scheduling data was generated by CASM 28.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16460 :visit-id "01" :proposal-version -1 :trans-version "20200619" :date "27-Nov-2020 12:48:31.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 2273792 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16460 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16460 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2758 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16460 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2747 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) true 2 0