16460( 2) - 30-Nov-2020 17:46:46 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16460 Version: 2 Check-in Time: 30-Nov-2020 17:46:46 STScI Edit Number: 0 Title Confirming a Gravitationally Lensed Quasar Candidate at z=5.07 ------------------------------------------------------------------------------------ Type Cycle GO 28 ------------------------------------------------------------------------------------ Investigators Contact? PI: Minghao Yue University of Arizona Y CoI: Prof. Xiaohui Fan University of Arizona N CoI: Dr. Jinyi Yang University of Arizona N CoI: Dr. Feige Wang University of Arizona N CoI: Mr. Haowen Zhang University of Arizona N ------------------------------------------------------------------------------------ Abstract 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. ------------------------------------------------------------------------------------ Observations Description ------------------------ 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. ------------------------------------------------------------------------------------ 16460( 2) - 30-Nov-2020 17:46:46 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSS-J002526 GALAXY, QSO, QUASAR RA=00H25M26.8300S, J2000 SDSS g=22.82, SDSS r=19.57 .83-014532.5 DEC=-01D45'32.50" Reference Frame: ICRS Extended: NO Comments: Coordinates and magnitudes from SDSS ------------------------------------------------------------------------------------------------------------------------------------ 16460( 2) - 30-Nov-2020 17:46:46 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.262 Line_Spacing 0.192 Coordinate_Frame POS-TARG Pattern_Orient 18.39 Angle_Between_Sides 68.14 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16460( 2) - 30-Nov-2020 17:46:46 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSS-J00252 ACS/WFC ACCUM WFC1-CTE F606W 1 400 S PATTERN 1 1 6.83-014532 see below .5 (2064 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSS-J00252 ACS/WFC ACCUM WFC1-CTE F435W 1 400 S PATTERN 1 2 6.83-014532 see below .5 (2072 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SDSS-J002526.83-014 1 ACS/WFC ACCUM WFC1-CTE F606W 1 none none none 1 516.0 S 532.5 SDSS-J002526.83-014 1 ACS/WFC ACCUM WFC1-CTE F606W 2 none none none 1 516.0 S 532.5 SDSS-J002526.83-014 1 ACS/WFC ACCUM WFC1-CTE F606W 3 none none none 1 516.0 S 532.5 SDSS-J002526.83-014 1 ACS/WFC ACCUM WFC1-CTE F606W 4 none none none 1 516.0 S 532.5 SDSS-J002526.83-014 2 ACS/WFC ACCUM WFC1-CTE F435W 1 none none none 2 518.0 S 532.5 SDSS-J002526.83-014 2 ACS/WFC ACCUM WFC1-CTE F435W 2 none none none 2 518.0 S 532.5 SDSS-J002526.83-014 2 ACS/WFC ACCUM WFC1-CTE F435W 3 none none none 2 518.0 S 532.5 SDSS-J002526.83-014 2 ACS/WFC ACCUM WFC1-CTE F435W 4 none none none 2 518.0 S 532.5 16460( 2) - 30-Nov-2020 17:46:46 - [ 5] Summary Form for Proposal 16460 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1-CTE ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, PATTERN 1 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F435W, F606W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SDSS-J002526.83-014532.5 ------------------------------------------------------------------------------------------------------------------------------------