17084( 6) - 21-Sep-2022 13:50:47 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17084 Version: 6 Check-in Time: 21-Sep-2022 13:50:47 STScI Edit Number: 0 Title Zooming In On Two Strongly Lensed Galaxies During the Epoch of Re-Ionization ------------------------------------------------------------------------------------ Type Cycle GO 30 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Matthew Bayliss University of Cincinnati Main Campus Y CoI: Prof. Michael D. Gladders University of Chicago N CoI: Prof. Keren Sharon University of Michigan N CoI: Mr. Joshua Aaron Roberson University of Cincinnati Main Campus N CoI: Dr. Gourav Khullar University of Chicago N CoI: Dr. Keunho J. Kim University of Cincinnati Main Campus N CoI: Mr. Alexander Edwin Navarre University of Cincinnati Main Campus N CoI: Dr. Lindsey Bleem Argonne National Laboratory N CoI: Dr. Guillaume Mahler Durham Univ. N CoI: Juan David Remolina Gonzalez University of Michigan N CoI: Prof. Mark Brodwin University of Missouri - Kansas City N CoI: Dr. Behzad Ansarinejad University of Melbourne N CoI: Ms. Kate Napier University of Michigan N CoI: Michael S. Calzadilla Massachusetts Institute of Technology N CoI: Mr. Benjamin Floyd University of Missouri - Kansas City N ------------------------------------------------------------------------------------ Abstract Deep field observations with the Hubble Space Telescope have revealed several hundred galaxy candidates in the universe's first billion years leading up to re-ionization, but only a small fraction are bright enough (H<24 AB) for detailed, high-S/N spectroscopic follow-up study with the James Webb Space Telescope (JWST). We propose for WFC3/IR + ACS imaging observations of two exceptionally bright (F110W_AB~23.8) z~7 dropout galaxies that were recently identified in archival HST data. Both targets appear as multiply imaged pairs near the cores of massive foreground galaxy clusters, indicating that they are strongly lensed, and therefore highly magnified. While both lensed sources appear as exceptionally bright z~7 galaxies, their intrinsic brightnesses are much smaller. Unlike the brightest high-z galaxies discovered in deep fields, our target source are drawn from the population of faint high-z galaxies that are likely responsible for re-ionization. These lensed sources provide a unique opportunity to performe detailed studies of typical, intrinsically faint, galaxies during the epoch of re-ionization. Our proposed observations will simultaneously achieve three science goals: 1) inform a detailed strong lensing model for each system (necessary to recover their true intrinsic properties), 2) measure the stellar mass and UV spectral slopes of multiple spatially resolved (via lensing magnification) star-forming clumps in each dropout galaxy, and 3) reduce photometric redshift uncertainties for both lensed galaxies by a factor >3x (necessary to plan future spectroscopic observations). ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this prorgam is to observed two different targets in F814W with ACS 17084( 6) - 21-Sep-2022 13:50:47 - [ 2] and in F098M+F160W imaging with WFC3/IR. The purpose of the observations are to sample the spectral energy distributions of both foreground cluster galaxies and candidate strongly lensed dropout galaxies at z>6. Each target will receive two orbits of data. The first orbit for each target will be spent entirely on F814W (ACS) imaging, and the second orbit will be split between the F098M and F160W imaging using WFC3/IR. The observations will be organized into two visits, one for each target. Each visit will contain two orbits (one using ACS the other using WFC3/IR). This being a 4 orbit program, we are splitting orbits up quite aggressively. Our observations are designed with the biggest priority being that we obtain a minimum of 4 dithered observations in each band, for each target. For ACS/WFC F814W imaging we use the ACS-WFC-DITHER-BOX, and split a single orbit up into 4 equal exposures that use the full target visibility window. For WFC3/IR F098M and F160W we use a pattern composed of a macro-scale dither (a 2pt version of WFC3-IR-DITHER-BLOB) with a sub-pattern that has a small-scale dither (a 2 pt version of WFC3-IR-DITHER-LINE). For the WFC3/IR imaging we try to maximize the value of NSAMP to improve cosmic ray rejection and minimize readnoise. However, we are packing a lot of exposures (8) into a single orbit and so buffer dumping constraints require us to use longer individual integrations with lower values of NSAMP that would be strictly optimal from a signal-to-noise perspective. That said, our targets are quite bright and so we prioritize having 4 dither points over maximizing NSAMP in our exposures. Any thoughts/feedback/comments from the instrument experts would be very much welcome! ------------------------------------------------------------------------------------ 17084( 6) - 21-Sep-2022 13:50:47 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SPT-DROPOUT- GALAXY, GRAVITATIONAL RA=03H04M52.6893S, J2000 V = 30 +/- 1 F110W = 23.8 0304 LENS, HIGH REDSHIFT DEC=-54D03'58.06" GALAXY Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 SPT-DROPOUT- GALAXY, GRAVITATIONAL RA=02H16M35.8520S, J2000 V = 30 +/- 1 F110W = 23.8 0216 LENS, HIGH REDSHIFT DEC=-26D10'1.33" GALAXY Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 17084( 6) - 21-Sep-2022 13:50:47 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BLOB WFC3-IR-DITHER-LINE Pattern_Purpose DITHER DITHER Number_Of_Points 2 2 Point_Spacing 5.183 0.636 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 41.859 41.788 Angle_Between_Sides Center_Pattern YES NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 4 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 Pattern_Comments: This is the old (deprecated?) ACS-DITHER-BOX pre-defined pattern. ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 5 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.2637 Line_Spacing 0.1856 Coordinate_Frame POS-TARG Pattern_Orient 20.7 Angle_Between_Sides 69.02 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 17084( 6) - 21-Sep-2022 13:50:47 - [ 5] 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 SPT-DROPOUT WFC3/IR MULTIAC IR F160W SAMP-SEQ=SPARS25, NSAMP=10 1 DEF PATTERN 3 1-2 -0304 CUM (911.748 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SPT-DROPOUT WFC3/IR MULTIAC IR F098M SAMP-SEQ=SPARS50, NSAMP=9 1 DEF -0304 CUM (1611.744 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SPT-DROPOUT ACS/WFC ACCUM WFCENTER F814W 1 562 S PATTERN 5 3 -0304 see below (2244 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 | ------------------------------------------------------------------------------------------------------------------------------------ SPT-DROPOUT-0304 1 WFC3/IR MULTIAC IR F160W 1 1 none none 1 N/A CUM SPT-DROPOUT-0304 1 WFC3/IR MULTIAC IR F160W 1 2 none none 1 N/A CUM SPT-DROPOUT-0304 1 WFC3/IR MULTIAC IR F160W 2 1 none none 1 N/A CUM SPT-DROPOUT-0304 1 WFC3/IR MULTIAC IR F160W 2 2 none none 1 N/A CUM SPT-DROPOUT-0304 2 WFC3/IR MULTIAC IR F098M 1 1 none none 1 N/A CUM SPT-DROPOUT-0304 2 WFC3/IR MULTIAC IR F098M 1 2 none none 1 N/A CUM SPT-DROPOUT-0304 2 WFC3/IR MULTIAC IR F098M 2 1 none none 1 N/A CUM SPT-DROPOUT-0304 2 WFC3/IR MULTIAC IR F098M 2 2 none none 1 N/A CUM SPT-DROPOUT-0304 3 ACS/WFC ACCUM WFCENTER F814W 1 none none none 2 561.0 S SPT-DROPOUT-0304 3 ACS/WFC ACCUM WFCENTER F814W 2 none none none 2 561.0 S SPT-DROPOUT-0304 3 ACS/WFC ACCUM WFCENTER F814W 3 none none none 2 561.0 S SPT-DROPOUT-0304 3 ACS/WFC ACCUM WFCENTER F814W 4 none none none 2 561.0 S 17084( 6) - 21-Sep-2022 13:50:47 - [ 6] Visit: 02 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 SPT-DROPOUT WFC3/IR MULTIAC IR F160W SAMP-SEQ=SPARS25, NSAMP=10 1 DEF PATTERN 3 1-2 -0216 CUM (911.748 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SPT-DROPOUT WFC3/IR MULTIAC IR F098M SAMP-SEQ=SPARS50, NSAMP=8 1 DEF -0216 CUM (1411.742 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SPT-DROPOUT ACS/WFC ACCUM WFCENTER F814W 1 519 S PATTERN 5 3 -0216 (2076 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 | ------------------------------------------------------------------------------------------------------------------------------------ SPT-DROPOUT-0216 1 WFC3/IR MULTIAC IR F160W 1 1 none none 1 N/A CUM SPT-DROPOUT-0216 1 WFC3/IR MULTIAC IR F160W 1 2 none none 1 N/A CUM SPT-DROPOUT-0216 1 WFC3/IR MULTIAC IR F160W 2 1 none none 1 N/A CUM SPT-DROPOUT-0216 1 WFC3/IR MULTIAC IR F160W 2 2 none none 1 N/A CUM SPT-DROPOUT-0216 2 WFC3/IR MULTIAC IR F098M 1 1 none none 1 N/A CUM SPT-DROPOUT-0216 2 WFC3/IR MULTIAC IR F098M 1 2 none none 1 N/A CUM SPT-DROPOUT-0216 2 WFC3/IR MULTIAC IR F098M 2 1 none none 1 N/A CUM SPT-DROPOUT-0216 2 WFC3/IR MULTIAC IR F098M 2 2 none none 1 N/A CUM SPT-DROPOUT-0216 3 ACS/WFC ACCUM WFCENTER F814W 1 none none none 2 N/A SPT-DROPOUT-0216 3 ACS/WFC ACCUM WFCENTER F814W 2 none none none 2 N/A SPT-DROPOUT-0216 3 ACS/WFC ACCUM WFCENTER F814W 3 none none none 2 N/A SPT-DROPOUT-0216 3 ACS/WFC ACCUM WFCENTER F814W 4 none none none 2 N/A 17084( 6) - 21-Sep-2022 13:50:47 - [ 7] Summary Form for Proposal 17084 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, WFCENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=10, NSAMP=8, NSAMP=9, SAMP-SEQ=SPARS25, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 3 1-2, PATTERN 5 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F098M, F160W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SPT-DROPOUT-0216, SPT-DROPOUT-0304 ------------------------------------------------------------------------------------------------------------------------------------